NACA-AWS UPPER ATMOSPHERE RESEARCH PROGRAM PRIMARY VEHICLE LOCKHEED U-2

• Document Type: CREST
• Collection: General CIA Records
• Document Number (FOIA) /ESDN (CREST): CIA-RDP90T00782R000100040001-9
• Release Decision: RIFPUB
• Original Classification: K
• Document Page Count: 97
• Document Creation Date: December 19, 2016
• Document Release Date: February 2, 2004
• Sequence Number: 1
• Publication Date: January 1, 1956
• Content Type: REPORT

Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
DU 6 L I C. I v
NA - A WS LT --r" A T1140,31-7,RE R
A 1-..:SFA RC h PAOGR AM
PRIMA R Y V.F.
OCEI-IF Fr) u-2
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
TABLE OF CONTENTS
7 May 1956.
National Advisory Committee for Aeronautics
Initial Press Announcement.
2.
June 1956.
Extract from Air Weather Service (USAF)
Scientific Services Newsletter.
1.
9 July 1956.
NACA Press Announcement on Progress of
Upper Atmosphere Research.
11 February 1957.
NACA Press Release with Photographs of
tif-2. Aircraft.
S.
27 March 1957.
NACA Research Memorandum RM L 57A11,
6.
7 May 1957.
NACA Press Release with Photographs of
Special U-2 Instrumentation (LAL 57-1719
and LAL 57-1720).
7.
23 August 1957,
NACA Research Memorandum RM L 57G02.
8.
June 1958.
Air Weather Service Press Release on Typhoon
Kit with five photographs. (Exclusive to
Weatherwise Magazine, the official publication
of the American Meteorological Society.
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
NATIONAL ADVISORY COMMITTEE FOR AERONAUTICS
1512 H Street, N. W. Washington 25, D. C.
FOR RELEASE
MONDAY, MAY 7, 1956
NACA ANNOUNCES START
OF NEW RESEARCH PROGRAM
The need for more detailed information about gust-meteorological conditions
to be found at high altitude, as high as 50,000 feet, has resulted in the inaugura-
tion of an expanded research program to provide the needed data, Dr. Hugh L.
Dryden, Director of the National Advisory Committee for Aeronautics, announced
today.
"Tomorrow's jet transports will be flying air routes girdling the earth", Dr.
Dryden said. "This they will do ataltitudes far higher than presently used ex-
cept by a few military aircraft. The availability of a new type of airplane, which
is one of several that will be used in the program, helps to obtain the needed data
in an economical and expeditious manner."
The new airplane, the Lockheed U-2, is powered by a single Pratt & Whitney
J-57 turbojet engine and is expected to reach 10-mile-high altitudes as a matter
of routine, according to the NACA. A few of the Lockheed airplanes are being
made available for the expanded NACA program by the USAF.
The program is along lines recommended by the Gust Loads Research Panel
of the NACA's technical Subcommittee on Aircraft Loads. In its research pro-
grams, the NACA is charged with coordination of aeronautical research, and
with taking ak
acr'llvigiVol-WeiL12 Idiag5FSIFSIMPORAVAReoqhfacti-9
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
-2-
Among specific research goals will be more precise information about clear
air turbulence, convective clouds, wind shear, and the jet stream. Richard V.
Rhode, Assistant Director for Research of the NACA, said that as a result of in-
formation so to be gained, tomorrow's air travelers might expect a degree of
speed, safety and comfort beyond present hope of the air transport operators.
"The program would not have been possible," Mr. Rhode said, "without the
ability of American scientific effort to join forces."
Actually, according to Mr. Rhode, success of the program depends in large
degree upon the logistical and technical support which the Air Weather Service
of the USAF will be providing. USAF facilities overseas will be used as the
program gets underway, to enable gathering research information necessary to
reflect accurately conditions along the high-altitude air routes of tomorrow in
many parts of the world. The data gathering flights will also be used, at the
request of the USAF, to obtain information about cosmic rays, and the concen-
tration of certain elements in the atmosphere including ozone and water vapor.
The first data, covering conditions in the Rocky Mountain area, are being
obtained from flights made from Watertown Strip, Nevada. Mr. Rhode noted
that the data would be equally useful to technical experts of the Air Weather
Service in expanding their knowledge of atmospheric conditions at high altitude.
-END-
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
HEADQUARTERS
AIR WEATHER SERVICE
MILITARY AIR TRANSPORT SERVICE
UNITED STATES AIRFORCE
WASHINGTON 25, D.C.
EXTRACT FROM AMS SCIENTIFIC SERVICES NEWSLE=H
JUNE 1956
Air Weather Service Support of NAGA Program
AWS is giving its support to the NAGA atmospheric-research program
which was initiated some weeks ago and announced on 7 May by Dr. Thigh L.
Dryden, the Director of NACA. Early in 1956 the NACA. began planning for
an atmospheric-research program of broad interest to U.S. aeronautical
science, both civilian and military. Observations from various points
in the Northern Hemisphere will enable an integrated study of high-
altitude phenomena. The Lockheed built U-2 aircraft, capable of collect-
ing data at altitudes between 50,000 and 55,000 feet, is being used as
the primary test bed in the NAGA program. The main objective of NAGA's
program is the gathering of data on turbulence associated with the jet
stream and with convective clouds, wind structure, and temperature at jet
levels, cosmic ray effects etc.
EACA's program has already been launched in the U.S. and was recently
initiated in the European Theater. Since NAGA does not have independent
facilities for conducting teat programs abroad, the overimas program will
be based at upAF installations and supported logistically by appropriate
USAF commands,
The 1st Weather Reconnaissance Squadron, Provisional, activated by
AWS and rendering direct support to the NAGA program has been established
in the U.K. The weather reconnaissance conducted therefrom will be aimed
at collecting high-level data on jet streams associated with higher lati-
tudes, data charaCteristiOs of the northern side of the westerlies, and
weather information associated with the blocking patternS of northern
Europe. The 2nd Weather Reconnaissance Squadron Provisional, Ilea been
activated at Watertown, Nevada, within easy flying range of areas where
maountain waves are clearly defined, and relatively frequent.
This squadron later will relocate at another site, yet to be selected, at
Which a different variety of meteorological situations prevail. The lo-
cation will probably be at a lower latitude, where the more southerly
areas of the westerlies can be probed and where data from different kinds
of weather patterns can be secured for synoptic research. Still different
locations maybe utilized since it is desired that the upper levels of
the widest possible variety of synoptic situations be explored with the
U-2 data-gathering system.
AWS has a very strong interest in the MAGA program and the data it
will produce. Throughout its history the Air Weather Service has had to
operate under a heavy and unique handicap. Its position has been one of
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
having to forecast, and otherwise to provide weather service, for aircraft
operations at flight altitudes where weathermen previously had. little ob-
servational and no forecasting experience. Not only did our meteorologists
not know how to provide much needed forecasts, but also they had no way of
knowing what the critical weather problems were at the new altitudes being
probed operationally by faster and higher flying aircraft. Further, our
weather science had not even developed the instruments required for adequate
measuring of the meteorological elements in the rarified environments.
Early in 1955, in a letter addressed to General Power, Commanding General of
AREC, General Moorman put this deficiency on record and requested General
Power's assistance in lifting AWS off the "horns of its dilemma".
Concurrently, the NADA's Gust Loads Research Panel had under study the
requirements for an expanded program of turbulence-data collection. The new
NACA programmow underway is designed to satisfy not only its own require-
ments but those of the AWS as well. Many of the data gathered will be forward-
ed to the Geophysical Research Directorate of AREC to assist them in develop-
ing methods of forecasting meteorological phenomena which are important to
high altitude flight; some of the data will be processed and analyzed by NACA
to form the basis for statistical studies of turbulence.
a. The 13-2 and its Weather-Instrumentation System.
Many of the data are recorded on the KS-4 Aerograph System which
is designed to receive atmospheric-measurement inputs and. to indicate the
values both visually and graphically. The system can record six functions,
five graphically and one numerically, in different colors on a continuous-
roll paper chart. The recording equipment and other instrumentation
(described below) were provided by NACA and the Wright Air Development
Center.
b. Basic Meteorological Measurements.
Free-air temperature is measured by the ML-l70/A-8 vortex
thermometer system which was developed. by the Naval Research Laboratory to
measure temperatures with an accuracy of 1/2?C at airspeeds up to 500 knots.
The indicated free-air temperature and relative humidity are also measured
by the 1N/AM-7 temperature-humidity measuring system which was developed
for AWS by the Evans Signal Laboratory at Belmar, N.J. Here, a precision
thermistor measures the temperature and a new type of carbon strip measures
the relative humidity. Pressure altitude is measured by a precision pressure
transducer, and airspeed is measured by an airspeed transducer. The air-
speed, pressure altitude, relative humidity, and two temperature measurements
are recorded graphically on the KS-4 System. The magnetic heading measured
by a gyrosyn compass is fed into the K2-4 and recorded on the paper roll in
the form of a series of numbers. Winds are computed from: 1) the headings
and airspeed automatically printed on the KS-41 and 2) the drift and
groundspeed data recorded. manually by the pilot fram use of his driftmeter.
-2-
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
c* Special Meteorological Measurements.
A NACA developed VGH recorder includes two pressure sensitive
elements for continuoug measurement of airspeed and pressure altitude, a
galvanometer for measuring the output of a remote acceleration transmitter,
and a timing mechanism. Motion of each element is amplified by rotation
of a mirror which, in turn, moves a reflected lamp image across a 200 ft.
roll of 70 mm photographic paper. Also installed is a sensitive airspeed
recorder which is similar to the VGH recorder except that a higher sensitiv-
ity factor for airspeed is obtained by use of multiple mirrors on the air-
speed pressure element. The MAGA, further, has provided a VG recorder that
traces the upper envelope (or peak values) of accelerations as a function
of airspeed on a smoked glass plate which is ready for inspection immediate-
ly after completion of a flight. Finally, the NACA has provided for in
stallation of a turn-meter oriented to record the rate of pitch of the air-
craft; the meter records optically on a 50-ft roll of sensitized parer.
A new turbulence recorder developed by WADC? the Flight RecOrder
Model BB, continuously records the indicated airspeed, pressure altitude,
and normal acceleration on arc-sensitized paper. The record from this in-
strument is immediately available for inspection after flight of the air-
craft.
d. Equipment and Measurements for the Future.
Not only does the U-2 provide US with a platform from which badly
needed high altitude meteorological data can be secured, but it also gives
us the opportunity to teat certain new light-weight types of meteorological
instrumentation. The tests, furthermore, will have the advantage of having
been conducted under operational environment. Contemplated for tests, as
soon as current basic development work is completed at WADC, are an infrared
hygrometer for accurate measurement of dewpoint, an improved vortex tem-
perature probe, a vortex psychrometer for measuring free-air temperature and
relative humidity, a Means of measuring visibility, and improved turbulence
measuring and recording equipment.
e. Significance of Data Produced by the NACA Program.
Crews of the new B-52 bather have furnished disturbing reports of
turbulence at high altitudes. Military OperatiOns such as bombing, photo-
graphic reconnaissance, and air to air refueling are very sensitive to this
meteorological phenomenon, as well as are any jet aircraft flights made
near the "coffin corner". As to contrails, these artificially produced
clouds remain of great importance to high flying aircraft from the detection
stand-point. To learn how to forecast them for the aircraft of the future
we need direct observations of these two phenomena, in conjunction with
measurements of temperature, humidity, and possibly other meteorological
elements.
Approved For Release 2004/001-3 : CIA-RDP90T00782R000100040001-9
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
What about high-level layers of haze or very thin cloud formations in-
visible from the ground but of great significance whenever aircraft are
near each other at these altitudes? We must have more experience with
these things before we can learn how to predict them satisfactorily.
Encounters of the U-2 with high level Obstructions to visibility, and with
contrails are recorded by the pilot for comparison with other measurements
made by the meteorological instrumentation system and with synoptic data.
We suspect that very fast flying high altitude aircraft will begin
to discover brand-new problems which relate to meteorological and other
geophysical phenomena. Fluctuations in air temperature and density may
be critical at times with respect to aircraft skin temperatures and
engine performance. Various types of radiation present at high levels
maybe important to crews and equipment. Ozone may have unexpected effects.
To become aware of the problems and to find out how to solve them require
actual experience with the phenomena together with collections of data to
help us state the solutions in quantitative form.
Even from the point of view of indirect effects on Air Force operations
high level weather reconnaissance demonstrates its importance. Many:meteoro-
logists long have felt that ozone is important for a really complete synOptic
analysis. Occurrences such as Scherhag's "Berlin warming", in which he re-
corded phenomenal 24-hour temperature changes in the stratosphere over Berlin,
undoubtedly are associated with important synoptic Changes at other heights,
latitudes and longitudes. Kochanski's wintertime polar jet Which he discovered
through study of meager radiosonde data, and possibly other air currents at
very high altitudes, could be of both indirect and direct operational concern
to the Air Force. For proper diagnosis and prognosis of these phenomena, high
altitude weather aircraft observations are essential.
We have high hopes that the NACA program will furnish us with data en-
abling US to at least "get the jump" an the operational aircraft of the near
future. The outlook is promising:,
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
NATIONAL ADVISORY COMMITTEE FOR AERONAUTICS
1512 H Street, N. W. Washington 25, D. C.
FOR RELEASE JULY 9, 1956
High Altitude Research Program Proves Valuable
Initial data about gust-meteorological conditions to be found at
10-mile-high altitudes which have been obtained to date by the relatively
few flights of Lockheed U-2 airplanes have already proved the value of
the aircraft for this purpose, Dr. Hugh L. Dryden, Director of the
National Advisory Committee for Aeronautics, said today.
"The airplane has shown its capability to climb to 50,000 feet
and maintain that altitude for the time necessary to obtain the research
information desired," Dr. Dryden said, "Further, it has adequate
load capacity to accommodate the data-gathering instrumentation
required."
Research flights covering the western part of the United States
are being made from Watertown Strip, Nevada. Within recent weeks,'
preliminary, data-gathering flights have been made from an Air Force
base at Lakenheath, England, where the Air Weather Service of the
USAF is providing logistical and technical support. As the program
continues, flights will be made in other parts of the world.
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
-2-
Among specific research goals are more precise information
about clear air turbulence, convective clouds, wind shear, and the jet
stream. In addition, information about cosmic rays, and the concen-
tration of certain elements in the atmosphere including ozone and
water vapor, is being gathered at the request of the USAF. It is ex-
pected that considerable time will elapse before sufficient information,
covering all subjects of interest, has been obtained and reduced to
useful form.
The instrumentation carried by the 13-2 airplane includes
special equipment furnished by the Wright Air Development Center,
and the National Advisory Committee for Aeronautics.
Turbulence data is being recorded on the following specially
developed instruments furnished by Wright Air Development Center
and the National Advisory Committee for Aeronautics:
1. A VH recorder developed by the NACA contains two pres-
sure sensitive elements for continuously measuring indicated airspeed
and pressure altitude, a galvonometer element for measuring the out-
put of a remote acceleration transmitter and a timing mechanism.
Each element causes rotation of a mirror which in turn moves a re-
flected lamp image across the recording medium. Recording is
Offected on a 200 foot roll of 70 mm photographic paper;
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
-3-
2. A sensitive airspeed recorder similar to the VGH recorder ex-
cept that a high sensitivity factor for airspeed is obtained by use of
multiple mirrors on the airspeed pressure element;
3. A NACA VG recorder that scribes an envelope of acceleration
against airspeed on a smoked glass plate. This record is immediately
ready for inspection following flight;
4. A NACA turn meter that records optically on a 50-foot roll of
2-7/16' photographic film. This meter is oriented so as to record
the airplane's rate of pitch;
5. A new turbulence recorder developed by Wright Air Develop-
ment Center, "Flight Recorder Model BB" continuously records in-
dicated airspeed, pressure altitude and normal acceleration on arc-
sensitized paper. The record of this instrument is immediately
available for inspection following a flight.
Improved equipment to be added as soon as development work
currently is completed, will include an infra-red hygrometer for
accurate measurement of dew point, an improved vortex temperature
probe, a vortex psychrometer for measuring true free air temperature
and relative humidity, a means of measuring visibility and improved
turbulence measuring and recording equipment.
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
-4-
True free air temperature is being measured by a vortex ther-
mometer system ML-470/AMQ-8 that was developed by the Naval Re-
search Laboratory to measure true free air temperature with an accur-
acy of one half degree celsius. Air flows through a corkscrew type
spinner vane that creates a vortex, cooling the air at the center of the
vortex by an amount equal to the dynamic heating for that flight speed.
The temperature at the center of the vortex will then be equal to
ambient temperature. A precision wire wound resistance temperature
element is located in the center of the vortex. This temperature
measuring system has been tested on a whirling arm and found to have
an accuracy of better than one half degree celsius at speeds up to 500
knots.
Indicated free air temperature and indicated relative humidity
are being measured by temperature-humidity measuring set AN/AMQ-7.
The system was developed for the Air Weather Service by the Evans
Signal Laboratory at Belmar, New Jersey. It has a recovery factor
of about .87 and has a precision thermistor for measuring temperature
and a carbon strip for measuring humidity. The carbon strip is a new
element that consists of a humidity sensitive carbon coating whil*
changes in resistance as the humidity changes.
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
-5-
Pressure altitude is measured by a precision pressure trans-
ducer that furnishes an electrical signal to an aerograph recoriier.
Air speed is measured by an airspeed transducer.
The AN/AMQ-7 temperature-humidity measuring system and
the AN/AMQ-8 vortex thermometer have been modified to connect their
electrical output into the KS-4 Aerograph system for automatic record-
ing.
The KS-4 Aerograph system is designed to receive data inputs
of atmospheric measurements and to indicate these values both visually
and graphically. It is capable of recording six functions, five graphic
and one numerical. Each graphic recording channel consists of a com-
plete servo mechanism which positions a stylus on a lead screw in
proportion to the electrical angle of a transmitting synchro. The
servo mechanism consists of a two-phase motor, a, synchro lead screw
and stylus and suitable gearing. The printed material is impressed
on the chart by action similar to that of a typewriter, by tapping the
paper through an inked ribbon. Each recorded value has its own par-
ticular color and the ribbon is automatically advanced and oscillated
laterally so as to make full use of the width of the ribbon.
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
The magnetic heading measured by the gyrosyn compass is fed
into and automatically printed in numerical form by the KS-4 Aero-
graph.
Winds are computed from headings and airspeeds recorded on
the KS-4 Aerograph and drift and ground speed data recorded by the
pilot from the driftmeter.
Approved For For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
NATIONAL ADVISORY COMMITTEE FOR AERONAUTICS
FOR RELEASE FEBRUARY II, 1957
The Lockheed U-2 shown here, is being used by the National
Advisory Committee for Aeronautics, to obtain detailed information
about gust-meteorological conditions at high altitude. The research
program makes use of instrumentation furnished by the NACA and
the Wright Air Development Center of the USAF, and logistical and
technical support is provided by the Air Weather Service of the USAF.
Since the program began last spring, numerous data gathering flights
have been made in the United States and elsewhere in the world. The
NAGA has found the U-2 (powered by a Pratt and Whitney J-57) a most
useful research tool, especially because of its capability to maintain
flight at high altitude, as high as 55, 000 feet. Subjects under study
include clear air turbulence, convective clouds, and the jet stream.
1,AL-57-96 and LAL-57-97
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
RM L57All
RESEARCH MEMORANDUM
PRELIIVIINARY MEASUREMENTS
OF ATMOSPHERIC TURBULENCE AT HIGH ALTITUDE AS
DETERMINED kROM ACCELERATION MEASUREMENTS ON
LOCKHEED U-2 AIRPLANE
By Thomas L. Coleman and sack Funk
Langley Aeronautical Laboratory
Langley Field, Va.
NATIONAL ADVISORY COMMITTEE
FOR AERONAUTICS
WASHINGTON
March 27, 1957
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
NAGA RM L57All
NATIONAL ADVISORY COMMITTEE FOR AERONAUTICS
RESEARCH MEMORANDUM
PRELIMINARY MEASUREMENTS
OF ATMOSPHERIC TURBULENCE AT HIGH ALTITUDE AS
DETERMINED FROM ACCELERATION MEASUREMENTS ON
LOCKHEED U-2 AIRPLANE
By Thomas L. Coleman and Jack Funk
SUMMARY
An analysis of a sample of turbulence data obtained from VGH records
taken on Lockheed U-2 airplanes during research flight up to 55,000 feet
over England and Western Europe has indicated substantial reductions in
the number and intensity of gusts with increasing altitude. These results
on the variation of atmospheric turbulence over England and Western Europe
were found to be in overall agreement with previous turbulence data obtained
from airplane- and balloon-borne instruments over the United States.
INTRODUCTION
The collection of detailed information at high altitudes on atmos-
pheric turbulence and other meteorological conditions has, in the past,
been largely dependent upon the availability of operational airplanes.
As a consequence, the collection of such data has, in general, lagged
behind the development of airplane altitude capabilities. To the present
time, the available airplane measurements of atmospheric turbulence have
been almost entirely limited to flight altitudes below approximately
45,000 feet. For higher altitudes, the only information available is
some measurements obtained by means of balloon-borne instruments. (See
ref. 1.) These measurements have provided limited information on tur-
bulence variations with altitudes to approximately 60,000 feet. In addi-
tion to the altitude limitations of the foregoing investigations, the meas-
urements were also limited in regard to geographic areas and were largely
confined to continental United States. This lack of information on high-
altitude turbulence conditions around the world has been a handicap in
aircraft design studies and in operational analysis, both in regard to
aircraft load problems and in regard to stability and control problems.
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
2 NACA RM L57A11
During the early part of 1956, the National Advisory Committee for
Aeronautics, in cooperation with the Air Weather Service of the United
States Air Force, initiated a research program aimed at providing detailed
meteorological information both at higher altitudes than those covered by
present-day operating airplanes and for various geographic areas of the
world. The availability of Lockheed U-2 airplanes at the initiation of
this program permitted the coverage of flight altitudes to approximately
55,000 feet. The NACA activity in this program has so far been primarily
aimed at obtaining information on the amount and intensity of atmospheric
turbulence at these higher altitudes. The Air Weather Service has simul-
taneously provided instrumentation to collect data on humidity, pressure
variations, and winds.
The initial research flights of the U-2 airplane were undertaken to
cover two geographic areas, the United States and Western Europe. Because
of operational difficulties, a statistically significant sample was ini-
tially obtained only from the operations over England and Western Europe.
For these operations, measurements covering a total of 22,000 flight
miles were made and evaluated. Although this sample is small, the initial
results appear to be of sufficient interest to warrant publication. Accord-
ingly, these results are presented herein and are compared with the earlier
estimates on the variation of atmospheric turbulence with altitude given
in reference 1.
INSTRUMENTATION AND SCOPE OF DATA
The flight measurements were obtained during flights of several
Lockheed 11-2 airplanes for the high-altitude meteorological research
program of the NACA in cooperation with the Air Weather Service. The
Lockheed U-2 is a subsonic, straight wing, single-engine airplane
originally designed for use as a high-altitude test medium for engine
and aircraft-component testing. The high-altitude performance and economy
of operation of the U-2 airplane were the prime factors affecting its
selection for use in the present research program.
The measurements pertinent to this report consisted in time-history
records of airspeed, acceleration, and pressure altitude taken with NACA
VGH recorders (ref. 2). The time histories were recorded on photographic
paper moving at 8 inches per minute. Records were obtained on 17 flights
during operations from bases at Lakenheath, England, and Wiesbaden, Germany,
between May and September 1956. The flight plans used in the operations
consisted in climbing to an altitude of approximately 45,000 feet, cruising
initially at approximately 45,000 feet with the altitude gradually increasing
to approximately 55,000 as the fuel load decreased, and then descending to
the home base. For these initial operations, the flight schedules were
based primarily on airplane availability, and no attempt was made to schedule
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
NACA RM L57A11 3
flights to sample turbulence associated with specific meteorological
conditions. The turbulence encountered during the present operations
was, for the most part, in clear air, and no turbulence in heavy cumulus
clouds or thunderstorms is represented in these data.
The scope of the data in terms of miles flown within different alti-
tude intervals is summarized in the following table:
Pressure altitude,
ft
Flight miles
20,000 to
30,600
1,548
30,000 to
40,000
3,492
40,000 to
50,000
6,021
50,000 to
55,000
10,461
Total
21,522
Because of the operational procedures used, only a small amount of infor-
mation was obtained at the lower altitudes; consequently, only the data
above an altitude of 20,000 feet are included in this paper.
EVALUATION OF DATA
The VGH records were evaluated to obtain the vertical gust veloci-
ties, the percent of rough air at various altitudes, and the horizontal
extent of the turbulent areas encountered. The evaluation procedures
are similar to the procedures used in reference 1 and are discussed
briefly in the following paragraphs.
The vertical gust velocities were derived from simultaneous readings
of acceleration, airspeed, and altitude through the use of the gust equa-
tion which is given in reference 3 as
Ude -
2anW
mpoKgVeS
where
Ude derived gust velocity, fps
an peak normal acceleration, g units
airplane weight, lb
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
NACA RM L57A11
wing area, sq ft
Kg gust factor
Ve equivalent airspeed, fps
wing lift-curve slope, per radian
Po air density at sea level, slugs/cu ft
In evaluating the records, the accelerations were read to a threshold
sufficiently low to yield complete frequency counts of all gust velocities
greater than 2 feet per second. Values of airspeed and pressure altitude
were obtained from the records for each acceleration evaluated. The in-
flight weight loss was accounted for in determining the values of wing
loading W/S for use in the equation. Appropriate values of the gust
factor Kg were computed for each part of the record where rough air was
encountered. The values of the lift-curve slope m used in deriving the
gust velocities were based on data from the airplane manufacturer.
The gust-velocity values presented herein may be open to some question
because of effects of airplane flexibility and stability on the accelera-
tions from which the gust velocities were computed. The magnitude of these
effects is not known at present, and additional work is required before
their influence on the gust-velocity values can be assessed.
In addition to determining the gust velocities, the VGH records were
evaluated to obtain the horizontal extent of turbulent areas and the per-
cent of rough air at the different altitudes. For the purpose of deter-
mining the horizontal extent of the turbulent areas, the alrplane was
considered to be in rough air whenever the accelerometer trace was con-
tinuously disturbed and contained accelerations corresponding to gust
velocities greater than 2 feet per second; this threshold corresponds to
that used in previous gust studies such as reference 1. The length of
each turbulent area was found simply by multiplying the true airspeed by
the time spent in the rough air. The summation of the lengths of the
individual areas of rough air was dividtd by the total flight distance for
given altitude intervals in order to obtain the percent of rough air for
that interval.
RESULTS AND DISCUSSION
Overall Gust Distributions
The gust velocities derived from the acceleration and airspeed data
are presented as frequency distributions in table I for four altitude
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
NACA 104 L57A11 5
intervals between 20,000 and 55,000 feet and are shown in figure 1 as
cumulative frequency distributions per mile of total flight for each
altitude interval. The cumulative distributions give the average num-
ber of gusts per mile of total flight which exceeded given values of
gust velocity. Inspection of the results of this investigation in fig-
ure 1 shows that, over the altitude range covered, variations on the
order of 10 to I exist in the frequency with which given gust velocities
were encountered. In general, the distributions depict a consistent
decrease in gust frequency with increasing altitude. The data for the
altitudes of 30,000 to 40,000 feet deviate from this pattern to some
extent, however, and indicate a lower frequency for the higher gust
velocities than would be expected from the general pattern. Because of
the limited sample size, this deviation from the general pattern may not
be real, but due to a sampling error.
For comparison with the present data, the cumulative frequency
distributions of gust velocity were determined from the results of ref-
erence 1 and these distributions are also shown in figure 1. These dis-
tributions are based on the basic distribution of non-thunderstorm tur-
bulence and the variation of gust intensity with altitude given in fig-
ures 5 and 1, respectively, of reference 1. Comparison of the two sets
of distributions in figure 1 shows that the slopes of the two sets of
distributions are about the same but that, in general, the data of this
investigation indicate somewhat lower gust frequencies than those obtained
from reference 1. One possible reason for the lighter level of turbulence
for the present data is the limited seasonal coverage, the present data
covering only the summer months; whereas the results from reference I
represent average turbulence conditions for operations throughout the
year. More severe clear-air turbulence may be anticipated during seasons
of the year other than summer and particularly during the winter months
when the winds at high altitude are likely to be the strongest.
Intensity of Turbulence
In order to compare in further detail the gust measurements of this
investigation with the results from reference 1, it is helpful to con-
sider separately the variations in the intensity and in the amount of
rough air with altitude. As an indication of the severity of the rough
air alone, the cumulative frequency distributions of gust velocity per
mile of flight in rough air are plotted in figure 2 for the different
altitude intervals. For comparison, the corresponding gust distributions
for non-thunderstorm turbulence were calculated from reference 1 and are
also shown in the figure. Inspection of the present data in figure 2
shows that, in general, the gust frequency per mile of rough air also
decreased with increasing altitude. However, again, the data for the
altitudes of 30,000 to 40,000 feet do not follow this pattern and, in
this case, indicate a lower frequency than is shown for the other
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
6 NACA BM L57A11
altitudes. Examination of the time-history records revealed that this
low gust frequency resulted mainly from two long (50 to 50 miles) areas
of turbulence of low intensity. In view of the peculiarity of the data
for the altitudes of 50,000 to 40,000 feet, the present indication of a
low gust frequency for this altitude interval is open to question.
Comparison of the results of this investigation on the gust inten-
sity, based on miles of flight in rough air, with the corresponding
results from reference 1 shows not only that the two sets of distribu-
tions have approximately the same slopes but also that the gust inten-
sity is considerably lower for the present data. (See fig. 2.) For a
given frequency of occurrence, the gust velocities shown by the present
data are, in general, only about 75 percent as large as the gust velocities
given by the results from reference 1 for the same altitude interval.
For the altitude of 30,000 to 40,000 feet, the percent is even lower,
it being about 50 percent. Thus, in general, the intensity of the rough
air for the data of this investigation is substantially lower than that
given by reference 1.
In addition to the direct comparison of the gust intensities given
in the preceding paragraph, it is of interest to compare the relative
variations of the gust intensities with altitude for the two sets of gust
distributions. In figure 5, the variations of the gust intensity with
altitude for the present results and the results based on reference I
are given in terms of the ratio of the maximum gust velocity expected
in a given flight distance in rough air at the lower altitude interval
(20,000 to 50,000 feet) to the maximum gust velocity for the same flight
distance in rough air at higher altitudes. The data in figure 3 were
obtained by determining from the gust distributions of figure 2 the maxi-
mum gust velocity expected in a given flight distance in rough air at
different altitudes for each sample of data. For this purpose, a gust
frequency of 0.05 per mile in figure 2 was selected as being through the
more reliable range of the present distributions. The values of maximum
gust velocity obtained from figure 2 for each set of distributions were
then normalized to the gust velocity for the lower altitude interval in
order to obtain the gust-velocity ratios plotted in figure 3.
Figure 3 shows that the relative variation of the gust intensity
with altitude for the present data is in good agreement with the results
from reference 1 except for the data for the altitudes of 50,000
to 40,000 feet. As previously noted, however, the reliability of the
data at this altitude is open to some question. The comparison presented
in figure 3 implies that the variation in gust intensity with altitude
over Western Europe, at least for the summer season, is similar to that
indicated in reference 1 for this country.
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
NACA PM L57A11 7
Amount of Turbulence
The percent of the flight distance within each altitude interval
which was in rough air is presented in figure 4. Similar results, based
on airplane and telemeter data from reference 1, are also given in the
figure for comparison. Figure 4 shows that the results of this investi-
gation are in good agreement with the results from reference 1 for alti-
tudes above 35,000 feet. Below this altitude, the present data indicate
slightly higher percentages of rough air than do the data from refer-
ence 1. The high percentage of rough air for the altitudes of 30;000
to 35,000 feet resulted from the two areas of 30 to 50 miles of turbulence
of low intensity that were mentioned previously. Thus, in general, the
amount of rough air at the various altitudes is fairly close to that
given in reference 1, with the principal difference between the present
results and those from reference 1 being associated with the less severe
intensity of the turbulence noted previously.
Size of Turbulent Areas
The distribution of the horizontal extents or lengths of the turbu-
lent areas, determined from the acceleration records, is given in fig-
ure 5 as the percent of the total number of areas within class intervals
of 10 miles. The distribution is based on 115 turbulent areas encountered
during the present operations between 20,000 and 55,000 feet. The dis-
tribution of turbulent areas given in reference 1 is also shown in the
figure for comparison. For the present data, approximately 75 percent
of the turbulent areas were less than 10 miles in length and less than
2 percent of the rough areas exceeded a length of 40 miles. Additional
analysis of the data indicated that the distributions of the lengths of
turbulent areas did not vary significantly with altitude for altitudes
between 20,000 and 55,000 feet. Figure 5 shows that, on the average, the
sizes of the turbulent areas for the present data appear to be somewhat
smaller than those given by the results of reference 1. The smaller sizes
for the present turbulent areas may also be associated with the limited
seasonal coverage of the data of this investigation.
CONCLUDING REMARKS
An analysis of a small sample of turbulence data obtained from NACA
VGH recorders during research flights of the Lockheed U-2 airplanes to
attitudes of 55,000 feet over England and Western Europe during the summer
of 1956 has indicated substantial reductions in the number and intensity
of gusts with increasing altitude. The results indicated that the length
of turbulent areas was less than 10 miles for about 75 percent of the
areas encountered and that less than about 2 percent of the areas of rough
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
8 NACA BM 1,57All
air extended more than 40 miles. These results on the intensity, amount,
and extent of atmospheric turbulence were found to be in overall agree-
ment with the results given in NASA RM L55G15a for operations over the
United States. The principal difference between the results of the two
investigations was the indication that, on the whole, the turbulence
encountered during the surveys over England and Western Europe was about
25 percent less severe than that for operations over the United States.
Langley Aeronautical Laboratory,
National Advisory Committee for Aeronautics,
Langley Field, Va., December 17, 1956.
REFERENCES
1. McDougal, Robert L., Coleman, Thomas L., and amith, Philip L.: The
Variation of Atmospheric Turbulence With Altitude and Its Effect
on Airplane Gust Loads. NACA RM L55G15a, 1953.
2. Richardson, Norman R.: NACA VGH Recorder. MCA TN 2265, 1951.
3. Pratt, Kermit G., and Walker, Walter G.: A Revised Gust-Load Formula
and. a Re-Evaluation of V-G Data Taken on Civil Transport Airplanes
From 1935 to 1950. NACA Rep. 1206, 1954. (Supersedes NACA TN's 2964
by Kermit G. Pratt and 5041 by Walter G. Walker.)
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
411111k
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
NACA RM L57A11 9
TABLE I.- 1EEQUENCY DISTRIBUTIONS OF DERIVED GUST VELOCITY BY ALTITUDE
Gust velocity,
Ude, fps
Frequency distribution for altitudes, ft, of -
20,000 to
30,000
50,000 to
4o,o00
40,000 to
50,000
50,000 to
55,000
2 to 2.9
94
84
70
74
3 to 3.9
44
42
51
28
4 to 4.9
21
10
12
12
5 to 5.9
8
4
5
3
6 to 6.9
4
1
4
3
7 to 7.9
2
--
--
--
8 to 8.9
2
--
1
1
9 to 9.9
__
__
__
__
lo to 10.9
1
--
1
--
Total
176
141
144
121
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
10 NACA BM L57A11
-e
Preserd
o
0
0
L.
Rei: /
A/blade, fl
20 74030
30t040
40 to 50
52 to 55
x/03
----
-
-
A
0
0
01\*\
A
0\
0
\
A
\
\
\
\
\
\
A
A
0
0
0
\
\
\
\
\
\
.
\
\
\
\
\
\
\
\
,
\
\
\
\
\
-
4
usL yethe//57, f/05
Figure 1.- Comparison of present results on the frequency of exceeding
given values of gust velocity per mile of total flight with results
from reference 1.
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
NACA RM L57A11 11
/0
0
Present
0
0
0
&
1
1
Ref: /
Aliduote
20 710
30 /0
442 to
50 io
I
30 A103
10
-CV
5.5-
- - -
-
0
A
is
a
\4)
a \
\
_
A 11
U ?
?
A ?\
u:
\
\
?
\
4
\
\
\
a
?
.
?
.
\
\
\
\
\ \
\
\
\
\ \
?
\
\
\
\
\
\
\
\
\
\
\
\\
\
/2 /6
Gast velocz/y, flias
20
Figure 2.- Comparison of present results on the frequency of exceeding
given values of gust velocity per mile of rough air with results from
reference 1.
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
L2 NACA BM L57A11
25-0
46)
20
/I, /4.,
\CI
0
\
....-...-
0
PP(' ,5 i
-'/) I
2 .4 .6
GI 0/ c//,/'de
of 25;000 ft
/0
Figure 3.- Variation in relative gust velocities with altitude.
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
3
Cr)
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
NACA RM L57A11
sent cloii
.erence /
/
0
0
0
O
o
,
0
0
gq-
(*"?(7/
Izo
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
13
Variation in percent of turbulent air with altitude.
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
14 NACA FM L57A11
Percent of for,e/J/e/274 areos
80
60
40
20
PPese/2/- da/a
Referepco /
^
?12462 60 80 /00
LeNgIh, miles
Figure 5.- Distribution of the lengths of turbulent areas for altitudes
between 20,000 and 55,000 feet.
Approved For Release 2004/05/13 : CIA-RDP90T00782R00010004000t4 v-
Approved For Release 2004/05/13*eIA-RDP90T00782R000100040001-9
NACA RM L57A11
National Advisory Committee for Aeronautics.
PRELIMINARY MEASUREMENTS OF ATMOSPHER-
IC TURBULENCE AT HIGH ALTITUDE AS DETER-
MINED FROM ACCELERATION MEASUREMENTS
ON LOCKHEED U-2 AIRPLANE. Thomas L.
Coleman and Jack Funk. March 1957. 14p. diagrs.,
tab. (NACA RM L57A11)
An analysis of turbulence data obtained from VGH
records covering approximately 22,000 flight miles
. taken on Lockheed U-2 airplanes during research
flights up to 55,000 feet over England and Western
Europe is presented. Substantial reductions in the
number and intensity of gusts with increasing altitude
are indicated. The results on the variation of the
amount and intensity of turbulence with altitude are
compared with turbulence data previously obtained
from airplane- and balloon-borne instruments over
the United States.
Copies obtainable from NACA, Washington
1. Loads, Gust - Wings
(4.1 .1 .1 . 3)
2. Gusts, Atmospheric
(6,.1.2)
3. Operating Problems (7)
I. Coleman, Thomas L.
II. Funk, Jack
M. NACA RM L57A11
NACA RM L57All
National Advisory Committee for Aeronautics.
PRELIMINARY MEASUREMENTS OF ATMOSPHER-
IC TURBULENCE AT HIGH ALTITUDE AS DETER-
MINED FROM ACCELERATION MEASUREMENTS
ON LOCKHEED U-2 AIRPLANE. Thomas L.
Coleman and Jack Funk. March 1957. 14p. diagrs.,
tab. (NACA RM L57A11)
An analysis of turbulence data obtained from VGH
records covering approximately 22,000 flight miles
taken on Lockheed U-2 airplanes during research
flights up to 55,000 feet over England and Western
Europe is presented. Substantial reductions in the
number and intensity of gusts with increasing altitude
are indicated. The results on the variation of the
amount and intensity of turbulence with altitude are
compared with turbulence data previously obtained
from airplane- and balloon-borne instruments over
the United States.
Copies obtainable from NACA, Washington
1. Loads, Gust - Wings
(4.1.1. 1. 3)
2. Gusts, Atmospheric
(6. 1. 2)
3. Operating Problems (7)
I. Coleman, Thomas L.
II. Funk, Jack
M. NACA RM L57A11
NACA RM L57A11
National Advisory Committee for Aeronautics.
PRELIMINARY MEASUREMENTS OF ATMOSPHER-
IC TURBULENCE AT HIGH ALTITUDE AS DETER-
? MINED FROM ACCELERATION MEASUREMENTS
ON LOCKHEED U-2 AIRPLANE. Thomas L.
Coleman and Jack Funk. March 1957. 14p. diagrs.,
tab. (NACA RM L57A11)
An analysis of turbulence data obtained from VGH
records covering approximately 22,000 flight miles
. taken on Lockheed U-2 airplanes during research
flights up to 55,000 feet over England and Western
Europe is presented. Substantial reductions in the
number and intensity of gusts with increasing altitude
are indicated. The results on the variation of the
amount and intensity of turbulence with altitude are
compared with turbulence data previously obtained
from airplane- and balloon-borne instruments over
the United States.
Copies obtainable from NACA, Washington "
Approve
1. Loads, Gust - Wings
(4.1 .1. 1. 3)
2. Gusts, Atmospheric
(6. 1. 2)
3. Operating Problems (7)
I. Coleman, Thomas L.
II. Funk, Jack
NACA RM L57A11
e se 2004/05/13
NACA RM 1..57A11
National Advisory Committee for Aeronautics.
PRELIMINARY MEASUREMENTS OF ATMOSPHER-
IC TURBULENCE AT HIGH ALTITUDE AS DETER-
MINED FROM ACCELERATION MEASUREMENTS
ON LOCKHEED U-2 AIRPLANE. Thomas L.
Coleman and Jack Funk. March 1957. 14p. diagrs.,
tab. (NACA RM L57A11)
An analysis of turbulence data obtained from VGH
records covering approximately 22,000 flight miles
? taken on Lockheed 17-2 airplanes during research
flights up to 55,000 feet over England and Western
Europe is presented. Substantial reductions in the
number and intensity of gusts with increasing altitude
are indicated. The results on the variation of the
amount and intensity of turbulence with altitude are
compared with turbulence data previously obtained
from airplane- and balloon-borne instruments over
the United States.
CIA-RDP90T00782R000100040001-9
Copies obtainable from NACA, Washington
1. Loads, Gust - Wings
(4. 1 .1. 1. 3)
2. Gusts, Atmospheric
(6. 1. 2)
3. Operating Problems (7)
I. Coleman, Thomas L.
U. Funk, Jack
M. NACA RM L57A11
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
NACA RM L57All
National Advisory Committee for Aeronautics.
PRELIMINARY MEASUREMENTS OF ATMOSPHER-
IC TURBULENCE AT HIGH ALTITUDE AS DETER-
MINED FROM ACCELERATION MEASUREMENTS
ON LOCKHEED U-2 AIRPLANE. Thomas L.
Coleman and Jack Funk. March 1957. 14p. diagrs.,
tab. (NACA RM L57A11)
An analysis of turbulence data obtained from VGH
records covering approximately 22,000 flight miles
. taken on Lockheed U-2 airplanes during research
flights up to 55,000 feet over England and Western
Europe is presented. Substantial reductions in the
number and intensity of gusts with increasing altitude
are indicated. The results on the variation of the
amount and intensity of turbulence with altitude are
compared with turbulence data previously obtained
from airplane- and balloon-borne instruments over
the United States.
Copies obtainable from NACA, Washington
1. Loads, Gust - Wings
(4 .1 .1 .1 . 3)
2. Gusts, Atmospheric
(6. 1. 2)
3. Operating Problems (7)
I. Coleman, Thomas L.
U. Funk, Jack
M. NACA RM L57A11
NACA RM L57All
National Advisory Committee for Aeronautics.
PRELIMINARY MEASUREMENTS OF ATMOSPHER-
IC TURBULENCE AT HIGH ALTITUDE AS DETER-
MINED FROM ACCELERATION MEASUREMENTS
ON LOCKHEED U-2 AIRPLANE. Thomas L.
Coleman and Jack Funk. March 1957. 14p. diagrs.,
tab. (NACA RM L57A11)
An analysis of turbulence data obtained from VGH
records covering approximately 22,000 flight miles
. taken on Lockheed U-2 airplanes during research
flights up to 55,000 feet over England and Western
Europe is presented. Substantial reductions in the
number and intensity of gusts with increasing altitude
are indicated. The results on the variation of the
amount and intensity of turbulence with altitude are
compared with turbulence data previously obtained
from airplane- and balloon-borne instruments over
the United States.
Copies obtainable from NACA, Washington
1. Loads, Gust - Wings
(4'.1.1.1. 3)
2. Gusts, Atmospheric
(6. 1. 2)
3. Operating Problems (7)
I. Coleman, Thomas L.
U. Funk, Jack
NACA P.M L57A11
NACA RM L57A11
National Advisory Committee for Aeronautics.
PRELIMINARY MEASUREMENTS OF ATMOSPHER-
IC TURBULENCE AT HIGH ALTITUDE AS DETER-
MINED FROM ACCELERATION MEASUREMENTS
ON LOCKHEED U-2 AIRPLANE. Thomas L.
Coleman and Jack Funk. March 1957. 14p. diagrs.,
tab. (NACA RM L57A11)
An analysis of turbulence data obtained from VGH
records covering approximately 22,000 flight miles
. taken on Lockheed U-2 airplanes during research
flights up to 55,000 feet over England and Western
Europe is presented. Substantial reductions in the
number and intensity of gusts with increasing altitude
are indicated. The results on the variation of the
amount and intensity of turbulence with altitude are
compared with turbulence data previously obtained
from airplane- and balloon-borne instruments over
the United States.
Copies obtainable from NACA, Washington
1. Loads, Gust - Wings
(4. 1 .1 .1 . 3)
2. Gusts, Atmospheric
(6. 1. 2)
3. Operating Problems (7)
I. Coleman, Thomas L.
U. Funk, Jack
M. NACA RM L57A11
NACA RM L57A11
National Advisory Committee for Aeronautics.
PRELIMINARY MEASUREMENTS OF ATMOSPHER-
IC TURBULENCE AT HIGH ALTITUDE AS DETER-
MINED FROM ACCELERATION MEASUREMENTS
ON LOCKHEED U-2 AIRPLANE. Thomas L.
Coleman and Jack Funk. March 1957. 14p. diagrs.,
tab. (NACA P.M .1.,57A11)
An analysis of turbulence data obtained from VGH
records covering approximately 22,000 flight miles
taken on Lockheed U-2 airplanes during research
flights up to 55,000 feet over England and Western
Europe is presented. Substantial reductions in the
number and intensity of gusts with increasing altitude
are indicated. The results on the variation of the
amount and intensity of turbulence with altitude are
compared with turbulence data previously obtained
from airplane- and balloon-borne instruments over
the United States.
Copies obtainable from NACA, Washington
1. Loads, Gust - Wings
(4. 1 .1 . 1. 3)
2. Gusts, Atmospheric
(6.1.
3. Operating Problems (
I. Coleman, Thomas L.
IL Funk, Jack
NACA RM L57A11
Approved For Release 2004/05/13 :,cliLRDP90T00782R000
00040091-9:
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
NATIONAL ADVISORY COMMITTEE FOR AERONAUTICS
1512 H Street, NW. Washington 25, D. C.
FOR RELEASE MAY 7,1957
These special instruments are carried by a Lockheed U-2 turbojet
airplane in upper atmosphere research being conducted by the National
Advisory Committee for Aeronautics. Research flights have been made
at altitudes up to 55,000 feet over England and western Europe. First
results of the continuing project have been published by NACA in Research
Memorandum No. L57A11.
The instruments are:
1. Angular Velocity Recorder -- to record the airplane's rate of pitch;
2. Modified NACA VGH Recorder -- a highly sensitive device to
measure and record head-on gust components in flight;
3. NACA VGH Recorder -- measures airplane acceleration, airspeed
and altitude to provide record of magnitude and frequency of
vertical gusts;
4. Flight Recorder Model BB -- keeps continuous record on arc-
sensitized paper, of indicated airspeed, pressure altitude and
normal acceleration;
5. Electrical Distribution Box;
6. Heading Amplifier -- amplifies signal input from gyrosyn compass
and transmits to KS-4 Aerograph (No. 10);
7. Airspeed and Altitude Transducer -- measures pressure altitude
and indicated airspeed and transmits to KS-4 Aerograph(No.10);
8. NACA VGH Recorder -- scribes on smoked glass plate, acceleration
and airspeed data;
9. VGH Acceleration Transmitter -- furnishes electrical input signals
for VGH Recorder;
10. KS-4 Aerograph -- records pressure altitude, indicated airspeed,
heading, indicated free air temperature, relative humidity, and
true free air. temperature;
11. Temperature and Humidity Measuring Set AN/AMQ-7 -- measures
indicated free air temperature and indicated relative humidity
and transmits to KS-4 Aerograph;
12. Vortex Thermometer System ML-470/AMQ-8 -- measures true
free air temperature within one-half degree Centigrade at
high speeds and transmits to KS-4 Aerograph.
LAL 57-1719
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
LAL 57-1719
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
NATIONAL ADVISORY COMMITTEE FOR AERONAUTICS
1512 H Street, N. W. Washington 25, D. C.
FOR RELEASE
MAY 7, 1957
This is a close-up view of some special instruments carried by
a Lockheed U-2 turbojet airplane in upper atmosphere research being
conducted by the National 'Advisory Committee for Aeronautics. Re-
search flights have been made at altitudes up to 55,000 feet over England
and western Europe. First results of the continuing project have been
published by NACA in Research Memorandum No, L57A11.
The instruments are:
1. Temperature and Humidity Measuring Set AN/AMQ-7-- measures
indicated free air temperature and indicated relative humidity;
2. Vortex Thermometer System ML-470/AMQ-8 -- measures true free
air temperature within one-half degree Centigrade at high speeds;
3. NACA Angular Velocity Recorder -- measures airplane's rate of
pitch;
4. Timer -- synchronizes NACA recorders;
5. Modified NACA VGH Recorder -- highly sensitive, records head-on
gust components in rough air;
6. NACA VGH Recorder -- provides magnitude and frequency of gusts
by recording airplane acceleration, airspeed and altitude;
7. Flight Recorder Model BB -- records indicated airspeed, pressure
altitude and normal acceleration;
8. Circuit-Breaker Panel;
9. Heading Amplifier -- amplifies signal from gyrosyn compass and
transmits to KS-4 Aerograph system;
10, Electrical Distribution Box;
11. 400-Cycle Inverter -- operates from airplane power supply.
LAL 57-1720
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
6-1?000VOGUOSCA021013106632:1-VI3 ?1./90/MOZ.AVatell_icId_PeAoiddv
VGH RECORIXR
WARNING
? ttl...16 ??01411111JMOIL
-
4 ?
6- 1.00017000 1.00011Z9/001.06dCIU-VIO ?1490/1700Z aSeeleU Joj pancuddv
OgLT-Lg rIvrI
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
RM L57G02
RESEARCH MEMORANDUM
AIRPLANE MEASUREMENTS OF ATMOSPHERIC TURBULENCE FOR
ALTITUDES BETWEEN 20,000 AND 55,000 FEET OVER
THE WESTERN PART OF THE 'UNITED STATES
By Thomas L. Coleman and Emilie C. Coe
Langley Aeronautical Laboratory
Langley Field, Va.
NATIONAL ADVISORY COMMITTEE
FOR AERONAUTICS
WASH I NGTON
August 23, 1957
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
X
?
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
NACA RM L57002
NATIONAL ADVISORY COMMITTEE FOR AERONAUTICS
RESEARCH MEMORANDUM
AIRPLANE MEASUREMENTS OF ATMOSPHERIC TURBULENCE FOR
ALTITUDES BETWEEN 20,000 AND 55,000 FEET OVER
THE WESTERN PART OF THE UNITED STATES
By Thomas L. Coleman and Emilie C. Coe
SUMMARY-
A sample of data on atmospheric turbulence has been obtained from
NACA VGH records taken on Lockheed U-2 airplanes during research flights
covering approximately 40,000 miles for altitudes between 20,000 and
55,000 feet over the western part of the United States. An analysis of
these data has indicated that the intensity, amount, and extent of atmos-
pheric turbulence is in good agreement with earlier measurements obtained
over England and Western Europe. In comparison with past estimates of
average turbulence conditions over the United States, the results of this
investigation, in general, indicate somewhat lower gust frequencies and
lower gust intensities.
INIRODUCTION
During the early part of 1956, the National Advisory Committee for
Aeronautics, in cooperation with the Air Weather Service of the United
States Air Force, initiated a high-altitude flight research program aimed
at providing detailed meteorological information for various geographic
areas of the world (ref. 1). The NACA participation in the program has
been aimed primarily at obtaining information on the amount and intensity
of atmospheric turbulence at high altitudes for use in airplane and
missile response studies; whereas, the Air Weather Service has aimed at
collecting data on humidity, pressure variations, and winds for associ-
ated operational and meteorological analysis.
The initial flight operations included in the program were under-
taken concurrently over the western part of the United States and over
England and Western Europe in the spring of 1956 and covered altitudes
up to 55,000 feet. An analysis of the gust measurements obtained from
the operations over England and Western Europe has been reported in
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
2 NACA RM L57G02
reference 1. The results for the intensity and percent of rough air from
the European operations were found to be in overall agreement with the
estimates given in reference 2 for turbulence at high altitudes over the
United States, although some differences in the intensity of turbulence
for the two areas were indicated.
A. sample of data on atmospheric turbulence covering approximately
40,000 flight miles for altitudes between 20,000 and 55,000 feet has
been obtained from the operations over the western part of the United
States. The present paper presents the results obtained for the fre-
quency and intensity of the turbulence encountered in these operations
and compares these results with those given in references 1 and 2.
INSTRUMENTATION AND SCOPE OF DATA
The flight measurements were obtained during flights of several
Lockheed U-2 airplanes. The Lockheed U-2 is a subsonic, straight-wing,
single-engine, jet airplane originally designed for use as a high-
altitude test vehicle. A photograph of the test airplane is shown in
figure 1.
The measurements pertinent to this report consisted of time-history
records of airspeed, acceleration, and pressure altitude taken with
NACA VGH recorders (ref. 3). The time histories were recorded on photo-
graphic paper moving at 4 inches per minute.
Inasmuch as the major interest of the present program is in meteor-
ological conditions at high altitudes, the flight plans for the opera-
tions were selected to provide maximum sampling time and coverage above
50,000 feet. In general, the flight plans consisted of climbing to an
altitude of approximately 50,000 feet in the vicinity of the operations
base (Watertown Strip, Nevada), cruising initially at about 50,000 feet
with the altitude gradually increasing to about 55,000 feet as the fuel
load decreased, and then descending to the operations base. As a con-
sequence of this flight procedure, the gust measurements below 50,000 feet
were obtained only during the climb and descent phases of the flight and
the measurements above 50,000 feet were taken primarily during cruising
flight. The data below 50,000 feet essentially represent soundings of
the atmosphere and thus reflect the turbulence conditions which exist in
the general region of Watertown Strip, Nevada. The cruise portions of the
flights between 50,000 and 55,000 feet, in general, covered the Rocky
Mountain and the Pacific Coast regions of the United States.
Records were obtained from 24 flights during operations from Watertown
Strip, Nevada, between May 1956 and March 1957 with about one-half of these
flights being made during the three-month winter season from December 1956
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
Approved For Release 2004/05/13: CIA-RDP90T00782R000100040001-9
NACA RM L57G02 3
to February 1957. The flight schedules were based primarily on airplane
and instrumentation availability, and no attempt was made to schedule
flights to sample turbulence for specific meteorological conditions.
Except for occasional penetrations of stable cloud formations while
climbing or descending, the flight miles flown during the present opera-
tions were in clear air. The data above 50,000 feet, therefore, are
felt to be fairly representative of clear-air turbulence conditions over
the western part of the United States.
The scope of the data in terms of miles flown within different alti-
tude intervals is listed at the bottom of table I. As shown in the table,
about 37,000 flight miles or approximately 90 percent of the total flight
miles were flown between 40,000 feet and 55,000 feet, and only a rela-
tively small number of flight miles were in each of the two lower alti-
tude intervals.
EVALUATION OF DATA
The NACA VGH records were evaluated to obtain the derived gust
velocities, the percent of_rough air at various altitudes, and the
length (along the flight path) of the turbulent areas encountered. The
evaluation procedures are similar to the procedures used in references 1
and 2 and are given briefly in the following paragraphs.
The vertical gust velocities were derived from simultaneous readings
of acceleration, airspeed, and altitude through the use of the gust equa-
tion which is given in reference 4 as
Ude mpoKgVeS
2anW
where
Ude derived gust velocity, fps
an peak normal acceleration, g units
airplane weight, lb
wing area, sq ft
Kg gust factor
Ve equivalent airspeed, fps
Approved For Release 2004/05/13: CIA-RDP90T00782R000100040001-9
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
4 NACA RM L57002
wing lift-curve slope per radian
Po air density at sea level, slugs/cu ft
In evaluating the records, the accelerations were read to a thres-
hold sufficiently low to yield complete frequency counts of all gust
velocities greater than 2 feet per second. Values of airspeed and pres-
sure altitude were obtained from the records for each acceleration
evaluated. The weight loss during flight was accounted for in determining
the values of wing loading WS for use in the equation. Appropriate
values of the gust factor Kg were computed for each part of the record
where rough air was encountered. The values of the lift-curve slope m
used in deriving the gust velocities were based on data obtained from the
airplane manufacturer.
The gust-velocity values presented herein may be open to some ques-
tion because of effects of airplane flexibility and stability on the
accelerations from which the gust velocities were computed. The magni-
tude of these effects is not known at present, and additional work is
required before their influence on the gust-velocity values can be
assessed.
For the purpose of determining the length of the turbulent areas,
the airplane was considered to be in rough air whenever the accelerometer
trace was continuously disturbed and contained accelerations corresponding
to gust velocities greater than 2 feet per second. This threshold value
of 2 feet per second corresponds to that used in previous gust studies,
such as references 1 and 2. The length of each turbulent area was found
simply by multiplying the true airspeed by the time spent in the rough
air. The summation of the lengths of the individual areas of rough air
was divided by the total flight distance for given altitude intervals in
order to obtain the percent of rough air for that altitude interval.
RMULTS AND DISCUSSION
Overall Gust Distributions
The gust velocities derived from the acceleration and airspeed data
are presented as frequency distributions in table I for several altitude
intervals between 20,000 and 55,000 feet. Inspection of the table shows
that the maximum gust velocities encountered in the present operations
were approximately 12 feet per second and were experienced in altitude
intervals from 20,000 to 50,000 feet and from 50,000 to 55,000 feet.
Only 19 gusts above 2 feet per second were encountered in approximately
7,000 miles of flight in the altitude interval between 4o,o00 and
50,000 feet and, consequently, the distribution of gust velocities for
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
NACA RM L57G02 5
this altitude interval is not well defined. As noted previously, the
data below 50,000 feet were obtained during the climb and descent por-
tion of the flights and may be biased by turbulent conditions peculiar
to the general region of Watertown Strip, Nevada.
The gust-velocity data from table I are shown in figure 2 as cumula-
tive frequency distributions per mile of flight for each altitude interval.
These cumulative frequency distributions give the average number of gusts
per mile of flight which exceeded given values of gust velocity. Exam-
ination of figure 2 shows that large variations exist in the frequency
with which given gust velocities were encountered in the various, altitude
intervals and that, in general, the gust frequency decreased with
increasing altitude.
Figure 3 compares the present results for the gust frequency at the
different altitudes with the results for corresponding altitudes from
references 1 and 2. The results from reference 2 are based on the basic
distribution of nonthunderstorm turbulence and the variation of gust
intensity with altitude; It should be noted that the present results and
those from reference 1 are for specific geographical regions, whereas
the results from reference 2 are estimates of average turbulence condi-
tions over the United States.
Inspection of figure 3 shows that the present results are in good
agreement with the results from reference 1 for operations over Western
Europe, except for the altitude interval of 40,000 to 50,000 feet. Both
sets of data from the present investigation and reference I indicate
lower gust frequencies for each altitude interval than those given by the
estimates based on reference 2. Thus, it appears that estimates of gust
frequencies for clear-air turbulence based on reference 2 may be somewhat
high in comparison with operations over the western part of the United
States and Western Europe.
Intensity of Turbulence
The overall gust distributions discussed in the preceding section
may be considered to reflect the combined effects of the intensity of
the turbulence and the percent of rough air at the various altitudes.
In order to examine the turbulence encountered in more detail, it is
helpful to consider separately the gust intensity and the percent of
rough air. As a measure of the severity of the turbulence, the cumula-
tive frequency distributions of gust velocity per mile of flight in
rough air are plotted in figure 4 for the various altitude intervals.
Inspection of figure 4 shows that differences on the order of 20 to I
exist between the frequency of occurrence of given gust velocities per
mile of flight in rough air at the various altitudes. Although the
results indicate a lower gust intensity for the highest altitude interval
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
0
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
NACA RM L57002
(50,000 to 55,000 feet) than for the lowest altitude interval (20,000
to 30,000 feet), these results do not exhibit the continuous decrease
in gust intensity with increasing altitude shown by previous results
(ref. 2).
In order to compare the present results for the intensity of turbu-
lence wIth previous results, the cumulative frequency distributions of
gust velocities per mile of flight in rough air within different altitude
intervals are shown in figure 5 together with corresponding results from
references 1 and 2. These results indicate that, in general, the inten-
sity of the rough air encountered in this investigation is approximately
the same as that reported in reference 1 for operations over Western
Europe but is lower than that estimated in reference 2 for average opera-
tions over the United States. For the altitude interval of 30,000 to
40,000 feet, in particular, the intensity of the turbulence encountered
in both the present investigation and in reference 1 appears to be much
lower than is shown by the estimates from reference 2.
Percent of Rough Air
The percent of the flight distance which was in rough air is presented
in figure 6 for each 5,000-foot altitude interval. For comparison, similar
results from references 1 and 2 (the latter results based on airplane and
telemeter data) are also given in the figure. Figure 6 indicates that the
percent of rough air from both the present flights and European flights
(ref. 1) is in fair agreement with the results of reference 2 at the lowest
and highest altitudes, but that the data from the present report and from
reference I indicate a much higher percent of rough air between 50,000
and 40,00C feet.
It may be noted that the percent of rough air (ref. 2) is based on a
fairing of some of the earliest available data on the variation of the
percent of rough air with altitude. Although some of these early data
indicated a peak in the percent of rough air at altitudes of 50,000 to
40,000 feet, this indication was given little weight in the fairing
because of the limited data available at that time. The consistency of
the two sets of results from the present report and from reference 1 and
reconsideration of the earlier data used in reference 2, however, suggest
that a peak does exist between 30,000 and 40,000 feet in the variation
of the percent of rough air with altitude. As noted previously, however,
the intensity of the turbulence for this altitude interval is relatively
low. This increase in the percent of rough air is probably associated
with high winds and wind shears which are prevalent at 30,000 to
40,00o feet for the regions covered by the data (refs. 5 and 6).
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
NACA RM L57G02 7
Size of Turbulent Areas
The distribution of the lengths of the turbulent areas is given in
figure 7 as the percent of the total number of areas which was within
class intervals of 10 miles. For comparison, the distributions of turbu-
lent areas given in references 1 and 2 are also shown in the figure.
Inspection of the results in figure 7 shows that the distribution of
turbulent areas from this investigation is in good agreement with the
results from references 1 and 2 and that the majority of the turbulent
areas were less than 20 miles in length. A breakdown of the present
data showed no significant variations between the distributions of the
lengths of turbulent areas for altitudes of 20,000 to 50,000 feet and
for 50,000 to 55,000 feet. This result is ii agreement with the results
of references 1 and 2.
CONCLUDING REMARKS
The results of an analysis of a sample of data on atmospheric turbu-
lence obtained from NACA VGH recorders during research flights of Lockheed
U-2 airplanes to altitudes of 55,000 feet over the western part of the
United States between May 1956 and March 1957 substantiate earlier indica-
tions of a decrease in the frequency of occurrence of gusts with increasing
altitude. The intensity of the turbulence, the percent of rough air, and
the length of the turbulence areas generally were found to be in good
agreement with the results given in NACA Research Memorandum L57A11 for
operations over England and Western Europe. In comparison with the
earlier estimates given in NACA Research Memorandum L53G15a for operations
over the United States, however, the present results generally show a
lower gust frequency and lower gust intensities. In addition, the present
results and those of NACA Research Memorandum L57A11 indicate a higher
percent of rough air between 30,000 and 40,000 feet than is given by the
estimates in NACA Research Memorandum L53G15a. These results, together
with a reconsideration of earlier data, suggest that a peak exists in
this altitude range in the percent of rough air with altitude. However
the intensity of the turbulence in this altitude range appears to be
light.
Langley Aeronautical Laboratory,
National Advisory Committee for Aeronautics,
Langley Field, Va., June 17, 1957.
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
8
1.
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
NACA RM L57002
REFERENCES
Coleman, Thomas L., and Funk, Jack: Preliminary Data on Atmospheric
Turbulence at High Altitudes as Determined From Acceleration Meas-
urements on Lockheed 11-2 Airplanes. NACA RM L57A11, 1957.
2. McDougal, Robert L., Coleman, Thomas L., and Smith, Philip L.: The
Variation of Atmospheric Turbulence With Altitude and Its Effect on
Airplane Gust Loads. NACA RM L55G15a, 1953.
3. Richardson, Norman R.: NACA VGH Recorder. NACA TN 2267, 1951.
4. Pratt, Kermit G., and
and a Re-Evaluation
From. 1953 to 1950.
TN's 2964 by Kermit
) .
Walker, Walter G.: A Revised Gust-Load Formula
of V-G Data Taken on Civil Transport Airplanes
NACA Rep. 1206, 1954. (Supersedes NACA
G. Pratt and 3041 by Walter G. Walker.)
Tolefson, H. B.: An Investigation of Vertical-Wind-Shear Intensities
From Balloon Soundings for Application to Airplane- and Missile-
Response Problems. NACA TN 3732, 1956.
6. Widger, William K., Jr.: A Survey of Available Information on
Wind Fields Between the Surface and the Lower Stratosphere.
Force Surveys in Geophysics No. 25, Air Force Cambridge Res.
Dec. 1952.
the
Air
Center,
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
NACA RM L57G02
TABLE I.- FREQUENCY DISTRIBUTIONS OF DERIVED GUST VELOCITY
FOR VARIOUS ALTITUDE INTERVALS
9
Gust velocity,
Frequency distribution of gust velocity for
altitudes of -
Ude' fps
20,000 to
30,000 ft
30,000 to
40,000 ft
40,000 to
50,000 ft
50,000 to
55,000 ft
2 to 3
142
83
18
120
3 to 4
41
13
1
57
4 to 5
16
4
28
5 to 6
8
1
10
6 to 7
6
1
9
7 to 8
1
3
8 to 9
1
1
9 to 10
0
1
10 to 11
1
0
11 to 12
0
1
12 to 13
1
Total
217
102
19
230
Miles of flight in
rough air . . .
114
216
57
366
Total flight
miles
1,203
1,430
6,962
30,244
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
Approved FstriMae_2apitooqupa:AipoRppi-ppmE,peopi0004p99,16
0-02,r1 Iii VOVN
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
NACA 1RM L57G02 11
/0-5 2 68 /0
Dewed ga,s7 fre/oeik ade fps
Ai/jade, it
0
2,0 to go X id'
El
30 To 40

40 to 50
A
..112 TO .4-c
--(-)\
a
u
N
/2
Figure 2.- Variation with altitude of the frequency of exceeding given
values of gust velocity per mile of total flight.
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
12 NACA FM 1,57G02
(a) 20,000 to 50,000 feet.
6
/6 ?0
velocrly, Ode
?, -
_
?
P ?I
6,
\
1 R
-,?-
\,
\i
\
\
\
\
-- --t-
_ I \n
_
,
\-
(b) 30,000 to 40,000 feet.
/2 /6 &)
(o) 40,000 to 50,000 feet. (d) 50,000 to 55,000 feet.
Figure 5.- Comparison at various altitudes of present results for the
frequency of exceeding given values of gust velocity per mile of
flight with results from references 1 and 2.
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
NACA RM L57G02
13
?
0
0
Ei
G
A
20
30
40
O74ir
A lt/ le/ de,
to 30
To id
to 50
4-13
Ii
f /43
.
3
k
0
A
0
??
0
NI
kik
a
0
a
0
0
A
T
4 6
Dery ved 9.6/31 veoc/7S C/d,, fpr
Figure 4.- Variation with altitude of the frequency of exceeding given
values of gust velocity per mile of rough air.
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
iIl
/0
/0
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
0 ese ?T
- -o- - Ref
pef,
It
NACA RM L57G02
(, 1 20,000 to 30,000 feet. (b) 50,000 to 40,000 feet.
ir /G
D,er ve-ci qu57 bc-locdy,
0 4 8
Ude 14Ps'
(c )40,000 to 50,000 feet. (d) 50,000 to 55,000 feet.
20
Figure Comparison at various altitudes of present results on the
frequency of exceeding given values of gust velocity per mile of
col:w;h air with results from references 1 and 2..
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
NACA RM L57G02 15
0 Present della
0
? .
i
0
0
---0
Aiiiwa iir
D a
co
0 0
cza
c) c\I
racv2//1/V
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
80
---
60
40
ii
20 L
NACA RM L57G02
Present data
Ref/
Ref. 2
20 40 60 849 /00
en9/h /mks
Figure Distribution of the lengths of turbulent areas for altitudes
bet,ween 20,000 and 55,000 feet.
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001 9ed
Va.
jr-
NAZA RM L57G02
Nalnal Advisory Committee for Aeronautics.
AI LANE MEASUREMENTS OF ATMOSPHERIC
TUW3ULENCE FOR ALTITUDES BETWEEN 20,000
ANO 55,000 FEET OVER THE WESTERN PART OF
TI UNITED STATES. Thomas L. Coleman and
E ie C. Coe. August.1957. 16p. diagrs., photo.,
tab- (NACA RM L57G02)
Antalysis of a sample of data on atmospheric tar-
bu ce obtained from NACA VGH records taken on
-Lo eed U-2 airplanes during research flights
co ing approximately 40,000 miles for altitudes
bet en 20,000 and 55,000 feet over the western part
of a United States is presented. The results for
theariation of intensity and amount of turbulence
withadtitude are compared with turbulence data pre-
viously obtained from similar operations over
Ena.nd and Western Europe and with earlier esti-
matos of average turbulence conditions over the
Unlijd States.
0
Com obtainable from NACA, Washington
CD
1. Loads, Gust - Wings
(4. 1 . 1 . 1. 3)
2. Gusts, Atmospheric
(6. 1. 2)
3. Operating Problems (7)
I. Coleman, Thomas L.
H. Coe, Emilie C.
IH. NACA RM L57G02
NACA RM L57G02
National Advisory ConimitteN for Aeronautics.
AIRPLANE MEASUREMENTS OF ATMOSPHERIC
TURBULENCE FOR ALTITUDES BETWEEN 20,000
AND 55,000 FEET OVER THE WESTERN PART OF
THE UNITED STATES. Thomas L. Coleman and
Emilie C. Coe. August 1957. 16p. diagrs., photo.,
tab. (NACA RM L57G02)
An analysis of a sample of data on atmospheric tur-
bulence obtained from NACA VGH records taken on
-Lockheed U-2 airplanes during research flights
covering approximately 40,000 miles for altitudes
between 20,000 and 55,000 feet over the western part
of the United States is presented. The results for
the variation of intensity and amount of turbulence
with altitude are compared with turbulence data pre-
viously obtained from similar operations over
England and Western Europe and with earlier esti-
mates of average turbulence conditions over the
United States.
Copies obtainable from NACA, Washington
0
1. Loads, Gust - Wings<
(4.1 .1 . t3)
2. Gusts, Atmospheric
(6.1)
3. Operating Problems -(s7)
I. Coleman, Thomas L
U. Coe, Emilie C . 2.
IlL NACA RM L57G02
CD
NA6. RM L57G02
Na nal Advisory Committee for Aeronautics.
Al LANE MEASUREMENTS OF ATMOSPHERIC
TUIWULENCE FOR ALTITUDES BETWEEN 20,000
A 55,000 FEET OVER THE WESTERN PART OF
T UNITED STATES. Thomas L. Coleman and
Emae C. Coe. August 1957. 16p. diagrs., photo.,
tab? (NACA RM L57G02)
An galysis of a sample of data on atmospheric tur-
bulCke obtained from NACA VGH records taken on
Locaeed U-2 airplanes during research flights
coving approximately 40,000 miles for altitudes
betioen 20,000 and 55,000 feet over the western part
of the United States is presented. The results for
the variation of intensity and amount of turbulence
with altitude are compared with turbulence data pre-
viously obtained from similar operations over
England and Western Europe and with earlier esti-
mates of average turbulence conditions over the
United States.
Copies obtainable from NACA, Washington
1. Loads, Gust - Wings
(4.1 . 1 .1 . 3)
2. Gusts, Atmospheric
(6. 1. 2)
3. Operating Problems (7)
I. Coleman, Thomas L.
H. Coe, Emilie C
NACA RM L57G02
NACA RM L57G02
National Advisory Committee for Aeronautics.
AIRPLANE MEASUREMENTS OF ATMOSPHERIC
TURBULENCE FOR ALTITUDES BETWEEN 20,000
AND 55,000 FEET OVER THE WESTERN PART OF
THE UNITED STATES. Thomas L. Coleman and
Emilie C. Coe. August 1957. 16p. diagrs., photo.,
tab. (NACA RM L57G02)
An analysis of a sample of data on atmospheric tur-
bulence obtained from NACA VGH records taken on
-Lockheed U-2 airplanes during research flights
covering approximately 40,000 miles for altitudes
between 20,000 and 55,000 feet over the western part
of the United States is presented. The results for
the variation of intensity and amount of turbulence
with altitude are compared with turbulence data pre-
viously obtained from similar operations over
England and Western Europe and with earlier esti-
mates of average turbulence conditions over the
United States.
Copies obtainable from NACA, Washington
th
5
-o
co
a
1. Loads, Gust - Wings?
(4. 1 . 1 . 14)
2. Gusts, Atmospheric r%)
(6.1M)
3. Operating Problems g)
I. Coleman, Thomas L.0
U. Coe, Emilie C.
IJI.0
NACA RM L57G02
0
NACA
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
Lt. Col. Robert C. Bundgaard
Technical Services Officer
Headquarters 8th Weather Group
Air Weather Service
APO 925, USAF
r/o PM, San Francisco, Calif.
1993 words
THE FIRST FLYOVER OF A TROPICAL CYCLONE
By Lt. Col. Robert C. Bundgaard
For the flying weathermen of the Weather Reconnaissance
Si,eadron, Provisional (3rd), the mission was a new one, never
previously tried. It was their task to conduct a reconnaissance of
Typhoon Kit from above using the Perkin-Elmer Model-501 tracking
camera. This horizon-to-horizon aerial camera would wipe Kit's
image onto 70mm film with a continuously-rotating scanning-prism.
The Model-501 is small and light enough to be carried aloft by
VI:1.SP/ 3's U-2 jet aircraft, operated by the Air Weather Service
in support of the National Advisory Committee for Aeronautics'
upper air research program.
rri Americans back home, last year's Typhoon Kit in the
s probably not cloaked with as much ill-repute as was her
eldest sister Agnes, that earlier brought havoc and destruction to our
military installations in Okinawa. But Kit is well remembered in the
i:tepublic of Philippines. Coinciding with the recent presidential
election, Kit behaved very much unlike our Lady of Liberty and
suspended for upwards of a million citizens of the Republic the
exerciinfpP4vVelk8rcIlkikilAittlble.15PliPltIW-IT19140T00782R000100040001-9
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
-
,Surveyed in her aftermath, Kit wrought over five million
dollars damage to public works, private property, the maturing rice
:And palay crops. She rendered some 58,900 known persons homeless,
probably many more. Despite her vicousness, miraculously she claimed
the lives of only 39 persons, but including United States Marine Private
First Class Charles Leon Davis, with a provisional camp of "Operation
6,f-rang Back," drowned in the valley-widened Coronel River. Yet, for
all her waste, suffering and lives lost, Typhoon Kit could well have led
to a far greater catastrophe, were it not for the typhoon warnings
2romptly and amply provided days in advance by Lt. Col. Howard
Berg's 54th Weather Reconnaissance Squadron, based at Guam's
Andersen Air Base, and utilizing the proven WB-50 aircraft.
Meandering westward over the Eastern Carolines Islands
during the early days of last November, the South Pacific tradewinds,
t might be presumed, momentarily wobbled and recurved northward,
spanking rotation and life into a small depression there. The mother-
ing trades then nursed this feebly turning depression with her moisture-
enriched hot breath. Doddering westward attached to the trades'
apron strings, the progressively strengthening and growing whirl
gained in storm intensity. On the morning of November 8th, Colonel
Berg's vigilant typhoon chasers first spotted this new, trade-spawned
storm practically in their own backyard, just 170 miles south-southwest
of Guam. When first found, it was already spewing 50-mile-per-hour
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
Approved For Release 2004/05/1a :c1A-RDP90T00782R000100040001-9
winds. By that same afternoon, the storm had intensified into a full
blown typhoon, to be dubbed Kit. The watching of Kit by the 54th began.
Typhoon Kit plowed west-northwest at 20 miles per hour toward
the Philippines, 930 miles away. Riding herd on Kit during the next
three days of fatiguing and teeth chattering flights, the 54th weather
s:rews twelve times boxed the typhoon and penetrated into its very eye.
Flirting with death in Kit to give precious warning for the safety
of the Philippines, little did these flying weathermen suspect that
fate had destined among them a crew to be lost soon in these very same
waters, now lashed and churned below them by Kit in all her devilish
fury; just two months later a WB-50 from the 54th disappeared into
Typhoon Ophelia, following Kit's same path, and was never heard from
again.
On November 11th, the eve of the Philippines national elections,
Kit packed 200 mile-per-hour surface winds, only a day out of Luzon.
Despite the fury of these howling winds, the 54th continued to look
three times more into Kit's bewitching eye, as she skirted north past
Gatanduanes Island, passed within 60 miles to the north of the Bicol
Pctninsula, and until at last she poised to stab into East Central Luzon
--It Baler Bay.
As Kit travelled inland, the rugged mountainous terrain of Luzon
took a lot of wind out of her, at least in the lower part of the typhoon.
Steered under the influence of the upper southerlies, Kit now curved
A:-.7truptley northward into a parabolic swing, barely sideswiping Clark
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
Approved For Release 2004/05AT: CIA-RDP90T00782R000100040001-9
Air Base. Apparently with the prophetic power that would be the envy
of even the greatest of soothsayers, USAF typhoon forecasters had gathered
at Clark Air Base from throughout the Far East and were midway through
a two-week Typhoon Workshop, being carried out under the auspices of
Professor C. S. Ramage and Major James Sedler from the University of
Hawaii. The workshoppers followed Kit closely, predicting her movement
by various techniques. Only one technique successfully called for
Kit's sudden swing northward through Luzon after its four-day trek
westward. This technique is an empirical method recently developed
by Keith Veigas and Robert Miller at Traveler's Weather Research Center,
Hartford, Conn., under the leadership of Dr. Thomas Malone.
Noon the next day, after exhausting her strength in battering
the 1417;on land cap, Kit bid her pallam, or adieu, and slipped out of
the Ilocos coast, at a point 30 miles east of the coastal city of Aparri,
the Cagayan delta. Now subdued, erratic Kit turned back to the
Pacific, zigzagging sluggishly northward and skirting east of the Batanes
Islands.
But now, as Typhoon Kit threatened to recurve to the northeast
in the direction of Okinawa, the responsibility for watching her passed
to the 56th Weather Reconnaissance Squadron and the 3rd Weather Recon-
naissance S4uadron, Provisional, both units based in Japan. Again the
WB-50 was dispatched to keep a watchful eye on Kit. The suspense of
such flights was now beginning to appear among the personnel of WRSP/3.
By noon on the 14th of November, Typhoon Kit had reached a
Approved For Release 2004/05/13 : CIA-RDP90.100782R000100.040001-9
critically interesting degenerative stage. r ew opportunities had thus far
- 5 -
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
been afforded to scientists for studying the manner in which typhoons
dissipate into tropical storms, thence into tropical depressions or
3ometimes into fast moving sub-tropical cyclones. Sometimes, typhoons
temporarily weaken into separate storms, such as Kit did, only to be
rcborn again as typhoons. Scientists had long hoped for the opportunity
to examine a typhoon from above with the hope that it might shed some
light upon which of these dissipating atmospheric processes man, in the
future, might himself most easily seek to alter in order to control typhoons.
as Kit mauled indecisively at Z001?1 and 123?E, Dr. Robert D.
Esletcher, past president of the American Meteorological Society, visiting
with the WRSP/3, suggested that now was the time for WRSP/3 to dispatch
one of its U-2 research aircraft to seek Kit out. Approaching the storm
area the WRSP/3 pilot was guided by giant cloud "streets" spiraling
in toward a coliseum-like wall of nimbostratus which surrounded Kit's
eye. In the wide converging sectors between these towering squall
hands, a floor of soft flat clouds hid the ocean frortthe pilot's view.
Climbing into the storm center, the U-2 hedge-hopped over the towering
48,000 foot cloud wall which surrounded the eye of Kit. Once within
this wall, 10 miles above the ocean's surface, the pilot saw the angried
ocean and far below him the waves were clearly visible through the long
arcing moats, clear of cloud. Downdrafts of hot air had gouged out
these moats at the eye-wall's very edge. Looking much like the froth
on a boiling caldron, a large moat-ringed island of low and hard
r-auliflowery clouds blearied Kit's eye. Around an island centered hub-
c lou
dApt*OvOltleF611RelbScitu2104/030131:1T4IVI4Fona-Tinfli2Redgi000411111149ilot
Approved For Release 2004/05/1.34 CIA-RDP90T00782R000100040001-9
counted nine such cat eyes within the center of Kit. These false-eyes
were parasitically consuming the dying typhoon, much in the manner so
aptly described by L. F. Richardson in his famous book Numerical Weather
Prediction (1922, p. 66):
g whirls have little whirls that feed on their velocity,
And little whirls have lesser whirls and so on to viscosity.
Thus, the primary motion of Kit formed by the instability of large-
scale vertical and horizontal motions, having been subjected to destabi-
lizing processes through loss of moisture supply in passing over Luzon,
now had led to the creation of secondary smaller whirls. These false-
were partly of dynamic nature, caused by the disorganization of
Kit's kinetic energy, and partly of thermal type.
fiere, then, was the eye of Kit, the first ever seen in its entirety.
The WRSP/3 mission had been accomplished. The furor of Kit was now
recorded on film. Kit 1,?..,s dying a normal death, but in her last gasping
breaths she had provided scientists with a new area of interest. The
WRSP/3 had also found an entirely new mission to perform. Through the
cooperation of NAGA and their willingness to utilize the U-2 in flights
ver typhoons the way had been opened for a better understanding of
Nature's most disastrous storms.
* * *
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
Approved For Release 2004/05/1-3 YCIA-RDP90T00782R000100040001-9
Description of Figures
. 1. - The path of Typhoon Kit through Luzon, Philippines. Along
the path, shown by the continuous solid curve, the circles bearing tics
represent fixes of Kit made by weather reconnaissance aircraft having
penetrated Kit's eye. These fixes are labelled with the date, first
the day in November, 1957, followed by the time in GMT. The picture
of Kit's eye in Fig. 2 was taken at the easterly bend along the path
near the center of this figure.
wier 2 - Vertically above the eye of Typhoon Kit. The storm center
g located at 19?30'N and 123?35'E. This picture was taken at approxi-
lately 0422 GMT on November 14, 1957. It is an unconstituted mosaic
,sf aerial photographs taken from the WRSP/3 U-2 aircraft. The U-2
traversed the center of the eye on a 2350 heading. This traverse is the mid-
-lertical of this picture from top to bottom. Along this mid-vertical
appears a 39 nautical-mile length of cloudscape. From top to bottom
of this picture, the middle-third continuously depicts a nearly correct
vertically downward view toward the sea and clouds below. From side
to side, however, the picture falls gradually off toward the horizons.
The left side of the picture is toward the west-northwestern horizon.
At the time of this picture, which is approximately one hour and a
half after local noon, Kit is headed northward, which is toward the top
of the picture and slightly to the left (N. B. the compass directly
in this figure). The large bowl-shaped appearance of Kit's eye is
Approved For Release-2004/05/13 : C1A-RDP90T00782R000100040001-9
Approved For Release 2004/05/1-3 8 GIA-RDP90T00782R000100040001-9
approximately 30 miles in diameter. Kidney-shaped, the darkened strips
are portions of the sea surface visible through cloud-free moats.
A fetch of transverse sea waves may be seen in the fleur-de-lis shaped
moat just to the left of the picture's center. The tops of the cloud
turrets at the upper middle of the picture are at 48, 000 feet. Along
the right of the picture and curving counterclockwise in from the upper
left corner is a sheet of high cloud. As this cloud spirals cyclonically
into the eye's center, it appears to sink and dssipate, as part of
an upper indraft ventilating the typhoon center. This high cloud is
also represented by the dotted shading in Fig. 3. Congruent with this
picture in Fig. 2 and having the same orientation and coverage, Fig. 3
shows also for the storm center the horizontal streamlines indicated
by the apparent motion and structure of the clouds, as shown in this
picture, Fig. 2.
Fig. 3. - A horizontal steamline analysis made of the cloud picture
in Fig. 2 for the eye of Typhoon Kit. This figure has exactly the
same areal extent and orientation as Fig. 2. This figure shows that
within Kit's eye there are nine small cyclonic swirls, maked by the
NOTE: It may be desirable to have figures 2 and 3 appear the same
size in Weatherwise, opposite each other, for ready and direct
comparison.
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
TABLE I
CONCISE WEATHER REPORT FROM THE PHILIPPINES
IN CONNECTION WITH THE PASSAGE OF KIT
1. Barometric Minimum at MSL 937.0 nib at 0000Z,
November 11, and 921.0
mb at 0600Z, November 11.
Maximum sustained winds:
Over land 80 miles per hour at Virac,
Catanduanes, and Casiguran,
Quezon, at 2200Z, November
10, and 1600Z, November 12,
rF,.9p; 100 miles per hour
at San Vicente Quezon, at
1900Z. November 11.
Over water 200 miles per hour at 0600Z
oi 1\inve.rnber U.
Maximum 24-hour rainfall 16.66 inches at Baler,
Quezon, on November 12.
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
pproved For Rase 2004/05/ 3 : C ''0100140001-9
rAr-
Appro d For Re ease 2004/05/13 : CIA -RDP90 '0782R001 10004000 -9
Approved For Release
'\
Approved For Release 200 0 3 : CIA-RDP90T0 2R0001000400 1-9
*
****************** ? * ? *
" ? ? ? ."*"." ?
? ? ???????????
?
064.4
0100040001-9
/13 : CIA-RDP90
? ?
? ? . ? ? ? .. .......
4:::::::;?;?????????? ** ? *****
????????????? ** * *
_?!-!?!?!?!?:?:?:?:
Approved For Release 2004/05/13 IA-RDP90T00782R000100040001-9
proved For Release 2004/05/13:
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
nautics...expanding man's knowledg-e of the universe
ng and further developing the Atlas ICBM for the U.S. Air Force, CONVAIR-Astronautics
and experience useful for our operations in space. This intelligence, vital to the United States
peaceful pursuits, can be greatly expanded through advanced Orbital Systems developed
-om its experience with the Atlas.
CNVAIIR A DIVISION OF GENERAL DYNAMICS CORPORATION
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
Typhoon-Eye Cloud Patterns as Viewed from Above
ROBERT C. BUNDGAARD, ROBERT D. FLETCHER, JAMES R. SMITH
The Eye of Typhoon Ida from 50,000 ft.
Reprinted from \VEKTHERVVISE, Vol. 12, No. 2, April, 1959
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
FIG. 1. The eye of Typhoon Kit, with spiral
bands and secondary vortices; 14 November
1957, north of Luzon.
TYPHOON IDA:S TRACK
AND PRESSURE ANALYSIS
4 2100 I 26 SEP 19561
FIG. 2.
64 WEATHERwisE
TAlyealitEiVemiliffigital-PiPs9Vinffilafin?131-0VC
ROBERT C. BUNDGAARD, ROBERT D. FLETCHER, JAMES R. SMITH
Air Weather Service, U. S. Air Force
PRESUMABLY, one of the greatest im-
mediate benefits of meteorological satel-
lites will consist of presentations of large-scale
cloud patterns of meteorological phenomena
for use in weather forecasting and research.
It is contemplated that patterns ranging in
size from single convective-cloud develop-
ments to the collective cloud configurations
of frontal systems will be recorded and placed
at the disposal of the meteorologist.
In particular, it has been suggested that
satellites will locate the centers of typhoons
and hurricanes. Information as to the lati-
tude and longitude of the eye of a storm, the
character of the clouds in the vicinity of the
eye and in the spiral bands surrounding it,
and time changes in the cloud patterns, will
be of tremendous assistance to the forecaster
concerned with estimating the future position
and extent of the storm. It will also be of
great economic value to typhoon-reconnais-
sance people who no longer will have to search
wide areas in locating a possible storm; but,
instead, can direct aircraft to the exact loca-
tion of the center to probe its lower regions
for the wind, pressure, temperature, and pre-
cipitation data which probably will be beyond
the measuring capabilities of satellites for
some time to come.
The patterns of low-level winds and pres-
sures in tropical cyclones are well known to
meteorologists. So, too, are the cloud and
precipitation distributions as determined by
radar and by aircraft flying inside the vari-
ous sectors of the storms. The important
question has been raised, however, as to
whether typhoons and hurricanes are really
identifiable from above?from the vantage
point of the satellite.
The National Aeronautics and Space Ad-
ministration, with the support of the Air
Weather Service, since 1957 has been con-
ducting an upper-air research program in
Japan for the purposes of testing new and
improved types of meteorological sensing
equipment and collecting high-altitude mete-
orological data. The equipment includes a
April 1959
Perkin-Elmer Model-501 tracking camera to
record cloud patterns on 70-mm film. The
equipment is mounted in a U-2 jet aircraft
capable of flying at heights up to about 10
miles above sea level. Since November 1957
the aircraft has been able to fly over the tops
of three separate typhoons and to photograph
the cloud patterns of the centers. In each of
the three cases the individual photographs
have been fitted together into a mosaic show-
ing the configuration of the clouds over the
entire eye.
The first flyover, the details of which have
been reported by Bundgaard, occurred on
14 November 1957 over Typhoon Kit just
north of the Philippine island of Luzon. See
Weatherwise, June 1959. Clearly evident was
the general pattern of the clouds spiraling into
the center, as was the location of the eye, it-
self. In the case of Kit, there appear to be
several additional cyclonic whirls of which
Bundgaard has identified eight.
On 9 July 1958 the Air Weather Service's
54th Weather Reconnaissance Squadron, un-
der Lt. Colonel Dale Desper, noted on its
synoptic charts a "suspicious area" about 300
miles northwest of Yap Island. The area was
reconnoitered by WB-50 aircraft and by 11
July a full-fledged storm, Typhoon Winnie,
was located. During the ensuing four days
13 penetrations at 500 mb were made into
the center of the storm. On the 15th the
typhoon entered Formosa?the most destruc-
tive such storm, for the island, of the past
decade. Several hours before it reached the
east coast of Formosa a U-2 aircraft was dis-
patched to the storm. It found it could top
the clouds of the storm and did so, taking the
pictures which form the mosaic shown in
Figure 1. In overflying the storm the pilot
reported a completely smooth ride, which was
quite in contrast to the flights made some six
or seven miles lower by the WB-50's which
encountered severe turbulence. The eye was
a large one; the typhoon winds of its circum-
ference lashed the entire island. The photo-
graph is of the eye itself with the wall clouds
April 1959
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
FIG. 3. The eye of Typhoon Winnie, with "wall"
clouds discernible at edges of photograph; 14
July 1958, east of Formosa.
discernible in the very corners. The cloud
pattern of the eye is very chaotic with two
distinct layers clearly evident, one low and
the other probably at cirrus levels. The
photograph does not show the solid sheet of
cirrus surrounding the eye. As described by
the pilot there was no detail to this cirrus-
cloud cover?only a "solid mist which ex-
tended to all horizons."
Typhoon Ida developed near the Mariannas
on 21 September 1958. On the 22d it curved
northward and passed over the Tokyo area
near midnight of the 26th. When it was just
south of Japan its central pressure reached a
reported minimum of 877 mb and the maxi-
mum recorded wind was about 140 knots. It
was a devastating storm which produced, inci-
dentally, record-breaking precipitation in the
Tokyo area. In Figure 2 is shown the track
of the typhoon as well as its pressure pattern
as it was approaching the island of Honshu.
On the morning of the 24th a U-2 aircraft
reconnoitered the typhoon. As in the cases
of Kit and Winnie, the aircraft found it could
clear the cloud tops of Ida and locate the eye
of the storm. It made a succession of passes
over the eye, the pilot reporting a smooth
flight as was the case with Winnie.
The photograph of Ida's eye is shown on
the front cover. Here there is no question as
to the general circularity of the eye; in this
particular picture there is only a suggestion,
WEATHERWISE 65
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
however, of the spiral cloud bands. The
photograph shows a chaotic deck of broken
low clouds in the eye with no middle or high
clouds except, perhaps, for a few cirrus wisps
protruding inward from the north. From the
top of the low clouds to the top of the cirrus
is estimated to be five to seven miles. The
sun's reflection from the side of the cloud wall
and top of the low clouds is quite bright?
considerably more so than is apparent from
the amorphous cirrus of the surroundings.
The brightness within the eye is consistent
with reports of typhoon-reconnaissance mete-
orologists who say that they are often blinded
upon breaking through the wall of the eye.
It also suggests that the excessive reflected
radiation may in part account for the abnor-
mally high temperatures frequently reported
in the eye of a typhoon or hurricane.
From the three flyover photographs con-
sidered in this paper a few tentative conclu-
sions can be drawn as to future satellite ob-
servations of typhoons and hurricanes:
1. Usually, although not necessarily al-
ways, the spiral structure of the clouds
around the eye will aid in locating the
center.
2. Usually the eye itself will be identifiable,
although at times the existence of sec-
ondary vortices will require study by a
trained analyst.
66 WEATHERWISE
3. Usually there will be clouds within the
eye; they will be chaotic and broken,
with patches of sea surface visible; usu-
ally they will be lom, and often there
will be no high clouds.
4. At certain times of the day, and with a
center essentially free of high clouds,
the eye may appear to the satellite to
be a circular region of maximum bright-
ness imbedded in a large area of not-so-
bright cloud cover.
Much study is required to determine the
optimum resolution for pictures taken from a
satellite. Certainly a resolution of one mile
and probably one of five miles will suffice for
identification of the great majority of hurri-
canes and typhoons, but a resolution of 50
miles will probably hide the detail necessary
for distinguishing the eyes and spiral cloud
patterns. Further overflies will be made and
more detailed data will be collected to assist
in answering this and other important mete-
orological questions. In an overall sense, the
over-the-top photographs of Kit, Winnie, and
Ida indicate that cloud structures of hurri-
canes and typhoons are such as to make the
satellite an excellent reconnaiQsance vehicle
for their detection and location.
REFERENCE
Bundgaard, Robert C.: The First Flyover of a Tropi-
cal Cyclone. Weatherwise, Vol. 11, No. 3, pp.
79-83; June, 1958.
April 1959
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
NASA MEMO 4-17-59L
NASA
MEMORANDUM
AIRPLANE MEASUREMENTS OF ATMOSPHERIC TURBULENCE AT
ALTITUDES BETWEEN 20,000 AND 55,000 FEET
FOR FOUR GEOGRAPHIC AREAS
By Thomas L. Coleman and May T. Meadows
Langley Research Center
Langley Field, Va.
NATIONAL AERONAUTICS AND
SPACE ADMINISTRATION
WASH I NGTON
June 1959
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
MEMORANDUM 4-l7-59L
AIRPLANE MEASUREMENTS OF ATMOSPHERIC TURBULENCE AT
ALTITUDES BETWEEN 20,000 AND 55,000 FEET
FOR FOUR GEOGRAPHIC AREAS
By Thomas L. Coleman and May T. Meadows
SUMMARY
Measurements of clear-air turbulence by use of airplane-borne instru-
ments have been obtained from NACA VGH recorders during research flights
of Lockheed U-2 airplanes at altitudes between 20,000 and 55,000 feet
over Western United States, England and Western Europe, Turkey, and Japan.
An analysis of these data has indicated that at the higher altitudes
(40,000 to 55,000 feet) turbulence is both less frequent and less severe
than at the lower altitudes (20,000 to 40,000 feet). Turbulence appears
to be encountered at the high altitudes for only about 2 percent of the
flight distance as compared with 5 percent or more at the lower alti-
tudes. Moderately heavy turbulence exists on occasion at altitudes of
about 50,000 feet over Japan and appears to be associated with the strong
character of the jet stream in this area and also with a mountain-wave
phenomenon.
INTRODUCTION
Recently, the National Aeronautics and Space Administration, in
cooperation with the Air Weather Service of the United States Air Force,
initiated a high-altitude flight-research program aimed at providing
detailed meteorological information for various geographic areas of the
world. The primary purpose of the NASA participation in the program
was to obtain information on the amount and intensity of atmospheric
turbulence at high altitudes for application to response studies of
missiles and airplanes; whereas, the aim of the Air Weather Service was
to collect data on humidity, pressure variations, and winds for opera-
tional and meteorological analyses. In order to obtain data at alti-
tudes above the current normal operating level, the Lockheed U-2 air-
plane is being used in the investigation. Inasmuch as the U-2 airplane
is capable of extended flight at altitudes between 50,000 and 55,000 feet,
a significant increase in the altitudes that may be sampled with airplane-
borne instruments is possible.
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
2
In order to obtain data samples from various geographic areas,
flight operations have been conducted from four widely separated loca-
tions. The initial operations were undertaken over the western part of
the United States and over Western Europe in the spring of 1956. The
results from these operations (refs. 1 and 2) indicated somewhat lower
gust frequencies and gust intensities than did the previous estimates
given ia reference 3 for average turbulence conditions over the United
States and, in part, formed the basis for the turbulence estimates given
in reference 4.
Siace publication of references 1 and 2, data samples have been
obtained from operations over Turkey and Japan, and additional data have
been obtained from the operations over Western Europe. The combined 9
sample of data on atmospheric turbulence for the four operations presently 7
covers Approximately 150,000 flight miles at altitudes between 20,000
and 55,000 feet. This report summarizes the results obtained for the
frequeney and intensity of the turbulence encountered at various alti-
tudes in the four operations. In addition, the results on the varia-
tion of the percent of flight distance in rough air with altitude are
compared with the estimates given in. references 3 and 4.
INSTRUMENTATION AND SCOPE OF DATA
Atmospheric-turbulence data were obtained during flights of several
Lockheed U-2 airplanes. The Lockheed U-2 is a subsonic, straight-wing,
single-engine, jet airplane originally designed for use as a high-altitude
test veaicle. A photograph of the test airplane is shown in figure 1.
The measurements pertinent to this report consisted of time histories
of airspeed, acceleration, and pressure altitude taken with NACA VGH
recordes (ref. 5). The time histories were recorded on photographic
paper moving at four inches per minute.
Inasmuch as the major interest of the present program is in meteoro-
logical conditions at high altitudes, the flight plans for the operations
were selected to provide maximum sampling time and coverage at altitudes
between 45,000 and 55,000 feet. In general, the flight plans consisted
of climbing to an altitude of approximately 45,000 feet in the vicinity
of the operations base, cruising with the altitude gradually increasing
as the load decreased, and then descending to the operations base.
As a consequence of this flight procedure, the gust measurements below
approximately 45,000 feet were obtained primarily during the climb and
descent phases of the flights and essentially represent soundings of the
atmosphere in the general vicinity of the operations bases.
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
3
The flights were made from bases at Watertown Strip, Nevada; Laken-
heath, England; Wiesbaden, Germany; Adana, Turkey; and Atsugi, Japan.
(Two additional flights were made from a base in Alaska, and these data
have been combined with those from Japan.) A variety of flight paths
were flown from each of the bases in order to obtain a broad coverage
of the geographic areas. The areas sampled in the four operations are
indicated in figure 2. As shown in the figure, the samples were col-
lected mainly between latitudes 300 N and 550 N.
The scope of the data samples in terms of the number of flights)
total flight miles, and dates of record collection is summarized in
table I. The table shows that the data from Western Europe, which repre-
sent 87 flights and total 60,514 flight miles, constitute approximately
40 percent of the combined data sample. Each of the other data samples
represents about 23 flights and consists of about 15,000 flight miles
for the operations over Turkey to 40,000 flight miles over the western
part of theUnited States. A breakdown of the data samples into the
number of miles flown within the various altitude intervals is given in
table II. As shown in the table, the majority of the flight miles for
each sample was obtained at altitudes between 45,000 and 55,000 feet.
The flight schedules were based primarily on airplane and instru-
mentation availability and, in general, attempts were not made to schedule
flights to sample turbulence'for specific meteorological conditions.
(One exception to this procedure was that one of the flights from Japan
was specifically made over a reported typhoon in an attempt to obtain
meteorological data at high altitude associated with this type of storm.
This typhoon had largely dissipated when the flight was made, however,
and no turbulence was encountered at the flight altitude.) Except for
occasional penetrations of stable cloud formations while climbing or
descending, the present operations were in clear air.
EVALUATION OF DATA
The NACA VGH records were evaluated to obtain the derived gust
velocities, the percent of rough air at various altitudes, and the length
(along the flight path) of the turbulent areas encountered. The evalua-
tion procedures are similar to the procedures used in references 1 to 3
and are reviewed briefly in the following paragraphs.
The derived gust velocities were calculated from simultaneous
readings of peak acceleration, airspeed, and altitude through the use
of the gust equation which is given in reference 6 as
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
4
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
2anW
Ude - mooKgVeS
where
Ude derived gust velocity, fps
an peak normal acceleration, g units
airplane weight, lb
wing area, sq ft
Kg gust factor
Ve equivalent airspeed, fps
wing lift-curve slope per radian
po air density at sea level, slugs/cu ft
Ir evaluating the records, the accelerations were read to a thresh-
old sufficiently low to yield frequency counts of all gust velocities
greater than 2 feet per second. The values of wing loading W/S used
in the equation took into consideration the in-flight weight loss due
to fuel. consumption. Appropriate values of the gust factor Kg were
computed for each part of the record where rough air was encountered.
The va3laes of the lift-curve slope m used in deriving the gust veloc-
ities were based on data obtained from the airplane manufacturer. (it
should be mentioned that the gust-velocity values presented herein may
be affected to some extent by the effects of airplane flexibility and
stability on the accelerations from which the gust velocities were com-
puted. The magnitude of these effects is not known, however, and addi-
tional work is required before their influence on the gust-velocity
values can be assessed.)
For the purpose of determining the horizontal extent, or length,
of the turbulent areas, the airplane was considered to be in rough air
whenever the accelerometer trace was continuously disturbed and contained
accelerations corresponding to gust velocities greater than 2 feet per
second. This threshold value is approximately the same as that used in
previous gust studies, such as references 2 and 5. The length of each
turbulent area was found simply by multiplying the true airspeed by the
time spent in rough air. The summation of the lengths of the individual
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
5
areas of rough air was then divided by the total flight distance for
given altitude intervals in order to obtain the percent of flight dis-
tance in rough air for that altitude interval.
RESULTS AND DISCUSSION
The gust velocities derived from the acceleration and airspeed data
are presented as frequency distributions in table III for each operation
and also for the combined data sample. Table IV gives the frequency
distributions of gust velocity by 10,000-foot altitude intervals for the
four geographic areas of operation and also for the combined data. In
addition, the number of miles of flight in rough air and the total num-
ber of miles represented by each distribution are given in tables III
and IV.
Frequency of Occurrence of Gust Velocities
Variation with geographic area.- In order to obtain an overall com-
parison of the frequency of occurrence of gust velocities for the dif-
ferent geographic areas, the average number of gusts per mile of flight
which exceeded given values of gust velocity are given in figure 3(a) for
the four geographic areas of operation. The curves in figure 3(a) repre-
sent operations between 20,000 and 55,000 feet and were obtained by
dividing the cumulative frequency distributions of gust velocity for each
area of operation by the total miles of flight given in table III. Based
on the total data samples between 20,000 and 55,000 feet, figure 3(a)
indicates that the gust frequency for the operations over Japan was sig-
nificantly higher than that for the other three operations. The gust
frequencies for the operations over the western part of the United States
and Western Europe were approximately equal and tended to be somewhat
higher than the gust frequency for the operations over Turkey.
In view of the relatively high gust frequency indicated in figure 3(a)
for the operations over Japan, the data sample for this operation was
examined in further detail. This examination showed that the high gust
frequency for the Japanese operations resulted predominantly from two
areas of rough air which were encountered at approximately 52,000 feet
on two separate flights over Honshu Island. The contribution of these
two areas of rough air to the data is shown in table V in which are pre-
sented the frequency distributions of gust velocities for the total
Japanese data sample between 20,000 and 55,000 feet and for the two areas
of rough air encountered at 52,000 feet. The table shows that over one-
half of the gusts in the total Japanese data sample were experienced in
the 151 miles of rough air encountered on January 22, 1958 (flight CW-58-2).
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
6
The 196 miles of rough air encountered on February 26, 1958
(flight CW-58-4) also contributed a large number of gusts to the data
sample but the rough air in this flight was of less severity than that
in flight CW-58-2.
In order to determine the effect of these two areas of rough air on
the estimated gust frequency, the gust velocities encountered in the
two flights were omitted from the distribution of gust velocities for the
Japanese operations and the results are shown in figure 3(b). Comparison
of figures 3(a) and 3(b) shows that the omission of these two areas of
rough air tends to make the turbulence experience for this operation more
comparable with that measured over the United States, Western Europe, and 1
Turkey. 9
In order to ascertain whether the two cases of moderately heavy tur-
bulence encountered over Japan were representative occurrences or merely
reflected very unusual conditions, the meteorological conditions existing
at the times of the two flights were examined. Consideration of the sur-
face and upper-air charts for the two days of the flights showed that on
both days the Japanese islands were under the influence of moderately
severe surface cyclonic storms and that well-developed jet streams with
peak wind velocities of about 200 knots existed at about 35,000 feet over 044
the islands. These weather conditions would be expected to be conducive
to the development of turbulence. In addition, the strong jet streams
in combination with the mountainous terrain of Japan may be expected to
give rise to mountain-wave phenomena (ref. 7) which, in turn, are con-
ducive to the formation of turbulence at high altitude. Severe cyclonic
storms and strong jet streams are quite common over Japan, especially
during the winter months, and the weather conditions for the two days
on which moderately heavy turbulence was encountered do not appear to
represent unusual conditions. In view of these considerations, it would
appear that the turbulence levels measured on flights CW-58-2 and
CW-58-4 may represent a frequent occurrence rather than extreme condi-
tions. Additional data are required, however, in order to obtain a
reliable estimate of the frequency with which such turbulence conditions
occur.
Variation with altitude.- Previous investigations (ref. 5, for
example) have indicated that the frequency of occurrence of gust veloci-
ties generally decreased with increasing altitude. In order to examine
the variation of the east frequency with altitude for the present opera-
tions, the gust-velocity data for the combined data sample given in
table IV are plotted in figure 4(a) in terms of the average number of
gusts which exceeded given values of gust velocity per mile of flight
within given altitude intervals. The results in figure 4(a) indicate
that the gust frequency decreased with increasing altitude between
20,000 and 50,000 feet- The gust frequency for the altitude interval
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
7
from 50,000 to 55,000 feet, however, is higher than for the lower alti-
tude intervals. This reversal in the pattern of decreasing gust frequency
with increasing altitude is due to the inclusion of the two areas of
moderately rough air encountered at 52,000 feet over Japan, as previously
discussed. In figure 4(b), the gust frequencies for the various altitude
intervals again are given based on the combined data sample but with the
two areas of rough air encountered over Japan omitted. With this omis-
sion, the results indicate a significant and orderly decrease in the gust
frequency with increasing altitude for the altitude range (20,000 to
55,000 feet) covered by the data.
Percent of Flight Distance in Rough Air
The percent of the flight distance which was in rough air (clear-
air turbulence) is presented in figure 5 by 5,000-foot altitude intervals
between 20,000 and 55,000 feet. The results show that for the higher
altitudes (40,000 to 55,000 feet) rough air was generally encountered
during less than two percent of the flight distance. A slightly higher
percentage of rough air is indicated, however, between 50,000 and
55,000 feet over Japan. Each set of data in figure 5 shows a peak between
30,000 and 35,000 feet in the variation of the percent of rough air with
altitude. This rough air is, however, of relatively low intensity, as is
indicated in figure 4. The increase in the amount of rough air is prob-
ably due to the high winds and wind shears associated with jet streams
which are normally prevalent at altitudes from 30,000 to 40,000 feet for
the midlatitude areas covered by the data (refs. 8 and 9). In this alti-
tude interval, the percent of flight distance in rough air over the
United States and Japan appears to be significantly higher than for the
other two geographic areas.
The present results on the variation in the percent of flight dis-
tance in rough air with altitude based on the combined data samples are
compared in figure 6 with the estimates given in reference 3 and the more
recent estimates given in reference 4. Inspection of figure 6 shows that
the estimates in reference 4 are in better agreement with the present
data than are the earlier results from reference 3. In particular, the
results in reference 4 give a better representation of the peak in the
amount of rough air between 30,000 and 35,000 feet and the decreased
amount of rough air above 40,000 feet.
Size of Turbulent Areas
The probability distributions of the horizontal extents, or lengths,
of the turbulent areas encountered in each area of operation are given
in figure 7. The curves in this figure show the probability that the
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
8
length of a turbulent area will exceed a given value. Inspection of
the results shows that the probability decreases rapidly with increasing
length. The results indicate, for example, that less than 50 percent
of the turbulent areas exceeded 10 miles in length and, except for the
operation over Japan, only about 1 percent exceeded 30 miles in length.
In addition, it may be noted that turbulent areas 150 to 200 miles in
length were encountered over Japan, whereas the maximum lengths for the
other operations were less than 50 miles.
CONCLUDING REMARKB
Measurements of atmospheric turbulence by use of airplane-borne
instruments have been obtained during research flights of Lockheed U-2
airplanes to altitudes of 55,000 feet over four geographic areas:
Western United States, England and Western Europe, Turkey, and Japan.
The four combined data samples cover approximately 150,000 miles of
flight and represent the first extensive measurements of turbulence up
to this altitude. An analysis of these data has provided information on
the variation of the intensity and amount of turbulence with altitude.
The results of the analysis have indicated that turbulence is generally
both less severe and less frequent at high altitudes ()-0,000 to
55,000 feet) than at the lower altitudes. From the overall viewpoint,
the data reflect an orderly decrease in the turbulence intensity with
increasing altitude. A notable exception to this pattern appears to
exist over Japan, however, where on two occasions large areas of
moderately heavy turbulence were encountered at altitudes of approxi-
mately 52,000 feet. In both of these instances, the turbulence
appeared to have been associated with the strong character of the jet
stream and with a mountain-wave phenomenon over the Japanese islands.
Langley Research Center,
National Aeronautics and Space Administration,
Langley Field, Va., January 21, 1959.
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
9
REFERENCES
1. Coleman, Thomas L., and Funk, Jack: Preliminary Measurements of
Atmospheric Turbulence at High Altitude as Determined From Accel-
eration Measurements on Lockheed U-2 Airplane. NACA RM L57A11,
1957.
2. Coleman, Thomas L., and Coe, Emilie C.: Airplane Measurements of
Atmospheric Turbulence for Altitudes Between 20,000 and 55,000 Feet
Over the Western Part of the United States. NACA RM L57G02,
1957.
3. McDougal, Robert L., Coleman, Thomas L., and Smith, Philip L.: The
Variation of Atmospheric Turbulence With Altitude and Its Effect
on Airplane Gust Loads. NACA RM L53G15a, 1953.
4. Press, Harry, and Steiner, Roy: An Approach to the Problem of Esti-
mating Severe and Repeated Gust Loads for Missile Operations.
NACA TN 4332, 1958.
5. Richardson, Norman R.: NACA VGH Recorder. NACA TN 2265, 1951.
6. Pratt, Kermit G., and Walker, Walter G.: A Revised Gust-Load Formula
and a Re-Evaluation of V-G Data Taken on Civil Transport Airplanes
From 1933 to 1950. NACA Rep. 1206, 1954. (Supersedes NACA
TN's 2964 by Kermit G. Pratt and 3041 by Walter G. Walker.)
7. Corby, G. A.: The Airflow Over Mountains. Quarterly Jour. Roy.
Meteorological Soc., vol. 80, no. 346, Oct. 1954, pp. 491-521.
8. Tolefson, H. B.: An Investigation of Vertical-Wind-Shear Intensities
From Balloon Soundings for Application to Airplane- and Missile-
Response Problems. NACA TN 3732, 1956.
9. Widger, William K., Jr.: A Survey of Available Information on the
Wind Fields Between the Surface and the Lower Stratosphere. Air
Force Surveys in Geophysics No. 25, Air Force Cambridge Res.
Center, Dec. 1952.
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
10
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
TABU: I.- SCOPE OF DATA SAMPLES
Geographic area
Number
of flights
Total flight
miles
Dates of record
collection
Western United States
24
39,839
May 1956 to March 1957
Western Europe
87
60,514
May 1956 to Oct. 1957
Turkey
23
15,665
Nov. 1956 to June 1957
Japan
23
32,617
May 1957 to Feb. 1958
,
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
TABLE II.- DISTRIBUTION OF FLIGHT MILES BY ALTITUDE
FOR FOUR GEOGRAPHIC AREAS OF OPERATION
Altitude, ft
Flight miles for area of -
Combined
data
Western
United
States
Western
Europe
Turkey
Japan
20 to 25 x 103
695
3,153
333
890
5,071
25 to 30
508
3,754
451
602
5,315
30 to 35
609
3,263
693
698
5,263
35 to 40
821
5,632
978
1,172
8,603
4o to 45
1,358
6,316
1,152
1,421
10,247
45 to 50
5,604
10,528
4,497
4,642
25,271
50 to 55
30,244
27,868
7,561
23,192
88,865
Total flight
miles . . . ?
39' 839

60,514
15,665
32,617
148,635
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
12
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
TABLE III.- FREQUENCY DISTRIBUTIONS OF DERIVED GUST
VELOCITY FOR FOUR GEOGRAPHIC AREAS OF OPERATION
Derived gust
velocity,
Ude, fps
Frequency distributions for area of -
Combined
data
Western
United
States
Western
Europe
Turkey
Japan
2 to 3
363
625
142
864
1,994
5 to 4
112
265
62
444
883
4 to 5
48
80
14
246
388
5 to 6
19
29
5
133
184
6 to 7
16
19
102
137
7 to 8
4
6
58
68
8 to 9
2
3
28
33
9 to 10
1
23
24
10 to 11
1
13
14
11 to 12
1
6
7
12 to 15
1
4
5
13 to 14
1
1
14 to 15
1
1
15 to 16
o
o
16 to 17
3
3
17 to 18
o
o
18 to 19
o
o
19 to 20
0
0
20 to 21
1
1
Total
568
1,027
221
1,927
3,743
Miles of flight
in rough air .
753
1,276
241
1,545
3,815
Total flight
miles
59,839
60,514
15,665
32,617
148,635
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
6-1?000170001.000tIZ8/00106dCIU-VI3 : ?1./90/1700Z aseeieu -10d peACLICIdV
L-197
TABLE IV.- FREQUENCY DISTRIBUTION OF DERIVED GUST VELOCITY BY
ALTITUDE FCR FCUR GEOGRAPHIC AREAS OF OPERATION
Frequency distributions at altitudes, ft, of -
Derived gust
velocity,
20 to 30 x 103
30 to 40 x 103
40 to 50 X 103
50 to 55 x 103
Ude, fps
a US
bEcT
dj
Combined
- US
b E
c T
dj
Ccadttiedaus
IDE
cT
dj
Cat,ic,:ed
a US
bE
cT
d j
Cotitned
2 to 3
142
230
15
54
441
83
212
28
103
426
18
92
85
31
226
120
91
14
676
901
3 to 4
41
85
2
20
148
13
91
8
29
141
1
58
38
13
110
57
31
14
382
484
4 to 5
16
33
6
55
4
23
2
15
44
12
12
5
29
28
12
220
260
5 to 6
8
12
3
23
1
9
1
2
13
5
2
7
10
3
128
141
6 to 7
6
5
1
12
1
5
2
8
? 5
5
9
4
99
112
7 to 8
1
2
1
4
2
2
2
2
3
0
57
60
8 to 9
1
2
3
1
1
28
30
9 to 10
0
0
1
23
24
10 to 11
1
1
0
13
13
11 to 12
0
0
1
6
7
12 to 13
1
1
4
4
13 to 14
1
1
14 to 15
1
1
15 to 16
0
0
16 to 17
3
3
17 to 18
o
0
18 to 19
0
0
19 to 20
0
0
20 to 21
1
1
Total
217
369
17
85
688
102
342
39
151
634
19
174
137
49
379
230
142
28
1,642
2,042
Miles of flight
in rough air .
114
317
5
151
587
216
472
52
262
1,002
57
239
138
74
508
366
248
46
1,058
1,743
Total flight
miles
1,203
6,907
784
1,492
10,386
1,430
8,895
1,671
1,870
13,866
6,962
16,844
5,649
6,063
35,518
30,244
27,868
7,562
23,192
88,865
aUS
bE
CT
dJ
Western United States.
Western Europe.
Turkey.
Japan.
6-1?000170001.000t1Z8/00106dCIU-VI3 : ?1./90/1700Z aseeieu -10d peACLICidV
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
TABU' V.- FREQUENCY DISTRIBUTIONS OF DERIVED GUST
VELOCITY FOR OPERATIONS OVER JAPAN
)erived gust
velocity,
Ude) fps
Frequency distributions for -
Total sample
(23 flights)
Flight
CW-58-2
Flight
CW-58-4
,
2 to 3
864
396
120
5 to 4
444
257
65
4 to 5
246
175
31
5 to 6
133
119
9
6 to 7
102
87
7
7 to 8
58
55
2
8 to 9
28
26
2
9 to 10
23
,-),_,)
c
0
10 to 11
13
13
0
11 to 12
6
6
0
12 to 13
4
4
0
15 to 14
1
1
0
14 to 15
1
0
1
15 to 16
0
0
0
16 to 17
3
3
o
17 to 18
o
0
o
18 to 19
0
0
0
19 to 20
0
0
0
20 to 21
1
1
0
il
1,927
1,161
237
?' of flight
1 rough 1.1-' .
1,545
151
196
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
16
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
cross-hatched) sampled during four operations.
E
.
Figure 2.- Geographic areas
6-1?000170001.000tIZ8/00106dCIU-VI3 : ?1490/1700z aseeieu JOd 130A0iddV
1.0
0 Un deo' Sia/es
0 Wesi-ern Europe
A 71//"e9
O Japow
sk
&
& '6
12i
k&
1
6
a
? A
A .
a
'6
is
0
0
o
o
a
6
6
M
f
M
a
is
(a) All data.
/2
L-197
/6 20 0 4 5 /2 /6 eo
Derived qtis ve/oc dy, Ode, tps
(b) Flights CW-58-2 and CW-58-4 omitted.
Figure 3.- Frequency of exceeding given values of gust velocity per mile of flight for four geo-
graphic areas.
6-1?000170001.000tIZ8/00106dCIU-VI3 : ?1490/1700z aseeieu JOd 130A0iddV
6-1?000170001.000tIZ8/00106dCIU-VI3 : ?1490/1700z aseeieu JOd 130A0iddV
Id
/2 /6 20
Derived qusi veloct /y, Ode, f,os
I
?I
A Ihfude,
0 20 to
0 30 to40
0 40 to5O
A SO to
1/
s
30)(10
55
?
?
?
2
?.
. .
II
0
A
_
0 A
? A
?
A
-
:
?
?
A
?
(a) All data.
/2 /6
(b) Flights CW-78-2 and CW-58-4 omitted.
Figure 4.- Cumulative frequency distributions per mile of flight for various altitude intervals.
6-1?000170001.000tIZ8/00106dCIU-VI3 : ?1490/1700z aseeieu JOd 130A0iddV
60
50
40
/0
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
19
3
6,L/
.
1
0 Unded
Wedeni
Turkey
Sb/es
EUlOpe
II gi A
1
#
A otrt
....
- -
a J apc i
n
A
111 -----------,n
A,
c,--40
_
?
/2 /6 20
A'erce/7/ of fhahic,3,5k2/7ce //7 roagb o/p
Figure 5.- Percent of flight distance in rough air (clear-air turbulence)
at various altitudes for four geographic areas of operation.
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
20
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
60
SO
40
Q.;
20
/0
A I t.,/
a Corn6/i2ed
Re
a'7 /c7
fer-eipce S
4
- - - Re.fere,oce
oC\
l
\
0 \
\N ?'
1 6 \
\
1
I
0
0
/
/
/
/
0
I
I
I
\
\
N
-..
?
_ ------------_______
c) 4 6 / Id20
Pe rceipt of f//qh/ dislo.?ce /72 "ough Op-
Figure 6.- Comparison of percent of flight distance in rough air at var-
ious altitudes.
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
%me
Approved For Release 2004/05/13 : CIA-RDP90T00782R000100040001-9
0 D<
-
r??
fippriogo
21
NASA - LanAP prowl ffpu_Felease 2004/05/13 : CIA-RDP90T00782R000100040001-9
NASA MEMO 4-17-59L
N onal Aeronautics and Space Administration.
AIRPLANE MEASUREMENTS OF ATMOSPHERIC
TURBULENCE AT ALTITUDES BETWEEN 20,000
Alk$4 55,000 FEET FOR FOUR GEOGRAPHIC AREAS.
T -'as L. Coleman and May T. Meadows. June
19 . 21p. diagrs., photo., tabs.
(NA MEMORANDUM 4-17-59L)
Angnalysis is presented of data on atmospheric tur-
b4aice obtained from VGH records taken on Lockheed
U-0airplanes during research flights covering ap-
p4mately 150,000 miles at altitudes between
20290 and 55,000 feet over four geographic areas:
Wditern part of the United States, England and
WEaern Europe, Turkey, and Japan. The gust ex-
pence for the four geographic areas is compared
an 'the variations in the gust frequencies and the
pe dent of flight distance in rough air with altitude
aii:indicated. The results on the variation of the
peMent of flight distance in rough air with altitude
arCEompared with previous estimates.
Cops obtainable from NASA, Washington
cri
0
NA_. MEMO 4-17-59L
Na nal Aeronautics and Space Administration.
AIRPLANE MEASUREMENTS OF ATMOSPHERIC
TTJULENCE AT ALTITUDES BETWEEN 20,000
AN 55,000 FEET FOR FOUR GEOGRAPHIC AREAS.
Th as L. Coleman and May T. Meadows. June
19$1.Z 21p. diagrs., photo., tabs.
(1%118A MEMORANDUM 4-17-59L)
0
An4Ina1ysis is presented of data on atmospheric tar-
bullgce obtained from VGH records taken on Lockheed
U-1tairplanes during research flights covering ap-
prcelmately 150,000 miles at altitudes between
20,00 and 55,000 feet over four geographic areas:
Western part of the United States, England and
Western Europe, Turkey, and Japan. The gust ex-
perience for the four geographic areas is compared
and the variations in the gust frequencies and the
percent of flight distance in rough air with altitude
are indicated. The results on the variation of the
percent of flight distance in rough air with altitude
are compared with previous estimates.
Copies obtainable from NASA, Washington
1. Loads, Gust - Wings
(4. 1. 1. 1. 3)
2. Gusts, Atmospheric
(6. 1. 2)
3. Operating Problems
(7)
I. Coleman, Thomas L.
H. Meadows, May T.
HI. NASA MEMO 4-17-59L
NASA
1. Loads, Gust - Wings
(4. 1. 1. 1. 3)
2. Gusts, Atmospheric
(6. 1. 2)
3. Operating Problems
(7)
I. Coleman, Thomas L.
U. Meadows, May T.
Hi. NASA MEMO 4-17-59L
NASA
NASA MEMO 4-17-59L
National Aeronautics and Space Administration.
AIRPLANE MEASUREMENTS OF ATMOSPHERIC
TURBULENCE AT ALTITUDES BETWEEN 20,000
AND 55,000 FEET FOR FOUR GEOGRAPHIC AREAS.
Thomas L. Coleman and May T. Meadows. June
1959. 21p. diagrs., photo., tabs.
(NASA MEMORANDUM 4-17-59L)
An analysis is presented of data on atmospheric tur-
bulence obtained from VGH records taken on Lockheed
U-2 airplanes during research flights covering ap-
proximately 150,000 miles at altitudes between
20,000 and 55,000 feet over four geographic areas:
Western part of the United States, England and
Western Europe, Turkey, and Japan. The gust ex-
perience for the four geographic areas is compared
and the variations in the gust frequencies and the
percent of flight distance in rough air with altitude
are indicated. The results on the variation of the
percent of flight distance in rough air with altitude
are compared with previous estimates.
Copies obtainable from NASA, Washington
1. Loads, Gust - Wing9
(4. 1. la. 3)
2. Gusts, Atmospheric-
(6. 1. 2)71
3. Operating Problemg
(7)
I. Coleman, Thomas gl
IL Meadows, May T. E
III. NASA MEMO 4-17-FL
CD
tri
NASA
5
co
NASA MEMO 4-17-59L
National Aeronautics and Space Administration.
AIRPLANE MEASUREMENTS OF ATMOSPHERIC
TURBULENCE AT ALTITUDES BETWEEN 20,000
AND 55,000 FEET FOR FOUR GEOGRAPHIC AREAS.
Thomas L. Coleman and May T. Meadows. June
1959. 21p. diagrs., photo., tabs.
(NASA MEMORANDUM 4-17-59L)
An analysis is presented of data on atmospheric tur-
bulence obtained from VGH records taken on Lockheed
U-2 airplanes during research flights covering ap-
proximately 150,000 miles at altitudes between
20,000 and 55,000 feet over four geographic areas:
Western part of the United States, England and
Western Europe, Turkey, and Japan. The gust ex-
perience for the four geographic areas is compared
and the variations in the gust frequencies and the
percent of flight distance in rough air with altitude
are indicated. The results on the variation of the
percent of flight distance in rough air with altitude
are compared with previous estimates.
Copies obtainable from NASA, Washington
1. Loads, Gust - Win
(4. 1. 1 3)
2. Gusts, Atmospherie
(6. 1. 2)=34
3. Operating Problemee
(7) 0
I. Coleman, Thomas a
H. Meadows, May T. 0
III. NASA MEMO 4-17-@L
0
NASA