ENGLISH TRANSLATION OF TECHNICAL MANUAL ON SOVIET AIRCRAFT DRIFT INDICATOR AB-52

• Document Type: CREST
• Collection: General CIA Records
• Document Number (FOIA) /ESDN (CREST): CIA-RDP80-00247A001200270001-7
• Release Decision: RIPPUB
• Original Classification: S
• Document Page Count: 13
• Document Creation Date: December 27, 2016
• Document Release Date: January 8, 2014
• Sequence Number: 1
• Publication Date: September 1, 1964
• Content Type: REPORT

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CENTRAL INTELLIGENCE AGENCY
50X1-HUM
This material contains information affecting? the National Defense of the United States within the mailing of the Espionage Laws, Title
18, U.S.C. Secs. 793 and 794, the transmission or revelation of which in any manner to an unauthorized person is prohibited by law.
S-E-C-R-E-T
NO FOREIGN DISSENI
50X1-HUM
COUNTRY
USSR
REPORT
SUBJECT
English Translation of Technical
DATE DISTR.
September
1964
Manual on Soviet Aircraft Drift
Indicator AB-52
NO. PAGES
1
50X1-HUM
RFFFRFNIf-Fq
DATE OF
INFO.
PLACE &
DATE ACQ.
50X1-HUM
THIS IS UNEVALUATED INFORMATION. SOURCE GRADINGS ARE DEFINITIVE. APPRAISAL OF CONTENT IS TENTATIVE.
English translation of a Russian-language manual
entitled Aeronavigational Naviptor's Drift Indicator AB-52 50X1-HUM
(Aeronavigatsionnyy bortovoy vizir shturmana ABL52)
Distribution of Attachment
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Air:
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1 copy
1 copy
1 copy
1 copy
1 copy
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1 copy (forwarded previously)
1 copy
2 copies
1 copy
1 copy
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GROUP I
Excluded from axiomatic
downgrading and
declowificatien
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3
2
1.
sAC50X1-H UM
INFORMATION REPORT INFORMATION REPORT
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AE RONAV I GATIONAL
NAVIGATOR' S
DRI FT INDICATOR
AB-52
S-E-C-R-E-T
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EV-Fitds
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TABLE OF CONTENTS
Page
I. Designation and Operating Principle 1
II. Parts Assembly, 2
III. Description of the Drift Indicator 2
IV. Basic Technical Specifications of the Drift Indicator 6
V. Operating Instructions 6
A. Installation of the Drift Indicator 6
B. Handling Instructions 7
C, Preflight Checking and Readying of the Drift Indicator 7
Q. Operating the Drift Indicator in Flight
VI. Maintenance
9
VII. Storage, Packing, and Transportation 10
SECRET
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I. Designation and Operating Principle
The Aeronavigational Navigator's Drift Indicator AB-52 (Fig. 1)
is designated for inflight determination of the following:
Fig. 1
1) average values of drift angles;
2) average values of ground speed;
3) deviation of aircraft's compass, which can be corrected in
flight if necessary.
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According to its construction and operating principle, this in-
dicator should be classified as an optical, rigidly attached naviga-
tor's drift indicator.
Determination of drift angles is performed directly by measurement
of the angle formed between the axis of the aircraft and the direction
of its movement. Determination of ground speed is based on measuring
the time (with a stopwatch) the aircraft takes to cover a course equal
to the optical baseline of the indicator. Inflight determination of
deviation in the aircraft's compass is based on comparing the magnetic 4
and compass courses of the aircraft, wherein the aircraft's compass
course is determined With the indicator through ground reference line
whose magnetic bearing is either known or may be determined from the
map.
II. Parts Assembly
The parts assembly of the indicator includes:
1.
Aeronavigational drift indicator
1 each
2.
Indicator bracket
1
3.
Mounting units
1 set
4.
Stopwatch (on the cover of the indicator l
1 each
5.
Description
1 copy
6.
Nameplate
1 "
7.
Parts list (on box cover)
1 "
8.
Photograph of installation (on box cover)
1 "
III. Description of the Drift Indicator
A basic element of the indicator is the optical system (Fig. 2)
consisting of objective 1, two mirrors 2 and 3, intermediate lens 4,
grid 5, and ocular 6. The indicator is equipped with a device for
determining drift angles which includes a pantograph and two concen-
tric disks. In addition, a flight computer is located on the cover of
the indicator which is used to find the flight speed according to the
true altitude and the time for the aircraft to cover the base line of
the range finder.
Objective 1, mirrors 2 and 3, intermediate lens 4, and the grid 5
are mounted in the metallic tube of periscope 7 (see Fig. 1) which is
fastened to cast base 8 of the indicator. Ocular 6 (see Fig. 2) is
mounted in cast tube 9 (see Fig. 1) which is secured by hinges to
base 8. On the end of tube 9 is placed protective annular cushion
(eyepiece) 10 made of soft rubber.
Visible through ocular 6 (see Fig. 2) are four parallel lines 11
(Fig. 3) of the grid called "drift lines"; these lines are intersected
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77:
at their edges by two "time lines" 12, and by two lines 13 in the center,
which are auxilliary lines used for determining deviation during flight.
Stopwatch 29 (see Fig. 1) is mounted on the hinged cover of the in-
dicator ahd is used for finding the flight time when determining ground
speed.
Pantograph 14 (see Fig. 3) is located inside the metal cover of
the indicator which serves as a base for tube 9 (see Fig. 1) of the
ocular. The pantograph consists of the system of hinged levers 14 (see
Fig. 2) equipped with stylus holder 15 and pointer 16, visible on the
grid background of the indicator when viewing through the ocular.
Fig. 2
The end of pointer 16 is coated with a luminescent substance which
facilitates using the indicator in night flights.
For the same purpose drift angle scale 25 and index 26 are illumi-
nated with lamp 32. The lamp is assembled from the lower side of base 8
(see Fig. 1). The lamp is protected with a shade on the side adjoining
index 26 (see Fig. 3).
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Fig. 3
The intensity of illumination of scale 25, lines 24, and index 26
is regulated with rheostat 31 (see Fig. 1).
When viewing through the indicator, lamp 32 (see Fig. 3) should be
turned off and is turned on only when it is necessary to take readings
from the drift angle scale 25, since the light from the lamp may fall
on the grid of the indicator and interfere with the observation.
For working with the indicator in night flights, grid 5 (see Fig. 2)
is illuminated with lamp 17 (see Fig. 3), and to enable working with
the indicator on weakly illuminated reference points and to eliminate
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light flashes observed in the field of vision, there is a red light
filter located in the housing of the indicator between the lamp and
the grid. The intensity of illumination is regulated with rheostat
30 (see F,ig. 1). Turning lamps 17 and 32 (see Fig. 3) on and off may
be done with master switch 18, or individually with rheostats 30 and
31.
The base of the indicator has connector 19 (see Fig. 1) for con-
necting the indicator with the aircraft circuit.
Under the pantograph stylus are located two concentric disks.
Upper transparent disk 21 (see Fig. 3) is stationary and the stylus
of the pantograph moves on it. Lower disk 22 rotates about its center
and is kinematically connected with the grid of the indicator.
To increase the moment of friction between drift angle disk 22
(see Fig. 2 [sic]) and base 8 (see Fig. 1) the disk is seated rigidly
on an axle by which it is pressed against the base with a flat spring,
mounted on the lower side of the base.
Knob 23 fastened on disk 22 serves to rotate the grid and disk 22.
On the surface of disk 22 are 15 parallel lines 24 and scale 25 which
has divisions and numeration to 550 for reading, according to sta-
tionary index 26, the values and directions (t) of drift angles. Angles
of right drift are designated with a plus sign (+) and angles of left
drift with a minus (-) sign.
The flight computer on the cover of the indicator consists of two
annular logarithmic scales. The logarithmic design of the scales per-
mits multiplying or dividing the scale numeration by 10 to establish
the necessary data. On outer stationary scale 27 (see Fig. 1) are in-
scribed altitudes (or ground speeds).
By multiplying the numeration by 10, it is possible to obtain any
altitude from 100 to 9000 meters.
Example. If the base line time measurement was 1 minute 30 seconds,
it is necessary to reduce the time to seconds (which will be equal to
90 seconds) and set the altitude of flight opposite 9.
On inner movable scale 28 are inscribed seconds. By multiplying
the numeration by 10, it is possible to establish seconds greater than
45.
The speed of the aircraft is determined on outer, stationary scale
27 by markings inscribed on inner disk 28 in km./hr., m.m/gac (nautical
miles per hour), and in a.m/lac (English miles per hour).
Note. A nautical mile equals 1.85 km. An English mile equals
1.61 km.
The indicator is secured in the aircraft with a special bracket.
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IV. Basic Technical Specifications of the Drift Indicator
1.
Drift angle measurement limits
?300
2.
Course angle measurement limits
.1550
3.
Ground speed measurement range
100-900 km/hr
4.
Field of view, minimum ...
30?
5.
Range finder base line
0.511 (H m alt in m)
6.
Rated voltage for lighting of indicator
27 v
7.
Dimensions of indicator with bracket (with
guides in horizontal position
282 x 335 x 280 mm
(wdth x lgth x hgt)
8.
Weight of indicator:
a) without bracket, with power cable 2.7 kg
b) with bracket, power cable and mounting units 3.3 kg
V. Operating Instructions
A. Installation of the Drift Indicator
The drift indicator is mounted in the navigator's compartment, on
the right side of the aircraft. The basic' requirements for installa-
tion to provide normal operation of the indicator are as follows:
1. The plane passing through the lower runners of the base of the
indicator should be horizontal.
2. When aligning the 0 of scale 25 (see Fig. 3) on disk 22 with
index 26 of line 24 of disk 22, and consequently also "drift lines" 11,
the grid lines of the drift indicator should be parallel to the long-
tudinal axis of the aircraft.
3. The height at which the drift indicator is to be installed
above the compartment floor should be selected, on one hand, so as to
provide for facility of operation with the indicator and, on the other
hand, so that the side covering of the aircraft would not fall into the
field of view of the indicator (installed too high).
Prior to installing the drift indicator the aircraft is po-
sitioned in a level-flight attitude on a horizontal platform (wings
level).
The fasteners for the bracket are installed and the bracket is
adjusted in them so that the plane formed by its guides is horizontal
-(checked with a level). The drift indicator is installed in the bracket
and simultaneously the position of the rubber collar on the objective
tube is adjusted so that it [the rubber collar] comes in full contact
with the skin of the fuselage.
On the ground beneath the aircraft a string is stretched in
such a way so that it is parallel6 to the longitudinal axis of symmetry
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of the aircraft and is in the field of view of the drift indicator. The
zero division on scale 25 is aligned with index 26 using knob 23 and the
adjustable screws fastening the indicator to the side, and, if necessary,
by adding spacers under these adjustable fasteners so that "drift lines"
11, visible on grid 5 (see Fig. 2), are parallel to the string stretched
Oh the ground.
The levelness of the plane formed by the guides of the bracket
is checked again with a level. It is checked to see that the side cover-
ing of the aircraft or any other of its parts do not fall into the field,
of view of the drift indicator. The power cable for lighting the in-
dicatof is plugged into the indicator and the aircraft electrical cir-
cuit.
This completes the instarration:of the drift indicator. r-
B. Handling Instructions
1. When the drift indicator is not being used the pantograph should
be positioned on the lower rest and firmly secured by holder 20 (see
Fig. 3).
2. Care should be exercised that no hard objects strike the in-
dicator.
3. Do not use excess forces when using the indicator and when
packing it in its box.
4. Clean the external optical parts carefully with the tissue pro-.
viaed with the unit.
5. The hinged cover with tube 9 (see Fig. 1) should not be opened
in such a way that it will strike the rheostat since the cover of the
rheostat is made of carbolite and the rheostat can be damaged.
6. When changing the light bulb it must be checked to see that
there is no excess of solder on the bulb base, otherwise, when screw-
ing in the bulb the sliding contact will seize in the solder and the
bulb will not screw in completely.
C. Preflight Checking and Readying of the Drift Indicator
Prior to every flight the following must be done:
1. Check the surfaces of the grid, ocular, objective, and the
mirror in the objective elbow of the indicator.
If they are dirty, wipe them carefully with a soft cloth
(do not use paper or chamois as these might damage them). Wipe off
the surface of the transparent disk below the stylus of the pantograph.
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2. Check for proper illumination of the grid and drift angle scale.
3. Check to see that the bracket of the indicator is firmly se-j
cured to,the fuselage.
4. ?Check and fasten the stylus in the clamp on the pantograph.
5, Test tht stopwatch.
D. Operating the Drift Indicator in Flight
a) Determining the Drift Angle ?
While looking into the ocular of the drift indicator and checking
the relative movement of the ground, turn the grid together with disk
22 by means of knob 23 (see Fig. 3) and set it so that "drift lines"
11, which can be seen through the ocular, coincide with the direction
of movement of the ground references. Then index 26 will point out on
scale 25 the magnitude and direction of drift ("plus" indicates drift to
the right and,"minus" indicates drift to the left).
In actual practice, due to yawing of the aircraft and continuous
changes in the speed of the wind the angle.of drift also changes within
known limits. Therefore using the procedure indicated above it is
possible to determine only instantaneous values for the angle of drift.
Determination of averaged angles of drift with the indicator consists
in the following. While observing the surface of the ground through
the ocular, the pantograph mechanism is moved by the stylus until the
end of pointer 16 coincides with some ground reference and then these
are held in this matched position for the time it takes the referpnce
to move through the field of view of the indicator. In the meantime
light pressure is applied to the stylus which traces the line for the
actual direction of movement of the aircraft. Several of such lines
can be drawn to achieve higher accuracy. Afterward, disk 22 is turned
so that lines 24 on it are parallel to the lines traced by the stylus
on disk 21 and then the magnitude and direction of the angle of drift
[sic] is read off scale 25 as shown by index 26.
b) Determination of Ground Speed
In order to find the ground speed using the drift indicator it is
necessary to know the true altitude of flight over the locality and
the aircraft must be in level flight.
? The following must be done:
1. Measure the angle of drift by one of the methods indicated
above.
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2. Align the corresponding division on scale 25 with index 26
and, while looking through the ocular of the indicator, find with use
of the stopwatch the time it takes any ground reference to cover the dis-
tance betyeen the "time lines" 12 on the grid of the indicator.
3. On a flight computer set the mark, which corresponds to
time found with the stopwatch (in sec), opposite the division correspond-
ing to the true altitude of flight in meters, and find the value for
the ground speed in km/hr on the outer scale opposite the mark which is
noted in km/hr or in nautical miles per hour (units), opposite the mark
noted in m.m/gac [nautical miles per hour], or in English miles per hour
opposite the mark noted in a.m/tiac [English miles per hour].
c) Checking Compass Deviation
To determine deviation in the aircraft's compass for any given head-
ing, the course angle in horizontal flight is compared with a ground
reference line, whose magnetic bearing is either known or can be deter-
mined from the map (such as a railroad, highway, etc.). For this purpose
knob 23 is used to move "drift lines" 11 on the grid to coincide with
the direction of the selected reference line; if scale 25 shows a devia-
tion in the direction of positive drift angles by pointer 26, the course
angle may be read on scale 25 from 0 to 550 (or from 180 to 235?). If
scale 25 shows deviation in the direction Of negative drift angles, the
angle as shown by pointer 26 will be supplemental to 3600 (or 180?).
Lines 13 of the grid may be used if necessary to determine the course
angle by also lining them up with the direction of a ground reference
line. Now, when scale 25 shows a deviation in the direction of positive
drift angles, 900 should be added to the reading of scale 25 to deter-
mine the course angle. If scale 25 shows negative deviation, the angle
on scale should be subtracted from 900 to determine the supplemental
angle (up to 360?).
The magnetic heading MK of the aircraft is found from the known
course angle KU and the magnetic bearing MP:
MK = MK - KU,
whereby the sought compass deviation is equal to
k = MK . KK,
where KK is the compass course of the aircraft.
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VI. Maintenance
,5
After a minimum of two or three flights, the shaft of the pantograph
and connecting rod, as well as all other moving parts of the indicator,.
should
should be lubricated with oil MVP.
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A
After a minimum of SO hours of flying time, it is necessary to do
the following:
a) check the condition of the pantograph. To do this, one should
first allgn 0 on scale 25 with pointer 26 and then trace out on disk 21:
with the stylus of the pantograph the direction of one of the "drift
lines" 11 of the grid. If the traced line deviates from the direction
of parallel lines 24 on disk 22 by more than 1030' (check with scale 25),
the indicator is not suitable for use and should be sent to repair;
b) check the installation of the indicator in the aircraft (see
part V.).
VII. Storage, Packing, and Transportation
Up to installation in the aircraft, the drift indicator should be
stored in the case in accordance with instructions on storage of
property in technical depots for aviation equipment.
The indicator is transported in the packing case.
On long trips, the packing cases with,the indicators are trans-
ported in a special box. A warning notice must be put on the box.
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