IN ACCORDANCE WITH YOUR REQUEST WE HEREWITH RESPECTFULLY SUBMIT A PROPOSAL TO DESIGN AND CONSTRUCT FOUR LIGHTWEIGHT COLLAPSIBLE LENSES.

• Document Type: CREST
• Collection: General CIA Records
• Document Number (FOIA) /ESDN (CREST): CIA-RDP78-03172A000200040029-6
• Release Decision: RIPPUB
• Original Classification: C
• Document Page Count: 7
• Document Creation Date: December 22, 2016
• Document Release Date: February 21, 2012
• Sequence Number: 29
• Publication Date: June 4, 1957
• Content Type: LETTER

Declassified in Part -Sanitized Copy Approved for Release 2012/02/21 :CIA-RDP78-03172A000200040029-6
~""(~iV~`~~~1, l/'~V 25X1
June 4~ 1957
In accordance xith your request xe herexith respectfully
submit ~,a proposal? to design_ and, ,c~t.~..~o,.,~.t,~e,~i,ght
collaps~.lle lenses.~g~~
The price for these units xould be $ 9865.00 F.O.B. Aash-
ington D. C. and xould include reproducible draxings and
six (6~ copies of an instruction manual xith photographs
of the units.
Delivery xould be xithin five (5) months from the date of
contract.
Very truly yours
L1 ~u~ BYE
DD~R Y DATB ~
ORIG CDb9P OPI t1fPE
C~ftEG DLA55 PAGES ftEY CLSlSS
"L NEXT REY~~ At11~Hs NR 75.2 1
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Declassified in Part -Sanitized Copy Approved for Release 2012/02/21 :CIA-RDP78-03172A000200040029-6
 Declassified in Part -Sanitized Copy Approved for Release 2012/02/21 :CIA-RDP78-03172A000200040029-6
Declassified in Part -Sanitized Copy Approved for Release 2012/02/21 :CIA-RDP78-03172A000200040029-6
 Declassified in Part -Sanitized Copy Approved for Release 2012/02/21 :CIA-RDP78-03172A000200040029-6
Lightweight Collapsible Lens
L J
~:C~NFiENTIAL
Declassified in Part -Sanitized Copy Approved for Release 2012/02/21 :CIA-RDP78-03172A000200040029-6
 Declassified in Part -Sanitized Copy Approved for Release 2012/02/21 :CIA-RDP78-03172A000200040029-6
ILLEGIB
Lightxeight Collapsible Lens
June 4, 1957
1.0 Statement of the Problem.- A desire has been expressed
to design and manufacture a lightxeight, collapsible lens
barrel mo~mt for the fs6.3, 4U inch Astro lens. The
present collapsible lens mount, xhich utilizes part of the
standard Astro lens mount, xith aluminum tubes and machined
aluminum mounting rings, xeighs appraac3mately 20 p?unds.
Tt is understood that to save xeight the iris diaphragm
assembly may be eliminated. A goal of 8 pounds has been
set. The xeight of the glass elements is estimated as 4.5
pounds.
Z.C Approach to a Lightxeight Design.- The present lens mount
design is the result of several compromises dictated by
the folloxng facts:
(a} The tub3s-g sizes chosen xere made from the
very limited available sizes.
(b) ~Trnught aluminum alloy xas used for the tube
ring sections.
(c) The front part of the standard Astro mount
xas used to preserve the diaphragm assembly.
To reduce xeight to the exteat desired, extremely careful re-
design becomes necessary.
ii'e have analysed the problems of xeight reduction in this de-
sign on the basis of the folloxing criteria:
(a) The best material choice.
Declassified in Part -Sanitized Copy Approved for Release 2012/02/21 :CIA-RDP78-03172A000200040029-6
 Declassified in Part -Sanitized Copy Approved for Release 2012/02/21 :CIA-RDP78-03172A000200040029-6
ILLEGIB
(b) The best fabr3.cation methods using the
chosen material.
2.1 Comparison of Ph~rsical Constants of Available Mater3.als.-
The f olloxiag is a tabulation of pertinent facts on varioes
available mater3.als a
Material
Density
1bs/in3
Modulus
~ E1ast
psi x 10
nEn
"P" to
Density
Ratios
Aluminum A1.3.oy
0.09?
10.0
1.03
' Steel
0.284
28.5
1.00
' Magnesium
0.063
6.5
1.03
Fiberglas 8c 8esia
0.061
1.7
0.28
2.2 Choice of Material.- The tabulation above sho~rs aluminum
alloys steel and magnesium to have near]y identical modules
of elasticity to density ratios. Glass reinforced plastics
appear to be xe11 belox the other four.
An analysis for minimum tube xa11 thickness xith aluminum
shoxs that a section of .002 in. xould 3ust buckle wader
the assumed loads of structure xeight~ 1ens~ and camera
loads. This is probably a conservative estimate since it
assumes that the tube ends are not constrained.
Since the critical buckling moment is a function of the
square of the xall thickness, a reasonable xa11 of, for
example .015 in. xould produce a section xhose critical
moment is 50 times that xith the minimum xa11 thickness
above.
2.2.1 Fabrication Considerations.- The foregoing analysis
c
Declassified in Part -Sanitized Copy Approved for Release 2012/02/21 :CIA-RDP78-03172A000200040029-6
 Declassified in Part -Sanitized Copy Approved for Release 2012/02/21 :CIA-RDP78-03172A000200040029-6
ILLEGIB
indicates that vary thin walls may be used in the
tube sections. Since the walls have a finite 13ait,
due to fabrication methods, titanium would appear
to be the best choice, magnesium next, and aluminum
third. Titanium would be difficult to obtain and
fabricate. 1~Sagnesium is hazardous to machine, and
all of the tubes would require castings. Aluminum
alloy appears to be a quite satisfactory choice for
the tubes. These tubes could be wrought tubing machined
to the proper thiclrness, butt welded, wrapped sheet
material, or spun alucainum sections.
2.3 Proposed Design.- A restatement of the problem has both
permitted, and required a chaage in the design concept.
It is cow believed that a preferred design would have
the following features
(a) Telescoping lane barrel sections will
be fabricated by spinning aluminum
tubes, with end flanges.
(b) The end flanges will be reinforced with
thin rings.
(c)
Bevy?net pin couplings with either cam or
spring loading will be used to couple tube
sections.
(d) The lens barrel would fit either the ~ca~kta
or the Alpha 35 mm cameras.
(e) A simple cam focusing device of liwtited
range, as unaffected by dirt as possible
.would be provided.
(f )
c
The elixination of the iris diaphragm and
the use of approximately seven tube sections
and a hoods should permit a total collapsed
Declassified in Part -Sanitized Copy Approved for Release 2012/02/21 :CIA-RDP78-03172A000200040029-6
 Declassified in Part -Sanitized Copy Approved for Release 2012/02/21 :CIA-RDP78-03172A000200040029-6
ILLtI~IB
w~C~~~i~~i'~~iAt-
length of about seven inches. This
feature has been lade possible by the
use of the spun tube sections and a
simple bayonet lock fcs" each section.
At the same time it is estimated that
the total weight including the glass
elements xi11 be under eight pounds.
0
~~~(AL
Declassified in Part -Sanitized Copy Approved for Release 2012/02/21 :CIA-RDP78-03172A000200040029-6