INVESTIGATION OF A TIME DELAY MECHANISM

• Document Type: CREST
• Collection: General CIA Records
• Document Number (FOIA) /ESDN (CREST): CIA-RDP78-03639A000500100001-8
• Release Decision: RIPPUB
• Original Classification: K
• Document Page Count: 32
• Document Creation Date: December 22, 2016
• Document Release Date: May 3, 2011
• Sequence Number: 1
• Publication Date: April 15, 1958
• Content Type: REPORT

Sanitized Copy Approved for Release 2011/05/03: CIA-RDP78-03639A000500100001-8
SF 4
E-t m4L- VZ~OIDIQ~- V:~% t_E
60&W50 V, f1 Lt.0t4) , 61- .LIT - WLjOW
w NVESTIQATION OF A
TIME DELAY MECHANISM
Report to
FREE EUROPE COMMITTEE, INC.
STAT
April 15, 1958
C-60385
STAT
ARTHUR D. LITTLE, INC.
Sanitized Copy Approved for Release 2011/05/03: CIA-RDP78-03639A000500100001-8
 Sanitized Copy Approved for Release 2011/05/03: CIA-RDP78-03639A000500100001-8
April 15, 1958
Free Europe Committee, Inc.
2 Park Avenue
New York 16, New York
Gentlemen: C-60385
We submit herewith our report on the investigation of a time
delay mechanism. We have enjoyed working with you on this
problem and would look forward to working with you once again.
Respectfully submitted,
Sanitized Copy Approved for Release 2011/05/03: CIA-RDP78-03639A000500100001-8
 Sanitized Copy Approved for Release 2011/05/03: CIA-RDP78-03639A000500100001-8
TABLE OF CONTENTS
List of Figures and Table
Pale
iv
I.
SUMMARY
1
II.
INTRODUCTION
2
III.
SELECTION OF DEVICES FOR STUDY
3
IV.
LEAKAGE MECHANISM
14 ~SC-c P, /0)
V.
ELECTROCHEMICAL OR CHEMICAL CORROSION
14
VI.
CLOCKWORK RELEASE MECHANISM
16
VII.
TORSION DEVICE
18
VIII.
RADIOTRIP MECHANISM
20
IX.
BALLASTED RELEASE MECHANISM
21
Appendix 22
Arthur D. Little, Inc.
Sanitized Copy Approved for Release 2011/05/03: CIA-RDP78-03639A000500100001-8
 Sanitized Copy Approved for Release 2011/05/03: CIA-RDP78-03639A000500100001-8
LIST OF FIGURES
AND TABLE
Figure
Number
Page
1
Prototype Design
2
Model III Timer - General Arrangement
2A
Typical Parts Detail - Model III Timer
3
Prototype Timer III - Time vs. Travel
8
4
Comparison of Models - Time vs. Travel
9
5
Electrolytic Corrosion Cell
15
6
Clockwork Release Device
17
7
Torsion Test Jig
19
Table
Number
1 Dimensional Stability Test of Cylinders 11
Arthur D. Little, Inc.
Sanitized Copy Approved for Release 2011/05/03: CIA-RDP78-03639A000500100001-8
 Sanitized Copy Approved for Release 2011/05/03: CIA-RDP78-03639A000500100001-8
I. SUIQART
PURPOSE AND SCOPE
This report summarizes the work done by Arthur D. Little, Inc.
for the Free Europe Committee, Inc. in a feasibility study and design
of a suitable device for the time-delay release of leaflets from balloons.
CONCLUSIONS
1. The most satisfactory device is based on the controlled leakage
of gas in a plastic cylinder-and-piston mechanism driven by the balloon's
load of leaflets.
The device consists of a 1-inch diameter by 4-inch long cylinder
of polyvinyl chloride (PVC). The cylinder contains a PVC piston and piston
rod with a fixed orifice in the piston head to meter the flow of gas
from one end of the cylinder to the other. The top cap of the device
is a hermetically sealed flat PVC disc. The piston rod passes through
a hole sealed by an 0-ring held in the bottom cap of the device. The
load is held by a PVC arm attached to the external end of the piston
rod by a string loop and passed through a plastic eye affixed to the
outer cylinder wail. Thus, the load is hold in position until the arm
travels down to the point for snap-action release. The release time of
the device is set by the initial positioning of the piston within the
cylinder.
2. The existing carbon dioxide release system could be improved
to give more accurate results.
Arthur D. Little, Inc.
Sanitized Copy Approved for Release 2011/05/03: CIA-RDP78-03639A000500100001-8
 Sanitized Copy Approved for Release 2011/05/03: CIA-RDP78-03639A000500100001-8
II. INTRODUCTION
The Free Europe Committee, Inc. is engaged in a program of
dissemination of information behind the Iron Curtain by balloon-borne
leaflets. A time-release mechanism based on the loss of weight by
sublimation of solid carbon dioxide is currently being used to drop
the leaflet load over the proper target.
Since the present release system is inaccurate--some loads have
been dropped as much as 70 miles off target--the Committee asked Arthur
D. Little to study the feasibility of and to design a device that would
meet the following requirements:
1. A timing accuracy of + 5 per cent in a range of 1 to 18 hours.
2. Satisfactory operation at temperatures to -60?F.
3. Satisfactory operation at altitudes to 25,000 feet.
L. Manufacture and assembly costs of not more than $1.00 per unit.
When the Arthur D. Little program was under way, the Committee
advised us of two further requirements:
5. The device should contain no metallic parts.
6. The device must release its load if it fails at any time to
function properly.
study.
These added requirements disqualified some of the devices under
Arthur D. Little, Inc.
Sanitized Copy Approved for Release 2011/05/03: CIA-RDP78-03639A000500100001-8
 Sanitized Copy Approved for Release 2011/05/03: CIA-RDP78-03639A000500100001-8
III. SEIECTION OF DEVICES FOR STUDY
At the first meeting between Arthur D. Little staff and the
Free Europe Committee officials, it was agreed that ADL should select
a variety of release mechanisms based on different principles. These
would be studied with an eye to engineering feasibility, proper
functioning under required conditions, and cost.
The timing mechanisms selected for basic study were:
1. Gaseous or liquid leakage
2. Chemical or electrochemical corrosion
3. Clockwork
4. Torsion creep
5. Radio-signal release
6. Ballast-weight loss
Initial evaluation of these possibilities led us to reject
mechanisms 4, 5, and 6 and to conduct a more intensive study of the
remaining three.
Further study indicated that the gaseous leakage mechanism
most closely met all of the Committee's specifications, and design
and development work on that system was continued.
The design, description, and evaluation of all six systems
are discussed in Sections IV - IX.
Arthur D. Little, Inc.
Sanitized Copy Approved for Release 2011/05/03: CIA-RDP78-03639A000500100001-8
 Sanitized Copy Approved for Release 2011/05/03: CIA-RDP78-03639A000500100001-8 Lt
IV. LEAKAGE MECHANISM
This mechanism is based on the leakage of a gas through a
fixed orifice. Theoretical calculations are given in the Appendix.
Our first prototype of such a?device (shown in Figure 1)
was a metal cylinder capped at both ends. Inside the cylinder was a
piston and rod with the rod extending through one capped end of the
cylinder. In the opposite cap was a needle valve that could be set
for various leakage rates. A helical steel spring in the cylinder
supplied the driving force for the piston, and as an alternative,
we tested a pressurized gas reservoir.
The spring-driven mechanism gave remarkably linear results
of time versus piston travel; the gas-pressured system gave results
that were not as linear. Nevertheless, both systems were believed
acceptable.
We constructed several spring-driven mechanisms and found them
to perform reproducibly both on a single-sample basis and on a sample-
to-sample basis. We then reduced the weight and size by substituting
some plastic parts for metal. The final prototype, was constructed of
PVC with a metal piston, needle valve, and spring (these we kept metallic
for sake of accuracy and reproducibility).
When we were informed of the nonmetallic requirement, we
redesigned the device as follows:
A fixed orifice in the piston replaced the needle valve.
The flow of gas was metered by several layers of filter paper placed
in the orifice and held by a retaining ring.
A plastic piston was built and sealed in the cylinder with an
0-ring. A plastic piston rod was sealed through the bottom cylinder
cap with a second 0-ring. All moving parts were lubricated with powdered
graphite.
The steel spring was eliminated, and the driving force was
supplied by the 4-pound payload.
The payload was suspended in a "U" formed by the piston rod
and a plastic retaining arm attached on one end to the piston rod with
a string loop with its other end passed through a plastic eye affixed
to the outer cylinder wall.
As the piston and rod traveled down the cylinder, the retaining
arm slid through the eye until it fell free and released the load of leaflets.
The final design of this device is shown in Figures 2 and 2A.
Several such units were built and tested for uniformity of performance at
ambient conditions. The results of these tests are shown in Figures 3 and L.
These graphs show that the time-versus-travel function is quite linear
and uniform both within each unit and between unit and unit. On a hand-
made basis, each unit must be individually calibrated. In production,
however, it should be possible to make parts uniform enough so that
individual calibration would not be necessary.
Sanitized Copy Approved for Release 2011/05/03: CIA-RDP78-03639AO00500100001-8 Inc.
 Sanitized Copy Approved for Release 2011/05/03: CIA-RDP78-03639A000500100001-8
NEEDLE VALVE
---PIPE NIPPLE
--LAPPED PISTON
- COIL SPRING
P20TOTY PE DESIGN
Figure 1
Sanitized Copy Approved for Release 2011/05/03: CIA-RDP78-03639A000500100001-8
 Sanitized Copy Approved for Release 2011/05/03: CIA-RDP78-03639A000500100001-8
MODEL-1-II "'IMER
GEMERAL A2RAP.:GEMELJT'
Figure 2
Sanitized Copy Approved for Release 2011/05/03: CIA-RDP78-03639A000500100001-8
 Sanitized Copy Approved for Release 2011/05/03: CIA-RDP78-03639A000500100001-8
BODY TUBE
break-
~ ! --_ - -- ---- - --- -- --- - --
16
- -- - - - -- 1.001 ? .oc 1 1 P
- breaL
break-J
4 1 SCALE FULL
TOP CL05UZE
-
PLUG
- slob
~
1 r- 1/8-40N5 1/32 x 1/16
~T :?
r 1/8-40 N5
break -6
SCALE : FULL
SCALE = GX
P15TCN ROD
-/8 - 24 r
- f
- 32
G. 187 *--.rO1
T_
- -
5 --- -- ?1 SCALE Z X
PISTON-HEAD
BOTTOM CLOSURE
rte! ev_ __I1'3 Z 3/8- 24
r,i r -------
6
1/8 "10N.5 E9
- t
T 32
4
-~ -
1 1 I '~--- -C_1&7 (rl~bd'-
`-
C.2JV ` GcZ
break-1
16
+002
- 000
3
r 0.9 85 ' 005
1/6.1 radius on inside co~r,er _ fi_
~iFa rc1~11u Or +^-a-aP_ ~Grr~F;
k
P
r
riricq c,~rocw~ P_Urker ANN..;
1 r_f provICe .
h227E -3 O r1r;~
ar
e
of -rig Groove
rinC
tc be
d
.
~
ry
r
d
SCALE 2X (BOTH P'_CE. )
p
~ J
G
TYPICAL PAQ.T : DETAIL- -MODEL III TIMED'
Sanitized Copy Approved for Release 2011/05/03 :CIA-RDP78-03639A000500100001-8
 Sanitized Copy Approved for Release 2011/05/03: CIA-RDP78-03639A000500100001-8
t
;.'
r;t
4
~1
t
~I
} 1
'
I
t 1
}
I
+
I
i
i
1 r
{ J
1
{
,
$ 1
1
4-
1
,+tl
i
1 1
+
I
fl
:
I
t
~
+
t
r
}
+
f
t
7
,
I
{ r t
;
i
{ 1
t
1
..
~
_...
I i!
1
1
1 i f
1/
:
1 j
{
'.
t,
!
{
n
?
t,
1 1
,
1 }
W11
!
I
~
}
t ~
I
I I
,
j 1-
;
r
1
:
I -T
.
!S 3 Fi
1~N 1
e
Sanitized Copy Approved for Release 2011/05/03: CIA-RDP78-03639A000500100001-8
 Sanitized Copy Approved for Release 2011/05/03: CIA-RDP78-03639A000500100001-8
Sanitized Copy Approved for Release 2011/05/03: CIA-RDP78-03639A000500100001-8
 Sanitized Copy Approved for Release 2011/05/03: CIA-RDP78-03639A000500100001-8
These devices were sent to the Committee for field testing.
Two were test-flown in the United States. They released considerably
before preset time and were returned to us for examination.' The units
sent to Europe were tested at 25,000 feet with similar premature release.
In addition, it was reported that an obvious bulge appeared in the
cylinder walls which allowed the piston to fall freely.
Since the manufacturer's literature indicated that the plastic
should be dimensionally stable under the imposed conditions, we
conducted several tests of the material. We built several polyvinyl
chloride tubes of the same dimensions as the cylinders, capped one
end, and subjected them to an internal pressure of 14 pounds per square
inch. We checked the dimensions periodically for 2.5 hours. The results
of these tests are given in Table I. Little or no change occurred in
the tube dimensions.
(It is possible that the bulging noted in the European tests
could have come from plasticizer material in the entrapped air. In
view of this possibility, we believe that the parts should be joined
by heat-sealing instead of by organic adhesives. Extreme care must
be used in heat-sealing, however, since heat distortion can result.)
Further examination of the units tested in Europe showed that
gas had leaked between the piston rod and 0-ring seal. This leakage
was corrected by a decrease in the diameter of the hole in the bottom
cylinder cap. Two new devices with the above modification were built
and tested both in vacuum and under water. We found them to be
hermetically sealed.
In low-temperature tests, the units performed satisfactorily
at -20?F but they failed at -400F. This failure was blamed on the
accumulated thermal shrinkage at this lower temperature.
(A discussion of this problem with the Committee resulted in
a decision that material, not mechanical design, should be modified.)
We understand that these two units are now being tested at
reduced altitudes by the Committee.
PRODUCTION
Should the Committee consider future mass production of the
plastic devices, the following recommendations should be considered:
1. The device should not be put into initial large scale production.
Pilot construction of about 1,000 units should be undertaken with tentative
production techniques and tooling. For cylinder construction, such techniques
~f WW 9POo 'rbttSE TSTS Ret 86 0C cuRQo
? T FopUT y, L*Ov 2 14-t1'*4C. ? s fl 1 rJC
w RS "n, t Lrty ur s
Arthur D. Little, Inc.
Sanitized Copy Approved for Release 2011/05/03: CIA-RDP78-03639A000500100001-8
 Sanitized Copy Approved for Release 2011/05/03: CIA-RDP78-03639A000500100001-8
DIMENSIONAL STABILITY TEST OF CYLINDERS
Unit #1
Po
i-
Zero Readin
R
di
t 15 lb
I
t
s
g
---------
ea
ng a
s.
n
ernal Pressure ------------------------~-
tion*
Atmos. P.
13 hr 10 min
13 hr 45 min
14 hr 15 min
14 hr 45 min
15 hr 15 min
15 hr 45 min
la
1.3325"
1.3325"
1.330"
1.330"
1.331"
lb
1.3255"
1.3255"
1.3255"
1.326"
1.3255"
2a
1.3315"
1.3315"
1.3305"
1.3315"
1.330"
1.331"
1.331"
2b
1.3255"
1.325"
1.326"
1.325"
1.3255"
1.325"
1.3255"
3a
1.3315"
1.3325"
1.331"
1.330"
1.3315"
3b
1.3275"
1.3275"
1.326"
1.327"
1.326"
Unit #2
la
1.3295"
1.330"
1.3305"
1.331"
1.330"
lb
1.3285"
1.328"
1.3275"
1.3275"
1.3275"
2a
1.3316"
1.333"
1.331"
1.3315"
1.3315"
1.3305"
1.3305"
2b
1.3287"
1.3285"
1.327"
1.327"
1.327"
1.3275"
1.32711
3a
1.3315"
1.331"
1.330"
1.331"
1.3315"
3b
1.3285"
1.3285"
1.328"
1.3275"
1.3275"
Unit #3
la
1.327"
1.3275"
1.327"
1.3275"
1.327"
lb
1.3285"
1.328"
1.3275"
1.328"
1.3275"
2a
1.3285"
1.3285"
1.327"
1.328"
1.3275"
1.3275"
1.3270"
2b
1.3285"
1.328"
1.3275"
1.3285"
1.326"
1.327"
1.326"
3a
1.328"
1.3275"
1.327"
1.327"
1.327"
3b
1.328"
1.3285"
1.328"
1.3275"
1.327"
* Position la, 2a, 3a indicate equal spacing down cylinder in straight line.
Position ib, 2b, 3b same only rotated 900.
Sanitized Copy Approved for Release 2011/05/03: CIA-RDP78-03639A000500100001-8
 Sanitized Copy Approved for Release 2011/05/03: CIA-RDP78-03639A000500100001-8
TABLE I (Cont.)
DIMENSIONAL STABILITY TEST OF CYLINDERS
Unit
Posi-
Zero Reading
-------------------- Reading at 1 5 lbs. Internal Pressure ---------------------------
tion*
Atmos. P.
13 h r 10 m i n
13 hr 4 5 min
14 hr 15 min 14 hr 45 min 15 hr 15 min 15 hr 45 min
la
1.330"
1.331"
1.331"
1.331"
1.331"
lb
1.3265"
1.3275"
1.326"
1.326"
1.326"
2a
1.330"
1.333"
1.332"
1.331"
1.3315"
1.3315"
1.332"
2b
1.3275"
1.327"
1.328"
1.328"
1.327"
1.327"
1.3265"
3a
1.3315"
1.3315"
1.331"
1.3315"
1.332"
3b
1.3265
1.3265"
1.3265"
1.326"
1.326"
Position la, 2a, 3a indicate equal spacing down cylinder in straight line.
Position ib, 2b, 3b same only rotated 900.
Sanitized Copy Approved for Release 2011/05/03: CIA-RDP78-03639A000500100001-8
 Sanitized Copy Approved for Release 2011/05/03: CIA-RDP78-03639A000500100001-8 13
would probably require precision casting around a polished core. The
other parts probably could be stamped or heat-formed. The orifice should
be moved from the center to one side of the piston. All units produced
in the pilot lot should be tested under actual operating conditions so
that an inspection procedure could be devised that would do away with
the necessity for calibrating each device in production. If the results
of the pilot lot indicate that mass production is feasible, the Committee
should proceed with a limited production with further control testing.
2. The devices should be studied after storage under various con-
ditions so that any distortion may be noted. Cold flow due to forming
stresses in the plastic could change the dimensions. Such a condition
could be eliminated by proper. selection of materials and exact production
conditions.
3. The Committee should consider the use of unskilled labor to
assemble and test the device. A minimum amount of training would be
required.
Arthur D. Little, Inc.
Sanitized Copy Approved for Release 2011/05/03: CIA-RDP78-03639A000500100001-8
 Sanitized Copy Approved for Release 2011/05/03: CIA-RDP78-03639A000500100001-8
V. ELECTROCHEMICAL OR CHEMICAL CORROSION
This system involves the use of either an electrolytic or a
chemical cell. In our study emphasis was placed on the former, since
it was known that such a system is less temperature-dependent than is
chemical corrosion. A preliminary design is shown in Figure 5.
The mechanism of such a cell involved the simultaneous plating
out of silver onto a silver anode and electrolytic corrosion of a metallic
retaining wire. Variations in time could be obtained by a change in
the external resistance of the cell.
This device met the requirements of cost and size but failed
in other respects. Under the best of conditions, we estimated a time
toleranco of not less than + 10 per cent, and with the specified operating
temperature of -60?F, it was doubtful if even this tolerance would be
realized. In addition, since the concentration of the electrolyte
would have to be high so that it would not freeze at the low temperatures
encountered, the tolerance spread would be further affected. Finally,
failure of such a device would most likely be caused by an open circuit.
Thus the mechanism would not release within a reasonable time. We decided,
therefore, that this system would not be studied further. The chemical
corrosion mechanism was known to have even more marked limitations and
was also discarded.
14
Arthur D. Little, Inc.
Sanitized Copy Approved for Release 2011/05/03: CIA-RDP78-03639A000500100001-8
 Sanitized Copy Approved for Release 2011/05/03: CIA-RDP78-03639A000500100001-8
Retaining Wire
Electrolyte
Filler Hole
Nylon Cell
Retaining Wire
(Load End)
15
(SilverBalloon End)
Wire Electrode
coated with AgG1
11
ELECTROLYTIC CORROSION CELL
Figure 5
Timing
Resistor
Sanitized Copy Approved for Release 2011/05/03: CIA-RDP78-03639A000500100001-8
 Sanitized Copy Approved for Release 2011/05/03: CIA-RDP78-03639A000500100001-8
VI. CLOCKWORK RELEASE MECHANISM
The most reliable timing mechanism would be based on a mechanical
clockwork-type device. We realized that such a device would undoubtedly
not meet the low cost requirement, but it was investigated because of its
extreme reliability. A proposed design is shown in Figure 6. After
conferring with clockwork manufacturers and fabricators, we estimated that
such a mechanism could not be produced for less than $1.70, with a more
realistic estimate of $2.00 or $2.50 per unit. In addition, we could
conceive of no obvious mechanism that would fail in the released position.
Therefore, this approach was not pursued. When we learned that no
metallic parts could be employed, it was our feeling that although it would
be possible to construct a clockwork device of nonmetallic parts, the
cost would not be significantly reduced. Furthermore, the mechanism
would be considerably less accurate than a metallic clockwork.
Arthur D. Little, Inc.
16
Sanitized Copy Approved for Release 2011/05/03: CIA-RDP78-03639A000500100001-8
 Sanitized Copy Approved for Release 2011/05/03: CIA-RDP78-03639A000500100001-8
(3)
(8)
(d)
L
(2)
(0)
(1)
Parts Identification
(1)
Clockwork (Westclox Model 66)
(a
)
Setting Knob
(2)
Mounting Frame (Sheet Aluminum)
(b
)
Winding Stem
(3)
Time-Scale Decal
(o
)
Holding Down Lug
(4)
#1 Hour Disc (Stamped Aluminum)
(d
)
Bent Ears
(5)
#2 Hour Disc (Stamped Aluminum)
(6)
Minute Disc (Stamped Aluminum)
(7)
Trip Lever (Bent Wire)
(8)
Rivet or Eyelet
17
Figure 6
Sanitized Copy Approved for Release 2011/05/03: CIA-RDP78-03639A000500100001-8
 Sanitized Copy Approved for Release 2011/05/03: CIA-RDP78-03639A000500100001-8
VII. TORSION DEVICE
This device involved the failure of a soft metallic bar when an
axial force was applied. Such a system might have the design as shown
in Figure 7. We designed a test jig to investigate the reliability of
such a system. Initial results with a 50/50 tin-lead-solder mixture
showed that the rate of creep was remarkably linear. We decided, however,
that the investigation of such a mechanism should be put aside in favor
of other mechanisms, since such a development would involve a lengthy
study of soft metallic alloys. In addition, even if a device could be
developed along these lines, a severe quality-control program would be
encountered in production, since nondestructive testing and calibrating
of such a device would be quite difficult.
Arthur D. Little, Inc.
18
Sanitized Copy Approved for Release 2011/05/03: CIA-RDP78-03639A000500100001-8
 Sanitized Copy Approved for Release 2011/05/03: CIA-RDP78-03639A000500100001-8
Rotating End
Torsion Bar
Figure 7
19
Sanitized Copy Approved for Release 2011/05/03: CIA-RDP78-03639A000500100001-8
 Sanitized Copy Approved for Release 2011/05/03: CIA-RDP78-03639A000500100001-8
VIII. RADIOTRIP MECHANISM
A radiotrip device could be designed which, on receipt of a
fixed control signal, would activate a release mechanism. However, such
a mechanism would require an internal power supply that would be costly
and heavy and would offer a supply difficulty. In addition, the success
of such a mechanism would require a knowledge of the exact location of
the balloons and a different signal for each balloon or group of balloons.
Arthur D. Little, Inc.
Sanitized Copy Approved for Release 2011/05/03: CIA-RDP78-03639A000500100001-8
 Sanitized Copy Approved for Release 2011/05/03: CIA-RDP78-03639A000500100001-8
IX. BALLASTED RELEASE MECHANISM
The release mechanism originally employed by the Free Europe
Committee involved a ballasted release mechanism activated by the loss
of weight of dry ice by sublimation. Other such mechanisms utilizing
the leakage of solid or liquid materials could be visualized. Considerable
thought was given to a liquid-leakage mechanism, since there are known
liquids that have little viscosity temperature change. However, for
operating times up to 18 burs, the amount of liquid required would
weigh too much.
We believe that the original carbon dioxide system could be
improved to the point where its time tolerance would be acceptable.
The first approach to such a redesign would be to cast the solid carbon
dioxide in a cylinder for a more stable sublimation rate. This would
be consistent with the practice employed by the manufacturer of propellants
for control of burning rates. Other improvements would include the
substitution of pinpoint fulcrums for the original looped hinges in the
wire release mechanism. It was felt that by such minor changes, the
original low-priced mechanism would then be made acceptable. It is
our understanding' that other considerations have caused this approach
to be eliminated.
Arthur D. Little, Inc.
Sanitized Copy Approved for Release 2011/05/03: CIA-RDP78-03639A000500100001-8
 Sanitized Copy Approved for Release 2011/05/03: CIA-RDP78-03639A000500100001-8
APPENDIX
Sanitized Copy Approved for Release 2011/05/03: CIA-RDP78-03639A000500100001-8
 Sanitized Copy Approved for Release 2011/05/03: CIA-RDP78-03639A000500100001-8
APPENDIX
Time as a Function of Distance of Travel
DERIVATION
With reference to the diagram, we establish the following relations:
L
D
V
0
Volume at any time t
V - a(D-s) + V
0
Volume at any time t
area of piston
distance between position of piston at time t
and its position at rest, i.e., when flow through
orifice has ceased
Distance between initial setting (t - o) and at rest position
Volume of gas retained in cylinder at rest position
Force on piston at any time t
Force of atmosphere + Force of spring
Force exerted by gas + Force of friction
apa + k(D-d) - ap + F
(1)
(2)
23
Arthur D. Little, Inc.
Sanitized Copy Approved for Release 2011/05/03: CIA-RDP78-03639A000500100001-8
 Sanitized Copy Approved for Release 2011/05/03: CIA-RDP78-03639A000500100001-8
pa atmospheric pressure
k - spring constant
p pressure of contained gas
F - force of friction
Relation between Pressure, Volume, and Mass of Contained Gas
PV - M RT
where m - mass of contained gas
M - Mlecular weight of gas
Flow Through Critical Orifice
For a critical orifice the mass rate of flow is directly proportional
to the upstream pressure, i.e.
at
where c is a constant for the particular gas and orifice (also involves
orifice area and temperature of gas).
A relation between elapsed time and piston position was derived from
the above equations in the following manner:
From (3) by differentiation
dv + Vd~ - RT dm
d dt M ME
substituting (4) in (5) and re-arranging
dt - RM cp - p d
Differentiation of (2) yields
-k adt
(3)
(4)
(5)
(6)
(7)
24
Arthur D. Little, Inc.
Sanitized Copy Approved for Release 2011/05/03: CIA-RDP78-03639A000500100001-8
 Sanitized Copy Approved for Release 2011/05/03: CIA-RDP78-03639A000500100001-8 25
also from (2)
Differentiation of (1) yields
Substituting (1) (7) (8) and (9) in (6)
k ds
a Bt
p k(D-s) +apa - F
+ Vo [icia
[a(D_s) + V 0I +
separating variables
kV
k(D-e) ds + do
a
k(D-d) + apa -F
a#
+ an a -
+ ds ` RTC dt
+ (F_apa) ln(F-apa -Qo
(8)
(9)
apa
For ease of integration let Q ? k(D-s) dQ - - kda do - -dQ/k
Q+apa -F
Integration yields
RCT dt
am
k y -apa -Q -(F-apa)ln(F-aPa-Q)-Y + apa+Qo
+ a? [,1 ln(F_apa-Q) + ln(F-ap -Q;i_ Q + Qo
a o
-
(Qo-Q) + (F-apa)
r V
In F-a
Pa- -4o) + V?
(-atep ) a a-Q
RTC do
- dt
RCT
aM
(F-apa-Qo) RCT
in t
Arthur D. Little, Inc.
Sanitized Copy Approved for Release 2011/05/03: CIA-RDP78-03639A000500100001-8
[k(D-s) + apa - F I
 Sanitized Copy Approved for Release 2011/05/03: CIA-RDP78-03639A000500100001-8
+ Vo In F-a & - kD)
a F-ap8 k(D-8)
F-ap
V-] 28 + k a + In
+ a
F-apa
0.533 Ac'
T
0.533 - constant for air and nitrogen
T - Absolute temperature in OR (OR - OF + 460)
A - Area of orifice in in2
CI - 1 (approx.), has units of ( oR/sec
R - 18,540 ( lb-in
R )
T - OR (OR - of + 460)
a - in2
M - lb
then s will be in inches
Expressing t in hours we obtain
2.81 x 10 8 A j
rr-
1+ a
P-ap
For nitrogen M 28.0 At 70OF T - 530
t - 3-43x10-8 a
f2a
rF_ap a Vo
I
26
Sanitized Copy Approved for Release 2011/05/03: CIA-RDP78-03639A000500100001-8 T__
F-ap a
 Sanitized Copy Approved for Release 2011/05/03: CIA-RDP78-03639A000500100001-8
Application
Preliminary calculations indicated that the volume of a cylinder would
have to be very large in order to achieve an elapsed time of 15 hours with
an orifice of any reasonable size, i.e. 10-6 in' , the latter being taken as
a lower limit. An example follows:
Assumptions
Dimensions of cylinder - I.D. - 2 ins
D. - bin
Spring constant k - 25 lb/in (This would result in a maximum
abs. pressure of 100 lb/in2)
Pa - 14.7lb/in2
F - 5 lb
t - 15 hrs
a - 3.14 in2
a - D - lain
V O - 0
3.143x10-8x3.11;
15
7.18x10-9
7.00 x 10-8
(a
{a
i
4 In
+ r
+ 1.613 In 0.315)
5-1;6.1
25
-4
Thus the annular space of the orifice (assuming it consists of a
needle valve)can only be 7 x X0-8 in2?
The area for the annular space is given by
A - -C (D2 - D22)
D1 - diameter of orifice
D2 - diameter of needle
Given D1 and A
D2 - D 2
1 - A
A..J. 1,.... n T4+i1 Inc.
Sanitized Copy Approved for Release 2011/05/03: CIA-RDP78-03639A000500100001-8
27
 Sanitized Copy Approved for Release 2011/05/03: CIA-RDP78-03639A000500100001-8
Using 12.5 x 10-3 in. as an orifice diameter (smallest drill readily used
and available)
D2 -\156.25 x 10-6 - 8.92 x 10-8
1.546 x l0-4
- 12.4996 x 10-3 inches
That is, the diameter of the needle would have to be 4 ten millionths of
an inch smaller than the diameter of the orifice to achieve a fifteen-hour
time interval.
28
Arthur D. Little, Inc.
Sanitized Copy Approved for Release 2011/05/03: CIA-RDP78-03639A000500100001-8