MONTHLY PROGRESS REPORT - ENGINEERING PROGRAM FOR THE PILOT PRODUCTION OF A LIGHTWEIGHT ANTITANK WEAPON

• Document Type: CREST
• Collection: General CIA Records
• Document Number (FOIA) /ESDN (CREST): CIA-RDP78-03642A000800060007-0
• Release Decision: RIFPUB
• Original Classification: S
• Document Page Count: 18
• Document Creation Date: December 27, 2016
• Document Release Date: August 8, 2011
• Sequence Number: 7
• Publication Date: July 1, 1960
• Content Type: REPORT

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_&K_"T__
HESSE-EASTERN
L
A DIVISION OF/ /-~
FLIGHTEX FABRICS INC.
((,*
SS.
No= It -LIN
EVERETT ASS. 9
REPORT NO. 7--60-50G-1 I I
MONTHLY PROGRESS REPORT
ENGINEERING PROGRAM FOR
THE PILOT PRODUCTION OF A
LIGHTWEIGHT ANTITANK WEAPON
L
A
CONTRACT NO. RD-I42
ORDNANCE PROJECT NO.
DEPT. OF ARMY PROJECT NO.
This document contains information affecting the
national defense of the United States within the
meaning of the Espionage Laws, Title 18, U. S. C.,
Sections 793 and 794. The transmission or the
revelation of its contents in any manner to an
unauthorized person is prohibited by law.
~~Gv ~i~/8/Go
COPY No.
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Hesse--Cas-tern SECRET 7-60-50G-iii
L S S E - E A S T E R N D 1 V I S1 ON
FLlGHl'EX FABRICS INC.
PROGRESS REPORT #3
Iv'G 1 NEER { NG PRO
OF
A LIGHTWEIGHT ANTITANK ROCKET
JULY 1960
CONTRACT NO. RD-142
PREPARED BY: ~l1 ?..;3 ~': , ~, / ^ ~,. (:.,~ t%'?!~
APPROVED 8Y: ?--~ ~ a=(~ ~ ~ ? ~ '... , ~
Thomas H. Forman Charles B. Weeks
Project Engineer General Manager and
Technical Director
SUBMITTED BY: HESSE-EASTERN DIVISION
FLIGHTEX FABRICS, INC.
EVERETT, MASSACHUSETTS
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fiORK ACCcMPL [SHED DUR i NG THE MONTH OF JULY 1960
SYSTEM EVALUATION PROGRAM
Production on complete launcher assemblies was started in July with the
first batch of 280 launchers delivered to the J-2 Range. The production
of the first batch was followed by a short period of evaluation and clean-
up of different areas in which better methods appeared to be required.
Pr-oducflon was resumed during the last week of the month. It is expected
that the flow of launchers can now be kept up until the full quantity has
been assembled.
The first batch of 266 HEAT heads was inspected at the subcontractor's
premises and found to be acceptable. The heads are presently at the J-2
Range, and pouring operations have started. Some minor difficulties have
to be overcome before the production of heads will reach the required rate.
The proof test as mentioned in last month's report was conducted on 22 July.
Ten complete systems were assembled and fired at both extremes of tempera-
ture. This brought to light the biggest problem yet encountered; one of
the ten fuzes failed to arm, and examination showed that it had "bounced."
The round containing this fuze was fired at hot temperature.
Action was
taken to remedy this situation. (See Fuze section of this report.)
Acceptable igniter parts have been received; however, the full quantity is
not yet on hand.
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The train functioning fixture has been redesigned, and the necessary number
of components has been manufactured. Testing will be done very shortly.
FUZE EVALUATION PROGRAM
Since the biggest problem encountered was the fuze, this will be discussed
first. As already stated in the introduction to this report, one fuze
fired at hot temperature bounced, i.e., the triggering sleeve released the
firing pin immediately after the triggering components were set back.
The parts were recovered, and a very thorough investigation was immediately
initiated. The only difference,which was soon found, between the R&D lot
of fuzes and the fuzes assembled for the pilot production was the supplier
of-the--firing-spring. This spring was examined and a comparison made
between it and springs left over from the R&D lot. it was found that the
new springs are an average of .025" shorter than the old ones. The records
from past firings were examined, and it was found that over sixty fuzes
had been fired at the hot temperature without malfunction. It must, how-
ever, also be pointed out that the last problem during the research and
development phase of the fuze was the problem of bounce at the high tempera-
ture. The difficulty was solved during the R&D phase by adding to the
thickness of the lead at the base of the inertia element. The hardness and
composition of the lead washers was examined and compared to the old lot.
No significant difference seemed to appear between the two.
In looking at the R&D program it was found that the static test, consisting
of dropping the fuze on its base from a height of 35 feet onto a heavy
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steel base, had been given up, since it was found that fuzes which would
bounce when subjected to this test would function properly under all
operating conditions in the rocket.
When trying to re-evaluate the fuze design, these facts were all taken into
consideration. It was concluded that the R&D lot of fuzes may have been
very much nearer to the bounce condition than was formerly believed. The
35 foot drop was re-established in order to come to some better understand-
ing of factors involved in creating this condition.
This work is not as yet complete, but enough evidence appears to be on hand
to conduct another firing test. This test will consist of using the same
components as before and changing the firing spring only back to the ori-
ginal length. It should be stated here that this change in length was
unintentional, and the new and shorter springs had slipped through the
numerous careful checks which are being made on all components in order to
determine not only whether they are according to print. but also whether
the print conforms to the parts as previously used.
The reason for deciding on this test was the fact that some other approaches
which were tried and statically tested did not show a sufficient improve-
ment to warrant their incorporation. Every effort will be made to deter-
mine at what temperature the fuze will start bouncing, regardless of the
final configuration which will be used. It is entirely possible that the
change to the longer spring will bring the fuze back into the 100% operating
condition. It is not felt that this would be sufficient. The main reason
for this is the fact that It is too dangerous to work at an unknown distance
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Hesse-Eastern
from some margin which, if overstepped in some manner, will create
conditions under which failures will be experienced.
A number of modifications to the lead backing of the inertia element have
been tried in an effort to absorb some of the energy upon setback by
deforming material. in order to clarify the situation and to refresh the
reader's memory, the bounce condition will be briefly described below
before we proceed to describe the modifications which are being tried out
at the present time.
A small steel sleeve (triggering sleeve) is used in conjunction with a
groove of spherical contour in the firing pin to prevent the firing pin
from being pushed into the detonator after the fuze has armed. Prior to
firing,this sleeve and the restraining balls and firing pin are in a for-
ward position so as to cause the rotor to be held in the unarmed condition.
When the round accelerates, the triggering components, which include the
triggering sleeve, are forced back against the base of the fuze. The
three restraining balls are housed in a component called the inertia
element. This inertia element is the part which makes contact with the
base of the fuze. The triggering sleeve is housed in a groove in this
inertia element. However, once the triggering sleeve has moved back from
the extreme forward position, it is free to move forward, restrained only
by the friction created by the pressure of the restraining balls,. which
are being pushed forward by the firing pin as the firing spring is being
compressed. Since the balls are housed in the inertia element in a manner
permitting them to move outward only (except for some play in the holes
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which house them), the force of the firing spring is deflected sideways
and acts as friction between the balls and the triggering sleeve. When
the components hit the base they are suddenly decelerated. This decelera-
tion is a value which is very much larger than any friction encountered
by the components. Since the components cannot move back any further,
they all tend to bounce forward again aided by the action of the firing
spring, which is now in the compressed state. The inertia element itself
is held from continuing forward by the latch spring. However, the trigger-
ing sleeve is held only by the friction of the balls. If the "bouncing
force" is greater than this friction, the..sleeve will move forward.
Should It move beyond a certain point, the firing pin will be released
and driven into the rotor. The rotor is thus prevented from arming.
One more factor has to be considered: if the action described above is
completed soon enough, the rocket will still be accelerating, which will
prevent the triggering sleeve from moving forward due to "G" loading.
This condition does exist in only a very minor degree when the fuze is
being dropped on its base against a solid steel base.
When firing at the hot temperature, the acceleration is over In from .008
AMMMU
to .012 seconds. Cold rounds will accelerate from .015 to .020 seconds.
The above should help to'show the.difference which exists between simulated
and actual firing conditions. The following modifications were tried
statically:
1) A series of indentations caused by twisting the end, of a small
knife after cutting .020" into the lead.
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2) A series of center punch marks.
3) Cementing sand particles to the end.of the inertia element (on
top of the lead).
4) A spacer behind the short firing spring.
5) The fuze as tested 22 July.
6) The fuze as tested 22 July but using the long firing spring.
7) Either spring and annular grooves skived into the lead causing
lead rings which have to be deformed.
8) Knife cuts I n lead.
The following is a tabulation of the test results:
Fuze Static Drop Test
Drop Height: 35 feet
Base Material: Steel
Date Inertia Element
Results
1) 7/22 Knife cuts in lead washer. Inertia element set back - rotor
armed-OK.
2) "
4) "
Inertia element set back - rotor
partly armed - bounced.
Center punch marks in lead Inertia element set back - rotor
washer. armed-OK.
5) " Sand particles cemented on Evidence of setback - inertia ele-
lead washer. ment did not latch.
8) "
9-17): "
Inertia element set back - firing
pin fired back Into hole- bounced.
Knife blade point twisted in Inertia element set back - rotor
lead washer. armed - OK.
Same as above.
Rotor armed - approx. 12 dimples
squashed up - OK.
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Results
18) 7/22 Knife blade point twisted in Inertia element set back - firing
lead washer. pin fired back into hole - approx.
10 dimples squashed - bounced.
19) 7/25 Knife blade point twisted in Bounced? Rotor turned approx. 45?;
lead washer - spacer behind approx. 15 dimples squashed.
spring.
20) " Same as 19). Bounced? Rotor turned approx. 15?;
24)
25)
26)
27)
28)
29)
30-38)
39-40)
41-48)
49-64)
Date Inertia Element
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approx. 13 dimples squashed.
OK - Approx. 14 dimples squashed.
OK - Approx. 15 dimples squashed.
OK - Approx. 13 dimples squashed.
OK - Approx. 12 dimples squashed.
OK - Approx. 12 dimples squashed.
OK - Approx. 14 dimples squashed.
OK - Approx. 12 dimples squashed.
OK - Approx. 12 dimples squashed.
Heavier spring - lead as is. Bounced (into same hole).
IT It It " it OK
New spring (unplated) -lead Bounced (into same hole).
as is.
Same as 39-40). OK
New spring (unpiated) - OK
annular grooves (2) in lead.
65) " Same as 49-64). Bounced - Rotor turned 15?.
66) tt it 't 't Fired.
67-68) tt It It it Bounced.
69) 7/26 New spring (unplated) -lead Bounced.
as is.
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Date Inertia Element
70-78) 7/26 New spring (unplated) -lead OK
79-8C)
81-88)
as is.
Old spring - lead as is. Bounced.
Same as 79-80). OK.
Results
The following is a table summarizing the results:
OK
Boul2r
Partly Armed
Total
Knife cuts only
I
I
2
Center punch
I
I
2
Sand particles
2 (not set
back)
Knife blade twisted
Knife blade twisted-
2
spacer behind spring
8
2
10
Heavier spring (spacer)
9
1
10
New spring (unplated)
New spring - annular
8
2
10
grooves
18
1
1
20
New spring
9
1
10
Old spring
9
2
-
10
75
9
4
88
As can be seen, there is no very significant difference between the modifi-
cations which were dropped in greater numbers. The sand particles may still
require investigation, since in this case the sand coating was too heavy and
prevented the fuze from latching together.
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The results of these static tests were interpreted in the following way:
1) Unless a combination of modifications is found which produces no
failures when dropping a test lot of 10 or more, a firing test with
the longer spring is indicated. This test should be conducted at a
temperature higher than the maximum which will be used in testing
samples from the pilot production lot, on the theory that the accelera-
tion will be over sooner on hotter conditions and bounce may therefore
occur more readily.
2) Investigation of the problem should continue at the highest priority
on the project, and, if possible, a combination of modifications which
surpass the present design in reliability should be found. When the
test under l) above has been conducted and static tests with an opti-
mum combination have been carried out, the results of both should be
considered before a decision is made to proceed with fuze production.
3) In order to run these tests, some of the components for the pilot
production will have to be used up. New components will be ordered
as soon as the scope of the tests and the number of additional compon-
ents, as well as the number of components used up In tests, ere known.
Work has started on the possibility of putting a small cushion behind the
triggering sleeve in order to minimize bounce. Theoretical evaluation of
this possibility has shown that it has great promise. Drop tests (static)
will be conducted as soon as feasible.
L-1 L
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PILOT PRODUCTION
PROOF T ST NG OF TE LO SYSTEMS
The pilot production is now in full swing with all subassemblies being
worked on and with propellant loading having been started at the J-2 Range.
The loading of the heads is also in the first stage.
Ten complete systems were fired at -20? and 1120?F. on 22 July. Some
difficulties were encountered in assembling the inner tubes into the
launcher tube. For this reason no screws were used to hold the outer and
inner tube together. Investigation has shown that this was caused by some
oversize inner tubes. These are being centerless ground to the correct
size. The drawing has been changed to take care of such a situation.
The size of this tube is a stock size, i.e., no machining is being per-
formed on the O.D. or the I.D. The drawing now calls for centerless grind-
ing the O.D. in case it is oversize. No more than .003" can be removed in
order not to weaken the wall of the inner tube.
The only other difficulty which is of any significance in this test is the
fact that the new launching fixture gave some trouble when firing one of
the cold rounds. This condition could be eliminated by having one of the
actuating shafts of the fixture run in a bronze bearing. This work has
already been carried out, and the fixture should give no further trouble.
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The following tabulation shows the results of the proof test. All rounds
were fired against a steel target at 50m range and 900 obliquity.
Proof Test
Head:
Motor:
Propellant:
HEAT (Dummy Booster)
New (Harvey)
New Final Lot
7 21
No.
60
Description
Temp.
Travel
Trigger
Pull
Scale
955
Component Functioning
(steel plate @50m)
(Final)
-20?F
.236
17#
-20?F
.230
160
-20?F
.231
20#
-20?F
.231
l8#
-20?F
.234
19I#
t120?F
.253
t120?F
.241
t120?F
.249
t120?F
.240
t120?F
.240
14#
Results
Ignition, flight, and
Because of high trigger
pull, some trouble pulling
off. Tube spit out (no
screws & nuts). Fuze OK.
Ignition, flight, and
fuze OK.
OK on ignition and flight,
but fuze bounced.
As far as the fuze malfunction Is concerned, this has already been discussed
in the Fuze section of this report. The launcher and motor worked satisfac-
torily. Dummy boosters were used in order to be able to evaluate the fuze
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results without danger to personnel. No information is available, therefore,
as to the function of the head. However, after conducting the planned train
functioning tests and the static test, comparing the new (pilot production
lot) to the old (ROD tot) heads, this should not present any great problem.
EA &P PRACTICE && MO-DULTION
The first shipment of 266 HEAT heads was inspected by the writer at the
manufacturer's plant. The heads were found to be acceptable; fifty heads
were checked for critical dimensions and found to be well within limits.
The rate at which the supplier is producing these heads, however, is most
unsatisfactory. This was strongly pointed out to them, but there Is little
hope of any Improvement. At the present rate, It looks as though the whole
order of heads will not be complete before September. This should not
necessarily interfere with the production schedule as planned, but it pro-
duces some additional difficulties, since It was originally planned to pour
and x-ray all the heads and to be done with this work early In the final
loading stage. In this way less personnel would be required to assemble
the systems.
The practice heads have been completed and are awaiting painting. A new
test schedule is being added to the specifications to take care of the fact
that that the practice rounds contain no fuzes. The graze test will be
eliminated from this schedule, and the rounds thus saved will be used for
additional shoulder firing.
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Hesse-Eastern
FUZE PRODUCTION
Pilot production of the fuze has proceeded satisfactorily as far as the
rate of assembling fuzes is concerned. One lot of 250 fuzes has been
assembled. No holdup is expected once the present problems have been
resolved. However, no more fuzes are being assembled until a decision
has been reached as to what course of action to take. (See Fuze section.)
LAUNCHER PRODUCTION
One batch of launchers was completed and sent to the J-2 Range during the
month. After carefully evaluating any small problems in production and
making some small changes in the procedure, production has been resumed
and Is currently proceeding smoothly.
A Change in procedure which,is of importance should be mentioned. This
consists In the fact that the checking out and selecting of travel,spacer,
etc. in the igniter assembly has been changed In such a way that most of
this work, with the exception of loading the black powder, is now going to
be done at Everett and not at the range. This will save some costs, since
range labor is more expensive than shop labor.
GNITER PRCDUCTION
The supplier of the Igniter parts is now setting up to finish the whole
order. Some problems have been experienced with this supplier (problems
with suppliers seem to be very common these days). The samples submitted
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early in the month wers moat asrlsfactory, but when the first batch of
igniter parts was received, it was found in inspecting them that the hole
in the cross piece was undersize and that the parts could not be assembled
for this reason. Remedial action is being taken, but a considerable delay
has been experienced. A sufficient number of igniter samples was on hand
to make it possible to conduct the proof tests and to prepare for the forth-
coming fuze tests.
Several hundred motors have been received from Harvey Aluminum. Inspection
has shown these motors to be acceptable. Some problems with the hydrotest
fixture have temporarily stopped the flow of motors. However, it is expected
that motors will be available in sufficient quantities for loading when
required.
PACKAGE
The necessary improvements to the canning machine have advanced to the point
where a final check-out only is required before it can be sent to the range
for installation and use.
DYNAMIC TEST SET -W
All components have been made and delivered to the test site. The set-up
now needs to be assembled and made ready for acceptance tests.
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