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Spec. 94-3040, "Jacket, Flying, Type A-2"
- Thread starter 33-1729
- Start date
The original 33-1729 Werber that Gary Eastman and John Chapman owned seemed like cotton. Silk was before then if used.
http://vintageleatherjackets.org/threads/original-1933-werber.19791/
http://vintageleatherjackets.org/threads/original-1933-werber.19791/
It may actually be spun silk for as Ken says "It's not easy to tell Spun Silk cloth from Cotton cloth if the weave spec is the same FACT".
Ken at Aero Leather
Well-Known Member
The last time Silk v. Cotton hit the "net" the discussion got quite nasty, this thread has produced nothing but positive info, thanks to all.
Great info from 1935 from Ole, looks like (what I always suspected) that silk was used on (all?) early contracts and dropped for cost, or more likely for ease of cutting, in later, larger contracts.
Laying up cloth for cutting with an industrial machine https://3.imimg.com/data3/XU/OM/MY-3299941/needle-plate-250x250.jpg is relatively straightforward with cotton, little movement and very stable stack, silk on the otherhand, even spun silk is much trickier to work with. Collar stands must have been a nightmare :>)
500 piece order, across say 5 sizes maybe , that's 100 layers of cloth..............I'd much prefer to have been using cotton!
Now we need to wait for the Wright Field letter....................
Great info from 1935 from Ole, looks like (what I always suspected) that silk was used on (all?) early contracts and dropped for cost, or more likely for ease of cutting, in later, larger contracts.
Laying up cloth for cutting with an industrial machine https://3.imimg.com/data3/XU/OM/MY-3299941/needle-plate-250x250.jpg is relatively straightforward with cotton, little movement and very stable stack, silk on the otherhand, even spun silk is much trickier to work with. Collar stands must have been a nightmare :>)
500 piece order, across say 5 sizes maybe , that's 100 layers of cloth..............I'd much prefer to have been using cotton!
Now we need to wait for the Wright Field letter....................
Ken at Aero Leather
Well-Known Member
Tibor............Andrew is correct, unless you've presonally handled and touched the lining there is no way you could identify Spun Silk from Cotton, especially in a photograph!!
Even after handling the cloth I think 99% of us would find it impossible to be sure.
Good match... you're right, it looks very much like the cotton, but if it's silk, I bet it stretches a bit more and is tricky to work with. It still looks like it has pretty coarse fibers, which seems more cotton/linen-like, but I've not been around silk variations from the period to know better. Very interesting.
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33-1729
Well-Known Member
Mr. Weinshenker thought the spun silk lining in a 2000 Aero may have had a "slickness to it" compared to cotton, but was also very clear that if not told it was silk he wouldn't have had any reason to believe it was silk. In other words, he may have felt a difference because he was told the material is different. The "touch" comparison is simply too subjective as Ken has, rightfully, mentioned many times.
The material properties of single-thread silk and single-thread cotton are not that different, with silk having a higher tensile strength than cotton (roughly 20%, but with significant variability). It's not like nylon at around 2X. Strength comparisons on the spun fabrics are not publicized, because they are strongly dependent on processing and simply too variable for meaningful comparisons. In other words, for spun fabrics subjective property tests to tell them apart wouldn't be a reliable method.
A burn test or other chemical analysis is required to be certain.
With the 25-Apr-1934 document reference we have, only three contracts may have been able to contain silk linings (32-485, 33-1729 and the elusive 34-518P), and we're not even certain if any used it. The 1932 Spec. 94-3040 is really needed to be certain and the 1939 Wright Field letter may also shed some light.
Have copies on the way, but can anyone post these earlier?
The material properties of single-thread silk and single-thread cotton are not that different, with silk having a higher tensile strength than cotton (roughly 20%, but with significant variability). It's not like nylon at around 2X. Strength comparisons on the spun fabrics are not publicized, because they are strongly dependent on processing and simply too variable for meaningful comparisons. In other words, for spun fabrics subjective property tests to tell them apart wouldn't be a reliable method.
A burn test or other chemical analysis is required to be certain.
With the 25-Apr-1934 document reference we have, only three contracts may have been able to contain silk linings (32-485, 33-1729 and the elusive 34-518P), and we're not even certain if any used it. The 1932 Spec. 94-3040 is really needed to be certain and the 1939 Wright Field letter may also shed some light.
Have copies on the way, but can anyone post these earlier?
Silver Surfer
Well-Known Member
an interesting thread, indeed. i have owned, and still own some pre war a-2s, and have noticed that some of the liners were slightly smoother to the touch then others. spun silk? worn smooth cotton? dunno. all of this writing leads me to ask, is areo considering the use of silk for their possible manufacturing of the aero leather tanning a-2, or other of their pre war aeros? and for that matter, have any of the other makers of pre war a-2s considered or talked about silk? since silk is a stronger material, the usual collar wear through could be forestalled......a little. also, it would seem to me to be another nifty selling point regarding authenticity.
33-1729
Well-Known Member
Saying silk is stronger than cotton is an accurate generality, more than a precise statement. Remembering back to my engineering classes and how many people quickly dozed off when going over the strength of materials I’ll keep this very brief.
Textile strength is typically measured in units of tenacity. What it means doesn’t matter here, just look at the relative values to get an impression on how items compare. Single strand cotton, dry, varies from 26.5 to 44.1 and single strand silk, dry, varies from 24.6 to 39.6. Take a test, can you tell them apart? No, the textile strength variation is too great to tell them apart.
For durability, in 1931, a tightly woven cotton gabardine would have been my top choice.
Ref.: Chemical Principles of Textile Conservation by Agnes Timar-Balazsy and Dinah Eastop (1998).
Textile strength is typically measured in units of tenacity. What it means doesn’t matter here, just look at the relative values to get an impression on how items compare. Single strand cotton, dry, varies from 26.5 to 44.1 and single strand silk, dry, varies from 24.6 to 39.6. Take a test, can you tell them apart? No, the textile strength variation is too great to tell them apart.
For durability, in 1931, a tightly woven cotton gabardine would have been my top choice.
Ref.: Chemical Principles of Textile Conservation by Agnes Timar-Balazsy and Dinah Eastop (1998).
Not speaking from any expertise at all, but by its nature it would seem that silk fibers would be smoother than cotton fibers and the silk weave would be less rigid. Silk slides against itself much more readily than cotton. Side by side it's probably more noticable, but if that early Werber is silk, tough call once it's lining a jacket. The thread count looks pretty similar if the Werber picture is silk.
33-1729
Well-Known Member
Probably the most significant use of spun silk in WWII was for Navy powder bags, since they burned cleanly without leaving any residue. Entering the war in 1939, I originally thought the 1939 letter from the Materiel Division of Wright Field that the use of silk in flying jackets had been officially discontinued was for this reason. May still be true, but for the A-2 the switch was much earlier for other reason(s).
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Bombing IP
Well-Known Member
The US entered the war in 1941 post December 7th not as you say 1939 that was England and its allies after the invasion of Poland .
BIP
BIP
Ken at Aero Leather
Well-Known Member
That's a thought ..........seriously though it would be totally un-economical these days............ there isn't the market for A-2s that there used to be and investing in 1000 yards of silk for one or two "specialist" garments for a very small potential market just isn't realistic.
30 years ago was very different, A-2s were going to Japan in their hundreds
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Silver Surfer
Well-Known Member
1000 yards? wow, that is some commitment for a "specialist" garment. you are correct, ken, it is not economiclly feasible. i was looking at the liners on my pre war a-2s last night, and frankly, other then some being smoother then others, and different colors, i wouldnt know silk from cotton. i always wondered, though, why the 16160 aero contract had a reddish brown [like rough wear] liner instead of the usual yellowish brown liner that aero used prior to and after ther the 16160 a-2. i for one, will be interested to see what you come up with regarding the aero leather tanning a-2.
Ken at Aero Leather
Well-Known Member
Close Up Photo of Spun Silk Fabric might help but, I suspect, NOT A LOT!!!!!
I've no idea why Aero used rust for the one solitary contract, I love that colour, I made an A-2 for myself using it a few years ago (not a specific contract repro , just the features, lining and leather I personally liked) Colour in the photo below isn't 100% accurate to actual "real life" but you'll get the drift :>)
Silver Surfer
Well-Known Member
my point, exactly.
33-1729
Well-Known Member
Still waiting for spec 94-3040 to arrive...
On a similar topic, the military pre-production A-1 service tests used both cape sheepskin and calf skin and the government would have tested spun silk lining for the pre-production A-2 service tests in 1930. "The original A-2" with a "light brown" spun silk lining may have been one of these pre-production service test A-2's. For the A-1 pre-production service tests they made thirteen (13) in cape sheepskin and three (3) calf skin (the A-1 service test samples are covered in Gary's book on pg. 116); so maybe 15 pre-production A-2's with spun silk lining produced? We can get an accurate count of how many were made with a spun silk lining if we find the A-2 service test documents like Gary did for the A-1. The original proposal to the documented results ought to contain what samples were used. Does anyone have a copy of the pre-production A-2 service test?
On a similar topic, the military pre-production A-1 service tests used both cape sheepskin and calf skin and the government would have tested spun silk lining for the pre-production A-2 service tests in 1930. "The original A-2" with a "light brown" spun silk lining may have been one of these pre-production service test A-2's. For the A-1 pre-production service tests they made thirteen (13) in cape sheepskin and three (3) calf skin (the A-1 service test samples are covered in Gary's book on pg. 116); so maybe 15 pre-production A-2's with spun silk lining produced? We can get an accurate count of how many were made with a spun silk lining if we find the A-2 service test documents like Gary did for the A-1. The original proposal to the documented results ought to contain what samples were used. Does anyone have a copy of the pre-production A-2 service test?
johnwayne
Well-Known Member
Is this not the most in depth matter ever covered in this forum? I'm not sure I'm any more informed now than when it started other than cotton and spun silk are apparently more alike than most would have thought!! Nice A2 that Ken by the way, nicely aged and I like the roll on the collar.
