S.h.a.m.

[Viper]

Hello, Im looking at a prop that is 9'6" long and has decals on each blade that are marked with S.H.A.M. and "BREVETE" "S.G.D.G." and Made in the USA on them. I believe the BREVETE and S.G.D.G. relate to French patents but Im not sure what the S.H.A.M. means.
The hub has eight bolt holes and the tips are canvas covered. Can anyone help identify this prop for me and possibly tell me which airplane or airplanes it may have flown on?
thanks

[Dbahnson]

Here's a list of some abbreviations, including "S.G.D.G.", but I still don't know what SHAM means. Maybe at this point pmdec, with a large knowledge base of French propellers, can fill us in.

Those are clearly French abbreviations, and if the prop was made in the USA it was likely under some kind of license agreement.

It would help if you could post a picture of the propeller and the hub. Are there any other stamped numbers/letters anywhere on the prop?

[pmdec]

.../... S.H.A.M. and "BREVETE" "S.G.D.G." and Made in the USA .../...

Yes perhaps I know the meaning of SHAM. Is the decal the same that the one I post?
Anyway, pics of the decals, of the whole prop and of each of the 4 sides of the hub (central part) and of each marking outside the hub are "mandatory" for an answer: it is kind of a reward for the work done to have the prop identified...
Please, clear and large pics (7, so you have to post 2 messages). If you can't post them on the forum, you can send them by mail and I will post them here.

Regards,
PM

[Viper]

S.h.a.m.

pmdec, yes, that's the same decal that is on the prop. I will try to attach some photos.

thanks, Viper

[Dbahnson]

Are you able to read all of the stamped numbers and letters? It's difficult sometimes to do that from a photo, as often you need to move it into different lighting to be able to determine the characters.

It's a nice looking propeller!

[pmdec]

Hi,

Excellent trove! Not rare in France but perhaps the only one "made in USA" surviving... And in very good shape!

SHAM means Société des Hélices Armées et Matricées, that could be translated in Company for Strengthened and Molded Propellers.
Those props are made very differently from the classical method. They use very thin laminations (around 5mm) with fabric between each lamination. The tips are reinforced with pigskin or parchment (you have to use a binocular loupe to know) painted in black.

More infos when I will have large pics of each of the 4 sides of the hub with stamping readable...

If you have access to a metal detector, some of these props are presumed to contain openwork metal sheets between laminations: could you try after removing the bolt?

Regards,
PM

[Bob Gardner]

Greetings Viper and Pierre-Michel,

Thank you for the photographs of the SHAM decals which I have added to my collection. Both are new to me, which is a rare occurrence these days.

I know nothing about French propellers, so I tread carefully when I note that this angular propeller has the shape of a Lang Propeller design. Dashwood Lang was British and also made props in America as the Lang Propeller Company of America, but I know of no connection with French propellers.

So, I look forward to Pierre-Michel's denouement!

With kind regards,

Bpb

[Viper]

I will send more pictures tomorrow. Thank you very much for your assistance!

Viper

[Dbahnson]

I will send more pictures tomorrow. Thank you very much for your assistance!

Viper

Please try to provide the stamped information on the hub. It might even require gentle cleansing of the hub with mild soap and water and adjusting the light to better discern those characters. Better close-up photos taken straight-on might help, but rarely work as well as direct inspection.

There are obviously some characters stamped on the hub. They can be critical for its identification!

[Viper]

More pictures of S.H.A.M. propeller

Okay guys, here are the pictures of the hub. One photo looks like the hub has a ragged hole in the side of the hub but its not. Its a raised blemish. The markings indicate the following:

On one side of the hub I was able to read the following (at least this is what I can read so far -

DE LA GRAX??LME - SHAM PROPELLER
TYPE No8
0-412


On the other side -

DH-4 LIBERTY 12
430 HP
1750 RPM

Any information is appreciated!
Viper

[pmdec]

Hi Viper,

Thanks for the pics. I think the markings read:
DE LA GRANVILLE - SHAM PROPELLER: name of the maker and of the brand
TYPE 11(?) N°8: propeller serial (11?) and propeller number
O-112: don't know!

On the other side -

DH-4 LIBERTY 12: aircraft and engine
430 HP: engine power
1750 RPM: rotation speed

See https://en.wikipedia.org/wiki/Liberty_L-12 where "The primary use of the Liberty was in aircraft. American-built versions of the Airco DH.4"
Power on the prop seems a little optimistic...

SHAM props where made by Mr Louis Paulhan (a well known pilot) and Mr Henri Joseph Léon Marie de la Chevardière de la Granville (*) from 1916 to the end of 1918. Probably they try to sell props in USA when the European market ends with the 11th november 1918 armistice.

Your prop has hub mounting marks (the circles around the central hole) but it is not sure it flew, perhaps only for a static show on a plane or on an engine.

I join a patent for this kind of prop. If you can try a metal detector on the prop, I would be very interested in the result. You can also take the prop through a security gate in an airport but I dont want to be responsible if TSA jails you...
In France, even with what is written in the patent, all SHAM props I saw were reinforced with fabric between the lamination and not metal sheet.

Regards,
PM

* In France, when some people have a so long name and somebody say it all, there is an habit to answer "que le dernier ferme la porte" (have the last one closing the door)!!!

EDIT: Added a pic to explain how the prop is built.

[Bob Gardner]

Pierre-Michel,

What an excellent reply. Thank you. I had heard of SHAM but only with a note that they were armoured propellers. This is a fascinating account.

With kind regards,

Bob

[Viper]

Thank you Pierre-Michel! Your insights are very helpful to me and I appreciated the other comments as well. I just learned about the restoration of a DH-4 Liberty in Bowling Green, Kentucky which is not far from my home. I look forward to visiting and perhaps volunteering some time to help restore the only flying DH-4 in North America. I understand there are some still flying in France?
Here is a link: http://www.savinglibertydh4.org/blog/

I accomplished a metal detection survey of the propeller. The only metal I discovered was on both blades where the pigskin cover begins. There is no metal between this spot and the tips and no metal discovered going back to the hub. I can see the thin lamination between the wood layers that appears to be metal near the hub but it must be a fabric layer (I assume).

[Dbahnson]

Ditto to Bob's reply above - lots of good information there, as usual from pmdec and Bob.

And Viper, thanks for posting the photos and text with the critical stamped information. You can see how quickly it leads to a definitive answer to the question of aircraft usage.

[pmdec]

Hi ,

.../... I understand there are some still flying in France?.../...

Sorry but I know nothing about aircraft and I have not heard of a surviving flying DH-4 in France.

.../... I accomplished a metal detection survey of the propeller. The only metal I discovered was on both blades where the pigskin cover begins. There is no metal between this spot and the tips and no metal discovered going back to the hub. I can see the thin lamination between the wood layers that appears to be metal near the hub but it must be a fabric layer (I assume).

Many thanks for that. I think there could be some small nails at the beginning of the pigskin.
Anyway, one more SHAM with fabric "armoured". So I attach another patent more in adequation with yours.

The very specificity of SHAM propellers is to be bent, almost not carved (just a little to remove the small "steps" of wood). After all the layers of wood and fabric are piled up with casein glue between each layer, the whole thing is pressed in a mold which give the pitch to the prop. Then, you have to wait 24 to 48 hours for the glue becoming hard. The productivity is, therefore, limited, and the price high. Another fact make the price higher: to have a lamination flat and straight enough, you have to remove about 3 mm on each side. With 21 mm thick classical laminations (cut in 27 mm thick planks), that is 6/27th of the wood to be lost, and if you add the loss when sawing the plank, it is around 8/29th. With 5 mm thick lamination, the wood lost become around 9/14th, more than double!

At the end of the war, Mr Valeri patented a "molded" propeller using very thin layers of wood: 1 to 2 mm thick. But Valeri used peeling wood (not sure 'peeling' is the right word), so there was no wood lost. I don't know if any of these Valeri prop came in use but I found one picture (only one!) of this kind of propeller. Sorry for not have the right to post it. And no decal is known.

PM