Helice Levasseur prop

[Bob Gardner]

Postscript;

I don't know what JN 4H means.

I enclose a photo of the original Ebora drawing number 95A prop for the SPAD S7. Note the shape of the hub. Its unusually tall or deep and matches the shape of yours.

Ginger

[Bob Gardner]

And here is a photo of the data on a hub from this propeller. There's rather a lot of it, much more than the usual Ebora presentation of data. Normally Ebora data was rather minimal.

Note the yellow arrow which points to the small letters EN.B in the same font, I think, as JN. 4H on yours.

I will tentatively add to this drg no. (in my database) a note that one example carried an atypical Levasseur decal.

With kind regards,

Bob

[Dbahnson]

Bob, do you think that this prop might have been a reproduction intended for a Curtiss JN4H (which used the Hisso engine, i.e. "H" after JN4)? I realize the JN.4H could be coincidental, and I know it's a bit short for the Jenny, but seeing an obvious aircraft model stamped on the top of the hub stampings makes me a bit suspicious that it was made for something else.

[Bob Gardner]

Hi Dave,

Ebora made a prop for the Curtiss engine used on the JN4 and the DH6 of the Royal Navy, but not for a Hisso engine on the JN4.

There was a British drg no. for the JN4H with the 150hp Hisso engine, 34889. I don't know what this number represents but similar numbers cover a range of British numbers for American aircraft used by the British, almost all by the Royal Navy.

It might be that an Ebora prop of this design was tried on a 150hp Hisso on a JN4, but I'm inclined to think that the small font of both JN.4H and EN.B indicate that it was of minor note and perhaps some sort of internal Ebora reference. But this is entirely a guess from me.

With kind regards,

Bob

[Biggles1946]

Hi Guys, it is getting more and more interesting. Fake?, genuine?, I'd like to think that with the history how and when I bought it, it has to be genuine. I was starting to believe that the SPAD was the no 1 candidate but then with the JN.4H printed on it, it may well have been made for the Jenny, (as was mentioned to me when I bought it).
See these references:
JN-4H — two-seat advanced trainer biplane with ailerons on both wings, 929 built for the U.S. Army, notable for introducing the use of the Wright Aeronautical license-built Hispano-Suiza 8 V-8 engine for greater power and reliability.

Like the re-engined 'JN-4H' version of the most-produced JN-4 subtype, the final production version of the aircraft was the JN-6, powered by a Wright Aeronautical license-built, 150-hp (112-kW) Hispano-Suiza 8 V-8, first ordered in 1918 for the US Navy.

After the successful deployment of the JN-3, Curtiss produced a development, known as the JN-4, with orders from both the US Army and an order in December 1916 from the Royal Flying Corps for a training aircraft to be based in Canada.[N 1] The Canadian version was the JN-4 (Canadian), also known as the "Canuck"

The Wright-Martin built Hispano-Suiza engines incorporated some improvements made by Wright engineers in 1922, although they had to be derated to 150 hp to be of any use. Whereas, the French production models produced 180 hp from the start.3 The Wright built engines were of too little power for combat use and some went into Curtiss JN-4Ds.

Over to you.
Biggles.

[Dbahnson]

Hi Dave,
There was a British drg no. for the JN4H with the 150hp Hisso engine, 34889. I don't know what this number represents but similar numbers cover a range of British numbers for American aircraft used by the British, almost all by the Royal Navy.

Bob, here's that exact prop (34889), which I sold in 2005 to the guy (Donald Sundman) who bought the famous inverted Jenny postage stamp, billed as "the most expensive piece of material in the world". (It was valued at several million dollars, and weighed a very small fraction of an ounce.)

(I see that the link to the stamp sale has been changed, and I'll try to fix that in a few days, but here's a snippet from Wikipedia):

Eventually, in late October 2005 this plate number block of four stamps was purchased by a then-anonymous buyer for $2,970,000. The purchaser was revealed to be U.S. financier Bill Gross. Shortly after purchasing the Inverted Jennys he proceeded to trade them with Donald Sundman, president of the Mystic Stamp Company, a stamp dealer, for one of only two known examples of the USA 1c Z Grill. By completing this trade, Gross became the owner of the only complete collection of U.S. 19th century stamps.[17]

EDIT: And now I see that Sundman sold the same stamp block for over $4,800,000!

[F.D.M]

Regarding the decal...
I do consider all Levasseur decals with a yellow propeller to be fakes / reproductions.

Another question comes to mind.
Are propellers usually lacquered before or after they are stamped?

Bob, PM, what do you think? I am inclined to think, stamping happens after lacquering.

[pmdec]

Regarding the decal...
I do consider all Levasseur decals with a yellow propeller to be fakes / reproductions.
.../...

Hi,

Why? There are at least five kinds of Levasseur decals...

About stamping and lacquering order, I don't know, except for French props. For French props, it is "complicated", because some markings are made before and others are made after, and there are different finition coat (varnish, varnish then French polish, French polish only, red-brown "military mandatory" varnish, lacquer, perhaps paint (never seen paint for real)). And it is different for a repaired prop... Many combinations that can tell if the prop has been refinished or not... And can be a lead to fake/replica prop because the different kind of varnishes react differently to UV light, and I will not tell how, because forgers have to find by themselves all that details

PM

[F.D.M]

Hi PM,

Thanks for sharing.

It is logical to reason that the decal depics the colours of the French flag, blue-white-red. Besides, I have seen photos of obvious reproductions having a yellow propeller. The yellow propeller can be explained by the discolouration of the decal on surviving propellers (yellowish tinge). Until now I have only seen creadable period Levasseur decals with a white or discoloured (yellowish) propeller. Even the propeller in Dave's good decal is discoloured. Discoloured whites are very common in decals. This is why I believe they all must have been white. It does not mean there hasn't been a yellow one, but I have yet to see it. Why would Levasseur switch to yellow?

As far as I know there is only one main Levasseur decal, excluding Vickers-Levasseur. However, there were more 'stencils' (versions) of the same decal.
Do you know of any other different decals?
Please let me know if I am wrong.

Best regards,

[pmdec]

Hi,

FDM, you are probably right about flag colors. I am very ashamed having not thought about that!!! And it is true that "classic" Levasseur decals with white or very pale grey color propeller do exist, even on very well preserved decals.

On the pic below, two early (pre-WW1) and one very late (post WW2) Levasseur decals I am 99.999% sure authentic. The first is from one of my props, the second was on this forum years ago and the last is a LeBonCoin (kind of Craig List in France) thing.

On the older decal, perhaps, after all, the prop was white, but I don't understand why all the letters can "pass" from gold to white on the first one, with the prop remaining yellow. On the second decal, the P and L have kept their colors, but it seems that all the gold or yellow is partially "wasshed" to white.

On the very late decal, the prop is clearly yellow. But... But the P is quite green, so it can be blue + yellow (- yellow to be strict!). And the yellow could came from the varnish.

What do you think?

Oh! Two are missing to make five: I am sure you have seen at least one. Look at the Levasseur from the years just before WW2... At least one has been posted on the forum. I see it many times before my brain told me anything...

Regards,
PM

@Dave: some "cryptics" writings are appearing in the picture insertion window just after clicking to upload (FireFox 44.0.2 with Win XP sp3 )

[Dbahnson]

Hi,

FDM, you are probably right about flag colors. I am very ashamed having not thought about that!!! And it is true that "classic" Levasseur decals with white or very pale grey color propeller do exist, even on very well preserved decals.

On the pic below, two early (pre-WW1) and one very late (post WW2) Levasseur decals I am 99.999% sure authentic. The first is from one of my props, the second was on this forum years ago and the last is a LeBonCoin (kind of Craig List in France) thing.

On the older decal, perhaps, after all, the prop was white, but I don't understand why all the letters can "pass" from gold to white on the first one, with the prop remaining yellow. On the second decal, the P and L have kept their colors, but it seems that all the gold or yellow is partially "wasshed" to white.

On the very late decal, the prop is clearly yellow. But... But the P is quite green, so it can be blue + yellow (- yellow to be strict!). And the yellow could came from the varnish.

What do you think?

Oh! Two are missing to make five: I am sure you have seen at least one. Look at the Levasseur from the years just before WW2... At least one has been posted on the forum. I see it many times before my brain told me anything...

Regards,
PM

Note that in all of those decals the axis of the decal is perpendicular (not parallel) to the grain axis of the wood.

[Dbahnson]

@Dave: some "cryptics" writings are appearing in the picture insertion window just after clicking to upload (FireFox 44.0.2 with Win XP sp3 )

I'm working on that. It's "harmless", but I want to keep those from appearing at all. I need a little time . . .

[Bob Gardner]

With reference to the discussion on Levasseur decals, a subject incidentally that I know nothing about at all, I have studied British and German decals. Colours on these are variable. Sometimes the original blue on a decal, such as Bristol's and Wolff's, can vary in shade and even become green. At first I tried to catalogue these variations. Eventually it dawned on me that the principal factor involved was sunlight and how the varnish reacted to it. Often it turns yellow to varying degrees. (Yellow and blue make green.) (Yellow and white make colours from cream to yellow.)

But other factors in colour variation might be;
War time shortages leading to the use of different varnishes as available.
Similarly for the colours used to print the decals; this might also include the use of different firms to print the decals.

The third German Axial decal is very variable in colour, more so than any other. Firstly there were two editions, one where shading was represented with single lines, the other with cross hatching. Also the propeller shapes in these two decals were slightly different.

The next factor in the appearance of the decal is the quality of the lacquer which declined as the Allied Blockade of sea trade had increasing effect. Initially the Germans used bootslac (yacht varnish) which reduced in quality for the next three years. The Royal Army Museum in Brussels discovered that on the original fabric of one of their WW1 aircraft the dope consisted of boiled down potato where the starch had been converted into a poor quality ersatz dope.

In 1918 the Propellermerkbuch der Luftshrauben-Abteilung der Prufanstalt und Werft der Fligertruppen issued an instruction that propellers in store were to be coated in heavy grease, to be removed before flight and replaced with a light grease, in turn to be replaced by heavy grease on landing. I interpret this to indicate that no form of varnish could be made. Possible collateral evidence is evident in WW1 photographs of Axial propellers which are comparatively common. Decals and an artistic art nouveau layout of different woods are visible in most. In some late war photographs Axial propellers are a uniform dark colour; no artistic shades of wood, no decals. I assume these are coated with grease.

The background colour of the most common Axial decal, the third one, almost always appears to be cream, and several reproductions, including some in German Aviation Museums use a cream background. The cream colour comes from degradation of the lacquer. The original colour was silver. About ten years ago whilst restoring an Axial propeller with a derelict decal we examined a flake under the microscope.

With kind regards,

Bob

[Biggles1946]

Dear All,

Firstly I would like to thank all of you who have contributed to this Forum for your valued and professional input. I have learned so much more about props, it has been a wonderful "ride",
Below I have picked out some of the comments which so far do not as yet tell me what aircraft this prop may have been destined for. So I still don't know. If I was to sell the prop, what do I tell my prospective Buyer???

I suspect it may have been mercilessly refurbished but it might be a fake. In its favour the Levasseur decal looks to be original. The layout and construction of the laminations look correct.
IMHO, if you paid more than some pounds for it, you have to claim for a refund.
The fact it is stamped and a mimic decal was put on it is clearly misleading and, perhaps, the seller could be sued.
Now that you have given us the data above I return to the inclination that it is genuine because;
the diameter of 7'8" is exactly right for the SPAD S7 with the 150hp Hisso.
So I conclude, after some oscillation, that your prop is genuine
Regarding the decal...
I do consider all Levasseur decals with a yellow propeller to be fakes / reproductions.
Why? There are at least five kinds of Levasseur decals…
Eventually it dawned on me that the principal factor involved was sunlight and how the varnish reacted to it. Often it turns yellow to varying degrees. (Yellow and blue make green.) (Yellow and white make colours from cream to yellow.)
All wooden props are a fixed pitch but I have seen some that say ‘variable pitch’ and these were as I have said, for testing purposes only.
The 150 hp Hispano V-8 engined Curtis Jenny was called a JN4-H, see: http://postalmuseum.si.edu/exhibits/...iss-jenny.html

Looking forward to your definitive answer,
Biggles.

[Dbahnson]

In my opinion the "noble" thing to do would be to point the buyer to this discussion and allow him or her to decide, because I don't think that at this point there is a "definitive" answer. I know as a collector I would have no interest in buying it, but not all buyers are collectors.

Wooden propellers are similar to tires. There were thousands of different "models", many different uses, and high damage rates. It's not always possible to identify the type of vehicle (or vehicles) it was designed for, and it's almost never possible to identify the actual vehicle used if it was ever mounted on one.

Of course one big difference between tires and propellers is that there is little incentive to collect tires . . .