Identifying please!!! Helice Eclair Paris, SPA, HS 150 HP,

[XmanProp]

Dear all,

I have recently purchased a wooden Propeller from an Antique store in London. This is an Eclair Propeller "Helice Eclair" with the following Markings:

Helice Eclair Paris (on the blade)
(on one side of the hub)
SPA
HS 150
n 1
Nf

(on the other side)

Serie No 6
No 366
HIS ---faded--- 150HP

It has 8 holes through the Hub
it is 240cm long and 150 wide at the hub

I would appreciate if anyone could provide any information regarding this propeller. I have found the story of the Helice Eclair but i am specifically looking to know what aircraft was this mounted on. I have found that the SPAD VII use this prop, and the marking "SPA" would probably confirmed it. Also there are a lot of inspection stamps which probably mean it has been used on several occasion. Checking the tip of the prop there seem to have been repaired with wood pin. I am wondering if this could have been flown and then damaged, repaired and flown again.

This propeller has definitely been refurbished so all the original paint is gone but I can see some residue of the red/burgundy paint in some area and inside the indentation and markings.

Thanks for your help on any information regarding this propeller.
Xavier

[JR44]

HIS would have been Hispano as in Hispano Suiza V8 aero engine.

[Dbahnson]

"Spa" usually refers to SPAD, but that Serie number (6) doesn't appear on any of my listings for SPAD propellers.



It also appears that the hub has been "re-stamped", perhaps after being sanded in an attempt to restore it. Notice the "ghosts" of original stamp marks below the much more crisp marks above it.




Note also that "N 366" also appears as a ghost on the opposite side of the hub, where it appears to have been stamped over by an "SFA" stamp and an "X".




So my best guess is that is an original SPAD propeller with a Hisso 150 engine, but that at some point in its history it was stripped, sanded, re-stamped with new characters and then re-varnished.







.

[JR44]

Yes I thought it looked re stamped.

[XmanProp]

Thanks a lot on all this good information and good catch from Dbahnson on noticing the No 366 on the other side. I didn't even see it.

Can you guys explain what the Series and No means?

As far as the ghost writing my hypotheses is that probably the prop was repaired and restamped. See attached picture of some close up of the repair. You can see the wood pin around the edge of a piece of wood that was added. Have you seen something like this before. Is this a repair or maybe a typical manufacturing process?

Regarding the aircraft that it was mounted on I found this interesting document (sorry it's in french) about french propeller manufacturer made by a reliable source (historian of the aeroclub de France). It has a list of prop's used on each engine and aircraft on which it was mounted on at the end:

https://www.hydroretro.net/etudegh/h...rsfrancais.pdf

I see in the table that the SPAD type VII had the Serie 6 propeller, and the dimension correspond to 240cm. (I am not sure how to check for the prop pitch though)

Any comments or futher information is welcome?
thanks a lot,
Xavier

[Dbahnson]

First, thank you for that .pdf reference with the listing of some additional propellers that I don't have in my data base, which was generated by the AEF. (I notice that some of the .pdf material includes photos from this web site, which I appreciate.) It's pretty clear that your prop was actually used on a SPAD VII, having so called "witness marks" on the hub, where the metal hub assembly compressed the wooden hub. In that sense it's an authentic WW1 prop, even though it has been "restored".

"Serie" is the French equivalent of "model", "drawing", "design", etc. used in English. It typically refers to a drawing ("blueprint") number that shows the layout as well as the specific length and pitch for the blades. Sometimes it's followed by "no" or "numero" but usually those prefixes are followed by a number that reflects a manufacturing sequence.

I highly doubt that the alterations to the propeller were done to keep it in service. I suspect that the propeller was damaged in service and then "restored" as a display piece (in this case with fairly good workmanship). But wooden propellers are actually quite fragile and were easily damaged. It was unwise to try to repair a damaged one and put it back in service as it would jeopardize the entire aircraft, so it was simply replaced by a new one. Consequently, the production of propellers FAR exceeded the number of aircraft using them, and to me the volume of propellers produced in WW1 is staggering - over 25,000 by one American manufacturer (Paragon) and the U.S. only had one aircraft model (DH4) that ever flew in the war.

[pmdec]

Hi,

Standard practice in France when the props were repaired:
- strip the varnish
- make the wood repair
- "hide" the old markings by filling them,
- restamp the prop with standard stamping but the details could vary from maker to another (example one wouln stamp "NUMÉRO 3600', another "N° 366" or simply "N 366")
- revarnish completly,
- add the airworthy stamp (SFA + one numer or one letter or one sign).

Éclair serial was approved for SPAD VII fitted with 150HP Hispano-Suiza. This engine was direct drive, so the prop is right handed (left handed for the HS 200 because it was geared).
But the appobation was cancelled before the end of 1917, it is why the prop is not in the prop list of Dave which was established later.

This prop has been repaired at least two times: there are the last marking, clairly visible, and TWO others. It was made by Éclair in Paris but repaired by another prop maker.

Regards,
PM

EDIT: I join a pic of a repaired Éclair serial 6 where the original stamping is partially legible (its "reparation varnish" has not been removed).

[pmdec]

.../...
I highly doubt that the alterations to the propeller were done to keep it in service. I suspect that the propeller was damaged in service and then "restored" as a display piece (in this case with fairly good workmanship). But wooden propellers are actually quite fragile and were easily damaged. It was unwise to try to repair a damaged one and put it back in service as it would jeopardize the entire aircraft, so it was simply replaced by a new one. Consequently, the production of propellers FAR exceeded the number of aircraft using them, and to me the volume of propellers produced in WW1 is staggering - over 25,000 by one American manufacturer (Paragon) and the U.S. only had one aircraft model (DH4) that ever flew in the war.

I think, this could have been true in England or USA, but not in France: Repairing propellers was very common in France during WW1.

For example, from 734 serial 34 Ratier propellers made by Ratier between 3rd March 1917 and 31st december 1917, 325 were repaired at least one time (almost half of them, and it is not because they were badly made!).
The serial 34 n°61 (made around April 1917, original billing on 15th June 1917) has been repaired three times: billings on 9th November 1917, 30th April 1918 and 7th June 1918. It was a prop used by Michelin for a new Breguet 14, and repairs were paid by SFA: see the joined pics.

The first pic is a double of a 15/3/17 bill for 6 propellers serial 34 n°56, 57, 58, 59, 61. It reads :
2 Caisses Ma remise ce jour au wagon d'aviation PLM [2 crates guven to PLM wagon]
ML 42.22 RT [crates numbers]
6 Hélices - Série 34. NO 56.57.58.59.60.61
pour avion 14B.2. - Dtre 2m94. Pas 1m92. Pales 0,240
Moteur Renault 300 HP
[The price is] 300 francs l'une [each, that is] 1800 (for 6)
Emballage [packaging] pour 6 Hélices 42 [francs 7 each]
Total price 1842

The second pic is a double of a 9/11/17 bill for a command by the SFA (Service des Fabrications de l'Aviation Militaire). It shows 5 sections:
- 3 props serial 34 revarnished ("Revernies")
- 14 props serial 34 repaired ("Réparées") including n°61
- 1 prop serial 34 scrapped ("Réformées")
- 2 props serial 38 revarnished
- 2 props serial 38 repaired
The repair price is 40 Francs for each serial 34 (vs 300 for a new one).

The third pic is a double of a 30/4/18 bill for a command fy the SFA. It shows 2 sections:
- 12 props serial 34 repaired including n°61
- 9 props serial 40 repaired.
The repair price is the same.

The fourth pic is a double of a 7/6/18 bill for a command by the SFA. It shows 2 sections:
- 26 props (22 serial 34 and 4 serial 40) repaired including serial 34 n°61)
- 4 props revarnished.
The repair price is also 40 francs each.

So, there is no doubt the props were repaired in France during WW1 (and also after). And the very same prop could be repaired more than one time. It is why surviving props from this era are often repaired ones. But there are also many of them restored "as is" they have been repaired. The difference is generally easy to make because "old" varnish is excessivly difficult to reproduce as is "right" stamping...

Best regards,
PM

[Dbahnson]

Thanks for providing that information, Pierre-Michel. It's new information for me!

[pmdec]

Hi Dave,

Looking at my database and picture, I was not able to find any restamped English ou US propeller... But French repaired props are very frequent.

To add to the Ratier documents shown, I post a picture of the first page of projected contact between SFA and Madame Veuve Calvet (perhaps a war widow!). Mrs Calvet was not a propeller maker. She did only repair work, and thus the props repaired in her workshop were not in makers archives. So, the proportion of repaired props deduced of Ratier archives could have been higher.
I have seen many contracts of this kind.

The beginning of the document reads:

Pour me permettre d'établir une convention devant tenir lieu de marché, je vous prie de faire ci-après des propositions de prix pour la réparations de TROIS CENTS hélices de différents types d'avions en service.
La réparation consiste en une remise à neuf complète, vernissage compris.
Les quantités indiquées sont susceptibles de varier de 1/4 en plus au gré de l'Administration Militaire.
La réception sera faite dans votre atelier par un Officier sésigné par le Directeur du Service des Fabrications de l'Aviation [SFA].
.../...
Google translation (seems correct):To enable me to establish an agreement to take the place of a contract, I ask you to make below price proposals for the repair of THREE HUNDRED propellers of different types of aircraft in service.
The repair consists of a complete refurbishment, including varnishing.
The quantities indicated are likely to vary by 1/4 more at the discretion of the Military Administration.
The reception will be made in your workshop by an Officer appointed by the Director of the Service des Fabrications de l'Aviation [SFA].

Regards,
PM

[Dbahnson]

Fascinating, and it's remarkable that several major countries that manufactured aircraft had such different policies on repairing propellers.

I'm reminded of the "whirling tests" in the U.S. where different propeller models were tested to failure to aid in their design/construction.