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Dbahnson
07-15-2015, 07:57 AM
I'm baffled by this propeller that I was asked to identify. It's obviously of French origin, but it's stamped "Spa" and "Serie 3". Besides the fact that it looks like the stamping person had a seizure while he was doing it, the only reference I can find to a Serie 3 propeller is one manufactured by Eclair and designed for the Nieuport with an 80 hp LeRhone engine. The "Spa" on this one almost certainly refers to "SPAD", as it appears on other identifiable props that way, and would be more consistent with the Hispano Suiza engine stamping on this one as well (I can't discern the HP stamping, though).

I'm hoping PMDec or someone with similar talent can sort this one out for me.

EDIT:
I have since found a Gallia propeller lister as Serie 3 that is the correct length (8feet, or 2.45 cm) as this one, so that's probably the correct listing, but I can't find that it matches any SPAD application. It seems to be the correct length for a SPAD VII, and I suspect that the stamping is for a 150 HP Hisso engine, but I can't be sure.



.

pmdec
07-15-2015, 05:50 PM
Hi Dave,

You are right, it is a Gallia serial 3, which was made for SPAD VII fitted with 150 HP Hispano (both standard and supercharged). This prop is marked for the supercharged Hispano (marking Sur for the French Surcompressé).
"Official" data : length 2450 mm, pitch 2100 mm, blade width 190mm, hub thickness 150 mm, central bore 70 mm and 8 11 mm bolts on a 150 mm circle.
542 is the prop number (in serial 3).

The prop has been repaired, so the double markings. It seems it was the standard practice to "mask" the first markings (filler, ...) then add the new ones which were often the same except for the airworthy stamp (SFA + letter ot digit). They did that because they have to strip off the varnish of all the prop and spend (right word?) new varnish.

The guy who stamped the prop had no seizure (or at least not before finishing his job :)): all the French props of the mid-1916-1922 era show only three letters for the brand name of the a/c (Bre for Breguet, Voi for Voisin, Sop for Sopwith, ..., and Spa for SPAD).

Regards,
PM

PS: With more detailed pics of the markings (three sides of the hub) it could be perhaps possible to give making and repair dates.

Dbahnson
07-17-2015, 07:29 AM
Thanks, PM. That helps.

So are you reading the stamping as "Hs 150 SUR"? I think I got fooled into somehow making that "HS SUI", but now that you point out the supercharger factor what I was thinking doesn't make much sense, as it's unlikely that they would put the horsepower between the "HS" and the "SUI" in the first place. :oops:

pmdec
07-17-2015, 07:13 PM
Hi,

Another example on a Ratmanoff serial HS+, this one for a SPAD XIII.

I do think the last letters are "big" S, "small" u and "small" r, not a "small" p (probably a "r" with a very curved "horizontal" bar).
But what is sure is that it is for or a "surcompressé" engine, as it is written on the "official" paper.

The Ratmanoff serial HS (without "+") does also exist, probably for not supercharged engine.
To be noted: IMHO, "surcompressé" is not supercharged in the way a compressor is used. It means the compress ratio was higher.

Regards,
PM

Dbahnson
07-17-2015, 07:16 PM
PM, your depth of knowledge never ceases to amaze me. http://woodenpropeller.com/forumvB/images/icons/icon14.gif

pmdec
07-18-2015, 07:32 AM
I have just followed the advices of Bob Gardner (look at as meany prop markings you can) ... and had the chance to find some papers about WW1 propellers in Gorrell (AEF History), at SHD (Service Historique de la Défense in Vincennes) and MAE (Air and Space Museum in Le Bourget)... :D