Helice Normale

[rolex1960]

Good Evening,

As the grandson of an aircraft designer (AC Brown B1892 ) I have been going through some of his old Fairey aviation bits and pieces and have found a block of laminated wood with the Helice Normale motif on it. I would be grateful if anyone can tell me if this was made from a prop and if so any more information. I will try to load a couple of pics to make life easier.

I thank you all in anticipation of your help

Regards

Keith Brown

[Dave]

I'd say that it's very likely that it's from a propeller, but interesting on the only Ratmanoff (Normale) propeller that I have the logo is placed perpendicular to the wood grain, where on yours it's parallel.

[rolex1960]

I'd say that it's very likely that it's from a propeller, but interesting on the only Ratmanoff (Normale) propeller that I have the logo is placed perpendicular to the wood grain, where on yours it's parallel.

Thanks very much for such a quick response i am most greateful

[pmdec]

Hi,

I have the same remark: "logo" perpendicular to wood grain (and glue lines). The blade tip is "above" the picture I post (and hub below). It is a serial KU for Gnome engines (a/c unknown for now).

@Dave: could you tell me what are the serial of your Ratmanoff (usualy letter or letters, sometimes letter(s) + digits)?

Regards,
PM

[Dave]

Hi Pierre-Michel,

I just now found numbers on it that I hadn't seen before, stamped just adjacent to the hub impression. They are B-78 then a space and then 843. I'm going to take it down and look more closely for other markings.

Do those numbers mean anything to you? I presume the 78 reflects the length of 7" 8", although I wasn't even aware that Ratmanoff might have used inches rather than centimeters.


Dave

[pmdec]

Hi Dave,

I just now found numbers on it that I hadn't seen before, stamped just adjacent to the hub impression. .../...
Dave

Markings at the blade foot is another particularity for Normale props...

I think the "78" is coincidental

Data about pre-WW1 French props are very scarce. On those I have about Ratmanoff, serial B is only 2m10 (6' 10 1/4). Are you sure of the "B"?

"843" is probably the prop number, which made it a very old one. I know a Ratmanoff envoice from September 1912 showing repair of 13 props. The prop numbers are between 1006 and 1972. As company was founded in 1909, the number 843 may be from 1911 or late 1910 (IMHO!).

Some times ago, I believed the number after the serial letter(s) was the prop number in this serial. It is false because it existed, for example, two serial KBF-6. Perhaps a batch number, as those two KBF-6 have two numbers in sequence.

Can you also re-measure your prop very precisely?

Regards,
PM

[Dave]

Hi Dave,
Markings at the blade foot is another particularity for Normale props...

I think the "78" is coincidental

Data about pre-WW1 French props are very scarce. On those I have about Ratmanoff, serial B is only 2m10 (6' 10 1/4). Are you sure of the "B"?

"843" is probably the prop number, which made it a very old one. I know a Ratmanoff envoice from September 1912 showing repair of 13 props. The prop numbers are between 1006 and 1972. As company was founded in 1909, the number 843 may be from 1911 or late 1910 (IMHO!).

Some times ago, I believed the number after the serial letter(s) was the prop number in this serial. It is false because it existed, for example, two serial KBF-6. Perhaps a batch number, as those two KBF-6 have two numbers in sequence.

Can you also re-measure your prop very precisely?

Regards,
PM

I'll try to take it down from the wall, photograph it in detail, re-measure it and put it on an updated web page on my web site. Hopefully I can do that tormorrow.

I have to say, this particular prop has always been one of my favorites, even though it's perhaps not as "glamorous" as some of the others. I was excited to find stampings on it just tonight.

[Dave]

PM, I stand corrected on several of my original specs, including those on the web page for this propeller. First, I measured it in inches and found 82 11/16" (7', 10 11/16"), which does equal 210 cms. in the calculator that I used. It's extremely close to the length you mention for the "B" series, and may be exactly the same if I measure it directly in millimeters. (Wood may also shrink very slightly even along its length over the 100 years since its manufacture.)



Secondly, I now think that the serial number is "B 278" followed by either "843" or "842", although I think that the last digit is more likely "3". The "B" and the "2" look well preserved by the varnish, and ironically are then more difficult to see. All of the other numbers have shed some varnish at the indentation and are actually a little easier to visualize because of the contrast.

I will get the entire page revised shortly, including another decal near the hub, but in the meantime, here is a close-up of the stampings. You can see how faintly the "2" appears, but once seen, it's quite "convincing".

[pmdec]

Hi Dave,

I think we agree about the lenght of 210mm (82.6769", or 6' 10 11/16")!

I agree also about B 278, but I can't read the "8" before 43...

I think the serial is "B" and "278" is something else, with ?43 a prop number.

Ratmanoff Normale serial B is present in two documents I have copies of:

- a price list dated October 1910, were B props are for Blériot XI fitted with a 3 cylinders Anzani 25HP, "advance for one turn" 0m76, speed 60km/h (so 1315rpm without slipping). Price 350F.
- a price list dated 1st January 1914, were B props are for Anzani 30HP at 1250rpm, with a length of 210mm and a speed of 70km/h. The prop has a nickname: "moineau" (sparrow). All props listed in this document have a bird nickname. Price 250F (lower than 1910 price).

So, this prop has been made for a relatively long time, but doesn't appear in WW1 props lists I have (one from French Military Authorities, dated end of 1917, supposed to be complete, nor in American AEF list dated 1918.).

I think this prop is a very good piece of history, one of the best I know.

Regards,
PM

[Dave]

This is a good example of how altering the light source can sometimes be used to better determine the stampings. Here's another photo taken with a flash. It shows the "8" fairly clearly and also makes the "3" more plausible, but the first "2" is barely visible. In the end, I feel comfortable that the composite of "B- 278" and "843" are accurate, however.


Thanks for you input on this, Pierre-Michel. It's much appreciated. I had always assumed that the propeller was designed for use on the Bleriot XI, but lacked much in the way of documentation of that assessment. I'll finish up the new web page and post here when it's done. Do you mind if I include your research information on that page?


P.S.

Also of some interest is the still partially visible notation at the base of the decal, which I presume to have read "marque déposée". I haven't seen that on the other decals, although I presume it was there but possibly worn off over time.

[pmdec]

Hi Dave,

This is a good example of how altering the light source can sometimes be used to better determine the stampings.
.../...
Also of some interest is the still partially visible notation at the base of the decal, which I presume to have read "marque déposée"..../...

Yes, different light sources and different view angles is often the only way to read the markings.
About "Marque déposée", you are right: it is exactly what is on commercial Ratmanoff papers.
Also, at the blades feet, you may have a stamp, on the intrados side.

Sure you may use the data I posted. I sent you a PM.

Regards,
PM

[Dave]

Here is the preliminary revision for the page showing the Normale propeller. Any suggestions for improvement or clarification is welcome . . .

[drrivah]

Anzani Helice Normale

Can you show a photo or describe the prop hub dimensions?

For example: dia main bore/front to back thickness of hub/dia of bolt circle.

Any idea what the propeller pitch is, or the type of wood?

Thanks.

-pete

[Dave]

Can you show a photo or describe the prop hub dimensions?

For example: dia main bore/front to back thickness of hub/dia of bolt circle.

Any idea what the propeller pitch is, or the type of wood?

Thanks.

-pete

I'll try to get measurements later today. I don't know what type of wood it is. Perhaps walnut (based on the appearance of the grain, primarily) with a more amber shellac but I can't be sure. The pitch is not stamped on it.

[drrivah]

Prop

I believe "PAS" is the French for pitch (of a screw). Should be about half the diameter.

Thanks.

-pete