Helice Normale

[mariusrex72]

Ratmanoff Normale drawings.

[drrivah]

Helice Normale: back to 1910

Is it known when Chauviere and Ratmanoff began using mechanical duplicators, and what were the tolerances for the machined props compared with completely hand-worked?

Also, Chauviere apparently set up a research lab to define best wood properties about 1911. Are there existing records from that laboratory work?

It seems apparent that Eiffel and Drzeweicki (the engineer whose patents formed the basis for Ratmanoff's airscrew intellectual property) were not only acquainted, but shared laboratory space.

Thanks, all.


-pete

[pmdec]

Hi,

During WW1, at least 3 "duplicators" have been made in Europe : Savoïa (Italian), Selmersheim (France) and Chauvière (France). I have seen pictures of the first two which confirm their existence in 1918 and 1917 respectively, the one I saw of the Chauvière was not dated. It seems they were not used for time saving, but because of a lack of sufficiently skilled workers. The Selmersheim machine seems the most efficient, because it worked the length way and carved 2 props at the same time (but was not fully automatic). I have published a picture there: http://ratier.org/archives/fichelices/Rati34_Selm.pdf

I think this thread is now too far from its beginning. Perhaps it would be possible to move the last posts toward "Design" section ? (easier to ask than to do ... isn't it Dave?).

Regards,
PM

[drrivah]

Prop Duplicator

Figure from Whyrill Park's treatise on airscrew design, ~ 1920. The model prop is seen in the upper right corner. The blank to be carved is below, right.

Wadkins & Co., Leicester duplicator for prop manufacture. At some point when demand increased, companies went from hand made to duplicator machines like these.

Was the duplicator invented in the UK or France?

Any idea how accurate the duplicator machines were, and the approximate date these were invented and introduced into the prop fabrication industry?

[drrivah]

Helice Bois

Good summary here:

www.hydroretro.net/etudegh/heliciersfrancais.pdf

-@pete

[D.Hicklin]

origin of thread

And to think, this wonderful thread all started by the member " rolex " with a picture of a block of wood that had the logo on it that says, " Helice Normale ". Truly impressive how it all links together.

Sincerely,
Dennis Hicklin
Seattle Washington.

[drrivah]

Anzani props

PM: Virginia like Spring this week. Narcissus near bloom, and snowdrops in bloom. We are "waiting for the other shoe to drop".

Very interested in further technical data comparing French, English and American walnut, eg., density, modulus of elasticity etc., and how these change with the age of sealed (varnished) vs raw stock wood/timber.

Thanks for this informative response with great technical detail.

-@pete

PS PM an email address: I'd like comments on my Ratmanoff model.

[pmdec]

Hi,

Returned (snowy!) home and to the books. Circa 1911, Ratmanoff props are all made with English walnut (that is French walnut for French ). Scientific name is Junglans regia, which is different from Junglans nigra, the American wallnut. Ratmanoff is said to use only timber from Auvergne (south-central part of France), where walnut grow slowly and regularly. This "sub-specie" is light colored (http://www.thewoodexplorer.com/maind...ts/we671_1.jpg)
English walnut wood density may vary from 0.45 to 0.65 (from different publications), so measuring density is not a method to determine the wood specie. A good cabinetmaker has to know the precise wood specie.

@Pete
About Anzani engines. There is a drawing of the "25HP" 3 cylinders (fan type) in Flight, October 30th, 1909 page 691. There are many models, even before 1914: for example, there was a "40-50HP" 5 cylinders at 1910 Paris Show (see Flight, October 29th 1910, page 886), a "60HP" 6 cylinders on a Blériot which flew on July, 11th, 1911 (see Flight, July 22nd 1911, page 642) and a "100HP" 14 cylinders appeared at 1911 Paris Show (see Flight, December 23th, page 1114).

It is not possible to determine a specific engine from metallic hub dimensions, even if these dimensions are a guess basis to engine power. All known metallic hubs from this period have a tapered interior hole with a cylindrical outside.

From the documents I have, the Ratmanoff Normal serial B is not suitable for other engines than Anzani "25 to 30HP" 3 cylinders. For the 1910 5 cylinders, there are serial Q and L1 and at the end of 1913, there are 23 different serials (from 2m000 to 2m800) for aircrafts fitted with one of the Anzani engines.

@Dave
Your picture is of the Caudron "Fauvette" owned by Guillaux. The engine is an Anzani 3 cylinders Y type, and the propeller is a Ratmanoff, perhaps a serial YA (diameter 2m10, with an advance by turn which give a speed of 120km/h). This picture is from 1912, probably between February and August (no later, as one postcard with this very picture is dated August 12th, 1912, and probably not earlier, as first pictures of Guillaux published by the postcards editor Briant are from February, same year). This very aircraft is recognizable with its small mascot, a little doll visible behind the upper cylinder.

I have to admit many of the props of this period have a six holes hub, but the picture with eight holes from l'Aérophile I posted is, for me, the more accurate about Blériot Trans-Channel flight, until I can look at a picture taken just after the landing.

Regards,
PM

[Dave]

A colleague has brought my attention to a table listing Anzani engine types, among which is an Anzani type 6B (1910), 1300 rpm, 40 hp, 6 cylinders. Is it possible that the "serial B" above matches this engine to the Ratmanoff Helice Normale?

-@pete

I have no idea.

Incidentally, I came across this photo of an early Anzani engine used on a Caudron in the mid teens, clearly showing a 6 hole hub.

[drrivah]

Helice weight and metrology

More speculation:

The density of wood from each species varies, but they generally have a range and engineering specs takes into consideration the variation. Later (191, there were specifications about wood density allowed in prop manufacture, usually a minimum density. In addition, as with modern aircraft wood grading, the allowable grain rise was also specified at least by 1918.

If the specs are accurate, a volume can be estimated by rough or more exact methods.

Rough guess on the Ratmanoff Helice Normale, given a lot of assumptions, is:

English walnut: 8.9 lb (grain <1/12)
Mahogany (H) 7.6 lb
Ash 9.3-10.1 lb (grain <1/10)
Pine (y) 6.9 lb

My guess on the estimates is +/-15-20% uncertainty.

While these guesses may be coufounded by overlap between species, a walnut prop shaped like the Ratmanoff should be about 8.9 lb.

Not sure how wood (walnut) changes density with time as this would be ~ 100 years since the prop was manufactured. My guess is that as wood dries over time, it becomes lighter (in weight, losing mass). If shellac/varnish is intact, this would be minimized.

Pure speculation, of course.

-@pete

[drrivah]

Ratmanoff serial B

"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)."

A colleague has brought my attention to a table listing Anzani engine types, among which is an Anzani type 6B (1910), 1300 rpm, 40 hp, 6 cylinders. Is it possible that the "serial B" above matches this engine to the Ratmanoff Helice Normale?

-@pete

[Dave]

The question was:
1) how to extrapolate from the prop hub detail, bore diameter, bolt pattern and spacing, back to which model Anzani engine it matches. Is it possible?

2) Are all Anzani hubs the same dimension?

BTW, thanks for hub vs crankshaft comment.

Looks like the more powerful six-cylinder 45-60/70 hp Anazani engines (late, maybe 1926-192 did, in fact, have 8-bolt hubs. The 22-35 hp appears to have 6 x 10mm @ 57.5mm radius hub.

Here are three Anzani crankcases. The one on the left is apparently a Channel 22 hp W-type (57o between cylinders) with valves behind the cylinders. Note: no "B te" marking at about 8 o'clock position on ther face.

Center is the Old Warden Anzani Military Type on display (not mounted on an airframe) at about 35 hp. The valves are on top of the cylinders and visible from front. Here, "B te" appears.

On the right is a later Y-Anzani of 35 hp with the "Brevete" spelled out ('Patented', Fr.).

Curious which prop markings identify the engine it was designed for.




(from:L Ghosts; middle N. Feltwell; right: Janes 191

-@pete

I also own this Chauviere propeller for a 125 HP Anzani engine, which clearly used an 8 bolt hole hub with entirely different dimensions than the smaller engine.

I find on many engines the hub is the same for various horsepower versions of the same engine. I don't know about Anzani engines, but the hub on the Ebora prop (which is stamped 28 hp Anzani) is identical to the hub on the Normale prop.

[drrivah]

Anzani: from prop to engine IDs

The question was:
1) how to extrapolate from the prop hub detail, bore diameter, bolt pattern and spacing, back to which model Anzani engine it matches. Is it possible?

2) Are all Anzani hubs the same dimension?

BTW, thanks for hub vs crankshaft comment.

Looks like the more powerful six-cylinder 45-60/70 hp Anazani engines (late, maybe 1926-192 did, in fact, have 8-bolt hubs. The 22-35 hp appears to have 6 x 10mm @ 57.5mm radius hub.

Here are three Anzani crankcases. The one on the left is apparently a Channel 22 hp W-type (57o between cylinders) with valves behind the cylinders. Note: no "B te" marking at about 8 o'clock position on ther face.

Center is the Old Warden Anzani Military Type on display (not mounted on an airframe) at about 35 hp. The valves are on top of the cylinders and visible from front. Here, "B te" appears.

On the right is a later Y-Anzani of 35 hp with the "Brevete" spelled out ('Patented', Fr.).

Curious which prop markings identify the engine it was designed for.




(from:L Ghosts; middle N. Feltwell; right: Janes 191

-@pete

[Dave]

I don't know if I've ever seen a taper on the prop itself, and the Normale prop and Ebora props both have cylindrical center bores. The tapered crankshaft end fits into the machined metal hub which has a cylindrical outside and a conical inside bore.

Was that your question????

[drrivah]

Anzani Hubshaft

Here are a few of Anzani engines from a colleague photographed recently at Old Warden. The black one is from an Anzani 6 cylinder. The silver, from an Anzani Militaire (3-cylinder fan type). The latter is a modification of the Channel Bleriot Anzani. No photos of the actual Channel Anzani crank/Bleriot.

A question: these cranks look tapered. Is the hub bore on the Ratmanoff Helice Normale straight or tapered with increasing diameter anterior to posterior? If no taper, bore on both faces of hub will be identical diameter.

If tapered, the difference in diameters at 94mm depth should give the exact taper angle. The crank from the 6-cylinder looks to have an anterior-to posterior curve.





-@pete