Helice Normale

[pmdec]

Hi Pete,

Intrados side (the surface closest to the pilot of tractive props) is flat on Ratmanoff Normale props.

If you want to understand how those props are computed and made, and why they are like they are, you have to read two books from Stefan Drzewiecki, who was the man who computed the Ratmanoff props (Normale Ratmanoff props were "Drzewiecki patented":
- Des Hélices Aériennes, Théorie Générale des Propulseurs Hélicoïdaux (About air Propellers, Global Theory of Helicoid Propellants), published in 1909,
- and Théorie générale de l'Hélice (General Air Screw Theory), published in 1920.
I can't make copies, because they have too many pages, and all had to be read. Pretty fun: the back cover of the first one is a Chauvière advertisement You may find the second one in Google Books.

About your sections. IMHO, I think you take it the other way round. Sections are deduced from propeller full size drawings, and used to make templates to control the work in progress. Sections have to show the different laminations, because workers use the shape of the glue lines to make the prop right. Except if you use a numeric cutting machine, but then you will never have a credible replica, because softwares are not designed to make "old fashion" propellers...

About lamination thickness: have you find something? I have looked at some props and found different thiickness, from 16 to 22 mm., but 20 mm. seems to be the most common. I have two Levasseur WW1 props of the same serial, one made by Levasseur and the other by a subcontractor. All measurements are identical, but one have 8 laminations and the other have 9 for a 180 mm. thick hub: look at the pictures...

And I do not understand what you want to do. Prop replica? Airworthy ones? Or to sell them on eBay ?

Regards,
PM

[drrivah]

Ratmanoff Helice Normale

Dave:

I have used a calculation to estimate sections and helical angles at the labeled radii for the Ratmanoff Helice Normale prop from the photos. Now to test how good the fit is, if you will indulge me.

Dave, if the sections below were scaled to the bottom width at the radii indicated, are they close to the actual sections on the Ratmanoff prop?

Are the section bases (the surface closest to pilot) flat as shown here, or concave?

-pete

[pmdec]

Hi,

.../...
I would disagree on the board thicknesses: all sawmills cut boards to a standard thickness, even a century before 1910. Ask anyone who has done carpentry. The one thinner board in front or back is a means of saving material on a part of the hub that is not full prop length, not a result of having random board thicknesses.

Let me see if a 20 mm thickness fits with other photos of European props.

Thanks.

-pete

I was not speaking about boards, but about laminations. There was, during WW1, and probably before, a kind of standard thickness for boards use to make laminations: 27mm. It was NOT 1 1/16, because metric system was in use for a long time, and before it, there were some different "archaic" measurement units in different France areas.

And I didn't tell there was random thickness for lamination, but use of different thickness in the same prop, all planned (same for all props made from a particular blue print: prop blue prints include laminations thiskness, even in 1910 (I have no blue print example before)).

During WW1, some standards appeared, for example hub thickness: they were 95mm, 100mm, 103mm, 150mm and 180mm. As you can see, the "greater common divisor" is one millimeter... Even if yoo look only for 100, 150 and 180mm hubs (95 and 103 are discontinued for new designs after about 1915), the "greater common divisor" is only 10mm. And props were not made with 10mm laminations (but there were some built from 5mm, even less: it is another story).

Perhaps, if you clarify why you are looking for, and which data do you need, I may (or not) write what I know (or believe to know), without handing in all directions!

Regards,
PM

[drrivah]

Helice

If I understand, then the pitch "0m76" would be 760 mm, or 76 cm? I understand your point about significant digits and metrology.

From an engineering point of view this apparent 76 cm pitch for a Ratmanoff prop doesn't make sense for a 208 cm prop. Should be minimum of 100 cm.

I would disagree on the board thicknesses: all sawmills cut boards to a standard thickness, even a century before 1910. Ask anyone who has done carpentry. The one thinner board in front or back is a means of saving material on a part of the hub that is not full prop length, not a result of having random board thicknesses.

Let me see if a 20 mm thickness fits with other photos of European props.

Thanks.

-pete

[pmdec]

Hi,

@ Dennis : great pictures, thanks!

@ Pete : there is no standard thickness for laminations before 1916 in France. An often used thickness is 20mm, but one, or both, "last" laminations were often thinner, so you can't deduce lamination thickness from hub size.

"2m08" is 2.08 meters. "WmXY" is a common writting for W,XYm, that is W.XY (in France, the coma is used in place of the dot to mark decimal). "2m08" writting is not "official", but easier to read: you don't tell "two coma zero eight meters" in current language, but "two meter zero eight". And strictly speaking, 2m08 is 2.08 meter, or 208 centimeters, but not 2080 millimeters, as if there are only 2 digits after the dot, it implies you don't know the measure with a millimeter accuracy, while 2080 millimeters "tells" it is not 2081 or 2079.

Regards,
PM

[drrivah]

Anzani Props

Hi Dennis:
Great photos: any idea of the prop specs?

In the U.S., a 1-inch board is actually dressed to a final thickness of 3/4 inch.

In France in 1909, I am curious what the "standard" wooden board thickness
would be.

In addition, I am still puzzled by the notation "2m08". Does this translate to
2080 mm diameter?

-pete

[D.Hicklin]

additional pictures of the anzani

As you can see, it really does blast a lot of air, it was a pleasure to see and hear this rare engine run and sling a lot of oil.

Sincerely,
Dennis Hicklin
Seattle Washington

[D.Hicklin]

anzani fan engine run up

I thought I would join the conversation with a bit of show and tell. A few years back when I used to drive the round trip from seattle to oshkosh and back, I always had some extra time to visit unique airfields going back home.

I was fortunate enough to be over at Brodhead airport in Brodhead Wisconsin during the annual grassroots fly in and there was a work in progress that had a " fan type " Anzani engine that ran. The person in the pictures had old clothes set aside for the run up, as castor oil was blown back at him in large amounts, he was really soaked by the oil.

The reason the exhaust stacks are pointed forward, was thought by many to be that way to disperse the oil a bit before being blown backwards, I checked with the owner of the project, it was later revealed that the shape of the exhaust stacks would not clear the arc of the prop if installed the other way.

I hope you all enjopy the pictures.

Sincerely,
Dennis Hicklin
Seattle Washington

[pmdec]

Hi,

It is absolutely certain the Blériot XI which crossed the Channel was fitted with an "Intégrale" Chauvière prop. It was not exactly the same which was fitted to the aircraft when it made its precedent flight, as written in L'Aérophile I gave the references: same diameter (2m0 but "a slight higher pitch" (no number given). This page is correcting data written in the August 1st copy. And those data were 2m08 for diameter and 0m85 for pitch (L'Aérophile 1909 page 352). So, we know the diameter of the "Trans-Channel" flight propeller, and its pitch had to be a little higher than 0m85. But this is far from enough to build a prop! The hub thickness was probably between 90 and 100mm, and the blades width may be guessed from the pictures. But nothing about the shape of the prop: "Intégrale" Chauvière from this period had a concave intrados (how much?) and the pitch was not constant along the blade (higher near the tip): I do not think anybody know how the pitch was varying along the blade.

My conclusion: except finding a blue print of this very propeller, it is not possible to make the same prop. Anyway, I don't think it is possible to run a restored Anzani (or a replica) engine with the same torque and power curves it had in 1909: for example, do you know which fuel was used? So…

About the Ratmanoff Normale: the pitch is NOT stamped on those props before 1914 (diameter neither), at least for civilian use. And neither after 1915, because French markings for military in use after 1915 don't include pitch and diameter.

Ratmanoff Normale props factory probably did not exist on August 25th, 1909.


ABOUT BLÉRIOT TRANS CHANNEL FLIGHT: if anybody has access to Daily Mirror Digital Archives, please try to get a picture where the broken propeller (and undercarriage) is visible. The aircraft has been exposed for 10 days in England at Sheperd's Bush, and it is said that as many as 300 000 people came to see it. I can't believe not finding a single picture of the front of the aircraft there (I have a very bad one of left view).
As Lucien Chauvière advertised in many newspapers, perhaps he asked no picture of his broken propeller to appear anywhere: when the aircraft was shown in Paris in September, the prop had been changed.
THE Blériot is exposed in Arts & Métiers museum in Paris, and is described as original and not restored ... but nor the prop nor the undercarriage is broken. Therefore, those two parts are not original ones.

Regards,
PM

[drrivah]

Ratmanoff/ Anzani B Pitch?

Hi Pierre, Dave and Bob:
I agree this is quite interesting historically.

On considering prop pitch, your comment below "***...***" may be an important clue to pitch of the Ratmanoff Helice Normale for the Anzani engine.

The P/D ratio (pitch/diameter) for period props is usually in the range of 0.5-0.9. If we take diameter = 2080:

0.5 = pitch 1040
0.7 = pitch 1456
0.9 = pitch 1872

"Advance for one turn" is the definition of pitch of a helix/airscrew.

So, "0m76" is the pitch. How to interpret? "1076" (roughly 0.5 above), or
"1876", close to 0.9 above. Is it possible "m" is an "8" on its side? Or,
"Om" is "1 meter"?

In addition, the 70 km/h is a good number: it is the translational velocity for
the engine/airframe, and is exactly 43.5 mph, just what the top speed of the Bleriot XI was reported to be by Bleriot himself on the Channel crossing, albeit probably with a Lucien Chauviere prop, not the Ratmanoff here.

Finally, a nice touch found in period news clippings: at 4:30 am July 25, 1909,
Bleriot's engine was started for him by none other than the engine designer, Mr. Anzani...

Thanks, Gentlemen.

-pete

Hi Dave,
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

[drrivah]

Ratmanoff Helice Normale

Thanks for feedback on hub bolt circle, bolt diameter and central bore: making progress on overall diameter. Next to deduce or measure the face pitch. There are at least three or more approaches.

Hub looks to be about 88 mm deep at deepest (adjacent center bore). Can you see the number of boards used in this Ratmanoff prop from looking at the side of the hub?

Could be: 5 boards at 17.6 mm (11/16") thick

or

6 boards at 14.6 mm (9/16")

This is the next easiest step.

Thanks.

-pete

[Dave]

Hi,

About the bolts diameter of Dave's Ratmanoff, I think they are 10mm, and the hole 10.5mm, because only metric was in use.
If a 3/8 drill is "just right", may be it is a 9.5mm hole for a 9mm bolt (3/8 is 9,52mm).
Even later, during WW1, English propellers dimensions were in metric measures.

Regards,
PM

I agree that the measurements are almost surely all metric. I don't really have a good way to measure the bolt holes, and 3/8" was "close". Also, it's not unusual for wood to shrink very slightly perpedicular to the grain over a long period of time, so the hole may no longer even be completely round.

[pmdec]

Hi,

I must apologize to drrivah about W engines. He is right from an Anglo-American point of view, but in France we don't call W engines radial ones. This W designation is reserved for 12 and more cylinders engines. You can compare the English and the (very poor) French Wikipedia pages ( http://en.wikipedia.org/wiki/W_engine and http://fr.wikipedia.org/wiki/Moteur_avec_cylindres_en_W ).
So, this point is closed, and I withdraw my misplaced remark...

About the 8 bolts of the Chauvière propeller used by Blériot to cross the Channel, I refer to what I think is the best source: a picture in L'Aérophile dated August 15th 1909 page 367. I post a (bad) copy there:


You can access this page of L'Aérophile from USA in PDF at this address: http://catalog.hathitrust.org/Record/000520243 (I can't from France for copyright issue, and have to use an US proxy to do that): go to the volume 17 line, and then to page 367. There is an interesting description (in French) of the propeller.

About the bolts diameter of Dave's Ratmanoff, I think they are 10mm, and the hole 10.5mm, because only metric was in use.
If a 3/8 drill is "just right", may be it is a 9.5mm hole for a 9mm bolt (3/8 is 9,52mm).
Even later, during WW1, English propellers dimensions were in metric measures.

Regards,
PM

[Dave]

I've measured the dimensions as accurately as I can on the Helice Normal prop, probably within +/- 1 mm.

The center bore diameter is 46 mm
The bolt hole circle is 115 mm
The metal hub assembly plate is about 128 mm.

The bolt holes allow passage of a 3/8" drill with very slight wobble, so it is very CLOSE to 3/8".

Both this prop and the Ebora prop, which is clearly stamped for the Anzani engine are 6 bolt hole hubs.

[drrivah]

Anzani

The "Y" and "W" refer to the radial orientation of cylinders. It is not a coincidence that the "fan/W" looks like a period V-twin motorcycle engine.

The inverted "Y" had radially symmetrical orientation at 120 degrees offset. The "W" is synonymous with "fan", with all three oriented above thrust line.

Because Y cylinder spacing is radially symmetrical, the cylinders fired in equally timed pulses, whereas the "W" pulses were unequal: the W runs less smoothly than the Y.

If anyone has a photo of an eight-bolt Anzani hub, please post. Like to see it. Each "W"/fan Anzani (~ 25 hp) on the web looks to have just 6 bolts as common for low horsepower engines.

Usually 3/8" prop bolts (~10mm) are used. Absent an engineering drawing, be of interest to see if 10 mm bolts fit the holes on the Anzani props here, and if the hubs fit metric threads.

Below is the Old Warden Anzani/Bleriot XI in a photo taken by a colleague a few days ago:



Unclear what sort of prop is mounted here, or the specs.

Props usually are stamped with just two numbers: diameter (usually in cm for European props) followed by pitch (again, cm). It would be useful on the forum if hub type photos and dimensions could be posted: hub often dictates the prop and the engine/aircraft.

Again, thanks.

-pete