Left Hand Chauviere identification help please ???

[gyrowoody]

Hi all :
I have come into possession of this propeller. It appears to be a Chauviere (going by the shape)?. The diameter is close enough to 250 cm. The markings on the hub are difficult to read.
The strange thing is that this is a left hand propeller?????
Can anyone with some degree of certainty determine what the propeller was used for ? Le Rhone engine in PUSHER configuration maybe ?
Is there any way of making the markings more readable without ruining the prop ? The varnish has “crocodiled”(if that is the proper term for it) ?
there also seems to be a vague stamping of the the number 226 or something on the flange face.
Any help is appreciated, since this isa LH propeller as far as I can tell? This must be quite rare ? Any idea of the value , being LH ?
Many thanks for any help /clarification/info/data from the knowledgeable folks on this forum!!
woody
How do I post several pictures on this forum please ????

[gyrowoody]

Pics part 2. Left Hand Chauviere

[gyrowoody]

More pics of the LH Chauviere .
Any help as to identification, how to make the numbers more visible, and the value of this propeller are more than welcome !!

Best wishes for the New Year to all !!
Woody

[pmdec]

Hi,

From your pics, I read the markings as:
- Side 1: NUMERO 14831 (or 14031?) / SERIE 2206 [Prop number and serial number]
- Side 2: DIAMETRE 250 / PAS 1?0 (probably 130) [Diameter and pitch]
- Flat side 1 ! 220 (or 226?) I don't know what is this number for on Chauviere props.
- Flat side 2 : nothing

It is a French made Chauviere, left handed, as you told. Probably a pusher, but not certain.

This kind of markings on French made propellers, with diameter and pitch but no aircraft nor engine, was in use before 1915.

The Chauviere serial 2206 is not included in props tables of the 1910's I know about.

There is no airworthy stamp, so it was not approved for military use. And there is no control stamps, so it was not made for military purpose. As no civil props were made in France after the beginning of WW1, it was probably made in 1914, for civil use, but it will be not possible to know for which aircraft nor for which engine. A diameter of 250 cm is a very common one in the 1910's for engine between 45 and 100 HP. The pitch (if 130 cm) is very low.

Regards,
PM

[Dbahnson]

Nice looking prop appearing to be in its original condition. It's very hard to determine a specific value without knowing its usage and with little or no comparable sales for reference. Unfortunately, if PM doesn't know what it was used on, I don't think anyone else will either.

[gyrowoody]

Hi all and thanks for the input.
pmdec and Dbahnson : if the pitch were 180 instead of 130 (130 being very low), it would open up the possibilities further to find out which aircraft this came from (pusher rotary engine or LH tractor configuration).
Is there any way I can measure the pitch on the propeller to determine whether it is 130 or 180 please ? This is usually done at 70 or 75 percent of the blade length or so ?
I have accurate angle measurement equipment available to measure this. What value am I looking for for pitch 130 and which value for pitch 180 please ?
Also is there a propeller table or list with comparable numbers anywhere ?
Many thanks.
WDS

[Dbahnson]

All I know is that pitch can be determined fairly easily by measurement. I just don't know how to do it.

[Dbahnson]

With respect to left hand rotation, there are several explanations:
1. Pusher configuration - the engine is simply mounted backwards but its rotation direction of rotation is unchanged. This likely the most common explanation.
2. Engine rotation is reversed - some engines were just built with a rotation direction opposite of "standard" direction
3. Geared engine - such as some SPADs. where an internal gear causes reversal of the direction
4. Twin engine aircraft - a variation of #2, where one engine was constructed to rotate in the opposite direction to balance "P" factor and its yawing force

[pmdec]

Hi,

Yes, to measure the pitch is very simple:
- You place the propeller on a horizontal table, with the rear face of the blades (this side of the blades is flat, i.e. not curved) facing upwards.
- You measure a distance exactly equal to 1 meter from the center. You can stretch a rubber band around the blade at this location, making sure that it is perpendicular to the axis of the blades.
- You measure the angle between the blade and the table by holding the measuring device against the rubber band, or "a" this angle. Some smartphones can do that with enough accuracy.

The pitch of the propeller at R meter is equal to 2 pi R tan(a), or, since the measurement is made 1 meter from the center, 6.28 x tan(a).

BUT...

At that time, there were 2 types of propellers:
- those with constant pitch*, i.e. those whose pitch is the same regardless of where it is measured.
- those with a variable pitch* with 4 subcategories:
oo those with an increasing pitch: it increases as you get closer to the end of the blades
oo those with a decreasing pitch: it decreases as you get closer to the end of the blades.
oo those with a pitch that first decreases, then increases along the blade.
oo those with a pitch that first increases, then decreases along the blade.

*: WARNING! "constant" and "variable" do not have the current meaning at that time.

BUT, measuring the pitch at 1 meter did not become the standard measurement point in France for propellers of less than 3 meters until around 1916. It is therefore not certain that this Chauviere from around 1914 uses this convention.

It could be a good idea to make 3 measurements, at 1 meter (6.28 x tan(a)), 0.80 meter (5.03 x tan(b)) and 0.60 meter (3.77 x tan(c)).

Anyway, I would be very surprised if the pitch was not around 1.30 meter from the serial number.

Regards,
PM

[gyrowoody]

I will do some measuring in the coming weeks hopefully and then we can compare what I find. In any case : many thanks for the great help and info gathered thus far. This forum is great !! Many thanks to all who have replied !!

[gyrowoody]

Dbahnson : were there SPADs with geared engines of this (low) horsepower ? I thought SPADs had more powerful engines (starting at 180 HP on the SPAD VII, I thought), and these were Hispano engines , I think. So this propeller probably did not come off a SPAD, I think, although the shape is typical for the La Chauviere props used on those planes.

I keep on searching what type it might have been fitted on, based on the dimensions.
Can anyone confirm the bolt pattern used on this propeller ? That may help in eliminating a number of impossibilities...

Many thanks, WDS

[Dbahnson]

I'd have to defer to Pierre-Michel on that one. He's clearly the expert on French propellers.

[pmdec]

Dbahnson : were there SPADs with geared engines of this (low) horsepower ? I thought SPADs had more powerful engines (starting at 180 HP on the SPAD VII, I thought), and these were Hispano engines , I think. So this propeller probably did not come off a SPAD, I think, although the shape is typical for the La Chauviere props used on those planes.

I keep on searching what type it might have been fitted on, based on the dimensions.
Can anyone confirm the bolt pattern used on this propeller ? That may help in eliminating a number of impossibilities...

Many thanks, WDS

Hi,

I think Dave writing about geared SPAD was "generally speaking" about LH props: yours can't be from a SPAD because it was made around mid-1914 and first SPAD flew only in 1916!

There are only two shapes for French made Chauviere propellers of the WW1 era: the serials numbered 1xxx, and the serials numbered 2xxx So, all 2xxx numbered Chauviere look the same whatever the plane it was made for*.
Exemple in Dave collection:
https://woodenpropeller.com/Nieuport24bis.html : a 2228 which has same "thin" blades normally viewed on, for example, a WW1 1650
https://woodenpropeller.com/AnzaniChauviere.html : "classical" shape of Chauviere props
https://woodenpropeller.com/Chauviere.html : early shape (before 1914).

Attached pic: end of WW1 1650 vs classical WW1 (a 2217 for Nieuport with a 80 HP Clerget)

About the bolt pattern: you have not given any measurement. Could you give the size of the central hole, the size of bolt holes and the size of the hole circle? It could be a lead to the engine, but some kind of standardization was already on the way in 1914. The thickness of the hub also could be useful. But the pitch is very important and we have to wait you made the measurement even if 99% of French made Chauviere serial 2xxx have diameter and pitch included in the serial number. IPC made Chauviere don't follow the same serial number pattern.

Regards,
PM

*: with at least one exception for serial 2228 which has the shape of a WW1 1xxx.


ChauviereShape1650vs2217.jpg

[gyrowoody]

I have now measured the pitch of the propeller at 3 different distances from the hub as PMDEC suggested :

At 1 m I found 15 degrees. 6,28 tan 15 = 1,68
At 0,8 m I found 19 degrees. 5,03 tan 19 = 1,73
At 0,6 m I found 24 degrees. 3,77 tan 24 = 1,68

Is the small variation measured at 0,8 m (5 percent) significant enough to take into account or can we say that the pitch of this prop is 1,70 m ? This does not bear any relation to the markings of pitch on the prop itself which is either 130 or 180 (the figure "3" is difficult to read and could be a figure "8" as well) ? So I took another picture of the pitch figure on the hub but with the light at a different angle and it seems to read 180 instead of 130 ? Please see the picture below.
Does this come close enough to the measured pitch of 1,68 m which I will round off to 1,70 m for simplicity since it is closer to 1,80 than to 1.30 m ?

The hub thickness of the propeller is 103 mm, the center hole is 60 mm diameter and there are 8 boltholes of 10 mm diameter, and these are centered at about 60 mm from the center hub.

With these new data can we get closer to determine which engine this prop was made for please ?

Most sincerely,

Woody

IMG_5977 3.jpeg

[Dbahnson]

"Pitch" isn't perfectly mathematical. Note on this schematic how there is several degrees difference between the mathematical amount and the actual design aamount.

airscrew.jpg

[pmdec]

Hi,

Thank you, Dave, for posting that : it will be easier to explain the difference between theoretical pitch and geometrical pitch.

From your Plan of blade :

PitchValuesFromPlanWPLHChauviere.jpg


Do you know what is the pitch stamped on your example? If it is the theoretical pitch, it would be 11' 6" (3.50 meters).

I don't know what was the "added angle" used by Chauviere in 1914. Ratmanoff used 2.5 degrees. And I have not made enough measurements to know if Chauviere stamped theoretical or true pitch.

@gyrowoody: I am not so sure the stamped pitch is 180. If you take out 3 degrees from your 15 at 1 meter from the center, you have 12 and then the theoretical pitch would be 6.28 x tan(12) = 1.33. It would give a speed of 104 km/h for 1300 rpm engine.

Have you verified that the angle indicated on the hub is zero? and can you give the angle at 1.20 meter?

Another possibility: A marking error. A 2.50 meters Chauviere with 1.80 pitch would have a serial number finishing with 16 (and not 06, which the standard for 1.30 meter pitch).

The thickness of the hub (103 mm), the diameter of the central hole (60 mm) and the diameter of the bolt circle (120 mm) is exactly what is expected for a standard French hub "type A", so you can't infer an engine model, only that it was engine with a power between 50 and 100 HP. I know 24 models of Chauviere propellers with exactly this hub size of which 14 are 2.50 meters (pitch from 1.45 to 2.00).

Regards,
PM

The Chauviere I know with same hub and diameter as yours:

ChauviereS_D2m50_HubA_Th103.jpg