Odd 7-bolt Chauviere Prop

[Dave Burnett]

Odd 7-bolt Chauviere Prop

Three more photos: hubfront, leftfront, and failed photo of engraved markings. Only long side view remaining.

[pmdec]

Three more photos: hubfront, leftfront, and failed photo of engraved markings. Only long side view remaining.

Waooh! It is a true treasure you have! I will come back later as I have kind of "administrative" stuff to do before tomorow morning.
Will come with pictures:
- of a Rapid prop with exactly the same hub appearance and which was undoubtly for Farman or Sommer pusher with a rotary Gnome (the guy found the prop with the crakcase attached)
- and of a partially destroyed Chauvière blade with the same yellow color fabric and which has to be dated between 1910 and 1912 because it was for a Sommer monoplane (tractor prop).

And I am sure the writing is 1,46: not so sure for the 6 but absolutly for the 1. I don't know if other European did the same (at least in the past), but in France we wrote the 1 like this (and put a small cross-bar on the 7 to distinguish it from 1: see the font "Bradley Hand" if you have it in Microsoft Word). A picture from the page http://villemin.gerard.free.fr/aHuma...e/Chiffres.htm which explains how digits writing is teached to child in France:



Regards,
PM

[pmdec]

Hi,

I am waiting (from the owner) for larger pictures of a "Rapid" propeller which was for a Farman or a Sommer pusher made between 1910 and 1914. I have only small ones for now, where the 7 holes are not all visible at a time (but they are there!). It seems this prop is very like Dave Burnett's one.

I think we have to consider also a Chauvière blade which have to be made between late 1909 and 1912. It was for a Sommer tractor (not a pusher), but the general aspect of the prop, specially the color, but the shape also, look like the Dave's prop.
I do think the Dave prop is French, but around 1910-1912, there were many prop makers in France (my list goes past a hundred). Someones made props shaped like Chauvières ones, and it is possible we never know who made this one, because too few have survived to compare.

Anyway, this prop is a true piece of history and I am sure it is in very good hands in Canada, away from foolish restorers...

There is a very interesting text which include first aviation hours in Norway here: http://www.europeanairlines.no/wp-co...06-01-2011.pdf
I would not be surprised if the prop would come from one of the aircrafts described (Farman or Sommer) or from a batch of spare parts for them. The script writing seems to be French (or of a "Latin" country), and might be a prototype or a very early prop, before the habit was taken to stamp them. I don't think it is a craft work, because the prop seem too well made and glued (no delamination).

PS: the "Carambar" on the Chauvière pictures is there as a color chart (I have to buy one): think those candies are available everywhere (yet at gold cost in USA!).

Regards,
PM

[pmdec]

Hi,

Dave Burnett told me by mail he doubts that the Farmans in the link I gave about first aviation in Norway could be the ones we are looking for, because those "Longhorns" had a rear prop but not a "sanwiched" one and he seems right. So the search has to be continued.

I eventually found a booklet with a drawing of a Gnome which clearly show how the prop could be "sandwiched" (could because the blueprint shows the two possible fittings on the same drawing).
The picture came from this page: http://bleriot11.pagesperso-orange.fr/
The yellow and red colors have been added by me. Not only this sectional view is interesting by showing the two ways the prop could be fitted, but if you look closely the front fitting show 2 bolts (so they must be 6 or 8 ) and the "sandwich" fitting show only one, so they have to be in an uneven number of bolts!
One can see also that the sandwiched prop has a counter-bore at the rear, and could have another one at the front to have a thicker one.
I will made measures on the drawing as soon as I find a precise dimension

Regards,
PM

[Dave Burnett]

Odd 7-bolt Chauvier Prop

Thanks to the work of PM I think that we now know that the 7-bolt configuration was unique to a specific rotary engine pusher application where the propeller was sandwiched ahead of the engine cylinders. In trying to eliminate Germany as a possible source for my prop I find plans that show Albatros Werke GMBH did intend to build a copy of the French Roger Sommer design. Can anyone find evidence that this specific design was produced and if so how many? I know that at the time they quickly modified their aircraft and changed to other configurations and engine types.
http://earlyaviators.com/esommer2.htm