Wooden Propeller Forum  

Go Back   Wooden Propeller Forum > Wooden Propeller Identification > "Early" Wooden Propellers

Reply
 
Thread Tools Display Modes
Old 09-06-2013, 09:45 AM   #11
MartyF
 
Join Date: Aug 2013
Posts: 8
Default

Just re-read previous post and realise my question 1 is already answered!
Also, if this was formally a Ratmanoff, who put Mercure decals on?
MartyF is offline   Reply With Quote
Old 09-06-2013, 10:26 AM   #12
Dave
Moderator
 
Join Date: Jan 2006
Location: Vermont
Posts: 2,831
Default

It doesn't look like there are any Ratmanoff-like drawing numbers in the markings, so I suspect it's not "originally" a Ratmanoff propeller, even though the designs are similar.
__________________
Dave
Dave is offline   Reply With Quote
Old 09-06-2013, 05:11 PM   #13
pmdec
 
Join Date: Nov 2006
Location: France
Posts: 439
Default

Hi,

Quote:
Originally Posted by MartyF View Post
Hi PM
Many thanks for your comparisons. I guess we can make no further progress with identification.
There are just a couple of things which are bugging me:
1. Which came first the 8 or the 6 hole hub modification?
2. I notice elsewhere in the forum (under Abbreviations) that the prefix AP (mine is AP16) refers to Aeromarine Plane & Motor Co in 1918. Does this refer to the U.S.A. only?
3. You refer to your collection (museum?) in France. Where exactly are you.
(I happen to be driving through France next week, though I am going to the South East and I think you are in the South West.)
Colin
1: as you just written, I think it is a 6 holes modified in 8 holes, with 4 dowels in the no more used holes (see last pic of my post)
2: I think the vertical bar of your P is a scratch. It is not oriented correctly to make a P. For me it is Aº (A exponent 0), perhaps A^5 (A exponent 5), but A^5 Ratmanoff was 2,40 meters long and yours is 2,29 as you said me in a mail.
3: Our small museum is in Figeac (Lot). A (relative) long way from south east of France. You have a Google map there: https://maps.google.fr/maps/ms?msa=0...5&source=embed (sorry for the length of the address!).
If you are going there, send me a mail before.

@Dave: Yes, pre-war Ratmanoff serials have this drawing number pattern. A3, A3bis, A5, A6, A8, J1, J3, K5, K5bis, K6, K7, K8, L1, L4, U2, X1, X2 and X3, all with capiltal letter and digit in exponent place. And the habit about Ratmanoff serial is a number just after this X² and another number after a space. To my knowledge, they are the only props with exponent digit after a capital letter before WW1.

If this prop is a A^5, it could have been modified in Mercure shop to fit another aircraft: diameter reduced, 8 holes and tapered extremity of the central hole to fit a latter metallic prop hub. Ratmanoff A^5 was for Antoinette with a 50HP engine and made to have a speed of 92 km/h.

The pic is cropped from a pic sent by MartyF and with higher contrast. For me, the sign after A is not a P. It could be a 0 or a 5. Both are plausible. Look at the other digits on other pics: the boucle, when present, "thightens" at the extremity. All known pre-war Ratmanoff props have this kind of "font".

Regards,
PM
Attached Images
File Type: jpg Ao 16 (from P1000163).jpg (87.3 KB, 8 views)
pmdec is offline   Reply With Quote
Old 09-11-2013, 03:53 PM   #14
MartyF
 
Join Date: Aug 2013
Posts: 8
Default Pointed tips?

After further discussion with my seller, he informs me that he was told that the tips of this propeller were originally pointed. In this form, the aircraft would not fly properly and so the ends were 'squared off' to make it fly.
I cannot verify this information but it makes things even more complicated.

I would be interested if anyone has a picture of what kind of aircraft this would have been fitted to.
MartyF is offline   Reply With Quote
Old 09-11-2013, 05:38 PM   #15
Dave
Moderator
 
Join Date: Jan 2006
Location: Vermont
Posts: 2,831
Default

That makes sense, as 90" is a little shorter than most of the "typical" WW1 era propellers. You can tell somewhat by looking at the tip end on. It will be thick in the middle and thinner at the back and front.

"Squaring off" of the ends usually was the result of damage. It's possible that it was retrofitted to another engine and was simply too long, or it might in fact have had different performance with the tips removed, but generally if that was an aerodynamic problem they simply would have installed a different propeller.

Finding a picture is futile unless you can identify it further.
__________________
Dave
Dave is offline   Reply With Quote
Old 09-12-2013, 09:14 AM   #16
pmdec
 
Join Date: Nov 2006
Location: France
Posts: 439
Default

Hi Dave and others,

This "Mercure" prop (modified Ratmanoff for me) is clearly from before WW1 and was modified also before WW1 : Mercure decals after 1917/1918 are different and during WW1 there was not civil use of propellers. As all military propellers have airworthy stamps, this one have to be made and modified before 1914.
In these early times, small propellers (from 4') were used. Look at this Chauvière price list published before 1914 : half the props are under 2,50 mètres (98") :

Regards,
PM
Attached Images
File Type: jpg Dépliant 190x p3_cr_600px.jpg (34.0 KB, 9 views)
pmdec is offline   Reply With Quote
Old 09-12-2013, 10:04 AM   #17
MartyF
 
Join Date: Aug 2013
Posts: 8
Smile I think you are correct!

PM
After your latest comments, I have taken a closer look at the stamped numbers and on close inspection, it does show A^5 (complete with font end curls).
Dave
I have also taken an end shot to show the blade profile as best I can to answer your 'thickness distribution' comments.

PM
I will be driving past Cahors on Saturday en route to Perpignan but sadly will not have the time to come and visit. Perhaps some other time.

Thanks for your interest gents. So is this prop rare or not?
Attached Images
File Type: jpg P1000345.jpg (65.0 KB, 7 views)
File Type: jpg P1000347.jpg (91.9 KB, 8 views)
MartyF is offline   Reply With Quote
Old 09-12-2013, 11:11 AM   #18
Dave
Moderator
 
Join Date: Jan 2006
Location: Vermont
Posts: 2,831
Default

The photo of the tip end certainly looks more like an original than one that has been cut down. If it has been cut down, someone has shaped it to look original, but I think that's less likely.
__________________
Dave
Dave is offline   Reply With Quote
Old 09-13-2013, 08:23 PM   #19
pmdec
 
Join Date: Nov 2006
Location: France
Posts: 439
Default

Hi,

Yes, the tip seems original, but it could have been made like the original. Ratmanoffs have this kind of section. I will made a picture of the one we have from the same era and will try to find a "5" on a Ratmanoff to see if the bar is also curved.

About rarity: each prop of this era is a rarity! Many are the only one known of their kind. But if your question is a price matter, price of propellers has no direct relation with rarity.

Beware of speeding on your road to Perpignan: French state is looking for money!

Reagards,
PM
pmdec is offline   Reply With Quote
Old 09-14-2013, 09:51 PM   #20
pmdec
 
Join Date: Nov 2006
Location: France
Posts: 439
Default

Hi,

Two views of the tip of a Ratmanoff serial KU (from 1911/1913). And markings from a Ratmanoff serial B: the 5s look very similar to the one of A^5, with the curl at the end and the upper bar curved down.

For me, with 99.9% chance, your prop is a Ratmanoff serial A^5, shortened from 2,40 to 2,30 meters, with 1 centimeter lost (not in translation , but from time damage). The decals perhaps affixed in Mercure workshop? I think we can never know.
The only way to gain 0.1% to have a 100% Ratmanoff would be to find the remnants of Ratmanoff stamps: there were two on each blade, just near the hub, extrados side, and about 20 centimeters from the hub, intrados side.

Regards,
PM
Attached Images
File Type: jpg Rat KU IMGP9915_cr_600pxH.jpg (13.2 KB, 7 views)
File Type: jpg IMGP0999_Rat KU.jpg (28.1 KB, 6 views)
File Type: jpg IMGP1005_Rat KU.jpg (16.6 KB, 6 views)
File Type: jpg Ratmanoff série B-751 n°2356 .jpg (20.4 KB, 6 views)
pmdec is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -4. The time now is 12:01 AM.


Powered by vBulletin® Version 3.8.9 Beta 3
Copyright ©2000 - 2017, vBulletin Solutions, Inc.