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mobylarry
01-05-2016, 11:12 PM
Hi,

Can anyone recommend someone who can replace the metal leading edge sheathing? Or tell me what it is actually called and where I should look. They were missing from the prop when I got it, although there were several flush rivets that looked to be copper still in place.

In the US. Preferably eastern PA, southern NY, or NJ.
Blade is approx 1917 for an OX5.

I just want them for looks. I tried it myself, but couldn't get past the compound curves without wrinkles. I assume they were one piece originally, not two halves soldered together. I still would like to do it myself, if anyone can provide input on how it was done.

Thanks

Dbahnson
01-06-2016, 11:02 AM
Tough question. I don't think I have many metal sheathed props left, but I'll check on ones that I do. Seems to me that some of them are soldered at the seam of two halves.

I almost think that some of them were pre-stamped to fit the precise shape of the wooden blade, but I'm not sure.

Bob Gardner
01-06-2016, 12:27 PM
The best design was made in small segments. For a few years c1913 to 1915, it was common on props on pusher aircraft to have a sheath of metal covering much of the tip. When I come across such props this metal is now often slightly buckled because the prop flexed.

A firm patented sheathing marketed as lobster-shell, made of small pieces which could flex.

With kind regards,

Bob

mobylarry
01-06-2016, 02:34 PM
Thanks for the input.

Bob and Dave helped ID this prop somewhat a few years back. I just went to look at the old post and realized the links to the photos were gone. I'll attach them to the original post.

I'm not sure I described it well. It's the shiny copper bit in the photo attached. I did that with some copper foil I had laying around, very thin and it wrinkled easily. I used all the original rivet holes and didn't alter the prop at all. It looks halfway decent, right? :rolleyes: Actually, it's only covering one side. When I went to fold it over, I couldn't deal with the extra metal from the compound curve I ended up slicing it along the leading edge. That's what made me think about doing 2 halves and soldering along the leading edge. I think I could handle the shape then.

mobylarry
01-06-2016, 02:57 PM
This is what I was trying to achieve.

Dbahnson
01-06-2016, 08:48 PM
You know, that doesn't look bad at all, and since it's not original anyway it gives it a little appearance of "being used' and beaten around a little bit.

pmdec
01-06-2016, 09:22 PM
Hi,

Some pics of a Chauvière (1 to 4) and from a Ratier, both from WW1 (~1918 and 1915). Both have two halves copper parts, many parts for Chauvière and only two for Ratier.
Chauvière sheating is clearly from flat copper sheet, but Ratier is perhaps from preformed metal, by stamping or by electroplating.

Electroplating was commonly use in this era, for example to make ornements. It is relatively easy to produce such copper parts "in a kitchen".

A Happy New Year to all, and particularly to Dave and Bob*!

Regards,
PM

*The Ratier is the one you sold me more than seven years ago, Bob... ! It is now in our small museum!

mobylarry
01-07-2016, 11:04 AM
You know, that doesn't look bad at all, and since it's not original anyway it gives it a little appearance of "being used' and beaten around a little bit.

In the dark from 20 feet it looks great! I think the old camera was generous with hiding the overall bad points. The copper on there now is like aluminum foil one would use in the kitchen. If I were to try and vacuum dust off it, it would be sucked up quick along with the dust.

I think I will use 22mil copper sheet which is .217 in thick. That is used for roof flashing around here and is supposed to be somewhat easy to work, but still hold it's shape. I've never held it in my hand, so I'm not 100% sure it's what I'm looking for, but I think it's close.


pmdec, thank for the photos. I think the Ratier style is what would fit this prop. That seems to be folded and seamed at the tip curve only. Just to be sure I understand what I think I see, I attached a crude "drawing" below. The blue area is a fold and the green tab is the soldered section?


On the Chauvière one I understand the segmenting, but I'm not sure why the first four sections would need a soldered seam. It seems they could just be folded over. I'm sure they had a reason.

pmdec
01-07-2016, 10:45 PM
Hi,
Yes, it look like this, but I will take close ups of the Ratier sheating on saturday and will post them: there are holes at the tips which show part of the sheating section.
Ratier licensed sheating (http://ratier.org/archives/brevets/FR_523788.pdf and http://ratier.org/archives/brevets/FR_505632.pdf ) I have never seen made the first one. If you look closely at the second, you will see it is not a bent sheet.
Regards,
PM

mobylarry
01-09-2016, 09:28 PM
Thanks pmdec

The first patent is interesting. I see where that could make repairs in the field a lot easier and quicker. The second one looks like a camera. Ratier seems like he was an industrious fellow!

pmdec
01-09-2016, 11:43 PM
Hi,
Sorry for the patent number mismatch: the right one was http://ratier.org/archives/brevets/FR_505912.pdf And yes, Ratier was industrious, but not without success for the camera: they bought machinetools to make lenses but, as we know, they didn't sale any... made a propeller driven car instead!
And also sorry for the sheating pics: I forgot to make them past afternoon... I will return to the museum on monday and will try to post close up pics before tuesday!
Regards,
PM

mobylarry
01-10-2016, 04:56 PM
Thanks for the patent info. I see what you mean about it being preformed.

The cross-section drawing was very helpful. I wasn't even thinking that one of the rivet heads would end up on an angle because of the curvature. I'll need to remember to use the preformed head on the curved side.

Thanks

pmdec
01-15-2016, 10:21 PM
Hi,

Finally, the way the Ratier sheating of our serial 7 is made is not very clear. The small holes at the tips show a curved layer, with the same thickness that on the sides. If there is a place where the sheating is made as shown on the patent drawing, I cannot see it.

I join pics of a Régy serial 300 propeller (a 3 meters pusher for WW1 Voisin aircraft fitted with a Canton-Unné engine).

At first look, it seems that the sheating is thicker on the leading edge, but looking closer you see that both sheets (the intrados one and the extrados one) are curved and therefore there are two lyers at the leading edge.

Regards,
PM

EDIT: pic of Stefan added... I almost forgot ;)

mobylarry
01-15-2016, 11:13 PM
Hi

Thanks pmdec for the photos. I see what you mean on the serial 7 sheathing. It's not obvious at all how it is formed. Interesting. The cross section photo is similar to what I have been seeing in photos of period American made props. The majority seem to be two halves soldered together.

Thanks to everyone for the photos and comments, it is appreciated. I will take this information and give this project a try. I'll keep you updated with the progress and some photos. My projects seem to go slow... very slow, so it will probably be awhile!

Thanks again to everyone.

mobylarry
02-12-2016, 11:30 PM
Hi,

Well, I gave it a try. I'm satisfied enough for wall hanging.

I followed what I would think was the original procedures for forming it from photos I have seen and from the book "The Propeller" circa 1918. I ran into the same problem with the excess metal, this time on the edge that gets folded over. It's fine along most of the leading edge until the tight curve at the tip. The book mentions "rubbing" it with a hollow wooden block. Got me.

I had mentioned previously getting .021" copper, but I chose to go with .010" instead. It still firm enough to hold shape and still easy to form with your hands. The rivets were an exact match, 3/32 flat head countersunk solid copper.

Some photos are below. I didn't get a chance to file the solder as it's just to cold in the garage right now, and I didn't want lead dust in the house. You can see how the excess metal starts bunching up at the tip in the second photo.

I learned to hammer shrink metal, I guess that's good. I used that to get the copper to follow the contour on the curved side of the blade. It needs to be hammered from the inside, so it's shape it, then fit it, shape it, then fit it, over and over until it's right.

I can't see how they got that edge shrunk minus any wrinkles without the use of an English wheel or similar.

Anyway, it's finished until the winter cold breaks.

Again, thanks for the help.