PDA

View Full Version : A new ID (early Paragon or similar???)


Barf_Bag
10-31-2016, 02:39 PM
Hi folks,

I recently purchased this prop for office decoration, thinking from the crappy pics in the ad that it was just something someone had made and not a real prop, however I'm not so sure anymore. I don't really care about value since I'll keep it for decoration anyways, but if there's any possible info I can gather then I'm all ears.

I have spent a few days searching on the web and the closest thing I could find was here, hence my new account. The shape looks a lot like this one :
http://woodenpropeller.com/Paragon1912.html

This would also make sense since it seems from the wikipedia article that this manufacturer shipped a lot of props to Canada in the beginning of the century (it was found in eastern Canada).

However there are no markings or decals of any kind to help us.
Here are some basic specs:
- Diameter : exactly 6ft. (if the end wasn't chipped that is)
- Weight : Very light, maybe 10 lbs.
- Thickness : 2.5in. (at the hub)
- 4 Bolts
- Each bolt hole is exactly 2 in. from the center.
- It was apparently made from 2 halves (in thickness), you can see it clearly in the chipped part.
- The end was probably chipped a long time ago, seeing that the wood inside is all grey and rounded.

I have uploaded the pics here for better quality :
http://imgur.com/a/xlsDr

Many thanks!

Barf_Bag
10-31-2016, 02:48 PM
I should add that I noted, from the construction and the way it was obviously installed, that it looks like it was a pusher prop, making me think it could have been used on an early snowmobile or something similar (it's Canada after all).

Dbahnson
10-31-2016, 09:04 PM
Welcome to the forum . . .

A few comments, in no particular order:

1. There is no aerodynamic distinction between a pusher and a tractor propeller. Since many engines are used in both configurations, the difference in propellers is in the direction of rotation. So an engine type (e.g. OX5) could have a right hand tractor propeller and a left hand pusher propeller, but they are mirror images of each other, not separate designs. Yours looks like a left hand rotation, which is the more common pusher configuration for most of the WW1 era engines, but also does not have a hub configuration consistent with any of those engines, so it's really impossible to say at this point what application it was made for.

2. There are a lot of very old propellers that were used in the development of aircraft prior to WW1 and they take all sorts of shapes and sizes. Unfortunately, they are hard to identify without stamped information, and there are a lot of props made by "dabbling" in various forms by amateurs. Again, it's hard to know which end of that spectrum yours falls on, as it could be either.

3. The hub configuration is not consistent with any of the commonly used engines during and after WW1, but MIGHT have been used on an earlier engine of some kind. We just don't have any real data to help identify that.

4. The "witness marks" around the hub indicate that it was likely mounted and used on something, whether it was an aircraft or some other air-powered device, and the chipping on one tip may very well have occurred during use.

It's a good prop to keep as a "mystery". Someone may come along and be able to shed more light on it, but the longer you keep it the more mysterious it may become . . .

Barf_Bag
11-04-2016, 10:23 AM
Thanks a lot for chipping in.

It will probably stay a mystery then, and I'm fine with that. Great conversation piece for the price of a big mac combo! It will be installed in my office at the airport so quite a few fellow pilots will see it in the next few years, maybe someone will have an epiphany ...

I will have to disagree with you on point 1 though, here's my reasoning, though there is admittedly a lot of conjecture involved:

- The prop was made to spin only one way, that part is clear. See the picture second to last, the leading edge was bottom-left and upper-right. But then it's true you can install it one way or the other on the engine.

- However, the artifacts on the hub suggest to me that the "dirty" side was the crank side and the countersunk side was the bolt heads.

- Then I saw those wooden props were often installed with a crush plate, suggesting there shouldn't be obvious signs of bolt heads. However, it does look like this one was really installed without one, with the bolts going direct.

- What lead me there is this small document : http://www.princeaircraft.com/documents%5CPAC_Torque_Procedure.pdf
If you look at the pic at the top (what happens when it's installed without a crush plate), well my prop is cracked in the exact same manner. You can see it a bit in the first and last pictures, but when you have it in your hands you could properly break the whole prop in 2 with your bare hands.

So yeah, a lot of what-ifs, but the story it tells me thus far is that it was probably a pusher prop, mounted with bolts directly, without a crush plate, leading to it cracking at some point (could have been the same incident as the chipped end, a prop strike that both took off the end and cracked it in the middle).

That's probably as far as we'll get ...