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Old 09-02-2019, 04:25 PM   #21
Dbahnson
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Originally Posted by sanger22 View Post
The center hole diameter is 2 inches.
I'm not sure that measurement is correct. By looking at the photos the inch scribes of the ruler line up on the outside of the bevel, but the critical size is the shaft diameter, not where the rounding on the hole ends on the face.



You would need calipers to accurately measure the inner diameter of the bore, but a rough alternative would be to cut a piece of paper 1 3/4 inches and see how it fits in the hole without bending or without leaving extra space.

And although the diameter and pitch are in Imperial system measurements, the prop may have been designed for a metric built engine, and one would not expect to see different prop shaft diameters for any given engine, and it may be that the crankshaft diameter was the same for a variety of different horsepower engines by the same manufacturer.




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Old 09-02-2019, 05:11 PM   #22
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I completely understand and I appreciate everyones assistance. If you happen to run across any additional information I would love to hear it.
Sincerely, John
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Old 09-02-2019, 05:18 PM   #23
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Dave,
My apologies, I just noticed your post about measuring the hub correctly. I will do that and let you know. PM thank you for your thoughts also. I go to Vermont fairly often and would like to have Dave take a look someday.
Thanks again, John
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Old 09-02-2019, 06:21 PM   #24
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Dave,
The other side of the prop doesnít have a bevel. I measured it from that side and it is almost exactly 2 inches. I have attached a photo.
Thanks John
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Old 09-02-2019, 06:39 PM   #25
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Quote:
Originally Posted by sanger22 View Post
Dave,
The other side of the prop doesnít have a bevel. .../...
Hi,
If it may be of any help:The fact that there is a "non bevel" side of the central hole and this "non-bevel" is on the same side that the "flat side" of the blades shows it is a pusher. With the copper shielding it could (could!) be for a seaplane.

Regards,
PM
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Old 09-02-2019, 07:42 PM   #26
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PM,
Thank you, I am impressed with your knowledge. Why did seaplanes use metal sheathing on the blades vs wheeled aircraft?
Thanks John
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Old 09-02-2019, 07:44 PM   #27
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Does this change what you think about the possible age of the propeller? I apologies for all of the questions. Although I am ignorant in propellers I have been collecting antiques for a long time
Thanks John
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Old 09-03-2019, 04:19 AM   #28
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Hi,

On seaplanes, there is a very high risk the rotating propeller come in contact with water (directly the crest of a wave, or water "paquet" airlifted at takeoff).
But on pusher "landplanes" there is also a risk at takeoff from some dirt or stones propulsed by the wheels.
The difference (by the 20's: I don't know before) is that aluminium alloy is used on propeller of "landplanes" and copper alloy on seaplanes because salted water and aluminium don't mix very well!

Also, another remark: the prop is right handed and righthanded pushers are not common.

And no, it doesn't change what I am thinking about the age, even the contrary!

Regards,
PM
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Old 09-03-2019, 06:37 AM   #29
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I have two minor observations, neither of which will be new to regular forumites. I posted this observation about protecting props a few weeks ago.

During the course of WW1, various measures were introduced to protect wooden propellers. The RFC carried out tests in late 1912 and early 1913 into the effect of small arms fire and shrapnel on wooden propellers with the thought that perhaps wooden props should be armoured. The experiments showed that laminated wooden props could retain their integrity even if hit by several rounds, so the idea of armoured props was dropped.

Undercarriages had a degree of flexibility so three point landings were essential to prevent a prop tip hitting the ground. WW1 aircraft literally flew from unprepared fields which were far from smooth so propeller tips were sheathed in brass which gave some protection from slight contact with the ground, mole-hills etc.

Pusher aircraft such as the FE2b and the Vickers FB series had the engine mounted behind the pilot and the undercarriage so the propellers on this type of aircraft were subject to erosion from dust, sand, and similar detritus so brass sheathing was introduced on blade tips.

Aircraft fabric, Irish Linen, began to be used as another layer of protection against erosion and was first added to the propeller tips, then to the outer third of a blade, then two thirds and finally like your prop, to cover the entire blade.

Secondly, it is a flown example. There are slight creases on the brass sheathing which are caused by the wooden blade flexing. The blade was flexible enough to cope with this but the brass sheathing was not and has those characteristic slightly ridged creases.

With kind regards to everyone,

Bob
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Last edited by Bob Gardner; 09-03-2019 at 06:54 PM.
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Old 09-03-2019, 11:57 AM   #30
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PM and Bob Thank you for your input. PM was brass also used on seaplanes or was only copper used for sheathing? So this prop was used on a pusher engine that was counter rotation?
Thanks John
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