Just bought (and probably overpaid)

Emerson · 08-09-2019, 07:22 PM

Hoping someone can identify. My wife had to have it

Dbahnson · 08-09-2019, 10:44 PM

I'm not near my reference material to look that up, but it's a nice looking prop, probably from the 30s to 50s era.

Are there any other stampings on it?

Emerson · 08-09-2019, 11:47 PM

Wow. Thanks for your reply. Yes. Other stamping on other side of hub reads 370618. I was guessing it is a 1937?

Dbahnson · 08-10-2019, 07:28 AM

I think the other number is a serial number, not reflecting a date of manufacture.

When I'm home next time I'll try to look up that Type Certificate number ("ATC 87") and might be able to find the design number ("80A"). Those are the identifying markings. Is the prop 80 inches from tip to tip?

Emerson · 08-10-2019, 09:28 AM

No this prop is 9 feet

Dbahnson · 08-10-2019, 09:56 AM

So it's clearly not a Sensenich prop, and the manufacturer isn't clear, so we may not be able to identify it. I'll look for the type certificate information and see if I can come up with anything.

The metal sheathing is also a little different than you commonly see, so that might lead to some more manufacturing information if you can find an identifiable prop with the same type of sheathing.

Emerson · 08-10-2019, 10:03 AM

Thanks. Do you think because it is 8 hole and 9’ it may be older?

Dbahnson · 08-10-2019, 10:09 AM

Quote:

Originally Posted by Emerson

Thanks. Do you think because it is 8 hole and 9’ it may be older?

That's certainly possible, although "older" may just be 20s or 30s, when aircraft technology was evolving quickly. See this page and carefully measure the hub dimensions. It will eliminate a number of engines and narrow down the aircraft possibilities.

"Overpaid" is relative, especially when the wife is pushing you to buy it.

Emerson · 08-10-2019, 10:20 AM

Thanks. I will have to measure at a later day. We bought at auction out of our area and we left it at my brother in laws house. I’ll have home measure.

Bob Gardner · 08-10-2019, 11:19 AM

I assume this prop is American? My interest is British and German props from WW1, so I'm not really qualified to comment on this prop except to note that the brass sheathing is the most extensive I have seen on a prop.

Brass sheathing is used to protect wooden props from FOD such as twigs, loose grass and leaf litter thrown up by the wheels of the aircraft into the rotating arc of the prop, causing erosion to the prop blades.

On tractor props, a small brass leading edge is sufficient. On pusher aircraft with the engine behind the pilot much more of the FOD thrown up by the wheels can reach the propeller disc, and the size of the brass sheathing is much larger. This also applies to seaplanes.

So my minor observation is that your prop was intended to be used where lots of FOD existed. This would include mud, grass, and twigs; snow and ice; and lastly to seaplanes or flying boats where spray and bodies of water could be thrown up in the path of the prop.

The witness marks around the bolt holes show that the prop is a flown example. The construction of the prop with large laminations suggest that it was built in the 1920's.

The riveting holding the brass sheathing to the prop suggests the style of AAD Lang in Britain who devised the use of such protective sheathing using counter sunk screws which were then filled by a small amount of silver solder which was then smoothed to maintain the aerodynamic surface. He patented the design in GB in 1913 and in the USA in 1915.

In 1917, when the USA entered WW1, Lang was loaned by the British Admiralty to the USN to advise those US firms competent in wood-working that were recruited to make aircraft propellers in volume.

There's a lot of supposition in what I have written above and you should not regard it as anything more than an exploration of possibilities.

With kind regards,

Bob

08-10-2019, 11:19 AM	#10
Bob Gardner Moderator Join Date: Jan 2006 Location: The North of England Posts: 1,812	I assume this prop is American? My interest is British and German props from WW1, so I'm not really qualified to comment on this prop except to note that the brass sheathing is the most extensive I have seen on a prop. Brass sheathing is used to protect wooden props from FOD such as twigs, loose grass and leaf litter thrown up by the wheels of the aircraft into the rotating arc of the prop, causing erosion to the prop blades. On tractor props, a small brass leading edge is sufficient. On pusher aircraft with the engine behind the pilot much more of the FOD thrown up by the wheels can reach the propeller disc, and the size of the brass sheathing is much larger. This also applies to seaplanes. So my minor observation is that your prop was intended to be used where lots of FOD existed. This would include mud, grass, and twigs; snow and ice; and lastly to seaplanes or flying boats where spray and bodies of water could be thrown up in the path of the prop. The witness marks around the bolt holes show that the prop is a flown example. The construction of the prop with large laminations suggest that it was built in the 1920's. The riveting holding the brass sheathing to the prop suggests the style of AAD Lang in Britain who devised the use of such protective sheathing using counter sunk screws which were then filled by a small amount of silver solder which was then smoothed to maintain the aerodynamic surface. He patented the design in GB in 1913 and in the USA in 1915. In 1917, when the USA entered WW1, Lang was loaned by the British Admiralty to the USN to advise those US firms competent in wood-working that were recruited to make aircraft propellers in volume. There's a lot of supposition in what I have written above and you should not regard it as anything more than an exploration of possibilities. With kind regards, Bob __________________ Bob Gardner Author; WW1 British Propellers, WWI German Propellers http://www.aeroclocks.com Last edited by Bob Gardner; 08-10-2019 at 03:11 PM.

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08-09-2019, 10:44 PM	#2
Dbahnson Administrator Site Admin Join Date: Nov 2008 Posts: 1,333	I'm not near my reference material to look that up, but it's a nice looking prop, probably from the 30s to 50s era. Are there any other stampings on it?

08-09-2019, 11:47 PM	#3
Emerson Join Date: Aug 2019 Posts: 12	Wow. Thanks for your reply. Yes. Other stamping on other side of hub reads 370618. I was guessing it is a 1937?

08-10-2019, 07:28 AM	#4
Dbahnson Administrator Site Admin Join Date: Nov 2008 Posts: 1,333	I think the other number is a serial number, not reflecting a date of manufacture. When I'm home next time I'll try to look up that Type Certificate number ("ATC 87") and might be able to find the design number ("80A"). Those are the identifying markings. Is the prop 80 inches from tip to tip?

08-10-2019, 09:28 AM	#5
Emerson Join Date: Aug 2019 Posts: 12	No this prop is 9 feet

08-10-2019, 09:56 AM	#6
Dbahnson Administrator Site Admin Join Date: Nov 2008 Posts: 1,333	So it's clearly not a Sensenich prop, and the manufacturer isn't clear, so we may not be able to identify it. I'll look for the type certificate information and see if I can come up with anything. The metal sheathing is also a little different than you commonly see, so that might lead to some more manufacturing information if you can find an identifiable prop with the same type of sheathing.

08-10-2019, 10:03 AM	#7
Emerson Join Date: Aug 2019 Posts: 12	Thanks. Do you think because it is 8 hole and 9’ it may be older?

08-10-2019, 10:20 AM	#9
Emerson Join Date: Aug 2019 Posts: 12	Thanks. I will have to measure at a later day. We bought at auction out of our area and we left it at my brother in laws house. I’ll have home measure.