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dstrasser
02-16-2018, 03:06 PM
I inherited this propeller from my father's estate. I am trying to determine what type of aircraft used this propeller as well as its value. Here are the dimensions of the propeller. Length- 100", Center bore- 3 3/16", Bolt hole circle-8 7/16", Diameter of hub-11 5/8", Number of holes- 8, Bolt hole diameter 7/16", Hub thickness- 3 11/16". Identifiers on the Propeller- Lang Logo, RDW, PNA, RESINST, USNAVY, N1117 on side of hub. Any help you can provide would be very much appreciated.

Dbahnson
02-16-2018, 04:30 PM
I certainly don't recognize those stampings, but the propeller does resemble this commonly found prop (http://woodenpropeller.com/HS2L.html) used on the Curtiss HS 2L, which is half of a "two part 4 blade" propeller formed by stacking of two separate props on top of each other.

Are you measuring the bolt circle diameter on the centers of the bolt holes? A Liberty engine hub would have those 8 inches apart across the center of the hub. It sounds as if you might have added 7/16" by adding a bolt thickness to the measurement.

Bob Gardner
02-17-2018, 07:14 AM
The hub appears to be comparatively thin, suggesting as Dave observes that this is half of a four bladed prop.

The maker, Dashwood Lang, was one of Britain's leading prop makers, lent to the US Navy in 1917 to advise on the mass production of wooden props.

This info is well known to regular forumites, but repeated here for newcomers.

With kind regards,

Bob

dstrasser
02-17-2018, 09:04 PM
I certainly don't recognize those stampings, but the propeller does resemble this commonly found prop (http://woodenpropeller.com/HS2L.html) used on the Curtiss HS 2L, which is half of a "two part 4 blade" propeller formed by stacking of two separate props on top of each other.

Are you measuring the bolt circle diameter on the centers of the bolt holes? A Liberty engine hub would have those 8 inches apart across the center of the hub. It sounds as if you might have added 7/16" by adding a bolt thickness to the measurement.

You are correct the measurement is 8 inches and I was including the bolt thickness. It is so very interesting to know which aircraft used this propeller. I have to admit when I measured the width, it seemed narrow compared to other propeller dimensions. The stacking of the props on top of each other explains that aspect. Thank you so much for your response and link.

Dbahnson
02-18-2018, 11:15 AM
So this prop is identical in so many ways to the commonly found props for the HS 2L - the size, shape, hub measurements and the left hand rotation. What's intriguing is the "RESINST" stamped on the hub area. I'm just wondering if this was a test or sample model supplied to the Navy Bureau of Steam Engineering as part of a bid to get the contract to build a large number of them. Ultimately, the ones that were acquired were stamped with "S.E. 50_0" where the "_" contained a digit that represented the propeller pitch. The "S.E." prefix stands for "Steam Engineering".

Bob Gardner
02-18-2018, 01:05 PM
Hi Dave,

Some repetition from previous posts.

The Lang decal indicates that Dashwood Lang was firmly established with the USN when this prop was made. (For newcomers, when the USA entered WW1 in 1917 it discovered that the state of its aviation was way behind European levels, where three years of aerial warfare had provided a catalyst to rapid development. The USN asked the British Royal Navy for help in organising the mass production of propellers. The British Government sent Dashwood Lang to advise on mass production and Dr Watts to advise on propeller design. Lang initially bought in propellers from Canada, whilst the USN built a factory on Long Island for him. His new company was called the Lang Propeller Company of America.)

I don't know what RESINT means. From what you say it might be that it was a demonstration prop for American wood-working firms?

If the decal can be deciphered (which I doubt) it might reveal whether this prop was imported from Canada or made from early 1918 onwards by the new Lang Factory on Long Island.

With kind regards,

Bob

Dbahnson
02-18-2018, 01:43 PM
I wondered if "RESINST" may have been a "resin strength test". Many of this particular model propeller that have survived as surplus have shown significant delamination, which I always attributed to either using a poor choice of wood or a poor choice of glue, and resin is a type of glue - pure speculation, of course.

dstrasser
02-19-2018, 03:50 PM
I was wondering if there is any significance to the bolt holes being filled in?

Dbahnson
02-19-2018, 04:48 PM
A number of those models that I've seen have had that. I think it might be cork and have been used to keep insects from lodging there during storage. Most of this model that I've seen were never actually mounted on an aircraft hub and were eventually sold as surplus.

In all of the ones I've seen, only one pair had sequential serial numbers, and unfortunately the owner sold them separately.

dstrasser
02-19-2018, 05:04 PM
Do you have an idea of what the value of this propeller would be?

Dbahnson
02-20-2018, 06:49 AM
I think there's a wide range of possibilities, and even those tend to fluctuate. It's not particularly rare, and it's really only half of a functional pair. On the other hand it's authentic, has a striking curvature, and is probably close to 100 years old and in original condition. I had a person just give me one once to get rid of it, but I've also seen them sell for around $1000 to $1500. Since there is not a lot of sales activity, though, it could sell for more than that on someplace like eBay where asking prices have soared. Those high priced props don't sell but they make more reasonably priced props look like a bargain in comparison, so it all depends on how knowledgeable (or misinformed) the buyer is.

dstrasser
02-20-2018, 01:05 PM
You have been so helpful, I can't thank you enough!! The website has given me an insight into the past that I otherwise would have never experienced.