Identify propeller?

[chuckpee]

Don't know anything about this propeller (other than it looks great in our kitchen!). Specs: 102" long, 8 bolt holes; hub approx. 8.75" across and 6.25" thick. Rear indentation approx. 8" diameter. No identification marks or decals. Can you help us identify?
Thank you

[Dbahnson]

It's not "identifiable" without a model (or "design" number) and even then it might fit several different aircraft.

The only thing specific to this prop is its diameter and the fact that it is a left hand rotation. Most often the left hand rotation is associated with either a pusher application using an engine that is typically a tractor engine, an engine designed to rotate clockwise as viewed from the front (many modern British aircraft engines do this), or a geared version of a common engine.

That might narrow the field of possibilities down somewhat, but it would be very unusual to narrow it down to a specific make and model aircraft.

It's nice looking display prop, whatever it was designed for.

[Bob Gardner]

Greetings Chuckpee,

Thank you for the excellent photograph of your propeller. Is any data stamped on or around the hub?

The diameter of 102 inches equates to a diameter of 2590mm, and occasionally 2600mm which was often used for propellers for French engines in WW1, many thousands of which were purchased from France by HMG to power British aircraft during WW1.

Most of these aircraft were built by the Sopwith Aviation Company which, in effect, was the aircraft maker to the British Royal Navy.

The following Sopwith aircraft were made with French engines for the RNAS and later for the RFC.

Sopwith One-and-a-half Strutter: 4500 made.
Sopwith Tri-plane: 150 made.
Sopwith Pup: 1770 made.
Sopwith Camel: 5,490 made.

AV Roe similarly fitted a French engine to the Avro 504 training aircraft and de Havilland fitted one to the De H 5.

The engines used on almost all Sopwith Aircraft were;

Clerget 110 and 130 hp
Gnome 80, 100 hp
Le Rhone 110hp

It is possible that your propeller is also of French design, but if so, probably made in GB under licence.

The brass sheathing is there to protect the prop from FOD. It was rarely used on land aircraft but was commonly used on propellers for sea-planes, so its presence on your prop is a trifle enigmatic.

It is statistically likely that your prop was made for a Sop Camel (5490 aircraft made) or for the Sop One-and-a-half Strutter, 4500 made.

With kind regards,

Bob

[Dbahnson]

Bob, this prop is a left hand rotation, which would eliminate most of the conventional aircraft tractor engines (e.g. Sopwith Camel) of WW1 era, most of which were right hand. The SPAD XIII was one notable exception using the geared Hisso 220 engine, the gearing reversing the direction of rotation and necessitating the use of a left hand tractor propeller design.

In looking through your long list of possible options for left hand tractor or right hand pusher in the more modern aircraft nothing published there seems to fit, although diameters and screw rotation are not specified for many of them. (I think the majority of those props are left hand tractor, however.)

It's too bad that nothing is stamped on the hub, as there is really very little to go by at this point. I would suggest that Chuckpee review this page, carefully measure the hub dimensions then go to the linked chart to eliminate any or all of the engines that don't fit. Unfortunately, there are other engines that might match but are not listed, many of which are more modern than the common WW1 engines.

[chuckpee]

I went over the propeller again looking for any markings but saw none. I did, however, notice that eight “plugs” are installed inside the eight ½” diameter bolt holes (attached picture).

I made the following measurements: Hub thickness = 6” (indented portion) and 6 3/8” total; Hub diameter = 7 7/8” (indented portion) and 8 ¾” total; Center Bore = 3 5/16”; Bolt Size = ½”; Bolt Circle = 6 5/8” center to center. The 8 plugs are 1 1/16” in diameter and 5 ¼” center to center.

Hope this helps. It doesn’t seem to align with anything on the dimension page, although my measurements could be a tad off.

[Dbahnson]

The "plugs" are actually just the natural wood which expanded under the metal hub and leaves bumps where the metal holes pressed against the wood. They indicate that the hub was mounted (vs. a surplus item).

I suspect that it may have been for a Wright A engine even though the measurements don't exactly match. (The Wright A was basically a copy of the Hisso engine) Wood typically shrinks over a long period, especially in a dry environment, and there was some leeway in some dimensions.

[chuckpee]

Should have known a jet background would eventually expose my ignorance in this field. Thanks for the explanation. I did circle the Wright A motor as a possibility, so thanks for your explanation there too. This is a wonderful site. So glad I found it because I have a few more propellers to put forward.

[pmdec]

Hi,

From the shape, it is not French.
From the hub (notch (is it the right word?) on the intrados side), it is clearly a pusher. Probably from a seaplane.

Regards,
PM

[chuckpee]

Thank you, PM.

[Bob Gardner]

Oops! Sorry. I forgot during my researches that this is a pusher prop. Mea Culpa.

The brass sheathing on the tips might now be explained. It was common British practice on props used in pusher configurations. Grass, twigs, stones and dust would be thrown up by the front wheel as the aircraft rolled over a grass airfield. The sheathing is there to protect the tip of the blade from damage and erosion.

But I still can't identify which aircraft or maker used such a prop. I have 2086 lines of data about WW1 props gathered from official Air Board sources of the time and none of them match a diameter of 102 inches or 2590mm with a LHT or RHP configuration.

Defeated!

Bob

[chuckpee]

Good info about the sheathing. Thanks again, Bob. I looked it over again after reading your email and cannot find any markings. Bummer. Sadly, my father-in-law, to whom many of these propellers belonged to, has long passed so any potential knowledge about its history is gone.

[chuckpee]

My closeup vision must be improving. I recently noticed the remnants of letters and numbers on the outside edge of the indented side hub of this unknown propeller. Most of it is barely discernible and unreadable, and the light has to be just right to even see them, which is why I missed them earlier. I took some more pictures (below).

Best I can tell is (left to right) a 1 or 4, unreadable, then O H then 8, but mostly just partial numbers. From your photo gallery, it looks similar to one used on a DeHavilland DH-4, but I believe this is a pusher so wouldn't that disqualify the DH-4?. Here again are some approximate specs:

102" long
8 Bolt holes 1/2" diameter
Bolt circle center-to-center is 6 5/8"
Hub diameter (total) is 8 3/4" (7 7/8" indented one side)
Hub thickness 6 3/8" (indented portion 6" thick)
Center hole 3 5/16".

[Dbahnson]

8 Bolt holes 1/2" diameter
Bolt circle center-to-center is 6 5/8"
Hub diameter (total) is 8 3/4" (7 7/8" indented one side)
Hub thickness 6 3/8" (indented portion 6" thick)
Center hole 3 5/16".

Earlier you posted this:

I made the following measurements: Hub thickness = 6” (indented portion) and 6 3/8” total; Hub diameter = 7 7/8” (indented portion) and 8 ¾” total; Center Bore = 3 5/16”; Bolt Size = ½”; Bolt Circle = 6 5/8” center to center. The 8 plugs are 1 1/16” in diameter and 5 ¼” center to center.

Where are the large 8 plugs that are 5 1/4" center to center? It sounds like a description of an OX5 engine filled with cork, but the cork size is way too large.

The bolt hole circle is critical. See this page and make sure you are measuring the right thing.

[JR44]

Earlier you posted this:



Where are the large 8 plugs that are 5 1/4" center to center? It sounds like a description of an OX5 engine filled with cork, but the cork size is way too large.

The bolt hole circle is critical. See this page and make sure you are measuring the right thing.

The 'plugs' are the marks left when it was bolted to the hub.

[chuckpee]

I earlier mis-identified the 8 "plugs" as being such, rather than indentations from a metal hub. My bad.

I re-measured with a caliper...center hole 3.137" and bolt hole diameter .470" (slight variances). Using a ruler I measured the bolt hole circle at 6 11/16" or 6.693". Looking at the chart, it appears to match a Wright A - except for the hub. Mine is 6 3/8" thick (vs. 7") and 8 7/8" wide (vs. 7 7/8").

Hope this helps....