Please help ID 4 Blade Prop

[steveh]

I have recently been given a 4 blade prop with the following info on the hub.

Curtiss 90HP
D2438
11647
AD503
LP
7.4.17

Lang Propellers Ltd decal on 2 of the 4 blades.

From checking in line I think this translates as being manufactured by Lang Propellers Ltd and is 8ft in diameter. I have had no luck identifying what I assume are the drawing/design numbers. I guess 7.4.17 is date of manufacture.

The propeller has 8 bolt holes.

I was told that the prop was originally from a Vickers aircraft but would like confirmation and more details if possible.

Thanks

Steve

[Bob Gardner]

Good Morning Steve and welcome to the forum.

Your prop was made by Lang for the British Admiralty ( AD in the drawing number indicates the Air Dept of the Admiralty, the staff branch of the Navy which looked after the RNAS.)

The prop was made for the Curtiss JN3 aircraft, used by the RN as a training machine. The data decodes as;

Curtiss 90HP The engine and hp
D2438 The diameter in mm
11647 The Lang serial number
AD503 The Drawing Number
LP Lang Propeller Co
7.4.17 A date. There are many examples of similar dates on British WW1 props almost all around April 1917. I think they are contract dates and I suspect they occur at the time of the great expansion of the British flying services.

With kind regards,

Bob

[Dave]

Steve, can you post or else email me a picture of the propeller?

I've not seen a 4 bladed version of the Jenny propeller. Very interesting . . .

[Bob Gardner]

Dave,

The four blade prop on the JN3 and 4 had a very low pitch, 1540mm compared with a pitch of 2438mm for the diameter.

The British RFC were constrained to buy the aircraft and engines made by the Government, at the Royal Aircraft Factory. But the Royal Navy could buy where ever they chose which meant they usually found the best aircraft. They bought a large number of Curtiss engines for use in the BE2 and the DH6, as well as various American aircraft such as the JN3 and JN4 and the two Curtiss flying boats.

Bob