Curtiss OX2?

[TimK]

I've been shown a propeller hub marked
AD543 RH
90HP CURTISS
OX2
D2520 P1580

This all ties in nicely with your reply, Bob, to another question on 21 Dec 2011, except for the "OX2". I can only find references to the Jenny and the DH6 having the OX-5 engine. Can it be a mistake on the hub or is there another explanation? Thanks.
Tim

[Dave]

Well, it's not just the hub. The table in WW1 British Aeroplane Propellers has that drawing number as well and the next in sequence, AD544, listed as an OX 2 engine, but it also identifies it as 90 H.P. (It also lists the Maurice Farnham Shorthorn and the DH6 as the aircraft for the AD 543 propeller. The AD 544 is a left hand thread and listed for NS airships.)

Something doesn't make sense. The Shorthorn was a pusher aircraft, and one would expect a left hand thread using an OX 5 engine in that application. I wonder if there even WAS an "OX 2" engine.

[TimK]

Thanks Dave. I think we have to assume the propeller was for an OX-5, even it does say "OX2" - unless anyone else can suggest an explanation?
Tim

[Dave]

That would be my best guess.