Ham Stan vs de-H props

The major propeller models produced by de-H in WW2 were licence built Ham Stan models. The bracket types were used mostly pre-war with the Hydromatics coming in a bit later and superseding most of the brackets.

The de-H props were, externally, identical to the Ham Stan props and in fact were just imported Ham Stans with home production beginning a little later.

The Ham Stan 23E30 hub assembly was very widely used on US aircraft (Avenger, B-17, B-24, A-26, B-25, C-47/DC3, Corsair and Hellcat, to name but a few) and the licence-built, de-H model was identical to the point that parts were interchangeable.

We used our de-H, 23E50 props on Stirling, Lancaster, some Halifax, and some Hurricanes, and sundry other types. The earlier bracket types naturally found uses on earlier pre-war types such as Spitfire, Battle, Hampden, Lysander, Blenheim and a few others.

Curtiss Electric props found fewer UK applications being mostly on lend-lease/imported US types such as Wildcat. As far as I am aware there were no UK production aircraft which used these propellers though a few US types did (Thunderbolt, P-38 and Marauder). I believe there was a problem with reliability and power transfer which wasn’t effectively sorted out until later on.

The Curtiss Electric prop was notable by its long spinner which was, in fact, just a thin, light-alloy shroud which covered the electric pitch-change motor and gearbox. Later, the ever-resourceful de-H took a licence on the Curtiss props and managed to mate the electric pitch change units to a hub similar to the bracket prop. This saw use, probably more for experimental reasons, on some Wellington aircraft.

The big Curtiss design breakthrough was the hollow steel prop blade, which allowed use of a material in less demand to be used in their construction. Again, de-H, having the licence for both Ham Stan and Curtiss types, successfully mated the two designs and produced a reliable unit which was used (post WW2) on all production Beverleys, most Britannias and the SaRo Princess. It used hollow steel blades on a one-piece hub with hydromatic (long-stroke, for a reversing capability) pitch change gear.

De-H went on, post war, to develop a mass of hydromatic types for all applications as well as continuing use of the bracket types for low-powered aircraft such as the Prentice and Heron.

Anon.