His ideas included reciprocating oars and an adjustable-pitch propeller that resembled a pair of fans.

James Means' "Aeronautical Annuals," published between 1895 and 1897, show that some of these, such as silk wing covering and adjustable-pitch propellers, were used by other experimenters before Whitehead.

It was then fitted with a metal, three-blade adjustable-pitch propeller and was delivered for testing at RAF Martlesham Heath, but was written off after its undercarriage collapsed on 2 February 1925.

The Körting engines could not be reversed and also had to run at full speed, since their rpm could not be varied to any useful extent, and as a consequence U-1 was fitted with adjustable-pitch propellers to allow her speed to be controlled.