buffnut453
Captain
They were using variable pitch propellers (at the least) on 109Cs. Variable pitch doesn't always mean constant speed. Variable pitch can mean two pitch, course and fine, with nothing in between. It can mean the pilot can, by means of a control, adjust the pitch anywhere between the two limits. Constant speed propellers have a governor that automatically adjust the pitch to keep the propeller turning at a preset value. Translation of books from one language to another often confuse the terms much like two speed and two stage superchargers. Perhaps the E-4 got a different type of propeller control for the same mechanism? Or different control lever arrangement? When did the Germans go to a single lever control? one lever to control the rpm, boost, and prop pitch?
Hamilton Standard introduced a constant speed propeller to the commercial market in 1935. They had introduced their variable pitch (2 pitch ?) prop in either 1930 or 1932. They were certainly not the first to build such propellers but were the first to achieve commercial success. The idea (and experimental) variable pitch propellers go back to before WW I and pictures show an S.E. 5A with an experimental variable pitch prop (continuously variable?) in 1917. The British had fooled around with several other designs of variable pitch props in the early 20s but all had faults or problems that could not be overcome at the time. This soured the air ministry on variable pitch props and it took a lot time and success by other countries (and a few forward thinking British companies) to change the air ministry's collective mind. It doesn't do a lot of good to licence a design if the air ministry won't buy them. The Air Ministry was changing it's mind by 1939 (if not a bit before) but by then they were facing a rapid increase in production of all types of aircraft and the demand exceeded supply (due to low orders in the mid 30s) for a while until the propeller factories could be expanded.
The US had been using 2 pitch propellers on the Boeing 247 airliner and others in 1933.
Hamilton Standard introduced the Hydromatic propeller in 1937 and this allowed full feathering of the propeller instead of setting the prop on the bad engine to course pitch and was a major change in twin engine safety.
Understood but your original post specifically mentioned constant speed. I'll try to do a better job in future of reading your mind before I respond so I can understand what you meant rather than what you wrote (and, yes, I say this entirely tongue in cheek).