109 prop pitch (rpm) and the supercharger

[JtD]

Originally Posted by bongodriver

surely the only RPM that can be refered to is prop RPM, I don't think there is an engine RPM gauge in most of these aircraft....

Partial quote, sorry. But what you're saying is not correct. The rpm gauges you see in the aircraft are engine rpm, I'm not aware of any aircraft showing prop rpm (unless the gear is missing and the ratio is 1:1). Also the rpm limits as listed in manuals give engine rpm limits. In case of the DB 601, the 2400 rpm is the 5 minute engine limit - and the prop will be at 1550.