109 prop pitch (rpm) and the supercharger

[Robo.]

Originally Posted by Crumpp

Cruising at Dauerleistungen 1.15ata @ 2200U/min our pilot wants to increase speed.

So he puts the propeller to fine pitch until the rpm gauge reads 2400/U min and then increases manifold pressure until the manifold pressure gauge reads 1.3ata.

The airplane acelerates and he coarsens the pitch to maintain 2400/U min.

Pretty simple stuff.....

Our pilot flies at 7km, he's struggling with performance up there, way above the FTH, his manifold pressure will not read 1.3 ata in the first place.

We're not talking about Dauerleisting below FTH. Down there the fiddling with rpm doesn't help much. You don't want to keep the engine at 2400/U, you want to coarsen down afterwards (your rpm drops down again), keep that speed and repeat that whole process again. That is the difference between 'change' and 'maintain'. Sorry I can't explain that any better or simpler. Just read what Steinhilper is saying and doing.