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Old 09-21-2012, 07:34 AM
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Robo. Robo. is offline
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Quote:
Originally Posted by Crumpp View Post
The rpm will vary and in a manual selectable pitch propeller, the pilot has to adjust the pitch to maintain rpm.
Well of course, this is how it usually works. BUT in this specific scenario (109E way above FTH) the pilots decided to change the rpm almost constantly up and down to get better performance, where their engines and supercharges struggled a bit. So they were adjusting the pitch almost constantly to mainatin speed. So you accelerate a bit by overreving the engine, but you won't be able to keep the speed just by 'adjusting the pitch to mainain rpm' (which is normally enough, say below FTH and this is where you are wrong or failing to understand what the big deal here is), they had to adjust it soon enough the opposite direction (=up) to overrev a bit and accelerate. As you see the trick is based on repeating the process constantly, hence changing the rpm constantly, not maintaining it. Just maintaining the rpm it would make them fly slower up there. The mechanism was based on the supercharger rpm.

So you say maintain rpm, Steinhilper says keep working on it constantly. I don't think you're saying the same thing. What you're saying is pretty obvious and this procedure is only mentioned because it is interesting and on topic of prop pitch (rpm) and supercharger at specific condition = high altitude.
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