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Old 24 August 2007, 16:20   #1
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New prop calcs

To stop hijacking Andys' build thread

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Originally Posted by DGR View Post
Who's doing the calcs? I always thought that prop selection was a bit of a black art - there are so many variables that the best way is to just try one!!

D...
Powertech marine. I'm sure it is a black art, but they said if they know top revs being achieved and a rough top speed, and prop size, they can work out the best way to go. We'll see.
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Old 24 August 2007, 17:01   #2
DGR
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OK - well it will be interesting to see how good they are at predicting performance. The number of variables involved would stump most models.

The usual assumption is that adding 1" pitch looses 2-300 rpm but adds 2-3 knots of top end speed (if it can get you there) - but that can go horribly wrong. And that's if you stick wth the same types of prop that you already have - not to mention 4-bladed, 5-bladed, duo props...etc, etc...

However, the weather has been reliable lately...
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