OS 25 FX prop
05-13-2007, 08:49 PM
#3
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RE: OS 25 FX prop
Hopefully you've got a tachometer. If not, it's a good idea to get one to help you set the pipe length. If you haven't used a pipe already, take a look at [link=http://www.macspro.com/tuning.asp]Macs tuning information[/link].
The 9x5 is a good starting point. There may be other choices depending on what you want to do with the plane. If you're going for speed you could also try out something like an 8x6 or 8x7. These would provide less overall pull, resulting in longer takeoff runs, but potentially higher overall speed.
The 9x5 is a good starting point. There may be other choices depending on what you want to do with the plane. If you're going for speed you could also try out something like an 8x6 or 8x7. These would provide less overall pull, resulting in longer takeoff runs, but potentially higher overall speed.
05-14-2007, 06:31 AM
#5
Senior Member
RE: OS 25 FX prop
iflyg450,
Sometimes you need to find a balance point...
Bolly have the Clubman prop in the 8.5x6 size and it is a very efficient prop.
You will have the higher pitch speed of the 8x6, and only a little less area than a 9x5.
On the MVVS .25-.28 engines it is the ultimate prop size.
You did not write what brand of props you are using now.
Sometimes you need to find a balance point...
Bolly have the Clubman prop in the 8.5x6 size and it is a very efficient prop.
You will have the higher pitch speed of the 8x6, and only a little less area than a 9x5.
On the MVVS .25-.28 engines it is the ultimate prop size.
You did not write what brand of props you are using now.
