Prop sizing

[vic008]

Would it be correct to say that if you get 2500rpm in neutral, and the same in gear, that your prop size is about right?

 

[oldgit]

 

[Halo]

If you are talking about max revs then all it tells you is your prop is not oversized.

 

[Asbo]

You may find that with no load the engine can limit its Max rpm. When we re engined , the advice was to adjust the prop pitch until the engine will only just reach Max rpm then cruising speed should be around 75% of that. But we have available pitch prop so finding that by iteration was easy. Harder it you have a fixed prop. Then there will be some complex calculations to estimate the right pitch.
I advise to look at the engine manufacturers spec to find the Max rpm under load.

 

[Asbo]

Available is VARIABLE