Javaprop numbers

Tim, can you post your most efficient settings that you got on javaprop? I figure it would be a good place to work off of.

Well I think I remembered the settings for power, velocity, and rpm that Tim used and I used those to work out efficiency.

For a 3 blade prop I got:

B=3
n=250
D=1
Dsp=.1
v=4.63
T=500

This gives an efficiency of 78.281%

For a 2 blade prop, everything stayed the same except D which was changed to 1.03m

This gives an efficiency of 78.06%


These are the best numbers I could get. It seems that keeping the overall diameter to about 1.0 meter leads to the best efficiency. I have also been messing around with the numbers, and I am pretty sure that diameter means total diameter, so 2 times the length of one blade and the radius of the spinner. This means that the blade length is (D-Dsp)/2

Neil, try a 4 blade prop. When we tested the small blades in the MIL, the 4 blade prop was the most efficient. I wanted to test them at lower rpms (ie for our application), but Andres said the thrust it would produce would be negligible.

Thanks!
Also, do you know how to CAD props? I posted a link on here somewhere that Chris (Neal, not Turner) sent me.

Hopefully we can meet up with micro air vehicles soon so we can start CNCing foam, and getting our hands dirty with the carbon fiber.

also, it gives you the geometry for those specs, right? so you can CAD up a blade from the program?