Looking for approximate thrust figures for OS .91 4 stroke spinning a 14x7 or 8" three blade prop in the 8.5-9K range. Anyone ever measure, or know of a chart?

According to ThrustHP (it's a free program, I don't remember where I got it, do a google search and it'll come up):

14x7 3 Blade at 8750 RPM = 17.7 pounds of thrust
Same with a 14x8 at the same RPM.

That's assuming a MA style blade. APC = higher by a pound or 2

This seems optimistic though...I've got an OS 70 four stroke that will onlyput out about 8 pounds (measured in real life), so I doubt you're getting 10 pounds extra. But it's a fun program anyhoo.


Reid

I found Thruss HP just shortly after I posted this question.
Actual figures are 14x7 MA 3 blade at 8500rpm: 11lbs thrust.
MA 3 blade 13x8 at 9000rpm: 9.17lbs thrust.

Woops! Yes you're right. I double checked and I accidently had 10800 RPM in instead of your 8-9k.

Reid