Static thrust

I'm wondering how much static thrust you can get from about 30hp piston engine. I guess, it varies with different prop configurations, but I have used a rough estimate of 70 kp or about 680 N in my calculations. Any comments about estimate ? Is it overly optimistic/pessimistic ?

 

Dear Max:
I am a recent visitor to the Eng-tips. In order to answer
your question, I need a few previous data:
Engine RPM
Power
Maximun Propeller diameter
Blade number
Are you using reduction unit ? if this is the case, which
is the relation ?
By the way I strongly recomend "Aerodynamic Design and
Analysis of propeller for Mini-Remotely Piloted Air Vehicles" by Henry V. Borst & Associates, January 1978
This publication is available via NTIS (U.S.A.) and works
with small propellers.
Sincerely
Miguel Angel

 

[insideman]

Two different questions here. The first one
is static thrust. Based on some tests done
years ago, your set up should deliver about
330 pounds static thrust. Probably more for
an optimised prop.

Second question deals with thrust while in
motion, but does not specify flight speed.

I have developed nomographs to design props
starting with rpm, power, flight speed. Let
me know added info and I will attempt a
better reply.