Hi guys and gals,

I have a OS .61 FX engine, I'm trying to figure out what propeller size i can use to get the max thrust? Currently, with a 13x6 blade, i'm getting around 7 pounds. I heard that some people have been able to get it to 9lbs with a certain blade ( i believe they said 13x8 or a 14 one). Besides the blade, can something else be done to the engine to get more thrust? i cant modify it, so making any physical changes to the engine is out of line.

any comments or recommendations will be greatly appreciated!


thanks

anwar torres

The largest dia prop spun at the highest rpm will give you more static thrust.

Try a 13-4 or 14-4?

Enjoy,

Jim

hi jim,


how can i get the engine to run at max rpm's?




anwar

Use a 13 X 4 sport prop http://www2.towerhobbies.com/cgi-bin...?&I=LXFGV3&P=7 and tune your needle valve for maximum rpm and then richen back up 300 rpm.

How did you measure the 7 lb thrust that you are now getting?

Enjoy,

Jim

Hi!
Just by chosing the right propeller!

May I ask why do you need to know max trust?? Most of the time in our airplane world this is totally worthless information.
A 13x4 APC propeller might do well here. As for hitting max rpm..there isn't anything like Max rpm! Well if you start the engine without the prop then it will rew up and reach its max rpm...but is this information really worth anything....? What you are after is probably chosing the right propeller for a certain airplane...and with that we can help you. What airplane do you have in mind and what engine?
Regards!
Jan K
Sweden

HI jim,


i initially got the 7 pounds of thrust by using a 13x6 apc blade. i do not know if that measurement was obtained at max rpm . i am pretty new in dealing with these engines.



thanks


anwar


PS: what part of the united states do you live in?

As Jan said. The rating of Maximum rpms by the factory is a totally useless piece of information. It's usually something like 15,000 rpm? You would need such a small prop to reach max rpms that your plane would not fly.

Enjoy,

Jim