....Hey ...... man,?? Does'nt any one check out the tachometer readings forum any more???...I need more info on prop fitting for more speed on a 6-7 lb P51 w.m. W/OS61FX

All the Time!


Happy Fly'n....

I'd use an 11-71/2, or an 11-8 Master Airscrew....
or an 12-7 zinger....

Balance the prop, spinner, and backplate to get
everything out of it.

Dave.

Get an OS .61 LA. According to MAN it puts out more power then the FX

Isn't it a OS 65LA. We have a few 65LA's at our field in a big Uproar and BIG STIK and and they move out pretty well.

I believe you are right. Guess those must be some good engines

The la is a bushing engine

Hey - don't knock bushing engines! I won many Control line speed contests in the 50's with a Fox 29X bushing engine! first class B engine I had that exceeded 150MPH!

As for more speed with the OS61FX. use an 11-7 or 11-7 1/2 APC,
get a tuned pipe or muffler (Performance Plus), and Wildcat 15% nitro - 18% oil - or put in an extra head gasket and go 25% nitro!

Phil

An 11x7 works and so does a 10x8. Probably the best speeds will come from those props, probably won't gain much by going down to a 9" higher diameter prop. Any larger prop then those above, don't seem to let the engine rev into its power band.

Not knocking bushed engines, but I simply can't believe a .65 LA is more powerfull than the .61 FX. I wish he would have done the testing without the baffle in the .61FX muffler. Also, the LA muffler does offer some tuning effect. I would also test the .61 FX with the Tower muffler which is I belive about 12 bucks.