RCU Forums - OS .25FP Any good???

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RE: OS .25FP Any good???

Quote:

ORIGINAL: gcb

Quote:

ORIGINAL: dennis
...As has been said many times the OS40FP, the Thunder Tigre 40GP and the Tower 40 were all completely interchangable in parts. I have seen motors with parts from all 3 of the motors combined...

Not sure about the .40 but the TT .10, .15, and .25 all have sprinkler venturies with the needle valve to the rear instead of centered.
Here is a TT .10 venturi:

George

The sprinkler system is not a major component part. Thunder Tigre engines for the most part have interchangeable parts. I believe that the 15 heads are different in the amount os screw holes in them but cranks,p/L and wrist pins, gaskets etc and crank cases can be used. The venturi that came on the Thunder Tigre engines was usually too big a bore and needed to be reduced for c/L stunt.
Dennis

RE: OS .25FP Any good???

The o.S. 25 FP is a great match for the Sterling Ringmaster, Yak-9 and P-51. Smoother running than a Fox .35, and starts easily and consistently.
I have used this engine with good results on several planes originally designed for the Fox / McCoy .35, and all flew well. It is also a great match for the ARF Flite Streak.

I use a tongue muffler to save weight, but the stock one works fine.
Hayes 2-3 oz plastic tank set up for clunk feed and muffler pressure, 3rd line for fill vent that is capped for flight. Fill it through the feed line and you won't flood the engine / fill the muffler with fuel.
.015 x58' lines and a 9x4 APC prop are good starting points.