OS 40 SF-S

[Garf]

Someone locally wants to know if this would make a good stunt engine.

[Airacobra]

I thought that Todd Lee was using them in his Mustangs. I believe they were reworked by Big Art.

[Jerry Bohn]

Don't know about Todd but his dad Jim was using a OS .46SF-S for a long time.
I have an OS .46SF-S, modified by Dixon. Mine is a sweet runner, plenty stunt grunt and run. I'd compare it to a ST.51 after the mods were done on the OS. It is a bit tricky to dial in the right set up (fuel, props, tank, muffler). Depends on your particulars.
Before mods mine kicked -ss like a 60, no stunt run, runaways if 4-2-4 tried.
OS SF-S .46 is same case as .40.  46 is lighter.
Ya might contact Todd if possible to see what he is using for sure and perhaps he can give particulars if it is a .40.

[James Lee]

Todd and I have both used the 46 SF-S, not the 40.  The -S crank is different in that the port timing is 5 deg less on both sides of the opening.  Todd's motors have had the addition of 'Big Art' power...    They have a LOT of grunt at about the same weight of the ST-51...     We both tend to fly in the 5.7-5.8 lap time range with no problems in the wind, just gotta be patient....
And to answer the actual question, I think the 40 would be quite similiar to the 46 except it is heavier.
Jim     

[RandySmith]

Someone locally wants to know if this would make a good stunt engine.

HI

Ther  OS SF  make a pretty good stunt motor if setup right, However  the  46 is a  far better motor than the  40, The 46 seems to be  much more stable and consistant as compared to the 40, This is not saying the 40 doesn't  work but I have had lots of experinece with both engines.
I would sorta compare it to the  Super Tigre  40  vs 46  the  40 was made to run fairly well  but was never  was the stunt engine that the  G-21 46 was

Randy

[Charlie Pate]

Bob Baron used both the 40 & 46 engines with various modifications and told me;every time he thought he had the 40 running good, he would try a flight with the 46(in the same plane) and then just toss the 40 over in the corner.
 I beleive Paul walker used these engines too,but with modifications.