Say you ran an OS .40 LA stock motor class... what fuel for the most umph?

[Accu157]

The motor only has to last a day's worth of pylon racing, and you want to crank as much power out of it as possible. Disregard break-downs, just aim for a 10-12 minute motor life, not 100's of hours. R/C car fuel? 70% Nitro 30% oil? No alcohol? Just want to know! :)

[RICH S]

The motor only has to last a day's worth of pylon racing, and you want to crank as much power out of it as possible. Disregard break-downs, just aim for a 10-12 minute motor life, not 100's of hours. R/C car fuel? 70% Nitro 30% oil? No alcohol? Just want to know! :)



I used to do tunnel hull boats 7. 5 cc, bear in mind they're water cooled ,and I recall 45% nitro 20% oil, they were "singing" as high as pitch as I ever heard a 2 cycle do. May want to check helicopter drag racing sites also (IRCHA).

[DaveSawers]

And run a small prop, perhaps an 8x6 or 8x7

[Terryoc]

Really the 40 LA is not a performance motor I doubt there would be to much difference in power from 15% fuel to 60% fuel so may as well run the 15% and save a few $$.
Same goes for prop size the motor will never be a rev maniac probably a 9+7 would be the smallest that would perform.
IMHO
Terry

[Nicetie]

The motor only has to last a day's worth of pylon racing, and you want to crank as much power out of it as possible. Disregard break-downs, just aim for a 10-12 minute motor life, not 100's of hours. R/C car fuel? 70% Nitro 30% oil? No alcohol? Just want to know! :)

You could get a lot of power from a 40LA for 10 or 12 minutes:

Add as many metal .002 inch thick head gaskets as it takes to run 60% Nitro, 10% caster oil, and 30% alcohol while using a tuned pipe and a small diameter high pitch prop (8X8 ?). Use a COLD glow plug and expect it to run for only one flight. If you don't reduce the compression using the gaskets
the fuel will detonate too soon and you will have LESS power instead of more!

You might have to go through 5 or 6 engines before you get the proper
head clearance selected for this much nitromethane. Shorten the tuned pipe
in 1/4 inch steps until the airplane has to be in a dive to "get on the pipe".
Remember to run on the rich side so there will be enough fuel delivered
when the engine is running at max RPM in the air.

If "stock" means no tuned pipe, then just use more nitromethane and less alcohol. You won't get near as much power, but it will still be a lot.

Silly answer for the silly question.

Ken

[B.L.E.]

Isn't the whole idea of classes like this to keep the costs of racing reasonable? It's probably a moot issue anyway since most racing on the national circuit makes the competitors use event supplied fuel.

[Nicetie]

Isn't the whole idea of classes like this to keep the costs of racing reasonable? It's probably a moot issue anyway since most racing on the national circuit makes the competitors use event supplied fuel.

....I dunno. Just saying how to get the very last HP out of the engine. I have
done it a long time ago with a cheap off brand engine and the power was
awesome for a few minutes.

Ken

[whopper]

Nitro-glycerine with 40% Enriched Uranium. Don't worry about the oil, it doesn't make power. This should make your 40LA go like a real bomb-shell...