Whirley Bird

My Feedback: (1)

Can someone tell me if there is a right way to match the fuel to the engine?
I see Guys mixing their own and I see others racing cars with engines running way to hot.
I run the small 40's and 46 size and now going up to the 60's size.
I'd like to get the max RPM and still keep the engine running cooler and still have the efficiency designed into the engine so the craft will do what it's supposed to do and not abuse the engine.

downunder-RCU

To get max power from your engine you need to use the maximum % of nitro the engine will handle. But then you're running the engine on the ragged edge and any mistake with needle settings could cause some damage. Some engines don't like too much nitro (Rossi, Irvine, MVVS and so on) but the more common ones will handle 15% quite well.

The most important thing in fuel is the oil if you're looking for long life. Quality of the oil is very important but that's a bit hard to determine with synthetics because they're all originally developed for things like chain saws, go-karts and snow mobiles etc. What's certain though is that castor (not medicinal) provides the BEST protection. A mix of castor and synthetics is fine though.

The next thing with oil is the amount. There's a commonly held view that adding oil reduces power. This is completely wrong. The engine doesn't care how much oil is going through it but it does care how much methanol/nitro is going through and that's what the needle is used to set.

I prefer to err on the safe side and consider 20% oil to be the minimum and usually use all castor but have tried a blend with synthetics. This gives a safety margin when things go wrong (and about the worst is losing muffler pressure for various reasons).

Whirley Bird

My Feedback: (1)

OK,
Well if you'll excuse me as i'm a bit dumb to RC fuel mixing.
Where do I get the raw fuel so that I can add my amount of castor oil?
Some local told me to buy the 0-5% and just add castor oil to that.
Dosen't seem right since the oil is factory mixed.
I'm running a 40 and a 46 and will be going to a 60 very soon.
But i have seen 15% nitro mixed fuel really cooking the small race cars.
I'm just assuming the aircract will take on more air for better cooling.
I'm open to any suggestions

downunder-RCU

The raw ingredients are just methanol, nitro and oil. Not being from America I can't say where to get these things other than speed shops that deal with drag racing, speedway or go-karts. I think things like Klotz oil is available from motor bike shops but hopefully someone else will chime in here

The trouble with buying a fuel then adding some castor is that some fuels give no indication how much oil is in them to begin with. So leave them strictly alone. Others mix by weight and not volume so you're likely to be shortchanged on oil anyway. There are one or two brands that seem to be pretty good as is (OK, if I'm pressed then I'd have to say that from what I've seen on a few fuel websites that I'd be inclined to go for Powermaster. Either their ducted fan fuel or the GMA stunt fuel ).

Yeah, I know it's confusing

Whirley Bird

My Feedback: (1)

Yes,
It is very much so.
Well I been running 0% or 5% nitro.
Everyone says run it a bit rich but no one said how rich.
Anyway my concern is that I read where a high nitro fuel will run the engine faster but also hotter.
So far I been running the engine by the book and the 46 size requires a lot of tweaking but it's purring nice now.
If I go to say 15% mix then can I go from a 11X4 prop to a 11X6 Prop?
I'm assuming the 15% mix will give the enging more HP to crank a prop with a bigger bite.