Originally Posted by
Dave Harmon
David.....I made some experiments some time ago and determined that glow fuel weighs about 1oz per liquid oz.
If you are allowing 1 lb for fuel....you'll have about 16oz of liquid weight.
You could likely plan for 12oz standard fuel and save a 1/4 lb or more while you are at it.
The reduced nitro (10%) used with the NR will remove half the nitro weight. The oil content will have an effect on the weight too.
You can weigh 1oz of the fuel you intend to use in a 1oz mixing cup and get a grip on it.
Dave,
that is an interesting thought. I never really put much stock into the
density of fuel. What with the conversion of fluid ounces to mass ounces being among the most straight forward in the world of imperial units!
But in short, yes, when I said a pound of fuel weight, I had a 16 oz tank exactly in mind. 16 oz of fuel = 16 oz of weight :-) Given my testing thus far, I'd say that a 16 oz fuel tank is the most prudent with this engine in a practice situation. Naturally, in competition, a 12 oz tank might just get through the routine and be preferable.
Say, is the density of nitromethane substantially higher than that of methanol? I'll have to look into that.
Before the 89' NATS in Washington State....I was using the YS RE ss and was running out of fuel on the next to last manouver.
I could not get a larger tank in the airplane (Suprafly) so I mixed my own fuel....13% total oil (8 castor/5 KLOTZ) 20% nitro 2% propolyne oxide.
This mix actually gave quite a bit more RPM than standard 18/20 fuel due to the much reduced oil drag.
The castor kept the engine happy without gumming up the works...and at the NATS I was landing with about 2 oz reserve.
I had to do this to gain more endurance...it's all about considerably reducing the viscosity of the fuel to allow the needle to be closed....less fuel through the engine....
How can you gain RPM with less fuel flow???
Reduced oil drag.
Works great.
Dave
Interesting story. How much fuel were you carrying on the Suprafly? What purpose does the 2% propolyne oxide serve?
Coincidentally, I have just been experiencing improved performance on the Speed 13 as a result of reduced oil drag. I've been running different fuels through it with different total oil content and blends. Going from 20% oil to 17% alone (although the mixture changed) improved engine performance. Not significantly but measurably.
David