Fuel again

[don Burke]

Back to the original topic.  At last weekend's speed/race contest at Whittier Narrows the speed flyers brought the standard fuel, as usual.  They had two bottles, one from last year, and one brand new for this event.  They test ran an engine on the stand and got a 1600 rpm difference between the old stuff and the new stuff.  Interesting results.  I think the old fuel was good for nothing by week killer!

The fuel was in plastic bottles.  IMO the reason for the difference permeation, by water, through the plastic diluting the alcohol.

Any other ideas?

[Jim Kraft]

I have no idea. I have kept stunt fuel around in plastic jugs for 5 or 6 years with no problem. Same for R/C fuel. It is kept in my garage which runs from 0 deg. to over 100 deg. and humidity ranging from 15% to 100 %. The plastic jugs had not been opened though until I started using the fuel.

[don Burke]

Stunt flyers would probably not see the difference, although fuel "aging" is a known fact.  It can explain changes in performance.

I have also had the plastic bottles split, but that was covered quite a while ago either here or on Stuka Stunt.

[Jim Kraft]

Me to on the split bottles. I now remove a little fuel from each jug I get and then squeeze the jug before tightening the lid so that there is a slight vacuum on the jug. Never had a problem since doing this.

[Randy Powell]

I use fuel that comes in metal cans. They do have the little, plastic seal plug on top. When unopened, it seems to last quite awhile.