ORIGINAL: da Rock

We're going into winter. Less nitro in the fuel means ''warmer'' combustion. Winter cold packs more oxygen into the air going into the engine, so you don't need nitro. It basically provides more oxygen for the combustion. So there are a couple of reasons to save on lower nitro fuel during the winter.

Truth is, 5% nitro is about the best value for sport flying. Better mileage, enough nitro to smooth out needle settings, and it's cheaper.

Until you've flown enough to be able to tell the difference, save some money on lower nitro fuel and spend the savings on props or such.