i have heard that the nitro provides oxigen, so you can add more fuel, and get more power. Also makes the needle settings less sensitive. and allows you to run extra rich keeping the engine cooler, while still producing flyable power. when i was a kid many of us added Nitros oxide injection to our cars, would add over 100 HP to some of those hot rod engines, but i dont' think the nitro does quite that much for these heli engines. nitro is almost free here compaired to eruope so everyone here uses a lot of it.