The 91 will get almost the same flight time and fuel economy as the 61 if you fly at the same speed, the 91 at 3/4 throttle will use almost the same amount as the 61 at full throttle. Throttle control is the key to fuel economy but when you have a 91 at your finger tips you will begin to PLAY, and ALL OUT FUN comes at a price, (shorter flight times) but 7 to 8 min of action packed craziness is all my nerves can stand anyway.