I have flown my classic flash with both a Rabbit and a Cheetah. The plane was around 22 lbs dry and the Rabbit flew it just fine. The Cheetah obviously flew it faster but it added weight and made it harder to land as it didn't slow down as well. Both had plenty of take off authority with 100 ft launches possible. If you are not sure I would advise the 140 class turbine as it has more applications. Also be sure you have trailing link gear if flying off of grass -- makes life with the Flash much more pleasant