I do it all the time. In particular, some of the SuperTigers are quite happy with no nitro and their instructions specifically mention that. I've had very good success with the diminutive G.34 which produces amazing levels of power on 80/20 FAI fuel. I clocked an old C/L Sterling Ringmaster at 93mph with the G.34 on 80/20 FAI fuel and that was spinning a fairly fat Taipan 9x6