No... its not quite that simple.... its actually so complcated I don't know how to explain it.[&:]

Airplanes and aerodynamics get EXTREMELY complicated explaining what happens with different density altitudes. In order to avoid each pilot getting a PHD in aeronautical engineering... the aircraft manufaturers give an operating manual wiht each aircraft sold... that manual lists specific procedures and tables of required runway length at different weghts and density altitudes. These proceedures and tables are obviously different for each airframe {aircraft design} and engine {rated design... they don't specificly test the individual engine except to see that it MEETS specs.} combination...

Simplisticly.. all you need is more runway to gain the required airspeed to fly. You already have a MUCH higher powe-weight ratio than any common 4-passenger private aircraft. (higher than many aerobatic demonstration or competition aircraft...)

Our typical at sea level powe:weight for a R/C trainer approaches 1:1. Typical 4 pasenger private aircraft would be VERY happy with 1:2 (or 0.5:1... double the weight compared to available thrust.) A full scale Piper J-3 Cub is down near 0.3:1. (try that power:weight on an RC model... you've just about got it with a 0.10 on a Dynaflite Butterfly.)

Its not POPULAR to point this out... but its the way things are. R/C modelers are spoiled about having excess power. if the model doesn't have "unlimited vertical" climb capability they think something is wrong. (at sea level ANY .40 will take a 5 lb trainer unlimted veritcal with the correct propellor...)