Using Compressed Air to Lift a 400lb Load

FredGarvin

The engine is there to provide the power the propeller needs to turn at the given speed. If you could turn the prop with a 30 HP motor, the only thing adding a 75 HP motor would do is give you 45 HP of excess power you're not using. The power requirement comes from the mass flow of the prop. If you don't change the prop or the speed at which it turns, excess power gets you nowhere except with more weight to carry.

CrazyEgg

ok thanks for the explanation

say i found a way to actually produce 400lbs of thrust, how much more thrust would i need to get the vehicle up to 30 feet
i.e. if the total weight of the vehicle was 400lbs fully loaded would 410lbs of thrust be enough to lift the load to 30 feet or will you need more thrust to get out of ground effect?