Minimum hp needed for powered flight?

Zaphod Beeblebrox

For something with around 400-500 pounds gross weight, IF you had sufficient wing area, about the minimum would be 25hp for sustained flight near sea level in cool temperatures. For safe performance margin you should have about 35hp. Besides that, you'd need an engine that could swing large, efficient propellers at a low rpm around 1,500) . Without a gear-reduction drive, those little engines you are looking at wouldn't work at all and they don't develop nearly enough power and a propeller won't work at the high rpm where they operate at full power.. In other words, you're dreaming and you need to learn the basics of aircraft engineering and design.

Ross

No, not much of a chance I'd say - shooting from the hip. It all depends on the glide ratio you can achieve, given the competing factors of wing length/surface area, overall aerodynamics and gross weight. If you know the glide ratio and gross weight, you can make a straight forward determination of required power to achieve a particular minimum rate of climb (essential if you are self-launching from a runway). An enigne under 100 cc seems extremely feeble for the weight. I once calculated an 18 hp motor to provide 200 ft/min climb of a sailplane with a 25 in 1 glide ratio. This, of course, is a very efficient design and the weight of the sailplane was probably about the weight you are anticipating. You can convert the weight and descent, at a particular glide ratio, into a negative power. This determines the power required to maintain level flight. Then you add to this power to provide an acceptable rate of climb. It is an interesting problem to puzzle over.

thomas f

I have read that bumblebees can achieve powered flight for less than 1/1000th hp.