Replies to post #1003 on Moller International (fka MLER)

[InventionStocks]

I've seen the videos of the hovering skycar but lifting and flying are 2 different things.

RE: Might want to check your math since, MI has already shown they can lift the M 400, the motors produce 3 hp for ever Lbs of motor

Answer: A person can lift a certain amount of weight. But can they run with that weight, jump with that weight, be put in a higher gravity with that weight.

A lot of forces act on an airplane in the sky in which wings kind of balance out any power deficiencies since they take on all of the vertical weight, i.e turbulence, multidirectional wind, passenger movement (inertia), plane ascents and turns (g-forces), etc. If the air car is flying slower than the minimum forward lifting speed (and the version with no wings will have to fly faster to achieve minimum lift) and these forces exist then the skycar will be unstable.

As a person goes up in altitude the air gets thinner. The Skycar says the ceiling is 36,000 feet. The air pressure at sea level is 14.694 pounds per square inch. The air pressure at 30,000 feet is 4.373 psi. This is a 62% drop in air density or 10.111 psi for a 26% drop at 10,000 feet for more realistic flying altitudes. More horsepower will be needed to hover or fly slow at higher altitudes.

Moller.com says the weight of the 400 is 2,400 pounds. And that all engines equal to 720 horsepower or 720/8 = 90 hp per engine. A 62% drop in air density means that the horsepower needs to be increased to 90 x (1-.62) = 34.2. 34.2 + 90 = 124 horsepower per engine or 124 x 8 engines = 992 hp total. This doesn't even take into account the forces mentioned above. The engines are 720 / 992 = .725 -1 = .27 or 27% underpowered. And this is the minimum because I haven't dove into exact calculations.

[j5mith]

"MI has already shown they can lift the M 400, the motors produce 3 hp for ever Lbs of motor"

Some comments:

The M400 has never flown with the engines intended for it (four of the two rotor 1060 cc engine). The only flying demonstrations were done with four 530 cc engines, without a pilot, and likely a minimum fuel load. Backyard tinkerers can easily exceed this performance, see Youtube.

3 HP per lb of motor - Perhaps this was accomplished, although I've never seen this independently confirmed. But for how long, and under what conditions? From a given motor, power output and reliability are inverse -- you can boost a motor to provide a lot more power than usual, but the time to failure drops dramatically.

As a joke, we used to test 12 volt electric motors on a 0 - 300 volt power supply. The motors would run at much higher voltages than they were rated for - but not for very long, and the failure was usually pretty dramatic.