Moller SkyCar: Wankel Rotary Engines and Lift

[imperium2600]

i was reading on the moller skycar which has multiple wankel rotary engines powering ducted fans for lift, i was wondering if anyone had any information on how many pound of lift one of these engines on a regular ducted fan would have

 

[AlephZero]

Try working backwards (and ignore inefficiency, for a first shot at the numbers).

For a ducted fan the lift comes from (1) pressure across the fan (2) change in momentum of the air downwards. For a given fan you should be able to calculate those quantites from the data sheets for different fan speeds. When you know what fan speed you need, the data sheet should say what power is needed to drive it. Then see what speed the wankel needs to run to generate that power. You may need a gearbox between engine and fan.

Repeat for different duct sizes and/or different numbers of fans till you get something that looks like a feasible design. If you find one, you might want to get in touch with Moller and help them out ;-)

The idea of controlling something as unaerodynamic as Moller's design safely just with an engine at each corner (and with "no knowledge of flight" required to operate it) seems optimistic to say the least. Best not to ask questions like what happens if one engine fails. And running out of gas at 5,000 ft would be kinda fun, with no wings and no helicopter autorotation to help you crash slowly.

It's no great surprise the FAA haven't given them a ticket to fly yet IMO. Don't hold your breath waiting for that to happen.

 

[FredGarvin]

The lift is going to be dependent on the fan itself. There is no such thing as a "regular" ducted fan. Fan designs vary greatly as do their performance and power requirements. The engines have to provide the power required for the fan to operate in the regime it needs to to develop the required output.

 

[imperium2600]

he skycar is completely gps and computer driven , with 2 backup computers and parachutes in case of emergencies... this frightens me, i can't even trust my computer to word process let alone fly a vehicle at 350mph without any manual overrides

 

[Danger]

Unless they've changed the design since I read up on it (that was the model 400), there are two Wankels in each engine pod. One is enough; the other is specifically a back-up. There are also full internal and external airbags.

 

[AlephZero]

I think I'll stick to something safe, like doing aerobatics in an open cockpit Tiger Moth wihout a safety harness. Hey, with a biplane, if two WINGS fall off at least you stlil have two spares...

 

[Danger]

And if they're both on the same side...?