Frank and Dorothy wrote:

Paul wrote:

This is extremely interesting to me as the Moller Skycar should be the next
mode of transport for the more wealthy among us.

[snip]

Some people poo poo the idea but it is entirely within the laws of physics
given the very high power to weight ratio of the Moller rotary engine.
See the chart below.

I'm more skeptical. Your own chart shows the Moller engine at something
50% better power-to-weight ratio than a turbine or a purpose-built race
engine. That sort of improvement calls for a technology leap which just
doesn't seem to be there.

BTW I think the development of the rocket powered ballistic parachute capable of letting
the entire aircraft down has added to to the Moller Skycar practicality.

Whilst a BRS would be a big plus for a Moller type vehicle, its
something I'm also skeptical about for regular GA aircraft.

Frank.

For one thing the small helicopter turbine shown has a gear box and the Moller 
rotary does not.

Trust me Frank its there or nearly there! Perhaps a tiny bit optimistic.
Our own Jeff Spitzer on here was the engineer on the Moller engine.  When 
you make the rotors smaller the RPM can go up so you get more HP per cubic 
inch of displacement or per pound of weight. m*V^2/r That is why a tiny model 
aircraft engine can develop a horse and a half at 20,000 RPM. That is also 
why piston engines sometimes go to 12 smaller cylinders. The Moller is a 
smaller two rotor. The Midwest and Wankel GmbH limit the RPM of their small 
two rotor engines to about 6000 RPM for some strange reason. 

The RPM limit of a rotary is controlled by rotor weight. 
Also an aluminum rotor with steel or other anti wear insert for 
the apex seal slot has not yet been tried to my knowledge. 
Nobody is running both peripheral and side intakes and
exhaust ports yet which should help the breathing at say 20,000 RPM.
If you don't mind the cost ceramic apex seals with half the density of
steel or cast iron work fine.

Even if the power to weight ratio is only as good as a turbine the rotary
is one tenth the cost.

Sirus is selling the heck out of their four place C172 competitor with BRS.
We shall see the first time one crashes. BRS makers claim many lives saved so far.

Paul Lamar
 
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