2017.07.02

Hello Paul,

I've found some infos about a rearly good looking plane. Propeller is driven by an electric machine, power comes from a RE RE ;-) (Rotary Engine Range
Extender) placed behind the seats - good weight distribution ...

It's just fun to look at the design ... ;-)


With kindest regards

Franky / Frank Herfert

It is so stupid having an engine driving a generator and then driving an electric  motor.

This is indicative of their defective technical education. The laws of physics are not just a good idea. They are the LAW!

When you multiply the efficiencies you wind up less than 20% over all fuel efficiency.

Technical education is being corrupted by Whacko environmental stupidity.

Paul Lamar


Of course the double transformation of mechanical energy into electricity and back to mechanical energy costs energy losses.
In the best practical case in a similar application I know the total losses can be as little as 10%, including the permanent magnet generator and the rectifier, the DC link and the so called "brushless motor" that is the combination of an inverter and a synchronous motor. At low power (30% of max rating), the losses are commonly up to 7.5% of max rating, thus the energy efficiency drops to 75%.

This is to compare to PSRU, or a more complicated shafts and gearboxes system in this case of flying boat.
Obviously the electric solution is at least double mass, and 4 to 5 times less energy efficient.

The Hybrid proposition that consists of a battery grafted on the DC link makes sense in applications where the average power is much lower than the short duration peak power. Perhaps is it the case of a flying boat ?

Would the electric power be produced directly without the first mechanical energy step, using fuel cells for instance, the electric drive would really make sense.
Is this project a first demonstrator step waiting for fuel cell development ?

DEJEAN Philippe

The P&W  gear box in the new geared turbo fan is 99% efficient.

Paul Lamar

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