MS-1e taxiing using powered wheels
This is an animated 3D-model of MS-1e taxiing. The propeller is not spinning. The forward movement is generated by small electric motors installed at the main wheels.
It is an idea which we are considering seriously. We are having brainstorming sessions about it regularly. It is not as easy as it seems at first glance. But, as of now, it could be an additional way to save some energy. Our first calculations seem to indicate that the extra weight caused by the motors and wiring could well pay off. The energy loss caused by an electric motor driving a propeller is higher than when having an electric motor drive a wheel. It is a simple mechanical transmission. Driving a propeller is less energy efficient.
For piston powered airplanes this might also make sense at first glance. However, not so much, because piston engines need warm up time anyway. In most cases the taxi time to the runway is not even sufficient to warm up the engine. That is totally different when it comes to electric motors and electric aircraft. The taxi time from the holding position to the runway centerline is enough to get the electric motor running and complete the tests.
Another advantage: Electric aircraft will be much quieter than piston powered planes. If you are moving your airplane on the apron with people working there, they might not hear you. In such a case the propeller poses an even more serious danger to personnel, fellow pilots, and passengers on the apron. Moving with the propeller standing still could be an important safety advantage.
For now, this is in idea stage. But it might very well come to fruition. It would also be something that could be scalable to the airline world. Large turbo-jet engines are terribly inefficient on the ground and during climb to cruising altitude. The airlines have been thinking about solutions for quite a while. Maybe our development will inspire them.