In this YouTube video, Robert Llewellyn visits the McLaren Technology Centre to talk to Peter van Manen about the motor that McLaren developed in the last four years and that is now in every Formula E racer. (Next year, other motors and car designs will enter the fray, but the current effort is exciting enough for now.)
One thing stands out: 26 kilograms (57.2 pounds) for 225 horsepower. That’s almost four horsepower per pound. Compare that to the average of about two pounds per horsepower on a modern aircraft engine and marvel at the 8:1 power density ratio between McLaren’s motor and what we fly behind today.
Old-school aircraft design wisdom said that for every pound of engine weight one could lose, one could reduce airframe weight by two pounds. Even granted the additional weight required for propeller speed reduction, what does this portend for a truly radical future for light aircraft design?