Not a turbocharging expert but have many hours flying sophisticated tc aircraft & I'll limit this to those generating 100's not 1,000s of hp. Some aircraft are turbocharged just to maintain sea level pressure (29.92 in mercury) at altitude. Others actually boost to 40, 50 or more inches and on top of that bleed off air to pressurize the vessel (cabin) to 5 psi differential or more. Suffice it to say that plenty of boost can be had from a turbocharger. Most aircraft never exceed 3000 rpm at takeoff and more often it's down around 2700 & develops full boost with nearly -0- lag. So rpm is NOT the controling factor. It's all a matter of the size turbocharger & the controller set up to do whatever you want to accomplish. Early tc aircraft actually had manually controlled wastegates with no controller at all. I think turbochargers are more adaptable than roots type chargers and if someone were to design a good one for H2s I'd consider doing it.
Okay, my pet peeve. Cars don't have motors, they have engines. Motors, as in electric motors require external power sources to generate energy. Engines generate energy without external power sources. Sorry, goes back to my school shop days.
