Or you could just use a turbo which make that all so easy and is more efficient to boot.
Or you could just use a turbo which make that all so easy and is more efficient to boot.
Superchargers are nice in cars as they work from zero rpm.
My dad bought a small turbo car in the early 80s. It was decidedly lukewarm till about 2000rpm then all hell broke loose as the torque tripled over a few hundred rpm. T3 turbo on a 1.3litre ohv, no wonder it was laggy. An aircraft doesn't mind the peaky characteristic of a turbo as prop loading torque varies with the square of revs. Add in automatic altitude compensation and higher efficiency and the choice should be clear.
An opinion...
Superchargers are what's known as positive air displacement devices, they turn at a given speed and each revolution displace 'X' amount of air. That's fine when at sea level but when you go up into thinner air then the volume that is displaced is reduced accordingly (because the air's thinner) so you might have say 8psi of boost at sea level but that might be reduced to 2 psi of boost at 5000 feet (whatever). Also note under load a supercharger can not produce more psi than the driven speed allows.
A Turbocharger relies on exhaust pressure that is usually in excess of what's needed to spin the turbines so if you have 8psi at sea level, the exhaust has enough excess energy to continue to speed up the turbo's turbine to continue to maintain that 8psi at 5000 feet (whatever).
Also under load and even at low rpm, the exhaust pressure is still increased by greater cylinder pressures to provide high levels of boost that a supercharger can not as it's limited by the driven rpm.
Just a suggestion but for these reasons you might consider changing to a turbocharged version that is far more suited for flying, possibly the supercharged's internals are the same.
If at all possible could you weigh and display?
I flew behind P&W supercharged engines and the superchargers work just fine.
The responses I have received on this post have generated more conversations than I anticipated. Please keep sending your opinions because the more information we have leads to better execution of a project like mine.
Thank you,
Blaine
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