Tom Smythe wrote:

Hi,

I know the supercharger is larger and draws horsepower from the engine
directly versus the smaller turbocharger and indirect horsepower draw
(backpressure). But, wouldn't the supercharger provide quicker response,
more even power increase with throttle changes (predictable power
changes versus the sudden turbo boost as the turbo gets into it's "sweet
spot"), and longer life (not exposed to the high exhaust temps)?

Again, I now the supercharger weighs more and is a bit more "complex" in
that it requires a drive mechanism off the engine. But, if a
supercharger fails, you revert to a NA engine (with appropriate gates to
prevent a close system - could be spring-loaded to allow opening should
MP fall below value "x" and the supercharger drive could be clutched to
prevent driveshaft lockup, as well). If a turbo fails, you've got
exhause issues to deal with that could be handled with a bypass of some
kind, but now you've got two paths of exhaust (two areas of high heat
under the cowl) to deal with instead of one that is already being snaked
around enough to get to the turbo. With the supercharger, you simply
dump the exhaust overboard via the quickest route possible (and
hopefully through a low backpressure muffler of some kind - spiral
perhaps?).

I thinkthat in real life turbos are more reliable than superchargers.  The
eaton ones I've been seeing lately are all plastic.

More efficiency, more power, why go with a supercharger.  There is no turbo
lag on an engine with a wide open exhaust and at the RPM's that an aircraft
runs at.

Hans

 
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