Stephen Opgenorth wrote:

Snip....

In order to be a viable thing for a single engine homebuilt any power
recovery system would have to be "fail safe".  If the system fails at any
point, the engine MUST keep working at least long enough to make a safe
landing.  One approach would be to keep the power recovery separate from the
main power plant.  A system something like the attached sketch, extending
from the side of the cowl (one on each side, i.e. one for each rotor) might
work.   It would look something like a Cri Cri with two tightly faired
little pods sticking out but with the main prop in usual place.  Just paint
the plane green and call it "Le Grasshopper"  ;-)

It would give you completely redundant induction systems (you'd need to have
EFI) and, properly designed, you could get some intercooling if you put
cooling ribs on the induction manifold and perhaps a fairing around it.  The
longer exhaust run to the turbo should also help keep the TIT down a bit.

I don't know with what sort of efficiency this system would turn waste
energy into usable thrust, or if you could build it small enough, light
enough and low drag enough to end up with a net gain to give you more mpg.
Any engineer types out there with the urge to do an analysis?  Well that's
my wacky idea for the night :-)

..Stephen..

This is a pretty good idea Stephen. The drawbacks are cost, prop
efficiency
and drag of the external nacelles. The props would have to be quite
large
in diameter to get the efficiency and that means moving the nacelles 
outboard.

Power_Recovery_small.gif

Paul Lamar
 
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