Can one start a rotary by hand proping?  If properly done, it's not

dangerous on

a recip, and you sure save dragging a lot of weight around for the rest

of the

flight.

Even a variable pitch prop remains directly coupled, so once you have

airborne

momentum, you have an air re-start capability, and like it or not ...

without

power, windmilling is more of a problem than not being able to "turn the

engine

over".

Any problem feeding hand torque back through the PRSU?  Does it "catch"
abruptly?  Too much compression, too quickly?  Or "piece of cake"?

Just curious,

Dale Smith

John Gibbons wrote:

 Hey Dale,

       Won't work. Your PSRU is going to cut the speed you can swing your
engine in at least half. I would also guess that you would then also have a
futher three fold reduction because of the gearing inside the rotary. Unless
you were to use magnetos you would still need a  of some sort to
power your ignition. With a Lycosaurus you can just swing it fast enough for
it to catch so you would have to increase your swing speed by 500 - 600 %.

Cheers,

John Gibbons

I think you have it backwards John. One rev of the prop is 2.17 revs in the
engine.

I am not sure hand propping engine speed is an issue with electronic ignition and
fuel injection properly timed for starting. You will need a battery of course.

Paul Lamar

Rev speed isn't an issue with mags & Lycosaurs either. A
properly timed Lyc/Con can be started by priming & then very
slowly (& carefully) moving the prop through TDC. The
impulse coupler spring winds up as the engine approaches TDC
& releases just after TDC, spinning the mag fast enough to
generate a spark. It has nothing to do with crank speed.
'Shower of sparks' mags can start an engine with no movement
of the prop at all if the engine is primed & positioned just
past TDC before turning on the mags.

Charlie England

 
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