Tracy Crook wrote:

<snips>   Until we can make our own variable props, the 2.75 - 1

ratio is too much for 200 mph and up aircraft.  Would be fine for a

slower

plane though.  The reason for this is a long story.  Many people have

fallen

into the trap of going for the theoretical best configuration (i.e.

longer &

slower props are better) only to find that real world considerations

make it

the wrong choice.

snips...


tcarrico wrote:

I want same size prop, just more Engine RPM.  I am on that small list of
people
that want 225hp - 250hp but don't want turbo or supercharger.

I am Planning on peripheral ports, EFI, 3mm seals, and the adjustable pitch
prop.
I would really like to turn 7000 RPM for takeoff, and much less for
cruise.  If I wanted to stay in the 2750 range for the prop that puts the
ratio at 2.54.

What are my options...Make my own gear set, or live with 2.17?  The 2.75
would
put me at ~7500 ERPM to get 2750 PRPM, still may be doable (Especialy since
I can change my mind ;) if it can be fitted into Tracy's unit.

tc

Well You sure are right out there Todd. Yes by all means run a higher
ratio. The variable pitch prop puts you over the hump. It is not a
IVO is it? Ross offers a 2.85 to one as I recall and with the latest Ross 
changes and improvements it might not be a bad box. A special six pinion
version of the C6 planetary should work in that as well. Might talk
to Chris Ross about it. (I want to keep Tracy focused :-))

Paul Lamar
 
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