argon39 wrote:

: Putting a CS prop on a fixed-gear bird will not get you any
: appreciable speed.

: The only thing it buys you is takeoff/climb performance, and unlikely
: to have increased your legal gross weight any.

: I never said that the prop did either of these things. What did change
: things was putting a 180hp O-360 in the place of a 150hp O-320. The
: extra 19hp at 65% power does in fact make it go faster. And the new
: legal gross weight per the STC is now 2500.

I wasn't disparaging your decision, just making a point. Lots of people bolt bigger engines on thinking that
it will make a plane go a lot faster. Actually, it's more or less the cube root of the ratio of horsepower.

My plane originally had a 150hp O-320, but it's been upgraded to a 180 O-360. I find that it helps with
load/climb/takeoff, but primarily it lets me cruise at the same speed at a lower percentage power and be kinder to the
engine and burn the same fuel. For me, the 2 gph difference between 60% and 75% and it's 5 kt difference in speed
isn't really worth the fuel burn.

Cool that you got a gross weight increase. Mine notsomuch.

-Cory

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* Cory Papenfuss *
* Electrical Engineering candidate Ph.D. graduate student *
* Virginia Polytechnic Institute and State University *
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