[Public-List] Standard Prop Size and Pitch

Brian Palmer Bpalmer at DigitalArsenal.com
Thu May 22 08:20:22 PDT 2008


On L'Esprit, I've got an Atomic 4 with the 13x7 prop.  The engine runs
strong and smooth, but when in gear, I can't rev higher than maybe
1900RPMs.  If I push the throttle higher, the engine doesn't go any faster.
I think it's just that the engine is working hard enough that it simply
can't spin the prop any faster under that load.

It's not a problem, since I can motor along at 6 kts or so on flat water.  I
hear people mentioning 2300RPMs...  It would be nice to have this as reserve
power if I was motoring against the wind and chop or something.  Do those of
you who also have A4s with the standard 13x7 2 blade find the same
limitation?

On a side note, Towney mentioned before that he had his 13x7 prop turned
down to a 12x7 prop after getting a nick in it or something.  He said the
engine ran like never before!  He had the same problem I speak of, with the
RPMs never getting high enough to take advantage of ideal HP and torque
available at those higher RPMs.  He said that once the prop was smaller it
felt like it was a better match for the A4.

-Brian Palmer

 1211469622.0


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