Claude, now that I've had time to think about your propellor
experimentation, I
think maybe you have some numbers mixed up, or that maybe this moveable
pitot
tube works strangely when it's within the turbulent prop wash.  If the 48
has a
much wider prop wash than the 50 and the air is moving much faster than
the 50,
the plane should go much faster with the 48.  After all, wider and faster
gives
you many more cubic feet of air being thrust backwards.  I'm no
aerodynamacist,
but that's how it seems to me.

Syd

>  Surprise surprise...
> The 48 had a much much wider propwash at low speeds than the 50! Since
both
> props have been to Carolina in the last 6 months for non destructive
testing
> (for cracks etc) and a pitch check (both had one blade slightly out of
pitch
> from the other) I assume they are within spec. Anyway the big difference
was
> how much airflow passed over the MLG lights on climb out and at full
> throttle cruise. For the 48 prop it was linear and stayed at 45-55 mph
above
> the indicated airspeed. If I powered back from redline to a 2150 or so
slow
> cruise It didn't change much. Now the 50 was like a storybook picture.
The
> airspeed at full throttle climbout or cruise was only 7-10 mph faster
and
> immediately upon powereing back even slightly was within 2-4 mph of
> indicated.

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