I probably am
overpropped at static and low speed. I told Clark Lydick to build me a
speed prop. I figured that being overpropped on take-off doesnt matter if
you have lots of HP and can get off the ground in 1200 ft and climb like a
banshee anyway. I'll be sending the prop back for adjustment once I get
solid numbers, but I don't think I'll want him to cut it back
much.
john Slade
What sort of top speed, and cruise
speed do you expect? What would be common for an O-360
powered plane?
Cheers,
Rusty (wishing the RV airfoil wasn't
so draggy over 220
mph)
I used to think the same thing (draggy
airfoil) but I think the problem with RVs over 220 is related to wing
/ tail / fuselage incidence. At 220 I get the
visual impression that I am in a dive during level
flight.
The early Citation jets used the same airfoil as
the lowly RV.
Tracy
Tracy,
As you known, the airflow over the
horizontal tail is such as to exert down force on the tail (Nose up) to
overcome the forward pitching movement of the CL of the wing airfoil.
I suspect that at the higher airspeeds the airflow over the wing could be
changed sufficiently that the tail surface might be providing less
downforce (nose up ) than required. In otherwords the
downforce on the horizontal stab is sufficiently lessened that the
nose lowers until the horizontal stab finds a new equilibrium point at your
higher airspeed. As nose goes down, more of the upper surface of the
horiz stab is exposed to the airflow causing more down force/nose up until
the new equilibrium is reached. Just a
thought.
Ed