Chris,
Ahh, too bad I can't translate Reynolds numbers into KIAS. I thought
the NASA airfoil tests were at slow speeds????
Oh well .. It does match my experience. At high speeds, flap in
reflex and nose down trim (on my airplane, small tail, actual TE of elevator is
down a bit from neutral) is a very interesting condition to
contemplate. After all, the elevator is an upside down wing (slightly
cambered on the bottom). Thus, nose down trim is actually with
the elevator in reflex. Since the chord of the horizontal stab was
positioned with a negative incidence to the longeron (-.5 to -1 degrees,
mine is -.8) and at cruise (about 180 - 190 KIAS), the longeron has
been measured to be at 0 degrees (hmmm, just like the plane
was designed), the horizontal may be at a positive AOA (relative air
flow?, think upside down) until one considers the position of the elevator and
its trim change on the AOA to a lesser AOA. Thus, less lift (anti
lift), less drag.
Egads, now my head hurts.
Blue Skies,
Scott Krueger
In a message dated 4/17/2012 8:53:25 A.M. Central Daylight Time,
chris_zavatson@yahoo.com writes:
I use the attached charts to describe the impact of reflex: Repositioning the drag bucket, a
drop of a few drag counts and a huge 3 to 1 change in pitching moment.
Chris Zavatson
N91CZ
360std
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