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Guys! You with the reflexible flaps!
Try this to get more mph(sorry; knots!). Get a level bubble at your local RV
(not Van's) supply store. They have a package with two, one for sideways,
one for fore and aft, made by Hobby. Mount the bigger one inside your canopy in
a fore-aft direction. I mounted mine on the bottom of the canopy just
forward of my arm so I could see it easily in flight. I set it
zeroed-out in line with the wing's chord-line at about 40% span, but the
zero reference really doesn't matter.
When you are flying, especially at high
density altitude and/or at high weight, start with your flaps fully reflexed,
and note the bubble reading. Decrease the reflex slightly to get the bubble
reading about one degree less. Watch your TAS reading for an increase of
one or two mph/kts over the next four or five of minutes. Note, too, that
the nose is slightly lower giving better visibility. Repeat this until lowering
the flaps more gives a speed decrease. Go back to the previous bubble
setting and enjoy about 2-4 mph/kts more speed, and better visibility over the
nose. And you with a fixed-pitch prop and an altitude hold, when you are
flying over slightly rising or descending air, you will see the
bubble change 1/2 or one degree, the rpm go up or down 10-30 rpm, and
TAS/IAS change 1-3 mph/kts.
As they used to say on Monty Python's Flying
Circus "Now for something entirely different". Drum roll, please, for a
little shameless self-promotion!
How about that four-blade ELIPPSE prop
on Tom Aberle's Phantom biplane? He has now increased his speed from 220 mph in
2003 with his original prop, to 240 in 2004 with the three-blade ELIPPSE at 250
rpm less, to 251.958, actually 252.862 if you used the IF1 distance around the
course, in the 2006 biplane Gold race at Reno. How's that for a an
IO-360 biplane? The only two planes that were faster around that
same course than his biplane were the IF1s of Gary Hubler at 257.057 and
David Hoover at 254.587! Pity the poor T-6s, relegated to the slowest race
planes at Reno!
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