Flaps and V-Tails of Death

"Bob Whelan" wrote in message ...
[snip]
Speed control is important in gracefully landing flaps-only gliders
(spoilers-only too, of course). What I've found - and often seen - is that
gliders' large-deflection flaps essentially 'quit working' as drag producing
devices if landed 'too fast.' True even for HP-16's. Come in too fast and
you _will_ float a long ways in flapped gliders...unless you slowly ease off
on the flaps, in which case the ship will gently settle...
[good stuff snipped]
IMHO, about the only situation I can envision where a flaps-only ship IS
worse than a spoilers-only one is that of getting low and slow on the
approach.
[snip]
Regards,
Bob W.

Hi, Bob and all.

With all humility and with the following caveats, I would like to
mildly disagree and vehemently agree with a couple of your points.
First the caveats: I am not all that experienced, and have only flown
my HP-16 for one summer, I think I am qualified to comment, but by no
means am an expert. The following comments ONLY apply to my HP-16,
N8DC, with 90 degree flaps, standard sized flaps (no flap was
sacrificed to improve the ailerons), and flown fairly CG forward.

Mild disagreement on the too fast comment. I think that the only way
to make my -16 float would be to be going too fast and then roll off
the flaps. 90 degree flaps require an impressive deck angle just to
keep the speed in the 60mph range on approach. If, when I get close to
the ground, I flare, any excess speed, and I mean ANY excess speed is
gone very quickly, and I land. Period. An approach with, say, 60
degrees of flap would indeed float if I had too much speed on, and as
such, one possible corrective action would be to roll off the flaps,
if I had slowed considerably...otherwise, more flaps is usually the
right answer. This airplane will not float with maximum flaps. There
have got to be 6 square feet of aluminum hanging perpendicular to the
airflow...we stop pretty quickly.

A minor expansion on that. It is very difficult to get the airplane to
accelerate with 90 degree flaps...If I should let the airspeed decay
on approach with full flaps, I need to push the nose down to
frightening angles...as in hanging from the straps...to
accelerate...or just roll off some flaps, which is what I do. This
presupposes that we are talking 45-60+ speed range. I would very much
not like to get much below 45 with full flaps. The aircraft's stall
characteristics are quite benign, but recovery requires a fair amount
of altitude with flaps at that level.

Conversely, speed control on appoach is quite trivial. Should I, for
whatever reason, let the speed creep up...more flaps...less speed. It
is amazingly linear...and better than any speed/lift control device I
have used, including throttle.

To agree emphatically on another point: Low and slow with flaps on is
a VERY BAD THING (tm). Too fast is no problem...roll the flaps in to
slow, roll them out to stretch. Too slow, and your options
are...well...gone. So that is an area of the performance curve that I
avoid.

I too went into the -16 wondering about all of the forked-tailed flaps
of doom talk. Turns out that my airplane is an absolute pussycat. If
yer ever planning on being around LaGrange, GA some weekend, drop me a
note. We might can work something out!

Jim