Flaps and V-Tails of Death

"Jack Glendening" wondered...
Wallace Berry wrote:
I never quite got to the
full 90 degrees mark as I had the nose down at a truly obscene angle
just to maintain 50 knots. Steeper than my 301 with the tailchute and
full divebrakes. Steeper than a Mosquito with everything hanging out.
This was more like parachuting than flying. Nothing but dirt out the
front of the canopy.

Anyone know what the actual L/D value is with 90 degrees of flaps ??

For my short-wing-span/long-flap-span HP-14, my guesstimate was somewhere
between 2:1 and 4:1, based on a number of approaches w. full flaps during
which I noted: a) altitude when crossing a plane (estimated to be)
perpendicular to the ground, and b) actual touchdown point. The horizontal
distance was later paced off. Crude, but it satisfied my curiosity. The
slightest headwind was easily apparent in the glidepath. Great Fun.

Two 'How steep IS it?" tales...

1) Before I fully appreciated how abbie-normal the '14's descent path
relative to other airplanes/gliders was, I once had a C-150 driver walk
across the field to where I was fiddling with my '14 not too long after a
routine landing. His first words after determining I was the pilot of the
ship were, "Boy! I thought a Cessna 150 had powerful flaps until I saw your
landing."

2) After another routine landing, a lady passing some time at the commercial
glider operator's location was reported to have screamed (in alarm/fear as
related to me) upon looking up and seeing the HP on a normal short final.

The HP's I've observed from the ground on approaches are distinctly
'different' when compared to 'normal spoilered gliders'. One difference is
it's kind of like a reverse winch launch in that you see the top of the ship
rather than its end-on profile. But unlike a winch launch during which the
ship goes uphill rapidly (compared to aerotow ascent rates), or, the descent
rate of a spoilered ship pointed so nose low, flapped ships comes downhill
ridiculously
slowly in the visual sense.

It wouldn't surprise me if this visual difference is *one* of the reasons so
much 'flaps are dangerously difficult glider landing devices' nonsense
arises. As others have previously noted, the view from the cockpit - while
different (in my supine HP-14 it initially felt like you were standing on
the rudder pedals) - is No Big Deal if you simply fly airspeed and altitude
(letting attitude fall out in the wash). You've a tremendously good view of
the landing zone, the ship is rock steady, and you have plenty of time to
make sound decisions on the way downhill. And as Moffat notes, should you
ever stall an HP-14 with full flaps (something I exploratively did many
times at altitude), the altitude loss is negligible since you're already
pointed/sliding downhill to begin with.

As a final note, the only reason I spouted off in this thread because a post
must've triggered my proselytization button. Yes, I'm a fan of landing
flaps. Yes, I wish my Zuni had my former HP-14's flaps. Yes, I learned on
spoilers. No, I don't lose sleep over the fact I'm apparently in a gliding
minority in my flap opinions...

However, I (sometimes, wry chuckle) DO speak up when misguided opinions that
undeservedly bash a wonderful (if little known and appreciated)
outlanding/safety aid just because it's 'different' are volunteered. It's
not the ignorance (we're all ignorant about some things) or the opinion
(we're entitled to our own) I object to - it's the sharing of both as
implicit fact. My experience in this silly/wonderful sport we're privileged
to be able to indulge in is that keeping an open mind about our areas of
ignorance often has soaring rewards not immediately apparent.

Regards,
Bob - skeptically opinionated - W.


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