Flaps and V-Tails of Death

The trick with landing in tall growth is not flaring at the top of the
'crop' but continuing to fly down to ground level. I flared early and
'landed' at 1.5 metre above the deck. The resulting 'loud bang' was the
ASW20's main wheel being pushed up into the fuselage. Thankfully the
structure absorbed the impact and I got away without any back injury.

Of course the problem with flying into the tops of uneven tall growth is the
potential to catch a wingtip and 'groundloop' at 1 metre with the resulting
potential for 'major' damage and resulting injury. In hindsight I'm not sure
that I didn't actually inadvertently do the right thing.

My incident happened when I changed my mind on finals just to be closer to
the field access road. Dumb, dumb, dumb, I was closer to the access road but
the damage took 6 weeks to repair!

Ian



"Brian Case" wrote in message
om...
Don't know about conventional tails. But I have been helping rebuild a
DG202 (T-tail) that landing in a tall wheat feild. It caught a wing
tip and turned sideways breaking nearly every part in the fuselage.
(Major Damage) Don't know if a conventional tail would have helped.

Brian

Mark wrote
It strikes me that the yaw of crop hitting a
wing is the real problem.

You're completely right about this. I got my LS-6 after its previous owner
tried to land in 8 foot high corn. The fuselage broke in 3 places, before
anything hit the ground. The major problem is catching a wing tip and then
performing a flying ground loop. My wing took the sudden reversal in direction
very well and was just scraped up a bit. The fuselage (mainly the tail mass)
wasn't able to turn that fast and failed (in compression) on the inside, of the
very rapid left turn that was commanded when the left wing tip hit the corn.
That's a massive moment arm (25 feet). The spar is tremendously strong when
loaded in this way (for and aft) but the fuselage isn't. The ASH-25 has an arm
of 43 feet and one must never place ones wing tip in any crops. Plowed ground
is my choice, because DIRT DON'T HURT.


JJ Sinclair

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 ??

Jack,

Here is an article written George Moffat:

http://www.soaridaho.com/Schreder/HP...NG_THE_14.html

The HP-14 answer to your question is found in the third from last paragraph.

Paul Bikle's T-6 version the HP-14 limited flap deflection to 68 degrees.
In the following article he states that 68 degrees provides a glide ration
of 6 to 1.
http://www.soaridaho.com/Schreder/HP-14/T-6.html

Wayne
http://www.soaridaho.com/Schreder



"Jack Glendening" wrote in message
ink.net...
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 ??

In article . net,
Jack Glendening wrote:
Anyone know what the actual L/D value is with 90 degrees of flaps ??

Probably no more than 4:1.

A friend let me fly his HP-11. His advice to me about how to flare when
using 90 degrees flap: wait until you're certain you're going to crash,
then count to three, then flare!

It works, too.

--
Dylan Smith, Castletown, Isle of Man
Flying: http://www.dylansmith.net
Frontier Elite Universe: http://www.alioth.net
"Maintain thine airspeed, lest the ground come up and smite thee"

Wayne Paul wrote:
The HP-14 answer to your question is found in the third from last paragraph.

The 40 degree angle given there equates to a 1.2:1 glide ratio - about
the same as that of the space shuttle !

"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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On a related note it appears that the Marske Monarch useds flaps
(and spoilers both?):

http://www.continuo.com/marske/kits.htm

Basically, this is a flying wing with neither elevator nor
canards. I'm curious as to how pitch is controlled.

--

FF

Earlier, (Fred the Red Shirt) wrote:

On a related note it appears that
the Marske Monarch useds flaps
(and spoilers both ... this is
a flying wing with neither
elevator nor canards. I'm curious
as to how pitch is controlled.

I don't think that that's quite an accurate assessment of the Monarch
configuration.

The movable control surface on the wing inboard trailing edge performs
the same function as the elevator on a conventional tailed aircraft.
It responds to fore-and-aft motion of the stick and controls the pitch
attitude. It is sometimes (but not always) called an "elevon" on a
tailless aircraft. Its location aft of the CG gives it adequate moment
arm to perform its function.

Another interesting tailless aircraft is the Brightstar SWIFT, which
is a swept-wing tailless glider that uses flaps for pitch control. The
name is an acronym meaning Swept Wing with Inboard Flaps for Trim.

The sweep of the SWIFT wing places the flaps far enough forward so
that deflecting them down causes a pitch-up moment. The value of this
feature is that pitching up is done by effectively increasing the wing
camber, which better suits the wing to slower flight.

Thanks, and best regards to all

Bob K.
http://www.hpaircraft.com

(Bob Kuykendall) wrote in message . com...
Earlier, (Fred the Red Shirt) wrote:

On a related note it appears that
the Marske Monarch useds flaps
(and spoilers both ... this is
a flying wing with neither
elevator nor canards. I'm curious
as to how pitch is controlled.

I don't think that that's quite an accurate assessment of the Monarch
configuration.

The movable control surface on the wing inboard trailing edge performs
the same function as the elevator on a conventional tailed aircraft.
It responds to fore-and-aft motion of the stick and controls the pitch
attitude. It is sometimes (but not always) called an "elevon" on a
tailless aircraft. Its location aft of the CG gives it adequate moment
arm to perform its function.

I see. There was some discussion on the site of cg shifting for pitch
control but it was't clear if that was used in the Monarch or not. It
seems to me that it would be wasteful to add weight for that purpose
though I suppose you could put the pilot's seat on wheels and
roll him back and forth for pitch control.


Another interesting tailless aircraft is the Brightstar SWIFT, which
is a swept-wing tailless glider that uses flaps for pitch control. The
name is an acronym meaning Swept Wing with Inboard Flaps for Trim.

The sweep of the SWIFT wing places the flaps far enough forward so
that deflecting them down causes a pitch-up moment. The value of this
feature is that pitching up is done by effectively increasing the wing
camber, which better suits the wing to slower flight.


Oh, cool. The flaps are functionally similar to canards.

Thanks for the info.

--

FF