Flaps and V-Tails of Death

Eric Greenwell originally replied...
If you believe that, perhaps you haven't been told "all the bad things".
For example, I've had HP pilots tell me getting sucked up into a cloud
can be "awkward" to deal with when all you've got is flaps.

My first and only flight in an HP went like Mr. Berry's; even so, I hope
anyone beginning to fly a flaps only glider gets thorough checkout,
because there are ways to go wrong.

Bob Whelan followed with...

No offense, Eric, but speaking from the vantage point of one with all
his
(greater-than)
1-26 glide-ratio time in flaps-only ships (C-70, HP-14, Zuni), the more
powerful the flaps, the _less_ 'exciting' it need be if you allow
yourself
to get sucked into a cloud.


Eric G. further replied...
The situations described to me were the difficulty of avoiding the cloud
entry in the first place. A pilot can open his spoilers at 90 knots and
begin descending immediately, but deploying the flaps at 90 knots first
increases your altitude, making it much harder to stay out of the cloud.
If you do lose control in a cloud, lots of drag is an advantage.

The main point I hoped to make is landings aren't the only way spoilers
and glide path flap operation differs, and one good landing isn't enough
to know the pitfalls, even for landings. I think everyone agrees the HP
series is a great ship to make off-field landings in the hands of a good
pilot.

I figured there was some nuance I was missing. No harm no foul. I agree
with all your points. For my part I just wanted to throw out for general
consideration that though flaps ARE different than spoilers, 'different'
doesn't necessarily strongly equate with 'bad.' Nor does 'different'
necessarily strongly equate with 'large cojones.'

Free information is always worth every cent paid for it, but (in my
flap-biased view) there seems to be more misleading/'flaps are bad'
information floating around about flaps than there is of the sort to be
found in this particular thread...which thus far contains accurate - if
necessarily incomplete - information in every post.

Just to provide a counterpoint to your scenario of avoiding the cloud in the
first place (always a good idea, if not always achieved), it's worth
pondering how ANYone comes to the decision s/he may require imminent cloud
avoidance techniques. Consider the particular case of a powerful western
U.S. cloud street. Odds are J. Pilot will be cruising along at 80+ mph and
suddenly have a "HolyCOW!' moment upon realizing cloud avoidance is
necessary. Options likely to spring to the surprised mind?: 1) course
change; 2) nosing over/adding energy; 3) adding gear drag; 4) adding
flap/spoiler drag. All will be exciting in a suddenly more thrill-filled
cockpit.

I've spoken to 2 pilots (years apart) soon after each first intentionally
opened spoilers at above-pattern speeds, one in a St'd Cirrus near 120 knots
trying to get below a finish gate in a regionals, and the other in an
Astir-CS trying to avoid being sucked into a big, wide, western cloudstreet
who had options 1, 2, & 3 prove insufficient. We laughed about things
because we were on the ground, but they were both wide-eyed recollecting the
BIG negative G event occasioned by opening spoilers at
higher-than-pattern-speeds, even though both had time to realize prior to
pulling the spoiler handle they were treading in new (for them, at the
times) territory. Playing Joe Test Pilot is always best done (IMHO) under
more controlled conditions than 'needing' to play JTP.

FWIW, I thought the St'd Cirrus pilot did by far the more foolish
thing...because he took an avoidable risk, whereas the Astir CS pilot felt
he had no other choice. Both whanged their heads on the canopy. The Astir
pilot wound up in a high-speed, gear-down, spoilers-out slip trying
desperately to stay out of the cloud street. About the time he could see he
was going to be successful avoiding the cloud, he heard a radio call to the
effect, "Glider at XXX over YYY, this is Cessna ZZZ. Are you OK?" Being at
XXX over YYY, he declined to answer (would've required a 3rd hand w/o a boom
mic), though afterwards he could appreciate a certain irony in the
situation!

Regards,
Bob W.



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Here are some pictures of Jim Harper's HP-16:
http://www.soaridaho.com/Schreder/HP...rst_Flight.htm

Wayne
http://www.soaridaho.com/


"Wallace Berry" wrote in message
...
Hi all,

I'm here to report that I cheated death and survived a flight in a
glider with the dreaded "Landing Flaps and V-Tails of Death". Jim Harper
graciously allowed me to fly his beautiful HP-16. What's an HP-16 you
say? Well, looks to be just like the HP-18 (or I should say the HP-18 is
just like the -16) except that the -16 has a large and comfortable all
metal cockpit instead of the narrow composite cockpit of the -18.

Jim's -16 is equipped with winglets and, as far as I know, the ailerons
are standard (not with the J.D. Colling mod, correct me if I'm wrong
Jim). Center stick. Tow was behind our 180hp Cessna 175 on a 275 foot
long rope. Started out in -2 flap position, went to + 5 at 40 knots. Had
no trouble keeping the wings level. The bird lifted off level and was
easy to fly on tow. Released and tried slow flight (no stalls), flight
up to 90 knots. Steep turns, etc. Well sealed and quiet. Good rudder
response and easy to coordinate compared to my 301 Libelle. More stable
in a thermal than my Libelle. Aileron response was a little slower than
my Libelle at thermaling speeds, but was positive and more than adequate
for centering thermals. Climbed a few hundred feet in a very week
thermal. Very nice thermalling glider.

Landing was the best part. I stayed high and close in the pattern. I
rolled on some flap on downwind, maybe 30 degrees or so. I was way high
on final so I started rolling in more flaps. 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. The horizon was visible more towards the top of the
canopy. I aimed at a target and just kept the nose pointed there. I
pulled back on the stick when I ran out of nerve. The bird settled on
with a slight bump of the tailwheel and a little bounce as the main
dropped on (I flared just a bit too much). I have no doubt that I could
easily put this bird in a tiny field much easier than I could my Libelle
(and that is not difficult at all).

So, I'd have to say that all the bad things I've been told about landing
flaps on gliders and V-tails are definitely untrue with respect to the
HP-16. It is a comfortable and easy to fly glider and compares very well
to my Libelle and also to other glass birds, including my favorites for
handling, the Mosquito and LS-4.

Wayne Paul wrote:

Here are some pictures of Jim Harper's HP-16:
http://www.soaridaho.com/Schreder/HP...rst_Flight.htm

Wayne
http://www.soaridaho.com/


"Wallace Berry" wrote in message
...

Wayne, what's it like to land an HP in a strong, gusty wind? Do you use
a higher approach speed and only partial flap?
--
-----
Replace "SPAM" with "charter" to email me directly

Eric Greenwell
Washington State
USA

"Eric Greenwell" wrote in message
...

Wayne, what's it like to land an HP in a strong, gusty wind? Do you use
a higher approach speed and only partial flap?


Eric,

I am a low time glider pilot and I think more experienced pilots could
provide more insight then I; however, from my limited experience you are
right on target.

Several years ago I purchase a HP-16T (now owned by Brian Case). I search
the web for information and found almost nothing, so I started a web site to
act as a repository of information relating to Dick's designs. The site was
well receive by HP/RS/RHJ owner and article, pictures, etc started arriving.
The result is http://www.soaridaho.com/Schreder The information on the site
reflects the cooperation of HP enthusiasts, not my expertise.

Bob Kuykendall started a complementary service by forming the hp-gliders
news group. (http://groups.yahoo.com/group/hp-gliders). The combination of
the two resources have served Schreder sailplane design owners over the past
five+ years.

After I sold my HP-16T to Brian I purchase a HP-14 which I have been
restoring for the past 3 years.

Here are some relevant landing related articles that I have collected:

Dick Schreder --
http://www.soaridaho.com/Schreder/St...r_on_Flaps.htm
Steve du Pont -- http://www.soaridaho.com/Schreder/Large-span_flaps.html

Bob Kuykendall -
http://www.soaridaho.com/Schreder/St..._HP_flight.htm

Wayne
http://www.soaridaho.com

On Tue, 18 Nov 2003 07:47:58 -0800, Eric Greenwell
wrote:

.... text deleted ...

Wayne, what's it like to land an HP in a strong, gusty wind? Do you use
a higher approach speed and only partial flap?
--

Eric, I resisted jumping into this thread, but for what it's worth,
while I no longer fly a PIK, I did own a PIK20B for 18 years and have
something over 2000 hours in this 90deg flap only ship.

Most of the important points on 90deg flaps have already been said.

- they are different, so there is an initial learning curve that is
made more difficult by the lack of 90deg flaped trainers. I often
recommended new PIK pilots to get an hour in a Cessna 150 to get a
feel for high flap deflection behavior.

- once mastered, they can be modulated during any portion of the
pattern with no problem. As has been said before, if you are floating
and can not get the ship down, put on more flap. Once the main wheel
is on the ground, dump the flap (full negative (up)) to plant the ship
on the ground.

- Like any flapped ship, so not get below the flaps up stall speed
during the pattern, until your final flare. This allows you to
modulate the flaps with no concern about pulling out flap and
stalling.

- On the PIK, I recommended new pilots move the PIK flap handle (5
turns total) in full 360deg increments, always stopping at the top of
the circle. This made modulation like normal spoilers, pulling the
handle back from the top position lowered flap, increased drag, just
like pulling back a spoiler handle. And the opposite for pushing
forward from a top position, less drag.

- Relating to your question, the only drawback I found in the 90deg
flaps was landing in very gusty conditions. Here I would limit the
down flap to something like 45deg. Since this only occured with strong
headwind components, I did not need large flap deflections.

- The strong advantage to the 90deg flaps was in short field landing,
where you could point the ship at a spot on the ground and modulate
the flaps to control airspeed. BTW, the only time in all my flying
that I used 90deg flaps was in off-field landings over a tree line,
and for routine practice. Typical landing flap varied between 30deg
and 60deg.

Bob

OK, It's winter time and I'm bored, so let me throw my 2 cents in here. The
only flight I ever had in a ship with flaps only was in a PIK-20B. It was a
test flight after a broken fuselage. Things went well until it got time to
land. I rolled in 45 degrees of flaps and everything looked just about right.
Came over the fence at 50 knots and waited for her to settle down. I waited and
waited and waited. By now I had floated down most of the 4000 foot runway and
I'm still floating about 1 foot off the ground. What do I do? Musn't dump the
flaps or she will drop like a stone, right? Finally got the wheel on the ground
and jumped on the brake.
That night I read the flight manual and it said to slowely crank off the flaps
in this situation. I think the flaps only ships are OK, but require a different
set of skills that must be mastered. Probably not for the low time pilot or
those who don't read the flight manual before flight. My real problem was being
about 5 knots too fast. Proper speed control is critical.
JJ Sinclair

JJ Sinclair wrote:

OK, It's winter time and I'm bored, so let me throw my 2 cents in here. The
only flight I ever had in a ship with flaps only was in a PIK-20B. It was a
test flight after a broken fuselage. Things went well until it got time to
land. I rolled in 45 degrees of flaps and everything looked just about right.
Came over the fence at 50 knots and waited for her to settle down. I waited and
waited and waited. By now I had floated down most of the 4000 foot runway and
I'm still floating about 1 foot off the ground. What do I do? Musn't dump the
flaps or she will drop like a stone, right? Finally got the wheel on the ground
and jumped on the brake.
That night I read the flight manual and it said to slowely crank off the flaps
in this situation. I think the flaps only ships are OK, but require a different
set of skills that must be mastered. Probably not for the low time pilot or
those who don't read the flight manual before flight. My real problem was being
about 5 knots too fast. Proper speed control is critical.

So I'm told. Our club had a member from Long Island, where the club
there had a 1-35. He said they got rid of it after a while because they
got tired of pulling it out of the weeds at the end. Without a landing
flap equipped two seater, they weren't able to train their low time
pilots well enough to land it properly. I think there would be a lot
more acceptance of HP style flaps if we had two seaters to train in.

--
-----
Replace "SPAM" with "charter" to email me directly

Eric Greenwell
Washington State
USA

Eric Greenwell wrote:

JJ Sinclair wrote:

OK, It's winter time and I'm bored, so let me throw my 2 cents in here. The
only flight I ever had in a ship with flaps only was in a PIK-20B. It was a
test flight after a broken fuselage. Things went well until it got time to
land. I rolled in 45 degrees of flaps and everything looked just about right.
Came over the fence at 50 knots and waited for her to settle down. I waited and
waited and waited. By now I had floated down most of the 4000 foot runway and
I'm still floating about 1 foot off the ground. What do I do? Musn't dump the
flaps or she will drop like a stone, right? Finally got the wheel on the ground
and jumped on the brake.
That night I read the flight manual and it said to slowely crank off the flaps
in this situation. I think the flaps only ships are OK, but require a different
set of skills that must be mastered. Probably not for the low time pilot or
those who don't read the flight manual before flight. My real problem was being
about 5 knots too fast. Proper speed control is critical.

So I'm told. Our club had a member from Long Island, where the club
there had a 1-35. He said they got rid of it after a while because they
got tired of pulling it out of the weeds at the end. Without a landing
flap equipped two seater, they weren't able to train their low time
pilots well enough to land it properly. I think there would be a lot
more acceptance of HP style flaps if we had two seaters to train in.


Flaps only ships are very rare in France and kowledge about their handling
is probably even more rare. I wonder how one can handle in such a ship what
is described in our flight Bible, the "blue book" (Manuel du pilote Vol a Voile,
i.e. glider pilot's manual) as the 3 most common mistakes when landing:
1) flare to high; 2) flare with excessive back stick action; 3) bounce.
In this 3 cases the glider comes a few feet above the ground at a speed
just marginally above stall speed and quickly decaying due to the drag of
open airbrakes. The immediate action to avoid that the glider falls on
the ground like a stone in the following seconds is to retract the air-brakes,
so that the drag stops killing your speed and you regain some lift, then
try to land better ahead. But what can you do with no air-brakes?

"Robert Ehrlich" wrote in message
...
Eric Greenwell wrote:

JJ Sinclair wrote:

OK, It's winter time and I'm bored, so let me throw my 2 cents in
here. The
only flight I ever had in a ship with flaps only was in a PIK-20B. It
was a
test flight after a broken fuselage. Things went well until it got
time to
land. I rolled in 45 degrees of flaps and everything looked just about
right.
Came over the fence at 50 knots and waited for her to settle down. I
waited and
waited and waited. By now I had floated down most of the 4000 foot
runway and
I'm still floating about 1 foot off the ground. What do I do? Musn't
dump the
flaps or she will drop like a stone, right? Finally got the wheel on
the ground
and jumped on the brake.
That night I read the flight manual and it said to slowely crank off
the flaps
in this situation. I think the flaps only ships are OK, but require a
different
set of skills that must be mastered. Probably not for the low time
pilot or
those who don't read the flight manual before flight. My real problem
was being
about 5 knots too fast. Proper speed control is critical.

So I'm told. Our club had a member from Long Island, where the club
there had a 1-35. He said they got rid of it after a while because they
got tired of pulling it out of the weeds at the end. Without a landing
flap equipped two seater, they weren't able to train their low time
pilots well enough to land it properly. I think there would be a lot
more acceptance of HP style flaps if we had two seaters to train in.


Flaps only ships are very rare in France and kowledge about their handling
is probably even more rare. I wonder how one can handle in such a ship
what
is described in our flight Bible, the "blue book" (Manuel du pilote Vol a
Voile,
i.e. glider pilot's manual) as the 3 most common mistakes when landing:
1) flare to high; 2) flare with excessive back stick action; 3) bounce.
In this 3 cases the glider comes a few feet above the ground at a speed
just marginally above stall speed and quickly decaying due to the drag of
open airbrakes. The immediate action to avoid that the glider falls on
the ground like a stone in the following seconds is to retract the
air-brakes,
so that the drag stops killing your speed and you regain some lift, then
try to land better ahead. But what can you do with no air-brakes?

Flaps, once deflected beyond about 10 degrees, produce mainly drag. In
steady-state glides, drag is drag whether produced by flaps or spoilers.
For a given amount of drag, a flapped glider will have the nose much further
down than a glider with spoilers, however. This gives a much better view of
the runway.

The main difference is in the transients as the drag devices are extended or
retracted. The trick with flaps is to manage the transients. Yanking on
flaps from the retracted position will produce a upward transient before the
drag steepens the glide path. Yanking on spoilers will produce a downward
transient before the glider settles into a steeper glide. This generally
means that the pilot should not make large, sudden changes in flap settings
near the ground - but this is good advice for spoilers as well.

Large flap deflections change the relationship between pitch and airspeed.
Large changes in pitch result in small changes in airspeed so that the nose
can be steeply down and the airspeed will not increase much. This invites
the technique popular with HP glider pilots of just aiming the glider
steeply down at the flair point with 90 degrees of flap deployed. If the
glide appears to be overshooting the aim point, pushing the nose further
down steepens the glide without much increase in airspeed. If it appears
that you are undershooting, just raise the nose a little and shallow the
glide. Extremely accurate landings are possible with no changes made in the
flap setting.

The height to start the flare is a bit tricky to judge at first and the
flare is greatly exaggerated compared to spoiler only gliders. If you flare
too high, the recovery is to just relax some of the back stick and let the
glider settle before completing the flare. "Leave 'em where they are" is
good advice when landing with flaps.

I really like flaps. They eliminate the discontinuity in the upper wing
surface created by the spoiler box. Once mastered, they permit much lower
energy landings than with spoilers.

A for as a trainer, the IS28b2 Lark can be landed with flaps only although
the glide is quite shallow. I looked at the flap drive geometry on my Lark
with the thought that it might be modified to allow 45 degrees or more of
positive flap just for training scenarios. It would be possible but the
paperwork would be a nightmare.

Bill Daniels

"Robert Ehrlich" wrote in message
...
Eric Greenwell wrote:

JJ Sinclair wrote:

OK, It's winter time and I'm bored, so let me throw my 2 cents in
here. The
only flight I ever had in a ship with flaps only was in a PIK-20B. It
was a
test flight after a broken fuselage. Things went well until it got
time to
land. I rolled in 45 degrees of flaps and everything looked just about
right.
Came over the fence at 50 knots and waited for her to settle down. I
waited and
waited and waited. By now I had floated down most of the 4000 foot
runway and
I'm still floating about 1 foot off the ground. What do I do? Musn't
dump the
flaps or she will drop like a stone, right? Finally got the wheel on
the ground
and jumped on the brake.
That night I read the flight manual and it said to slowely crank off
the flaps
in this situation. I think the flaps only ships are OK, but require a
different
set of skills that must be mastered. Probably not for the low time
pilot or
those who don't read the flight manual before flight. My real problem
was being
about 5 knots too fast. Proper speed control is critical.

So I'm told. Our club had a member from Long Island, where the club
there had a 1-35. He said they got rid of it after a while because they
got tired of pulling it out of the weeds at the end. Without a landing
flap equipped two seater, they weren't able to train their low time
pilots well enough to land it properly. I think there would be a lot
more acceptance of HP style flaps if we had two seaters to train in.


Flaps only ships are very rare in France and kowledge about their handling
is probably even more rare. I wonder how one can handle in such a ship
what
is described in our flight Bible, the "blue book" (Manuel du pilote Vol a
Voile,
i.e. glider pilot's manual) as the 3 most common mistakes when landing:
1) flare to high; 2) flare with excessive back stick action; 3) bounce.
In this 3 cases the glider comes a few feet above the ground at a speed
just marginally above stall speed and quickly decaying due to the drag of
open airbrakes. The immediate action to avoid that the glider falls on
the ground like a stone in the following seconds is to retract the
air-brakes,
so that the drag stops killing your speed and you regain some lift, then
try to land better ahead. But what can you do with no air-brakes?

The landing is executed in a way as not to use full 90 degree flap in the
final stages of the final. Rather manage the final approach in a way that
allows the use of less flap. You will have some flap action in reserve to
arrest any excessive sink, similar to using only partial spoiler.

In Fact, when looking at my flying style with the flap only glider,
I use the flap, like you would use the spoiler. I constantly make use of
them
during the pattern to place my self at any point I would like to be.
When making misjudgements it is no different to correct them, as with
spoilered gliders.

It is best for a newcomer to place the glider relative high on final
crank in full flaps and aim for the beginning of the run way.
That way you will have enough speed for corrections if you make a
misjudgement and if you are on glide path you burn of all the energy very
quickly. It really does not matter if you use and extra 200 feet.
In the end it the touch down speed that counts.

As for out landings into small fields with high obstacle, it requires
different approaches and only practice at your home field will make you
proficient.

Udo