Flaps and V-Tails of Death

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.

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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

"Robert Ehrlich" wrote...
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?

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...sort of the
flaps-only equivalent of easing on more spoilers if running out of field.
Certainly not a Big Deal if understood beforehand.

BTW, the most common mistake I've seen in flapped ships IS landing too
fast...probably fallout from: 1) (U.S. centric) training in Schweizer 2-33's
in which being too fast doesn't generally lead to landing alarm/excitement;
and 2) (worldwide?) training in reasonably benign (in the touchdown sense)
spoilers-only, nose-dragging trainers lacking a springy nosewheel. G-103's
in the U.S. often tell the tale of what bad can happen when trying to force
one of them on the ground at too fast a speed (PIO/fuselage damage/etc.).

Regarding your specific questions, in the event someone DOES manage to flare
too high (whether from doing a good flare but too high, or from
over-aggressive aft-stick motion/'ballooning', or simply bounces the
touchdown) in a flaps-only ship, the only proper recourse is to wait. If
you're savvy enough and have time, you can re-establish the proper pitch
angle for touchdown _then_ wait...but wait. Don't churn the stick and don't
adjust the flap position. The bad news is drag IS high and ground-effect
DOES hugely lessen as speed decays. The good news is there is usually a LOT
of downwash, even on a truly botched flare with full flaps, and it's not the
easiest thing to do to drop a flapped ship in from 3 feet. Certainly no
more difficult IMHO than doing so in a spoilers-only ship. Dropping in
either configuration is possible, of course.

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. Is there a spoilers-only driver alive who doesn't take some
comfort in the thought s/he can slam the spoilers shut in that situation and
not distinctly improve things in the near-term future? Get yourself in that
situation in a flaps-only ship and you're essentially out of options. The
GOOD news is that you're much more likely to get low and slow in a ship
having weak landing aids...generally not a problem in gliders having _only_
large deflection flaps as landing aids.

Regards,
Bob W.


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Bob Whelan wrote:
...
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. Is there a spoilers-only driver alive who doesn't take some
comfort in the thought s/he can slam the spoilers shut in that situation and
not distinctly improve things in the near-term future? Get yourself in that
situation in a flaps-only ship and you're essentially out of options. The
GOOD news is that you're much more likely to get low and slow in a ship
having weak landing aids...generally not a problem in gliders having _only_
large deflection flaps as landing aids.
...

Except for the presence of the runway instead of unlandable terrain below
the glider, this is exactly the situation of my question, and so the answer,
as I suspected, is that you are out of options.

Robert Ehrlich wrote
Except for the presence of the runway instead of unlandable terrain below
the glider, this is exactly the situation of my question, and so the answer,
as I suspected, is that you are out of options.

I think that's rather overstated. Unless you have botched the pattern
so throroughly that you are at 30 degrees of flap and coming up short,
you do exactly what you do in a spoiler-only ship - you retract the
flaps. The difference is this - you can't just retract completely, as
you would spoilers, because retracting that last 30 degrees is going
to cause a transient drop you won't like. However, going from 90
degrees to 45 causes no loss of lift at all, and a huge loss of drag -
thus causing airspeed to increase, which allows lifting the nose and
dramatically flattening the approach. This was certainly the case in
my HP-11, and I can't imagine it would be much different on other
flaps-only gliders.

Michael

Michael wrote:

Robert Ehrlich wrote
Except for the presence of the runway instead of unlandable terrain below
the glider, this is exactly the situation of my question, and so the answer,
as I suspected, is that you are out of options.

I think that's rather overstated. Unless you have botched the pattern
so throroughly that you are at 30 degrees of flap and coming up short,
you do exactly what you do in a spoiler-only ship - you retract the
flaps. The difference is this - you can't just retract completely, as
you would spoilers, because retracting that last 30 degrees is going
to cause a transient drop you won't like. However, going from 90
degrees to 45 causes no loss of lift at all, and a huge loss of drag -
thus causing airspeed to increase, which allows lifting the nose and
dramatically flattening the approach. This was certainly the case in
my HP-11, and I can't imagine it would be much different on other
flaps-only gliders.

This will work on approach, when you have the nose down attitude
corresponding to the flaps setting but not in the situation of my
initial question, i.e. just after a botched flare, a few feet above
the runnway and no nose down attitude. In this case retracting the
flaps will cause a loss of drag, but no so huge, i.e. the drag will
much more than in zero flaps or zero spoilers configuration and there
is no gain in lift and no change in the stall speed, you don't have
the altitude that you can convert into speed, so I think that you are
going to fall on the ground, with a slighly increased delay compared
to what would happen if you didn't retract some flaps.

Robert Ehrlich wrote
Except for the presence of the runway instead of unlandable terrain below
the glider, this is exactly the situation of my question, and so the answer,
as I suspected, is that you are out of options.

Let me ask you this, Robert. Put yourself 5 feet above ground, 1 knot
above stall in any glider. Flaps, spoilers, trailing edge air brakes,
drag chute, or whatever. It is probably not going to be a pretty
landing, is it? About all you can do is try and get the nose down a
bit and then rotate one last time to reduce the smiting the ground
will give you. But you asked a good question.

I personally like my flapped ships. If you do put yourself in the
situation (botched flare, bounce, etc) you can also roll on a bit more
flap just before the smiting and soften the blow a bit. Assuming, of
course, you weren't already at full flap. I have had to do this twice
in my 1100 hours of Zuni flying. Once in an off-field landing on a
gusty day with a strong wind shear encounter at about 50 feet (I think
I lost 15 to 20 knots, but I was too busy looking outside to know for
sure). I stopped with the tail less than 10 feet into the field. I
have pictures to prove it. And nothing was even so much as scratched.
The other was over a runway, again involving a bit of wind shear.
Works nice. Pull and crank.

I also have flapped time in an HP-16, and an HP-14. Spoilered time
includes Ka-6 and 604, among others.

Interesting safety note for you all to think about: We have all seen
incidents involving spoilers openning on tow. I bet you have never
seen an inadvertant flap deployment on tow, have you?

Steve Leonard
Second Highest Time Zuni Pilot
(Bob Whelan still has more hours in them than me)