"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