IDAHO FATALITY

wrote:
On Sep 6, 3:35 pm, Ramy wrote:

On Sep 6, 8:11 am, Jim White wrote:






I have changed the subject as we are well passed Idaho now.

I am having trouble with this stall warning stuff. I fly modern gliders:
ASW27, Duo Discus, ASK21 etc. All give clear warnings ahead of a stall.
When they do stall the nose drops, stick forward a bit, dada...stall
recovered. If they were to start into a spin (and the 21 shouldn't with
normal C of G positions), stick forward a bit, maybe a bit of pedal, and
dada...recovered.
None would lose significant amounts of height if recovered straight away.

I compete in the 27 and regularly fly it in thermals near the stall. You
feel for the break in laminar flow on the wings. This actually happens well
before the stall. It would be impossible to climb effectively if the stick
kept shaking!

And what would happen in a fully held off landing? I would also be a bit
****ed if the shaker went off when I was landing as slow as possible into a
very tight field in a light head wind!

This has to be about training and currency in gliders. We are not flying
747s with passengers down the back.

Final turns should be made at a sensible height with sufficient speed and
well banked so that they cannot be ruddered into a spin. This all should be
natural and obvious to a well trained pilot. No need for another mechanical
gadget to go wrong.

At 13:00 06 September 2011, kirk.stant wrote:

Modern gliders give very little indications of a stall (another reason
why training in old clunkers like the 2-33 is counterproductive). Add
a little distraction or a higher priority task (Bee in the cockpit!)
and you can be in a high-AOA situation without being aware of it. Add
to that a pilot who flies infrequently, and the benefit of a stall
warning system becomes even more clear.

Kirk
66- Hide quoted text -

- Show quoted text -

This is the point that puzzles me the most. I am sure that many of us
had never accidentally stalled/spinned a glider even in rough
thermals, due to the ample warnings. Incipient spin is the closest to
accidental spin I ever got, and this is only when grossly skidding in
rough thermal at safe altitude. Yet the majority of glider accidents
are attributed to stall/spin, and usually very experienced pilots, and
if my assumption above is correct, it was probably their first
accidental stall/spin. Which leads me to conclude that those stall/
spin happened without warning from one reason or another.
I think it will be very helpful to hear stories from pilots who
survived a stall/spin accident, and why they think it happened.
Anyone on RAS who survived such an accident care to share their story?

Ramy- Hide quoted text -

- Show quoted text -


I'm going out on a limb here and somebody out there will get the saw
out.
A stall does not happen without some warning.
The important element in training is understanding the warning signs.
I teach 6 signs and require all pilots I oversee to be able to
verbalize and demonstrate them.
#1- Reduced control effectiveness sensed by lower resistance to forces
applied by the pilot and reduced response of the glider.
#2- Nose high attitude. Yes we can stall at any attitude, but nose
high is almost always there in critical stalls.
#3- Reduced cockpit noise- Less noticable in modern gliders but still
evident.
#4- Stick pressure is back and likely significant- Exception is aft CG
or improperly trimmed glider.
#5- Low indicated air speed
#6- Buffet indicating flow separation preceding a stall.
It is worth noting that pilots previously trained in airplanes will
commonly mention #6 first , but almost none have been trained on the
other warnings.
I also note that the majority of pilots I check that have been trained
by others have a few (maybe a half dozen or so) log book entries
noting stalls. This, in my view, is completely inadequate. Recognition
and response must be automatic and instinctive, and this needs much
more emphasis and practice.
Off soap box
UH

People partizing winch launches knows that noe of these 6 signs are
present during the launch :

#1- Reduced control effectiveness : as during the launch there is a load
factor of 1.3 to 1.5, speed is higher than in unaccelerated stall and so
the resistance to forces applied is not abnormally low.
#2- Nose high attitude : this is the normal attitude during a winch launch.
#3- Reduced cockpit noise : again due to the load factor and increase in
tall speed, nois is not abnormally low.
#4- Stick pressure is back : normal during a winch launch.
#5- Low indicated air speed : again due to the load factor, speed in not
abnormally low.
#6- Buffet indicating flow separation preceding a stall : not all glider
exhibut this effect and it can easily be mistaken with the shaking due
to the glider going quick through the wind gradient.

The point 1 is not totally missing and is in fact the only remaining
sign. Forces and effectiveness of rudder and elevator are not abnormally
low, but there is a significant change on the action of ailerons and the
roll control. As the angle of attack at the wing tips approach the
critical one, changes in this angle of attack have a lower effect. A
consequence of that is the decrease or loss of roll damping and a
consecutive tendency to oscillate left and right.

On Sep 11, 5:22*am, Robert Ehrlich wrote:
wrote:
On Sep 6, 3:35 pm, Ramy wrote:

On Sep 6, 8:11 am, Jim White wrote:

I have changed the subject as we are well passed Idaho now.

I am having trouble with this stall warning stuff. I fly modern gliders:
ASW27, Duo Discus, ASK21 etc. All give clear warnings ahead of a stall..
When they do stall the nose drops, stick forward a bit, dada...stall
recovered. If they were to start into a spin (and the 21 shouldn't with
normal C of G positions), stick forward a bit, maybe a bit of pedal, and
dada...recovered.
None would lose significant amounts of height if recovered straight away.

I compete in the 27 and regularly fly it in thermals near the stall. You
feel for the break in laminar flow on the wings. This actually happens well
before the stall. It would be impossible to climb effectively if the stick
kept shaking!

And what would happen in a fully held off landing? I would also be a bit
****ed if the shaker went off when I was landing as slow as possible into a
very tight field in a light head wind!

This has to be about training and currency in gliders. We are not flying
747s with passengers down the back.

Final turns should be made at a sensible height with sufficient speed and
well banked so that they cannot be ruddered into a spin. This all should be
natural and obvious to a well trained pilot. No need for another mechanical
gadget to go wrong.

At 13:00 06 September 2011, kirk.stant wrote:

Modern gliders give very little indications of a stall (another reason
why training in old clunkers like the 2-33 is counterproductive). *Add
a little distraction or a higher priority task (Bee in the cockpit!)
and you can be in a high-AOA situation without being aware of it. *Add
to that a pilot who flies infrequently, and the benefit of a stall
warning system becomes even more clear.

Kirk
66- Hide quoted text -

- Show quoted text -

This is the point that puzzles me the most. I am sure that many of us
had never accidentally stalled/spinned a glider even in rough
thermals, due to the ample warnings. Incipient spin is the closest to
accidental spin I ever got, and this is only when grossly skidding in
rough thermal at safe altitude. Yet the majority of glider accidents
are attributed to stall/spin, and usually very experienced pilots, and
if my assumption above is correct, it was probably their first
accidental stall/spin. Which leads me to conclude that those stall/
spin happened without warning from one reason or another.
I think it will be very helpful to hear stories from pilots who
survived a stall/spin accident, and why they think it happened.
Anyone on RAS who survived such an accident care to share their story?

Ramy- Hide quoted text -

- Show quoted text -

I'm going out on a limb here and somebody out there will get the saw
out.
A stall does not happen without some warning.
The important element in training is understanding the warning signs.
I teach 6 signs and require all pilots I oversee to be able to
verbalize and demonstrate them.
#1- Reduced control effectiveness sensed by lower resistance to forces
applied by the pilot and reduced response of the glider.
#2- Nose high attitude. Yes we can stall at any attitude, but nose
high is almost always there in critical stalls.
#3- Reduced cockpit noise- Less noticable in modern gliders but still
evident.
#4- Stick pressure is back and likely significant- Exception is aft CG
or improperly trimmed glider.
#5- Low indicated air speed
#6- Buffet indicating flow separation preceding a stall.
It is worth noting that pilots previously trained in airplanes will
commonly mention #6 first , but almost none have been trained on the
other warnings.
I also note that the majority of pilots I check that have been trained
by others have a few (maybe a half dozen or so) log book entries
noting stalls. This, in my view, is completely inadequate. Recognition
and response must be automatic and instinctive, and this needs much
more emphasis and practice.
Off soap box
UH

People partizing winch launches knows that noe of these 6 signs are
present during the launch :

#1- Reduced control effectiveness : as during the launch there is a load
factor of 1.3 to 1.5, speed is higher than in unaccelerated stall and so
the resistance to forces applied is not abnormally low.
#2- Nose high attitude : this is the normal attitude during a winch launch.
#3- Reduced cockpit noise : again due to the load factor and increase in
tall speed, nois is not abnormally low.
#4- Stick pressure is back : normal during a winch launch.
#5- Low indicated air speed : again due to the load factor, speed in not
abnormally low.
#6- Buffet indicating flow separation preceding a stall : not all glider
exhibut this effect and it can easily be mistaken with the shaking due
to the glider going quick through the wind gradient.

The point 1 is not totally missing and is in fact the only remaining
sign. Forces and effectiveness of rudder and elevator are not abnormally
low, but there is a significant change on the action of ailerons and the
roll control. As the angle of attack at the wing tips approach the
critical one, changes in this angle of attack have a lower effect. A
consequence of that is the decrease or loss of roll damping and a
consecutive tendency to oscillate left and right.

Agree on all points which is why an AoA indicator with stall warning
would be especially useful for winch launch.