H201 Libelle and wing dropping

"ruediger" wrote in message
om...
Since 3 month I am proud owner of a H201B with 17m wingspan and
"Speizklappen". The glider I owned for 4 years, before i bought the
Libelle was a Astir CS77. I like the handling of the Libelle very
much, the only point I really have problems with, is that the Libelle
loves to drop a wing at the beginning of aero tow. Every take off that
a friend or me made with the glider was close to a aborted take-off.
Other Libelle Pilots said, I should try to open the air breaks for the
first 100m, but none of them owns a 17m version, which has extra
weight on the outer side of the wing because of the wingtip extension.

I am not used to this wing dropping by the ASTIR so I hope I can get
some additionell advice here.

It's an accepted fact that extending the spoilers or selecting negative flap
will enhance aileron control at low speeds. The magnitude of the effect
differs for various gliders so consultation with pilots experienced with a
particular glider is advised.

That said, there is another factor that may be involved.

I recall watching the grid depart at a regional contest where each glider in
turn dropped the upwind wing. There was about a 8 knot crosswind component.

After watching the show for a while I started to realize that the tugs prop
blast was drifting with the wind and striking the gliders down wind wing
causing it to rise violently. The onset of the effect occurred when the
glider had rolled about half the length of the tow rope or just after the
wing runner had released the wing tip.

When my turn came, I got ready to stuff in a lot of down wind aileron at
just the point where the glider encountered the tugs prop blast. It worked
nicely and I didn't drop a wing like those before me. Now I'm always ready
for the drifting prop blast.

Bill Daniels

On Fri, 15 Oct 2004 15:59:52 GMT, "Bill Daniels"
wrote:


"ruediger" wrote in message
. com...
Since 3 month I am proud owner of a H201B with 17m wingspan and
"Speizklappen". The glider I owned for 4 years, before i bought the
Libelle was a Astir CS77. I like the handling of the Libelle very
much, the only point I really have problems with, is that the Libelle
loves to drop a wing at the beginning of aero tow. Every take off that
a friend or me made with the glider was close to a aborted take-off.
Other Libelle Pilots said, I should try to open the air breaks for the
first 100m, but none of them owns a 17m version, which has extra
weight on the outer side of the wing because of the wingtip extension.

I am not used to this wing dropping by the ASTIR so I hope I can get
some additionell advice here.

It's an accepted fact that extending the spoilers or selecting negative flap
will enhance aileron control at low speeds. The magnitude of the effect
differs for various gliders so consultation with pilots experienced with a
particular glider is advised.

That said, there is another factor that may be involved.

I recall watching the grid depart at a regional contest where each glider in
turn dropped the upwind wing. There was about a 8 knot crosswind component.

After watching the show for a while I started to realize that the tugs prop
blast was drifting with the wind and striking the gliders down wind wing
causing it to rise violently. The onset of the effect occurred when the
glider had rolled about half the length of the tow rope or just after the
wing runner had released the wing tip.

When my turn came, I got ready to stuff in a lot of down wind aileron at
just the point where the glider encountered the tugs prop blast. It worked
nicely and I didn't drop a wing like those before me. Now I'm always ready
for the drifting prop blast.

Bill Daniels

In the commercial operation I used to run I saw this same wing drop
due to prop blast in the longer winged planes, specifically the Nimbus
2 and a ASW-22. I kept a 300 ft rope just for towing these guys. The
longer rope solved the problem.

You may wish to make up a 100 foot "weak link" to be used when towed,
(Assuming they are starting with a 200ft.) It would most likely
solve your problem.

JC wrote in message ...
On Fri, 15 Oct 2004 15:59:52 GMT, "Bill Daniels"
wrote:


"ruediger" wrote in message
. com...
Since 3 month I am proud owner of a H201B with 17m wingspan and
"Speizklappen". The glider I owned for 4 years, before i bought the
Libelle was a Astir CS77. I like the handling of the Libelle very
much, the only point I really have problems with, is that the Libelle
loves to drop a wing at the beginning of aero tow. Every take off that
a friend or me made with the glider was close to a aborted take-off.
Other Libelle Pilots said, I should try to open the air breaks for the
first 100m, but none of them owns a 17m version, which has extra
weight on the outer side of the wing because of the wingtip extension.

I am not used to this wing dropping by the ASTIR so I hope I can get
some additionell advice here.

It's an accepted fact that extending the spoilers or selecting negative
flap
will enhance aileron control at low speeds. The magnitude of the effect
differs for various gliders so consultation with pilots experienced with
a
particular glider is advised.

That said, there is another factor that may be involved.

I recall watching the grid depart at a regional contest where each glider
in
turn dropped the upwind wing. There was about a 8 knot crosswind
component.

After watching the show for a while I started to realize that the tugs
prop
blast was drifting with the wind and striking the gliders down wind wing
causing it to rise violently. The onset of the effect occurred when the
glider had rolled about half the length of the tow rope or just after the
wing runner had released the wing tip.

When my turn came, I got ready to stuff in a lot of down wind aileron at
just the point where the glider encountered the tugs prop blast. It
worked
nicely and I didn't drop a wing like those before me. Now I'm always
ready
for the drifting prop blast.

Bill Daniels

In the commercial operation I used to run I saw this same wing drop
due to prop blast in the longer winged planes, specifically the Nimbus
2 and a ASW-22. I kept a 300 ft rope just for towing these guys. The
longer rope solved the problem.

You may wish to make up a 100 foot "weak link" to be used when towed,
(Assuming they are starting with a 200ft.) It would most likely
solve your problem.

I fly a Nimbus 2C and just being alert to the possibility of prop blast
drift has worked for me so far. I like the idea of a longer rope though.

Bill Daniels

To prevent wing drop in Libelles:

Longer tow rope. 250-300 feet works well.

Start with open divebrakes on the 201 during the initial roll. But, be
very careful here. The Libelle's brakes aren't very powerful which makes
a brakes open on tow problem especially insidious. If they are open
after lift off, the tug driver probably won't notice immediately. You
will be way down the runway when you and the tuggy realize that
something is wrong. Take it from one who knows ; )!

Use negative flap on the 301. Works even better than opening the
divebrakes on the 201 and doesn't have the inherent hazard of open
brakes on tow.

Stick full forward from the beginning of the takeoff roll until the tail
comes up. This will get you aileron authority as quickly as possible.

My 301 has Kestrel landing gear which is even taller than the original
301 gear. This makes for an even greater potential for wing drop. Using
the above techniques, I rarely ever have a wing drop, even when being
towed by weak tugs.

--
Take out the airplane for reply

Wallace Berry wrote:
To prevent wing drop in Libelles:

snip


Stick full forward from the beginning of the takeoff roll until the tail
comes up. This will get you aileron authority as quickly as possible.

I suggst that this is not good practice in a cross-wind takeoff, where
you want the tail wheel firmly on the ground to help keep the glider
straight. It is probably not necessary in any case: by the time you are
going fast enough to lift the tail, aren't the ailerons already so
effective you won't drop a wing?


--
Change "netto" to "net" to email me directly

Eric Greenwell
Washington State
USA

In article ,
Eric Greenwell wrote:

Wallace Berry wrote:
To prevent wing drop in Libelles:

snip


Stick full forward from the beginning of the takeoff roll until the tail
comes up. This will get you aileron authority as quickly as possible.

I suggst that this is not good practice in a cross-wind takeoff, where
you want the tail wheel firmly on the ground to help keep the glider
straight. It is probably not necessary in any case: by the time you are
going fast enough to lift the tail, aren't the ailerons already so
effective you won't drop a wing?

What you state is exactly what I would expect. But, for whatever reason,
holding forward stick on my 301 seems to help significantly with
avoiding a wing drop. Even with the stick forward, the rudder is
effective before the tail comes up. So far, no problems with cross wind
take offs, which they nearly all are at our site. One thing I forgot to
mention, my Libelle only has the CG hook, the nose hook having been
glassed over by a previous owner. Because of this, the tail on my 301
tends to stay down a bit longer than one being towed by the nose hook.
With a long rope, negative flap and the stick forward, I've done
unassisted takeoffs with no trouble. Haven't tried that with a strong
crosswind.

--
Take out the airplane for reply

Wallace Berry wrote:
In article ,
Eric Greenwell wrote:


Wallace Berry wrote:

To prevent wing drop in Libelles:

snip


Stick full forward from the beginning of the takeoff roll until the tail
comes up. This will get you aileron authority as quickly as possible.

I suggst that this is not good practice in a cross-wind takeoff, where
you want the tail wheel firmly on the ground to help keep the glider
straight. It is probably not necessary in any case: by the time you are
going fast enough to lift the tail, aren't the ailerons already so
effective you won't drop a wing?


What you state is exactly what I would expect. But, for whatever reason,
holding forward stick on my 301 seems to help significantly with
avoiding a wing drop. Even with the stick forward, the rudder is
effective before the tail comes up. So far, no problems with cross wind
take offs, which they nearly all are at our site. One thing I forgot to
mention, my Libelle only has the CG hook, the nose hook having been
glassed over by a previous owner. Because of this, the tail on my 301
tends to stay down a bit longer than one being towed by the nose hook.
With a long rope, negative flap and the stick forward, I've done
unassisted takeoffs with no trouble. Haven't tried that with a strong
crosswind.

I got confused about who was flying what, and my comments were intended
for a 201. My 301 didn't drop a wing as long as I started in full
negative flap. It's been 20 years, but I think I used some back stick at
the start. Mine did have the nose hook.


--
Change "netto" to "net" to email me directly

Eric Greenwell
Washington State
USA

"Wallace Berry" wrote in message

One thing I forgot to
mention, my Libelle only has the CG hook, the nose hook having been
glassed over by a previous owner. Because of this, the tail on my 301
tends to stay down a bit longer than one being towed by the nose hook.
With a long rope, negative flap and the stick forward, I've done
unassisted takeoffs with no trouble. Haven't tried that with a strong
crosswind.

Using the nose hook will reduce the tendancy for wing drops.

Bob Salvo

201 does not have flaps

The 301 does I used to go from negative in the ground roll once I had
positive control I went to positive and the glider would lift off the ground
did not drop wing.

I have noted a growing trend to open airbrakes (spoilers) in Australia to
prevent dropping wings.

The 201 I launched today dropped the wing he did not use airbrake and I gave
the wing a good run.

Mal

It's an accepted fact that extending the spoilers or selecting negative
flap
will enhance aileron control at low speeds. The magnitude of the effect
differs for various gliders so consultation with pilots experienced with a
particular glider is advised.