H201 Libelle and wing dropping

[ruediger]

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.

[Bill Daniels]

"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

[JC]

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

>
>"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

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.

[Stephen Haley]

Find the junior/cadet who is a good sprinter for wingman otherwise the
airbrake tip does help as well as using a wing runner who only lightly
supports the wing as opposed to the gripper or thrower. It realy does help
to brief the wing runners - I have been given nasty scares once or twice
this year by various antics from people who really dont know what they are
doing.
If you use the airbrake tip it is best to tell the control & tower before
takeoff otherwise you might give the tuggie a heartattack and/or end up with
lots of helpfull souls telling you that your airbrakes are open..
rgds

"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.

[Bill Daniels]

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

[Bob Salvo]

I wonder if you have the same problem I had with my H301 35 years ago. Its
main wheel was not directly under the center line, so when the wing runner
leveled the wing and then let go of it, one wing would immediatley drop to
the ground. When this first happened, I thought one wing was heavier than
the other; but this was not the case. A closer examination revealed an
offset main wheel. The quick solution to this problem was to tell the wing
runner to find the balance point instead of holding the wings level. If
your main wheel is directly under the centerline, and the wings don't
balance when held level, one wing is heavier than the other; this can
happen if a repair was done to one of the wings.

"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.

[Andy Durbin]

(ruediger) wrote in message >...
> 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.

Did you try using the airbrakes?

Andy

[Chris OCallaghan]

Your friends are correct, you should open the airbrakes. You only need
them until you have passed the point where the tow plane started its
takeoff roll.

You have probably noted that you are consistently dropping the same
wing. It is a result of turbulence from the tow plane. Mark where the
tow plane began its takeoff roll and anticipate the turbulence as you
approach this point. Also, get the tail off the ground as soon as
possible to lower your angle of attack and enliven your ailerons.

Be sure to add a checklist item to your take off... to visually check
that the spoilers are not deployed after you break ground. You may
also want to keep a finger or two on the aft side of the spoiler
handle until you've gotten used to closing the spoilers and locking
them with each take off.

Hope this helps.

Chris OC

[John Sinclair]

Not a bad idea to check that your ship is tracking
straight, I test flew a 20 that would head for the
corn field on every flight. Walking it back from my
second aborted takeoff, I noticed it wouldn't keep
going where I pointed it. Did some checking and found
the factory installed tail wheel was a good 10 degrees
off center line. Tail skids are often reinstalled incorrectly,
also.
JJ


At 22:48 15 October 2004, Bob Salvo wrote:
>I wonder if you have the same problem I had with my
>H301 35 years ago. Its
>main wheel was not directly under the center line,
>so when the wing runner
>leveled the wing and then let go of it, one wing would
>immediatley drop to
>the ground. When this first happened, I thought one
>wing was heavier than
>the other; but this was not the case. A closer examination
>revealed an
>offset main wheel. The quick solution to this problem
>was to tell the wing
>runner to find the balance point instead of holding
>the wings level. If
>your main wheel is directly under the centerline, and
>the wings don't
>balance when held level, one wing is heavier than the
>other; this can
>happen if a repair was done to one of the wings.
>
>'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.
>
>
>

[Mal]

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.

[Wallace Berry]

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

[Eric Greenwell]

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

[Wallace Berry]

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

[Eric Greenwell]

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

[Bob Salvo]

"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

[Bill Daniels]

"Bob Salvo" > wrote in message
...

> Using the nose hook will reduce the tendancy for wing drops.
>
> Bob Salvo
>
Really? Why?

Bill Daniels

[Bob Salvo]

Bill,

Not sure, but when I sealed over my nose hook on the H301 and used the CG
hook for aertow, I had more trouble keeping a wing from dropping. I think
when the CG hook is used and there is a wind gust from the side at the start
of launch, there is more tendancy for the tail to swing, which usually
produces some roll. Using the nose hook, which is well in front of the
wheel, reduces the tendancy for a swinging tail. Another interesting thing
I found about using the nose hook is that if the ship happens to vere
towards, say the left, and the left wing starts to drop, the pull force of
the tow rope will try to roll the ship, lifting the wing. I believe this is
because of the larger moment arm (height) between the nose hook and the
pavement. On the other hand, the CG hook is a very close to the pavement,
so there is very little moment force to assist in rolling the ship back to
level. Of course, this could be a disadvantage if the roll force caused by
the tow is holding the wing down. But there are some cases when a wing
drops that releasing is the best thing to do. BTW when using the CG hook
(when there is little rolling force from the tow), I have found that the use
of rudder to pick up a wing works very well if I rudder (turn) towards the
wing that drops. When the ship is forced to turn in the direction of the
dropping wing, the ship will roll to bring the wing back up. Its like
riding a bicycle: if you happen to start falling to the left, you should
steer to the left, otherwise you will fall over. I'm sure that there are a
lot of pilots out there that don't believe this, but that's OK; this method
works for me.

Bob Salvo

"Bill Daniels" > wrote in message
news:MBefd.247116$wV.107530@attbi_s54...
>
> "Bob Salvo" > wrote in message
> ...
>
> > Using the nose hook will reduce the tendancy for wing drops.
> >
> > Bob Salvo
> >
> Really? Why?
>
> Bill Daniels
>

[Bill Daniels]

I honestly can't tell any difference. I've made turning takeoffs so as to
be able to stage off the side of an active runway where the fuselage at the
start of the roll was 30 degrees to the runway centerline. My Nimbus 2C
with a CG hook just tracks where I want it to.

I have no interest in adding a nose hook. I don't think it's a big deal.

Like all tailwheel gliders I try to hold the tailwheel down hard until I get
some rudder control then I lift the tail and just steer it where I want to
go. I use the ailerons aggressively right from the start to hold the long
wings level.

The CG hook doesn't help, but it doesn't hurt either. There have been many
millions of winch launches with CG hooks with no systemic problem with wing
dropping.

Bill Daniels

"Bob Salvo" > wrote in message
...
> Bill,
>
> Not sure, but when I sealed over my nose hook on the H301 and used the CG
> hook for aertow, I had more trouble keeping a wing from dropping. I think
> when the CG hook is used and there is a wind gust from the side at the
start
> of launch, there is more tendancy for the tail to swing, which usually
> produces some roll. Using the nose hook, which is well in front of the
> wheel, reduces the tendancy for a swinging tail. Another interesting
thing
> I found about using the nose hook is that if the ship happens to vere
> towards, say the left, and the left wing starts to drop, the pull force of
> the tow rope will try to roll the ship, lifting the wing. I believe this
is
> because of the larger moment arm (height) between the nose hook and the
> pavement. On the other hand, the CG hook is a very close to the pavement,
> so there is very little moment force to assist in rolling the ship back to
> level. Of course, this could be a disadvantage if the roll force caused
by
> the tow is holding the wing down. But there are some cases when a wing
> drops that releasing is the best thing to do. BTW when using the CG hook
> (when there is little rolling force from the tow), I have found that the
use
> of rudder to pick up a wing works very well if I rudder (turn) towards the
> wing that drops. When the ship is forced to turn in the direction of the
> dropping wing, the ship will roll to bring the wing back up. Its like
> riding a bicycle: if you happen to start falling to the left, you should
> steer to the left, otherwise you will fall over. I'm sure that there are
a
> lot of pilots out there that don't believe this, but that's OK; this
method
> works for me.
>
> Bob Salvo
>
> "Bill Daniels" > wrote in message
> news:MBefd.247116$wV.107530@attbi_s54...
> >
> > "Bob Salvo" > wrote in message
> > ...
> >
> > > Using the nose hook will reduce the tendancy for wing drops.
> > >
> > > Bob Salvo
> > >
> > Really? Why?
> >
> > Bill Daniels
> >
>
>

[Eric Greenwell]

Bill Daniels wrote:
> I honestly can't tell any difference. I've made turning takeoffs so as to
> be able to stage off the side of an active runway where the fuselage at the
> start of the roll was 30 degrees to the runway centerline. My Nimbus 2C
> with a CG hook just tracks where I want it to.
>
> I have no interest in adding a nose hook. I don't think it's a big deal.
>
> Like all tailwheel gliders I try to hold the tailwheel down hard until I get
> some rudder control then I lift the tail and just steer it where I want to
> go. I use the ailerons aggressively right from the start to hold the long
> wings level.
>
> The CG hook doesn't help, but it doesn't hurt either. There have been many
> millions of winch launches with CG hooks with no systemic problem with wing
> dropping.

There wouldn't be any with the nose hook, either, since most of the wing
dropping is due to towplane wake which isn't present with a winch, and a
smaller number due to slow acceleration (I'm guessing more winches
provide good acceleration than towplanes).

My experience, and that of many others, is gliders with long wings or
water ballast are less likely to drop a wing, simply because of inertia.

Nose hooks are a proven advantage over CG hooks for aerotow, but not
primarily for wing dropping reasons; of course, the size of the
advantage varies with the glider and the pilot.

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

Eric Greenwell
Washington State
USA