Winch Launch Safety Study

Can anyone tell me more about how a Standard Cirrus handles when
winched?
We use a GMC V8 325 HP petrol engine with standard automatic gearbox.
No problems until now with K8, K6 and Astir Jeans.
I plan to fit my Cirrus with a CG hook. Cirruses imported to France
where all equipped with a nose hook.

Willy VINKEN OO-ZNY


On 22 Mar 2009 10:00:06 GMT, Del C wrote:

As far I can find out, Bill has only done a few hundred launches on rather
underpowered and overgeared old US Gehrlein type winches, plus a couple of
launches on his 'US Superwinch' in a Grob G103 before the drum was
crushed by the synthetic cable, something else I warned him about! The
G103, being low winged and quite heavy, is not prone to over-rotation
accidents anyway, as identified in the Aerokourier report.

I have personally witnessed several vastly overpowered launches involving
K6 and K8 gliders, and have sat through 3 myself, in a K8, a Standard
Cirrus and a DG101. They really do go into a near vertical climb, often
despite the best efforts of the pilot to control the rotation.
Particularly in the DG case I was lucky not to join the accidents
statistics, as I slipped back up the seat as the glider rotated and was
only able to keep the stick just off the backstop with my fingertips.

Just about everyone in Europe, where we we have a lot of winch launching
experience, disagrees with Bill's views. As to engineering data, I have
seen none whatsoever from Bill, whereas I have supplied quite a lot plus
illustrative videos on the Yahoo Winch Design Group.

If you know the position of the belly hook and the centres of gravity and
pressure in a given glider, it should be possible to calculate the
rotational couple for various levels of pull, and at what level it will
overpower the elevator.

Derek Copeland

At 18:22 22 March 2009, Willy VINKEN wrote:
Can anyone tell me more about how a Standard Cirrus handles when
winched?
We use a GMC V8 325 HP petrol engine with standard automatic gearbox.
No problems until now with K8, K6 and Astir Jeans.
I plan to fit my Cirrus with a CG hook. Cirruses imported to France
where all equipped with a nose hook.

Willy VINKEN OO-ZNY

As long as you don't get an overpowered winch launch it's fine. The
ailerons are slightly ineffective at low speed, so try to choose a fit
looking wing runner if you can. If it's one of the all-flying tailplane
versions, just hold the stick about two-thirds forward and leave it there
until you are established in the full climb. Just concentrate on keeping
the wings level and the glider running straight during the ground run and
rotation. If there is any chance of dropping a wingtip onto the ground,
pull off immediately. It will naturally rotate quite enthusiatically after
lift off, but avoid ramming the stick hard forward to contain this, as this
is what can stall the tailplane.

Don't try to winch launch on a nose hook, because it will give a very
poor launch, and there is no back release mechanism on a the type of nose
hook fitted to this type.

The Standard Cirrus doesn't have the best positioned shoulder strap
mountings, so make sure you do your safety harness up as tightly as
possible to avoid slipping back up the seat, due to the acceleration.

Derek Copeland

At 19:30 22 March 2009, Del C wrote:
At 18:22 22 March 2009, Willy VINKEN wrote:
Can anyone tell me more about how a Standard Cirrus handles when
winched?
We use a GMC V8 325 HP petrol engine with standard automatic gearbox.
No problems until now with K8, K6 and Astir Jeans.
I plan to fit my Cirrus with a CG hook. Cirruses imported to France
where all equipped with a nose hook.

Willy VINKEN OO-ZNY

As long as you don't get an overpowered winch launch it's fine. The
ailerons are slightly ineffective at low speed, so try to choose a fit
looking wing runner if you can. If it's one of the all-flying tailplane
versions, just hold the stick about two-thirds forward and leave it
there
until you are established in the full climb. Just concentrate on keeping
the wings level and the glider running straight during the ground run
and
rotation. If there is any chance of dropping a wingtip onto the ground,
pull off immediately. It will naturally rotate quite enthusiatically
after
lift off, but avoid ramming the stick hard forward to contain this, as
this
is what can stall the tailplane.

Don't try to winch launch on a nose hook, because it will give a very
poor launch, and there is no back release mechanism on a the type of
nose
hook fitted to this type.

The Standard Cirrus doesn't have the best positioned shoulder strap
mountings, so make sure you do your safety harness up as tightly as
possible to avoid slipping back up the seat, due to the acceleration.

Derek Copeland


I concur with Derek. I brace my right arm against my thigh and hold the
stick part way down so any bumps on the ground run will have much less
effect. (I learnt on a UK hill site). Mine has a all flying tail and I do
what Derek describes. I don't need to adjust the position of the stick
(in terms of pitch) until well into the climb and that is just fine
tuning.

Yes, tighten the straps before launch and press firmly back on the pedals
before launch to compress parachute/back rest arrangements (I have 50mm of
dynafoam behind me) to ensure you don't slip back on launch.

No problems with a V8 power Tost winch.

Fitting winglets last season made the ailerons more responsive at low
speed.

Read the flight manual about launching (which basically says what Derek
and I have). Also look at the Standard Cirrus website
http://www.standardcirrus.org
and also look at the Std Cirrus Forum. There is a search facility so look
for 'launch'.

The Std Cirrus hook is well protected by 2 parallel metal strips.
Practice getting the cable on yourself so you can describe to helpers how
they should fit the cable. They tend to get a bit confused because they
can't see the hook like K8s and Astirs etc.

As my first CFI says: Its a glider - go any fly it as you would a glider!





Gavin
Std Cirrus, CNN now G-SCNN, #173
LSV Viersen, Keiheuvel, Belgium

In addition to what Gavin and Derek said I think it is also important
to know that the location of your Centre of Gravity has a significant
influence on the winch launch characterisitics of the Standard Cirrus.
Make sure it is no-where near the rear end of the allowable range. I
can't remember the figures but recall having it close to mid-range and
always felt comfortable.
To prevent sliding into the baggage compartment I always took the
pedals right back and trapped myself between pedals and rear canopy
rim during winch launch.

Marcel Dünner

Some of you might be interested in the latest British Gliding Association
(BGA) Winch Launching Safety Campaign, which includes some frightening
simulations of what can go wrong if you approach winching in a too
cavalier manner. Taking off with the stick hard back, possibly as a result
of sliding back up the seat, is one of them, and has been responsible for
several fatal accidents in the UK. See:

http://www.gliding.co.uk/bgainfo/saf...nch-safety.htm

Derek Copeland

At 12:45 24 March 2009, MaD wrote:
In addition to what Gavin and Derek said I think it is also important
to know that the location of your Centre of Gravity has a significant
influence on the winch launch characterisitics of the Standard Cirrus.
Make sure it is no-where near the rear end of the allowable range. I
can't remember the figures but recall having it close to mid-range and
always felt comfortable.
To prevent sliding into the baggage compartment I always took the
pedals right back and trapped myself between pedals and rear canopy
rim during winch launch.

Marcel D=FCnner

...... and do the quiz .....

chris

On 24/03/2009 1:45 PM, Derek Copeland wrote:
Some of you might be interested in the latest British Gliding Association
(BGA) Winch Launching Safety Campaign, which includes some frightening
simulations of what can go wrong if you approach winching in a too
cavalier manner. Taking off with the stick hard back, possibly as a result
of sliding back up the seat, is one of them, and has been responsible for
several fatal accidents in the UK. See:

http://www.gliding.co.uk/bgainfo/saf...nch-safety.htm

Derek Copeland

At 12:45 24 March 2009, MaD wrote:
In addition to what Gavin and Derek said I think it is also important
to know that the location of your Centre of Gravity has a significant
influence on the winch launch characterisitics of the Standard Cirrus.
Make sure it is no-where near the rear end of the allowable range. I
can't remember the figures but recall having it close to mid-range and
always felt comfortable.
To prevent sliding into the baggage compartment I always took the
pedals right back and trapped myself between pedals and rear canopy
rim during winch launch.

Marcel D=FCnner

At 18:22 22 March 2009, Willy VINKEN wrote:
Can anyone tell me more about how a Standard Cirrus handles when
winched?
We use a GMC V8 325 HP petrol engine with standard automatic gearbox.
No problems until now with K8, K6 and Astir Jeans.
I plan to fit my Cirrus with a CG hook. Cirruses imported to France
where all equipped with a nose hook.

Willy VINKEN OO-ZNY
We operated a Standard Cirrus for 3 years on the winch and found no
handling problems provided the elevator was moved progressively. The AMT
is quite powerfull and has been known to stall on full down deflection ,
but we never experienced it .

On 22 Mar 2009 10:00:06 GMT, Del C wrote:

As far I can find out, Bill has only done a few hundred launches on
rather
underpowered and overgeared old US Gehrlein type winches, plus a couple
of
launches on his 'US Superwinch' in a Grob G103 before the drum was
crushed by the synthetic cable, something else I warned him about! The
G103, being low winged and quite heavy, is not prone to over-rotation
accidents anyway, as identified in the Aerokourier report.

I have personally witnessed several vastly overpowered launches
involving
K6 and K8 gliders, and have sat through 3 myself, in a K8, a Standard
Cirrus and a DG101. They really do go into a near vertical climb, often
despite the best efforts of the pilot to control the rotation.
Particularly in the DG case I was lucky not to join the accidents
statistics, as I slipped back up the seat as the glider rotated and was
only able to keep the stick just off the backstop with my fingertips.

Just about everyone in Europe, where we we have a lot of winch
launching
experience, disagrees with Bill's views. As to engineering data, I
have
seen none whatsoever from Bill, whereas I have supplied quite a lot
plus
illustrative videos on the Yahoo Winch Design Group.

If you know the position of the belly hook and the centres of gravity
and
pressure in a given glider, it should be possible to calculate the
rotational couple for various levels of pull, and at what level it will
overpower the elevator.

Derek Copeland