New trainer from SZD Bielsko

"Sally W" wrote in message
...
But surely only the ones with winch experience teach
winch launching? So it's not an issue? And surely
no-one goes from aerotow to winching without getting
some instruction?


I'm sure that it's a rare situation. Fortunately, there is a lot of good
guidance on the web about winch proceedures from various national aero clubs
and quite a few instructors who read this guidance.

Bill Daniels

On Jun 26, 8:57 pm, "Bill Daniels" bildan@comcast-dot-net wrote:
"Sally W" wrote in message

...

But surely only the ones with winch experience teach
winch launching? So it's not an issue? And surely
no-one goes from aerotow to winching without getting
some instruction?

I'm sure that it's a rare situation.

I hope it's as rare as flying pigs.


Fortunately, there is a lot of good
guidance on the web about winch proceedures from various national aero clubs
and quite a few instructors who read this guidance.

And I'd hope the instructors have been doing a bit more than reading
the Internet for guidance.

Bill Daniels wrote:
"Sally W" wrote in message
...
But surely only the ones with winch experience teach
winch launching? So it's not an issue? And surely
no-one goes from aerotow to winching without getting
some instruction?


I'm sure that it's a rare situation. Fortunately, there is a lot of good
guidance on the web about winch proceedures from various national aero clubs
and quite a few instructors who read this guidance.

As you know, the training of the majority of winch qualified pilots
(i.e., those with a ground launch endorsement) here in the US consisted
of pulling a rusty underpowered Gerhlein out from behind a hangar,
plopping the transitioning pilot in the front seat of a nose hook
equipped 2-33, then three flights: pilot follows instructor on controls,
instructor follows pilot on controls, instructor signs off pilot, pilot
flies a solo launch.

There are several clubs that now use winches as their primary launch
method, and they take instruction (and safety) much more seriously.
But, much of the resistance to increased use of winches in the US comes
as a reaction to these past (for the most part) "training" activities...

Marc

On 26 Jun, 19:44, Cats wrote:
On Jun 26, 5:54 pm, Ian wrote:

There is at least one large club in England which teaches this as the
right way to winch launch.

Then if they are still doing that, I suspect they are not following
the latest BGA advice:

http://www.gliding.co.uk/bgainfo/doc...hlaunching.pdf

A document which I saw for the first time a couple of weeks ago. I was
rather struck by this

"There is no case of an airworthy glider being damaged by excessive
airspeed on a winch launch which is why it is not listed as a hazard."

which makes me wonder why it is imediately followed by this

"If the speed is excessive near the ground, climb gently to several
hundred feet and release, or signal if the excess speed is now
moderate."

If it's not a hazard, why do anything about it?

Ian

On Tue, 26 Jun 2007 14:10:57 -0700, Ian
wrote:

If it's not a hazard, why do anything about it?

To avoid breaking the cable?

Bye
Andreas

"Ian" wrote in message
ups.com...
On 26 Jun, 19:44, Cats wrote:
On Jun 26, 5:54 pm, Ian wrote:

There is at least one large club in England which teaches this as the
right way to winch launch.

Then if they are still doing that, I suspect they are not following
the latest BGA advice:

http://www.gliding.co.uk/bgainfo/doc...hlaunching.pdf

A document which I saw for the first time a couple of weeks ago. I was
rather struck by this

"There is no case of an airworthy glider being damaged by excessive
airspeed on a winch launch which is why it is not listed as a hazard."

which makes me wonder why it is imediately followed by this

"If the speed is excessive near the ground, climb gently to several
hundred feet and release, or signal if the excess speed is now
moderate."

If it's not a hazard, why do anything about it?

Ian


The "no case" statement just means don't take precipitous action if the
airspeed is too high. Accidents have occured from pilot actions that were
unwarranted. None have occured simply due to exceeding Vw by a small
margin.

Excessive speed near the ground means that acceleration and therefore the
winch power is way too high. The pilot is advised to release and land ahead.

However, both statements lead one to think that the winch is controlling
airspeed which is difficult since the winch driver has no idea what the
glilder airspeed is. If the winch is producing the right power, the pilot
can, and should, control airspeed with pitch.

The relationship of power and airspeed is exactly like an airplane. With
fixed power, raising the nose will reduce airspeed, lowering it will cause
airspeed to increase. The relationship between pilot and winch driver is
exactly like that between a pilot and flight engineer where the engineer
controls power and the pilot flies the airplane.

Bill Daniels

On Jun 26, 10:10 pm, Ian wrote:
On 26 Jun, 19:44, Cats wrote:

On Jun 26, 5:54 pm, Ian wrote:
There is at least one large club in England which teaches this as the
right way to winch launch.
Then if they are still doing that, I suspect they are not following
the latest BGA advice:

http://www.gliding.co.uk/bgainfo/doc...hlaunching.pdf

A document which I saw for the first time a couple of weeks ago. I was
rather struck by this

"There is no case of an airworthy glider being damaged by excessive
airspeed on a winch launch which is why it is not listed as a hazard."

which makes me wonder why it is imediately followed by this

"If the speed is excessive near the ground, climb gently to several
hundred feet and release, or signal if the excess speed is now
moderate."

If it's not a hazard, why do anything about it?

Ian

Because if you don't release the weak link is going to break, which
leaves you in a launch failure situation rather than a releasing at a
more moderate angle, which is preferable. A high-speed link break is
not very comfortable (I had one last weekend, when the winch driver
inexplicably floored the winch half way up a launch). Breaking the
weak link is also a major PITA for those on the ground (we lost the
strop+rings, which I believe is £££).

RE the club we're not naming - amazingly I understand they've not had
a winch launch accident, at least not recently. Other clubs have
though.


Dan

Ian wrote:
http://www.gliding.co.uk/bgainfo/doc...hlaunching.pdf

A document which I saw for the first time a couple of weeks ago. I was
rather struck by this

"There is no case of an airworthy glider being damaged by excessive
airspeed on a winch launch which is why it is not listed as a hazard."

which makes me wonder why it is imediately followed by this

"If the speed is excessive near the ground, climb gently to several
hundred feet and release, or signal if the excess speed is now
moderate."

If it's not a hazard, why do anything about it?

Ian

I think the point being made is that no-one has yet proved it to be a
hazard in practice by pulling the wings off, or more likely causing the
tailplane to fail.

However, if you read "Gliding" by Steve Longland (which is the book-form
advanced BGA manual plus), you will see that flying beyond the max winch
speed at some point takes the glider outside its design limits. Outside
the limits no-one knows what will happen to the airframe. Maybe it'll be
fine, maybe not (and the parts of the book about repeated stresses
outside design limits leading to gradual though invisible deterioration,
followed by catastrophic failure, give pause for thought).

As I read the advice, if your only choice is to accept excessive speed
or to accept something worse, then excessive speed is the safer choice.
If you can do something safe rather than overspeed, then do the other thing!

For example, from my experience driving a winch, I've seen numerous
pilots rotate and then immediately start wagging the glider's tail (the
UK signal for "too fast"). If you read about the physics of the launch,
at this stage the loads on the glider are low, and overspeeding presents
little or no hazard. The consequence is often (especially if the glider
is climbing through a wind gradient) that if the driver reduces the
speed, a few seconds later the glider is too slow - now that *is* proved
to be dangerous.

Experienced winch-launching pilots who I know are content to accept
overspeeding in the first part (say 1/3) of the launch and wait for the
speed to settle to the correct figure. If not (in the second 1/3 where
the loads are increasing) they signal to slow down. If speed is too high
in the top 1/3 (where the forces start to approach or exceed design
limits) then it's goodbye to the cable - but at that point you have
enough height to make a safe circuit so it's only an argument with the
driver about your wasted launch fee and not a case of recovering your
remains from the runway.

If the speed is madly excessive (and I've had this happen to me a couple
of times) then even signalling can be a problem. In that case, allowing
the glider to "float" up to circuit height with little or no load on the
airframe is the safest way of coping, followed by forcible re-education
of the winch driver.

On 26 Jun, 22:40, Andreas Maurer wrote:
On Tue, 26 Jun 2007 14:10:57 -0700, Ian
wrote:

If it's not a hazard, why do anything about it?

To avoid breaking the cable?

Then it would be a hazard!

Ian

On 26 Jun, 22:42, "Bill Daniels" bildan@comcast-dot-net wrote:

The relationship of power and airspeed is exactly like an airplane. With
fixed power, raising the nose will reduce airspeed, lowering it will cause
airspeed to increase.

It's not alwaysthat simple, and depends a lot on the construction of
the winch. It makes a big difference, for example, if it has a torque
convertor as opposed to a fxed ratio gearbox or a fluid flywheel. You
need to take account of the tension-speed relationships for both the
winch and the glider.

Ian (one time winch instructor)