New 29 Palms Winchfest Video

On Dec 11, 5:26 pm, Marc Ramsey wrote:
Bert Willing wrote:
Winch launch has nothing to do with free flight, and "angle of attack for
best L/D" has no meaning. On a winch launch, you simply try to fly at
Ca/max.

I don't agree. Common sense (and the mathematics) make it clear that
the most effective (highest altitude) launch is achieved by maximizing
the lift and minimizing the drag given the varying cable tensions
delivered during the climb phase of the launch. For a specific cable
tension, that speed will be equivalent to the best L/D for the polar
adjusted to the effective loading resulting from that cable tension.
The AOA for best L/D, however, is independent of the effective loading.
So, the optimal speed could be maintained during climb by keeping the
AOA at best L/D (which also, of course, keeps one below the stall AOA).

On my 1,200+ winch launches, I never felt the need of an AoA meter (nor did
I after releasing).

Well, in my 20+ winch launches I haven't been much concerned with
anything beyond getting to release without breaking anything. From a
training perspective, however, particularly in places (like the US)
where there isn't much overall experience with winch launching, an AOA
meter should be a great deal of help with learning to fly the launch
optimally.

I've got a lot more winch launches than you and a lot less than Bert,
but I've never felt the need for an AOA meter. I fly in the UK so was
taught by the BGA manual.

Cats wrote:
On Dec 11, 5:26 pm, Marc Ramsey wrote:
Bert Willing wrote:
Winch launch has nothing to do with free flight, and "angle of attack for
best L/D" has no meaning. On a winch launch, you simply try to fly at
Ca/max.
I don't agree. Common sense (and the mathematics) make it clear that
the most effective (highest altitude) launch is achieved by maximizing
the lift and minimizing the drag given the varying cable tensions
delivered during the climb phase of the launch. For a specific cable
tension, that speed will be equivalent to the best L/D for the polar
adjusted to the effective loading resulting from that cable tension.
The AOA for best L/D, however, is independent of the effective loading.
So, the optimal speed could be maintained during climb by keeping the
AOA at best L/D (which also, of course, keeps one below the stall AOA).

On my 1,200+ winch launches, I never felt the need of an AoA meter (nor did
I after releasing).
Well, in my 20+ winch launches I haven't been much concerned with
anything beyond getting to release without breaking anything. From a
training perspective, however, particularly in places (like the US)
where there isn't much overall experience with winch launching, an AOA
meter should be a great deal of help with learning to fly the launch
optimally.

I've got a lot more winch launches than you and a lot less than Bert,
but I've never felt the need for an AOA meter. I fly in the UK so was
taught by the BGA manual.


Of course you can winch launch without an AOA meter. Would an AOA meter
increase safety, enhance training, and/or result in higher launches? It
appears to me that it is worth examining...

Marc

I also am of the opinion that an AoA meter is totally unnecessary for
winch launches. Perhaps academic curiosity, but the best practices are
already well known.

One shouldn't self teach winch launches and certainly not by trying to
figure out what an AoA is saying in regards to flying the launch.

In any case, even a badly flown launch by the pilot only results in a
somewhat lower release altitude than if it is done optimally by the
pilot. So it's really the wrong focus.

Perhaps once someone has plenty of experience with winch launches like
several posters here, one can then perhaps play around with an AoA for
fun to see if it even helps attain maybe a 3% higher release altitude.
Other than that, it's useless.

For pilots and operations starting out and trying to gain experience
in safely and efficiently doing winch operations, an AoA serves no
purpose and is an unnecessary distraction.

Walk first, then run.

tommytoyz wrote:
For pilots and operations starting out and trying to gain experience
in safely and efficiently doing winch operations, an AoA serves no
purpose and is an unnecessary distraction.

I can remember when people would argue on R.A.S. that having a GPS or
PDA in the cockpit was an unnecessary distraction. For some of us,
flying gliders is mostly about "academic curiosity", and looking into
these sorts of things, whether ultimately practical or not, is what
makes the sport fun...

Marc

"tommytoyz" wrote in message
...
I also am of the opinion that an AoA meter is totally unnecessary for
winch launches. Perhaps academic curiosity, but the best practices are
already well known.

One shouldn't self teach winch launches and certainly not by trying to
figure out what an AoA is saying in regards to flying the launch.

In any case, even a badly flown launch by the pilot only results in a
somewhat lower release altitude than if it is done optimally by the
pilot. So it's really the wrong focus.

Perhaps once someone has plenty of experience with winch launches like
several posters here, one can then perhaps play around with an AoA for
fun to see if it even helps attain maybe a 3% higher release altitude.
Other than that, it's useless.

For pilots and operations starting out and trying to gain experience
in safely and efficiently doing winch operations, an AoA serves no
purpose and is an unnecessary distraction.

Walk first, then run.

That statement crosses the line forcing a response. It flies in the face of
everything that is known about aviation and flying. To argue that AOA
data is unneeded or 'wrong focus' invites use of the term "profound
ignorance".

Angle of attack is THE parameter in "flying the wing". If you don't
understand the need for, and use of, AOA information, then you really,
truely, don't know how to fly.

There is probably no area of flying where AOA data is more useful and
neccessary than in winch launch. Certainly, it matches landing on a carrier
deck where AOA data is used by all pilots. Incorporating an AOA indicator
in training on winch launch will pay huge dividens in accident reduction.

A long term study of all accidents, not just on the winch, shows that a huge
majority involve unintended excursions beyond the stalling AOA. It is
certain that a significant number of these accidents would have been
prevented had the pilot been aware of his AOA.

Bill,
How many winch launches do you have under your belt? On how many
winches have you launched under? How many students have you taught
flying off a winch?

I have over 400 launches off various winches in Europe and have spent
countless days in winch operations on airfields where there were 100+
launches per day.

If you ask any European pilot if they are trained to control airspeed
by pushing or pulling during a winch launch, I doubt you'll get a
response in the affirmative.

The one who determines the airspeed more than anything is the winch
driver and the wind gradient, not the pilot.

If you want to reinvent winch launching technique using AoA as the
guiding principal, knock yourself out.

Since nobody has used AoA yet for winch launches that I'm aware of,
it's all speculation on your part. You say that nowhere is an AoA
indicator more important than in winch launches, please spell out why
you think that in detail.

What exactly do you hope to achieve with the AoA during a winch launch
that you could not achieve without it? Please tell.

Remember, the AoA can not fix a sputtering winch engine or tell the
winch driver not to abort the launch. I hope you agree that the only
thing a pilot can do is to react to those circumstances and always
assume the worst can happen and fly the launch accordingly.

I don't see where the AoA helps there and a winch launch (take off) is
not a carrier landing in a jet. But since you say it so vital, please
explain. I'm all ears.

tommytoyz wrote:

If you ask any European pilot if they are trained to control airspeed
by pushing or pulling during a winch launch, I doubt you'll get a
response in the affirmative.

I am a European glider pilot an I respond affirmatively that I am
trained and able to control the airspeed by pushing or pulling during
the winch launch, at least to some degree. Whether pulling harder causes
the airspeed to rise (as in water ski) or to decrease (as in slowing
down the winch) depends on how much torque the winch develops.

John,
So you advocate pulling to increase your airspeed when it is falling
off? I was trained in Germany and have never head that as standard
practice. Matter of fact it's obviously dangerous as the fall off in
speed can be due to any number of things the pilot is not aware of
that pulling would not rectify, leaving you slow and nose up. See
accident report bellow.

But I guess there are some operations that teach that. I've just never
come across any such pilots first hand.

In my German club, when there was an obviously slow tow, sometimes
observers would yell (like yelling at the TV) "nose down, nose down"
or "Release!" Never "Pull More.".

As to pushing on a fast tow (From Essex Gliding Club):

"Speaking of which, what should you do if the launch remains "too
fast"? DO NOT LOWER THE NOSE before signalling or releasing the cable.
If you lower the nose whilst still connected, you may fly into the
cable. Unlikely though it may sound, such events have happened and
have always caused serious crashes, almost all of them FATAL. Make
your too-fast signal, and if necessary release under full tension, as
you would do if you launched into cloud. This is the current BGA
instructional policy. The winch driver can sort out a cable tangle on
the ground much more easily than you can sort out a cable over your
wing whilst airborne. A second after releasing the cable, it should be
far enough below for you to lower the nose to maintain a safe
airspeed, if you need to."

As to when too slow after established in full climb (accident report):

Registration:
BGA 3445 (Tail No 656)
Type:
Glaser Dirks DG600 Glider
Location:
Ridgewell Airfield near Great Yeldham, Essex
Date of occurrence:
18 September 2005
Category:
Sport Aviation/Balloons
Summary:
At a height of approximately 350 feet during a winch launch, the
glider was observed to be climbing at a slightly steeper than normal
angle. The glider's airspeed was perceived to be abnormally slow and
the winch engine lost rpm. The winch operator adjusted the winch
throttle setting to allow the engine to accelerate but this had little
effect. The glider stalled, yawed to the right and entered a right-
hand spin; during this manoeuvre the cable separated from the glider.
Height was insufficient for recovery and the glider struck the ground
whilst spinning, fatally injuring the pilot.

So I stand by my training:

1. Smooth pitch movements, except when aborting the launch (in that
case a quick nose over at 0g is best to 15 degrees down).

2. When speed bleeds off or is too slow, flatten the climb gradually
in case you need to abort. If power picks up, you can always resume
full climb.

3. Inform the winch driver of the speeds after the launch if not
optimal (he's in control of the power settings and winch speed, not
the pilot).

"tommytoyz" wrote in message
...
Bill,
How many winch launches do you have under your belt?
Since 1960, thousands, maybe tens of thousands.
On how many winches have you launched under?
Lost count
How many students have you taught flying off a winch?
Hundreds

I have over 400 launches off various winches in Europe and have spent
countless days in winch operations on airfields where there were 100+
launches per day.
Good for you. Now go read a book on how to fly.
If you are actually an instructor, I'm hoping you get a call from your
safety committee.


If you ask any European pilot if they are trained to control airspeed
by pushing or pulling during a winch launch, I doubt you'll get a
response in the affirmative.
You already have.

The one who determines the airspeed more than anything is the winch
driver and the wind gradient, not the pilot.
Profound ignorance.

If you want to reinvent winch launching technique using AoA as the
guiding principal, knock yourself out.
I intend to.

Since nobody has used AoA yet for winch launches that I'm aware of,
it's all speculation on your part.
Key words: "I'm aware of". I have used it and it works wonders.

You say that nowhere is an AoA
indicator more important than in winch launches, please spell out why
you think that in detail.
Ask your instructor. This is very basic flying stuff. Ground yourself
until you understand it - otherwise, you're just an accident looking for a
place to happen.

What exactly do you hope to achieve with the AoA during a winch launch
that you could not achieve without it? Please tell.

Would saving some lives work for you?

Bill Daniels
Stand by previous post.

tommytoyz wrote:
At a height of approximately 350 feet during a winch launch, the
glider was observed to be climbing at a slightly steeper than normal
angle. The glider's airspeed was perceived to be abnormally slow and
the winch engine lost rpm. The winch operator adjusted the winch
throttle setting to allow the engine to accelerate but this had little
effect. The glider stalled, yawed to the right and entered a right-
hand spin; during this manoeuvre the cable separated from the glider.
Height was insufficient for recovery and the glider struck the ground
whilst spinning, fatally injuring the pilot.

So, you are saying an AoA meter would be of no benefit, despite the fact
that it would have immediately indicated to the pilot that he was
pulling too hard given the cable speed and tension...

Marc