New 29 Palms Winchfest Video

[HoUdini]

One of the event participants patched together a good marketing video
for our club from this years Winchfest at 29 Palms California. Three
winches, four clubs participated in a "best practices" styled event.

Watch the Video : http://www.youtube.com/watch?v=x0hDZa41rVc

HoUdino

[tommytoyz]

Nice production.

I hate to be a pooper of sorts, but I can't let go unmentioned a
dangerous practice that is seen to be deliberately done by pilots in
the video:

Taking off with a wing low.

This can put a glider on it's back, or nose straight down in a flash.
It is very dangerous and happens before the pilot can even react. Even
if he/she does reactr extremely quickly, it'll still put the glider
into the ground nose first at high speed. This has happened several
times and I saw a picture sequence of just that in Aerokurier years
ago.

In a cross wind, a launch should still be wings level - always. After
the glider is over the safety altitude, the pilot can correct for the
cross wind - not before. So as not to be distracted by

What happens is that should a wingtip drag enough or God forbid snag,
full rudder may not be enough to correct and the other, high wingtip,
will rise up, turning the nose to the ground. If the pilot delays
releasing for even an instant, the glider will continue rotating till
inverted and lands nose first inverted or it smashes into the ground
nose first, going 90 degrees or so from the launch direction,
depending on glider type and relative position, tip drag, etc...

So please. Always launch with wings level, even in a strong cross wind
till safety altitude. Winch Launches are different from air tows and
require different considerations.
action.

[Martin Gregorie[_1_]]

tommytoyz wrote:
> Nice production.
>
> I hate to be a pooper of sorts, but I can't let go unmentioned a
> dangerous practice that is seen to be deliberately done by pilots in
> the video:
>
> Taking off with a wing low.
>
> This can put a glider on it's back, or nose straight down in a flash.
> It is very dangerous and happens before the pilot can even react. Even
> if he/she does reactr extremely quickly, it'll still put the glider
> into the ground nose first at high speed. This has happened several
> times and I saw a picture sequence of just that in Aerokurier years
> ago.
>
> In a cross wind, a launch should still be wings level - always. After
> the glider is over the safety altitude, the pilot can correct for the
> cross wind - not before. So as not to be distracted by
>
>
I also noticed the consistent series of tip drops: with so many launches
lowering the same tip it looks as if this was encouraged (or not
discouraged) by the duty instructors.

Despite what the OP said, that was NOT best practise. Keep the wings
level and use the rudder alone to keep straight. Could I suggest that
the clubs in question get copies of the BGA Instructor's Manual and/or
the winch safety leaflet and make sure that all instructors read it
before again acting as a winch launching P1?

See S&G for April/May 2006, p38 for reinforcement. It has pictures and
commentary of a tip touch with an ASK-13. The P1's glove slipped on the
release knob so it needed a second grab to release. The tip is still on
the ground after 1 second and the main wheel is just lifting off. After
2 seconds the glider is airborne and has swung 40 degrees. That's one
place I never want to be in.


--
martin@ | Martin Gregorie
gregorie. | Essex, UK
org |

[tommytoyz]

I certainly hope that winch launching becomes the norm in Southern
California where I now live. It's a far more fun and I think safer
method to get into the air VS. air tows, not to mention cheaper and
faster.

When flying in Germany, I had the pleasure of hundreds of winch
launches. The launch itself is a blast. As a result, air tows only
make up a fraction of the launches in all of Europe.

Living now in southern California, I hope that the local clubs learn
the best practices already learned elsewhere and avoid an unnecessary
accident. As with anything, if done incorrectly, it can be dangerous.
When done correctly, winch launching is very safe, IMHO.

[Martin Gregorie[_1_]]

tommytoyz wrote:
> I certainly hope that winch launching becomes the norm in Southern
> California where I now live. It's a far more fun and I think safer
> method to get into the air VS. air tows, not to mention cheaper and
> faster.
>
> When flying in Germany, I had the pleasure of hundreds of winch
> launches. The launch itself is a blast. As a result, air tows only
> make up a fraction of the launches in all of Europe.
>
> Living now in southern California, I hope that the local clubs learn
> the best practices already learned elsewhere and avoid an unnecessary
> accident. As with anything, if done incorrectly, it can be dangerous.
> When done correctly, winch launching is very safe, IMHO.
>
I couldn't agree more.

I've done 52 launches during 2007, of which only 13 were aero tow - and
11 of those were during visits to another field which only offers aero
tow. The remaining two, one was when out field was too soggy to tow
cables out and the other was part of my annual checks.

Unlike some, I prefer to fly xc off the winch on the grounds that this
gives me foresight of conditions between 1200 ft and cloudbase, which
may be useful if/when I get low during the flight. The only drawback I
can see is that I'm useless at picking lift when on tow.






--
martin@ | Martin Gregorie
gregorie. | Essex, UK
org |

[Soarin Again]

>One of the event participants patched together a good
>marketing >video for our club from this years Winchfest
>at 29 Palms California. >Three winches, four clubs participated
>in a 'best practices' styled >event.
>
>Watch the Video : http://www.youtube.com/watch?v=x0hDZa41rVc
>
>HoUdino

Having talked with a couple pilots who attended this
event, they related a few things that beg clarification.

1. They talked about some young pilot winch launching
a 1-26 who appeared to do a rather violent PIO on
launch. Which apparently resulted in his head going
thru the canopy, him blacking out and looping at least
once, possibly twice upon release before managing to
land in the opposite direction from launch. The pilot
was then taken to the hospital by helicopter.
Could someone else elaborate on this report.

2. I was at a seminar where Bill Daniels was quite
strong about the concept that pilots should lower the
nose to speed up and raise the nose to slow down.
I have been told that at this event pilots were told
the opposite, being raise the nose to speed up and
lower the nose to slow down. Why does there still
appear to be such opposing opinions as to what is
the correct procedure during launch? How can both
procedures be correct?

3. Pilots were told that while on winch launch they
are flying at zero angle of attack. Is this possible?

I'm no winch launch expert, just looking for some clarification

[Marc Ramsey]

Soarin Again wrote:
> 2. I was at a seminar where Bill Daniels was quite
> strong about the concept that pilots should lower the
> nose to speed up and raise the nose to slow down.
> I have been told that at this event pilots were told
> the opposite, being raise the nose to speed up and
> lower the nose to slow down. Why does there still
> appear to be such opposing opinions as to what is
> the correct procedure during launch? How can both
> procedures be correct?

Bill should have made it quite clear that he was talking about tension
controlled winches, of which there are very few in use (and none in the
US). For a conventional throttle controlled winch, once the transition
has been made to full climb, you can pull to speed up ("water skier"
effect) and push to slow down within limits, if the throttle setting is
simply wrong you must signal the winch driver accordingly.

> 3. Pilots were told that while on winch launch they
> are flying at zero angle of attack. Is this possible?

Not zero, but at a normal (i.e., not 45 degrees) positive AOA, ideally
that for best L/D. Hence the interest in AOA meters.

Marc

[Bill Daniels]

"Marc Ramsey" > wrote in message
...
> Soarin Again wrote:
>> 2. I was at a seminar where Bill Daniels was quite
>> strong about the concept that pilots should lower the
>> nose to speed up and raise the nose to slow down.
>> I have been told that at this event pilots were told
>> the opposite, being raise the nose to speed up and
>> lower the nose to slow down. Why does there still
>> appear to be such opposing opinions as to what is
>> the correct procedure during launch? How can both
>> procedures be correct?
>
> Bill should have made it quite clear that he was talking about tension
> controlled winches, of which there are very few in use (and none in the
> US). For a conventional throttle controlled winch, once the transition
> has been made to full climb, you can pull to speed up ("water skier"
> effect) and push to slow down within limits, if the throttle setting is
> simply wrong you must signal the winch driver accordingly.
>
>> 3. Pilots were told that while on winch launch they
>> are flying at zero angle of attack. Is this possible?
>
> Not zero, but at a normal (i.e., not 45 degrees) positive AOA, ideally
> that for best L/D. Hence the interest in AOA meters.
>
> Marc

As for the story about the 1-26 pilot, I have spoken at length with people
who were in attendance at Twentynine Palms and they didn't relate this story
to me so I assume the event either didn't happen or is extremely
exaggerated.

The point I made about airspeed control is that most, if not all, all US
winches are underpowered and therefore tension limited. Raising the nose
will increase cable tension and reduce airspeed by pulling down the winch
engine RPM. I have never experienced airspeed increase with increased
backpressure. The math says that for airspeed to increase with increased
pitch ("water skier effect") the cable tension would have to be in excess of
the weak link strength - it ain't gonna happen.

What does happen is that the glider is still accelerating during the
rotation into the climb and some pilots (Mostly pilots with no airplane
experience.) will jump to the conclusion that there is a cause and effect -
i.e. since the nose is going up and the airspeed is increasing, there must
be a reverse airspeed/pitch relationship. In realilty, once stabilized in
the climb the airspeed/pitch ralationship is normal. (Pitch up for less
speed and down for more) With the power involved, the airspeed response to
pitch changes is slower than in free gliding flight which will surprise the
uninitiated. The effect is exactly the same as takeoff in a powerful
airplane.

Bill Daniels

[Frank Whiteley]

On Dec 10, 11:37 am, Marc Ramsey > wrote:
> Soarin Again wrote:
> > 2. I was at a seminar where Bill Daniels was quite
> > strong about the concept that pilots should lower the
> > nose to speed up and raise the nose to slow down.
> > I have been told that at this event pilots were told
> > the opposite, being raise the nose to speed up and
> > lower the nose to slow down. Why does there still
> > appear to be such opposing opinions as to what is
> > the correct procedure during launch? How can both
> > procedures be correct?
>
> Bill should have made it quite clear that he was talking about tension
> controlled winches, of which there are very few in use (and none in the
> US). For a conventional throttle controlled winch, once the transition
> has been made to full climb, you can pull to speed up ("water skier"
> effect) and push to slow down within limits, if the throttle setting is
> simply wrong you must signal the winch driver accordingly.
>
I think this may have related to generally underpowered winches and
heavier gliders where pulling back will slow the glider and relaxing
back pressure will allow the speed to increase. With a powerful
winch, pulling back will certainly cause a speed increase. A light
glider like a 1-26 or a K-8 cannot overpower a similar winch and a
rather lighter touch is needed by the winch driver.

Launches from a nose hook like 1-34's and HP-14's will result in
porpoising due to elevator stall. I think the highest I ever launched
a 1-34 was 900agl and an HP-14 about 1100agl. Both types were
porpoising wildly despite steady power reductions. The only 1-26 I've
ever winch launched had a CG hook and got 1400 and 1500 agl on the two
launches.

Frank Whiteley

[HoUdini]

It's always interesting to see how the ras chatter builds....

The incident with the 1-26 was an over-reaction by the local medical
services on an otherwise boring day municipally. Pilot was out of 1st
aid within an hour. An overspeed situation poorly handled by the
pilot.

Echoing Bill, each winch is different....regretably. As is each
club's operation...regretably. Each airports facilities are
different. The lack of detailed modern SSA standards in the USA must
be fixed.

A little dirty laundry is purposely shown in the video, due to my
belief we here in the USA need to "catch-up". This opinion infuses my
two reports on the Winchfest at: http://www.socalsoaring.com/newsletter/scs_24_augsepoct2007.pdf

No time for witch hunt, but this is time for a little soul searching,
gents. Winch activity in the USA is on a rapid growth curve. We must
do better in 2008. THAT is the bell I'm ringing!

I look forward to a rousing discussion forward at this years SSA
Convention.

LT














On Dec 10, 12:16 pm, "Bill Daniels" <bildan@comcast-dot-net> wrote:
> "Marc Ramsey" > wrote in message
>
> ...
>
>
>
>
>
> > Soarin Again wrote:
> >> 2. I was at a seminar where Bill Daniels was quite
> >> strong about the concept that pilots should lower the
> >> nose to speed up and raise the nose to slow down.
> >> I have been told that at this event pilots were told
> >> the opposite, being raise the nose to speed up and
> >> lower the nose to slow down. Why does there still
> >> appear to be such opposing opinions as to what is
> >> the correct procedure during launch? How can both
> >> procedures be correct?
>
> > Bill should have made it quite clear that he was talking about tension
> > controlled winches, of which there are very few in use (and none in the
> > US). For a conventional throttle controlled winch, once the transition
> > has been made to full climb, you can pull to speed up ("water skier"
> > effect) and push to slow down within limits, if the throttle setting is
> > simply wrong you must signal the winch driver accordingly.
>
> >> 3. Pilots were told that while on winch launch they
> >> are flying at zero angle of attack. Is this possible?
>
> > Not zero, but at a normal (i.e., not 45 degrees) positive AOA, ideally
> > that for best L/D. Hence the interest in AOA meters.
>
> > Marc
>
> As for the story about the 1-26 pilot, I have spoken at length with people
> who were in attendance at Twentynine Palms and they didn't relate this story
> to me so I assume the event either didn't happen or is extremely
> exaggerated.
>
> The point I made about airspeed control is that most, if not all, all US
> winches are underpowered and therefore tension limited. Raising the nose
> will increase cable tension and reduce airspeed by pulling down the winch
> engine RPM. I have never experienced airspeed increase with increased
> backpressure. The math says that for airspeed to increase with increased
> pitch ("water skier effect") the cable tension would have to be in excess of
> the weak link strength - it ain't gonna happen.
>
> What does happen is that the glider is still accelerating during the
> rotation into the climb and some pilots (Mostly pilots with no airplane
> experience.) will jump to the conclusion that there is a cause and effect -
> i.e. since the nose is going up and the airspeed is increasing, there must
> be a reverse airspeed/pitch relationship. In realilty, once stabilized in
> the climb the airspeed/pitch ralationship is normal. (Pitch up for less
> speed and down for more) With the power involved, the airspeed response to
> pitch changes is slower than in free gliding flight which will surprise the
> uninitiated. The effect is exactly the same as takeoff in a powerful
> airplane.
>
> Bill Daniels- Hide quoted text -
>
> - Show quoted text -

[tommytoyz]

Speed is not controlled by the pilot on a conventional winch. Though
you can temporarily speed up by pulling on certain winches, that is
only a temporary effect, as the tension increases and the glider is
accelerated for a short burst.

However, that is really not a technique or effect that has much
practical meaning, one way or the other.

If the speed is too slow, the pilot has to slack off and be prepared
to release. How can the pilot know the reasons for the lack of
power?......pulling more just assumes it's only a winch driver related
issue - when it could be any number of reasons for the slow speed.

So yes, pulling will increase speed temporarily but only slightly and
pushing will decrease it, again only slightly depending on the
particulars of the winch - the effects are really not very noticeable
on a conventional winch. Pulling will reduce motor and drum RPM,
reducing the water skier effect.

Pushing will also not really reduce airspeed too much or perhaps not
at all depending on the winch, because motor and drum ROM will
increase when pushing.

But this is the wrong area to focus on in any case and can vary from
one winch set up to another - depending on the engine torque, glider
weight and engine RPM at which point the push or pull happens. But
again, it's academic and not practical from a pilot point of view:

I was taught this way:

- Wings level, not matter the wind direction
-Take off when sufficient air speed is reached with wings level
- If a wing drags on the ground for more than 1second - release
-Gradually rotate and increase rate of climb to normal climb attitude
within the safety zone to 200ft as airspeed remains constant or
increases
-If airspeed falls bellow a certain speed, be ready to push forward
and release ( In that order!)
-If airspeed falls even lower, quickly push forward and then release
-On the last 25% or so of the launch, gradually decrease the stick
back pressure. Remember that the launch is an arc with a constantly
changing climb angle relative to the horizon. So at the top of the
launch, the pitch is almost horizontal - so the aircraft nose should
also be almost horizontal there.

There has never been a case of a glider over stressing due to
excessive speed on winch launch, so that is not really a danger point.
But if it seems excessive, one can always just release and I've seen
that happen a few times, though rare. In any case, that is what the
weak link is for.

The only quick pitch movement should be when pushing over to release
in an aborted launch due to lack of winch power and speed. Otherwise
the pitch changes should always be smooth.

Keep it simple and do not try to micromanage the launch from the
pilot's point of view. There is no way the pilot can know what the
troubles are, if any - so he can not possibly know what effect
pushing, pulling or signaling will have.

This is all just my 2 cents.

[tommytoyz]

Discussing this brought more memories and perhaps I should fine tune
this by discussing some sceanrio's:

If the airspeed never picks up enough, but not low enough for a
release, just do not go into full climb mode even above the safety
altitude, just remain in a shallow climb till either the airspeed
increases or it falls further, where you push over and release if it
does fall off. But keep some tension on the rope so that the chute
doesn't open. So don't follow the rope or level off completely unless
you're aborting and releasing.

The signal to the winch driver that the airspeed is too slow is the
fact that the glider is in a shallow climb mode. The winch driver may
or may not add power. In no case can the pilot know. So the pilot
should not pull more and increase climb rate to speed up. That's
dangerous.

The same is when the speed starts falling off bellow a certain point.
I'm not talking about when it fluctuates and starts falling. But only
when it falls bellow a certain point. Then, for safety reasons, you
gradually shallow the climb angle when it falls too low, in case the
power dies or there is some other problem. If power picks up again,
you can resume the climb angle.

This is done for safety reasons and not to influence the air speed.
The winch driver can see if you're shallow or haven't started climbing
normally yet. Then again maybe he can't..............

But the reasons for the lack of power can be totally outside the fault
of the winch and the driver. For instance there can be strong and
sudden wind shears at certain altitudes at the beginning of the day
that nobody knows of, or when wind conditions change during the day.

There might also be a traffic conflict with another plane somehow that
the winch driver sees, but the pilot does not...............

This can result in a crappy launch with a low release altitude. So
what? Get another launch! It's cheap. Bad launches are fixed by
talking to the winch driver. In Germany, the winch drivers usually
called up to ask when that happens so they can make adjustments.

So pilots trying to influence speed is a good practice. The airspeed
will vary during a winch launch anyway. The best practice in this
regard is to have well educated winch drivers who know what power
settings are required for the different types of gliders being
launched and on the known wind conditions.

If this results in a crappy launch anyway, inform the winch driver of
the problem you had, (..."at 300ft the speed increased/decreased 15
knots, at 1,000ft it reversed again...") , and the driver can adjust
the power settings throughout the launch accordingly for good launches
there after for all types.

Of course tension controlled winches do not have these problem, but
there are none in the U.S and few even in Europe.

It's not the launching pilot who can really control the airspeed or
power application on a conventional winch. So please, do not pull to
increase speed as the low speed may be due to some problem you are not
aware of and where pulling may not help - rather you'll only increase
the risk should something else then happen - which you also can not
predict.

[tommytoyz]

I erroneously said:
"So pilots trying to influence speed is a good practice"

I wanted to say:
"So pilots trying to influence speed is NOT a good practice"

[Dan G]

I fly off a powerful winch and pulling back has never sped it up. It
increases the tension and, with the throttle held constant at the
winch, simply slows the engine down.

I've never pushed forwards on a launch unless the speed has been
falling away (not very clever to be nose-up with no speed). In the UK
winch drivers are trained to notice a glider "nosing over" and thus
gently feed in more power until the glider returns to a normal climb.

I think someone suggested buying a copy of the BGA Instructor's
Handbook and having it shipped to the US. That sounds a good idea. You
can buy a copy here:

http://www.gliding.co.uk/shop/product_info.php?cPath=23&products_id=65

It covers both theory and practicalities of winch launching well.


Dan

[Marc Ramsey[_2_]]

Dan G wrote:
> I fly off a powerful winch and pulling back has never sped it up. It
> increases the tension and, with the throttle held constant at the
> winch, simply slows the engine down.

The one time I consciously tried to slow down by pulling was in a K21 on
a Supacat 8. Airspeed kept increasing, but that may have had more to do
with the wind gradient that day...

Marc

[Bert Willing[_2_]]

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

"Marc Ramsey" > wrote in message
...
>>> 3. Pilots were told that while on winch launch they
>> are flying at zero angle of attack. Is this possible?
>
> Not zero, but at a normal (i.e., not 45 degrees) positive AOA, ideally
> that for best L/D. Hence the interest in AOA meters.
>
> Marc

[Martin Gregorie[_1_]]

tommytoyz wrote:
>
> [an over slow launch] can result in a crappy launch with a low
> release altitude. So what? Get another launch! It's cheap. Bad
> launches are fixed by talking to the winch driver. In Germany,
> the winch drivers usually called up to ask when that happens so
> they can make adjustments.
>
A very good point, and one that is seldom if ever mentioned here.

If you have a bad launch, talk to the winch driver and calmly discuss
the problem with him. Equally important, if he gets it spot on, let him
know! He'll appreciate that and remember what he did the next time he
launches you or another glider of the same type.

For instance, those of us flying 1st generation glass very often get
over fast launches because the drivers are used to heavier, more highly
loaded gliders. In my club the only 1st Gen glass is a pair of Libelles,
but we also have two SZD Juniors, which all our drivers are very
familiar with. The Junior has a similarly light wing loading to a
Libelle but is draggier and has a Vwinch of 70 kts against the Libelle's
65. A request to a winch driver who hasn't launched me for a while to
"launch me like a Junior, but 5-10 kts slower" gets a good launch every
time.


--
martin@ | Martin Gregorie
gregorie. | Essex, UK
org |

[Cliff Hilty[_2_]]

At 13:06 11 December 2007, Martin Gregorie wrote.
>
>If you have a bad launch, talk to the winch driver
>and calmly discuss
>the problem with him. Equally important, if he gets
>it spot on, let him
>know! He'll appreciate that and remember what he did
>the next time he
>launches you or another glider of the same type.
>
>For instance, those of us flying 1st generation glass
>very often get
>over fast launches because the drivers are used to
>heavier, more highly
>loaded gliders.

I have been reading with great interest the past few
months the threads about winches and launching on them.
And just a small observation about our own club in
Prescott is that we have a medium powered winch. Which
gives the heavier gliders, ie the Blanik and 2-33 fully
loaded, a full power launch with the pilot pushing
to increase speed once the winch driver has reached
full power and the lighter ones, 1-26 with light pilot,
a 60%or so power launch.

But what I havent heard here in these threads is any
one communicating via radio to the winch driver during
the launch? We use a simple method on the radio by
calling out the speed we are seeing. In other words
we start by telling the winch operator who, what, how
fast, and ready for launch. Then during launch we call
out our speed and the winch driver adjusts accordingly.
Example:

Blanik to winch, I am fully loaded, wings are level,
traffic pattern is clear, I am ready for a tow at 55
(short for 55mph).

Winch to blanik, roger, here we go tow at 55, no delay.

(after intial saftey climb to 200 feet and rotation
into 45 degree climb angle)

blanik says: five zero, five zero
(winch reacts with full throttle and says): Full power.

blanik says: Roger. (and decreases angle of attack
to increase airspeed to target of 55).

We then continue to call out airspeed every few 5 or
6 hundred feet. Until the winch driver tells us to:
Stand by------level off level off.

At which point we level off and release. Winch driver
then waits to see the chute and announces: I have the
chute.

There are many scenarios with different gliders and
weights but you get the picture. I have driven the
winch and this seems to work very well. You get an
idea of where the throttle has to be to start with
each glider and it usually is a small if any adjustment
throughout the launch.

I have not flown on any other winches, only car tows,
so my question is why no communication?

[Frank Whiteley]

>
> I have not flown on any other winches, only car tows,
> so my question is why no communication?

Did a similar thing in Oklahoma, using noise canceling headsets on the
winch and traffic frequency for speed hacks, but this was a new winch
and some new pilots, so had to shake things out. Works okay in a
remote area with today's low volume of transient power traffic. So
you visit or move to another club. Now, forget what you've used and
learn standard techniques. As a frequent winch driver, I'd rather
everyone was practiced in standard signals and is well ahead of the
glider and the process on each and every launch. Radio calls may not
work well at a big site where multiple winches or aero towing
operations are operating in parallel, or where the traffic frequency
is otherwise cluttered. I am also concerned about pilots in singles
using a hand held radio or mic for this, and even in two seaters, as
there may be very little time to react if something goes pear-shaped,
as there's the ever present danger of dropping either into a control
at the worst possible time. Sod's law. If you have boom or headset
mics and push buttons on the stick, okay, but this is generally no the
case in trainers and many singles. Some may not even have radios. We
use GMRS radios and/or flags to keep off 123.3 for staging and
starting the launch (as there are plenty of other users of the
frequency out there), but use the visual signals for speed control
during the launch.

One day soon, perhaps we'll have additional tools for this.

Frank Whiteley

[Marc Ramsey[_2_]]

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.

Marc

[Cats]

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.

[Marc Ramsey[_2_]]

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

[tommytoyz]

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.

[Marc Ramsey[_2_]]

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

[Bill Daniels]

"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.

[tommytoyz]

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.

[John Smith]

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.

[tommytoyz]

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).

[Bill Daniels]

"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.

[Marc Ramsey[_2_]]

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

[tommytoyz]

Bill,
You're obviously a hot head.

And with such strong statements, you fail to explain why I should
ground myself, that is, what is it that I am saying that is dangerous
or wrong. Why am I an accident waiting to happen? Unless you explain
yourself it's nonsense and a childish statement on your part. It
speaks to your character.

So to clear things up, please explain what precisely it is that I'm
saying that is dangerous.

You just plain fail to explain how an AoA would save lives and why it
is your pet project about which you feel so defensive. You just make
grand sweeping general statements with no explanation. But and
explanation shouldn't be so hard since you have experience with it and
obvious hard opinions about it.

Since you want full accountability here, your statement:
"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."

Is just not true. A carrier landing involves a constant AoA and
airspeed on approach, where as on a winch launch, they both
fluctuate. I mean you're starting from 0 and going to full climb mode.
That's hardly a landing. So I hope your reasoning on your AoA is
better than that. Which it very well might be.

[HoUdini]

I sure wonder how an fairly innocent post such as immediately follows,
gets into the goofy furballs that tend to occupy rec.soaring. I can't
wait to see what my next post will bring! Look for it soon, it will
be very on the edge of our sport.

Innocent post:

One of the event participants patched together a good marketing video
for our club from this years Winchfest at 29 Palms California. Three
winches, four clubs participated in a "best practices" styled event.

Watch the Video : http://www.youtube.com/watch?v=x0hDZa41rVc


HoUdino








On Dec 11, 9:44 am, Frank Whiteley > wrote:
> > I have not flown on any other winches, only car tows,
> > so my question is why no communication?
>
> Did a similar thing in Oklahoma, using noise canceling headsets on the
> winch and traffic frequency for speed hacks, but this was a new winch
> and some new pilots, so had to shake things out. Works okay in a
> remote area with today's low volume of transient power traffic. So
> you visit or move to another club. Now, forget what you've used and
> learn standard techniques. As a frequent winch driver, I'd rather
> everyone was practiced in standard signals and is well ahead of the
> glider and the process on each and every launch. Radio calls may not
> work well at a big site where multiple winches or aero towing
> operations are operating in parallel, or where the traffic frequency
> is otherwise cluttered. I am also concerned about pilots in singles
> using a hand held radio or mic for this, and even in two seaters, as
> there may be very little time to react if something goes pear-shaped,
> as there's the ever present danger of dropping either into a control
> at the worst possible time. Sod's law. If you have boom or headset
> mics and push buttons on the stick, okay, but this is generally no the
> case in trainers and many singles. Some may not even have radios. We
> use GMRS radios and/or flags to keep off 123.3 for staging and
> starting the launch (as there are plenty of other users of the
> frequency out there), but use the visual signals for speed control
> during the launch.
>
> One day soon, perhaps we'll have additional tools for this.
>
> Frank Whiteley

[tommytoyz]

HoUdini:
Soaring should be fun and we should exchange information, not insults.
But I have to defend myself and challenge someone who says I'm
dangerous.

I actually stopped soaring here in the U.S. for a while due to such
hard heeled opinions and egos.

One can disagree agreeably, no?

But dangerous I am not.

Happy to see that winch launching is getting more traction in my area,
as that's tons more FUN!

[Cats]

On Dec 11, 9:04 pm, Marc Ramsey > wrote:
> 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 people learning to fly it is. It only becomes of use once one is
starting to fly XC.

> 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

[Martin Gregorie[_1_]]

Marc Ramsey wrote:
> 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...
>
With all due respect, a copy of the BGA Manual in the hands of the
instructor and proper winch training should normally prevent this
situation from developing. The mere fact of that unfortunate pilot
continuing to pull in that situation shows a training problem: why
wasn't he monitoring the ASI?

Anyway, I bet the BGA Manual is a lot cheaper than an AOA indicator
thats accurate enough to use during a winch launch.


--
martin@ | Martin Gregorie
gregorie. | Essex, UK
org |

[Martin Gregorie[_1_]]

HoUdini wrote:
> I sure wonder how an fairly innocent post such as immediately follows,
> gets into the goofy furballs that tend to occupy rec.soaring. I can't
> wait to see what my next post will bring! Look for it soon, it will
> be very on the edge of our sport.
>
Speaking for myself, I watched the video and saw a succession of
launches with right wing low. As wing low launching is something that,
on my field, would earn you a talk with the duty instructor, I was
unhappy with the description of this being a "best practices" event and
said so.

Maybe in that locality its taught as good aero tow practice: I wouldn't
know about that. I've never flown there. What I do know is that where I
fly it is not good practice with either launch method.

Comment on launch speed. The rules we use are:
- after lift off, maintain a shallow climb until the ASI passes 50 kts
with steady acceleration.
- then and only then rotate slowly. The ideal is to complete rotation
not less than 5 seconds after lift off.
- we have a high torque, high inertia, fluid clutch winch. The pilot
cannot and should not attempt to control its speed except by
signalling the winch driver.
- if you're above Vwinch when the launch starts to flatten toward the
top (i.e. when the angle is below 35 degrees or so), release.
- if the speed drops toward 50 kts, lower the nose to maintain at least
50 kts and monitor the speed.
- if the speed picks up, resume the climb.
- if the nose approaches level and the speed doesn't rise, release.

My ASI is top and center in my panel - that's where I want it during
launch and landing. The vario takes a lesser position because it never
needs that degree of immediate attention and anyway I can listen to it.


--
martin@ | Martin Gregorie
gregorie. | Essex, UK
org |

[Marc Ramsey[_2_]]

Martin Gregorie wrote:
> Marc Ramsey wrote:
>> tommytoyz wrote:
>> 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...
>>
> With all due respect, a copy of the BGA Manual in the hands of the
> instructor and proper winch training should normally prevent this
> situation from developing. The mere fact of that unfortunate pilot
> continuing to pull in that situation shows a training problem: why
> wasn't he monitoring the ASI?

"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"

That sounds like it may have been a bit more complicated then a simple
failure to monitor the ASI, in particular, I suspect the initial
sequence of events may have been described out of order. From a pure
dynamics point of view, if you have the stick back during the final
stage of the rotation to climb and the winch looses power, will the
airspeed necessarily decay to near "stall" speed before the glider
actually stalls? It's worth thinking about.


> Anyway, I bet the BGA Manual is a lot cheaper than an AOA indicator
> thats accurate enough to use during a winch launch.

Absolutely, but if an effective and inexpensive AoA meter was available,
I'd want both...

Marc

[tommytoyz]

Marc,
Let us assume the accident report is accurate,unless you can show why
is would not be. The winch engine did not respond as anticipated and
the pilot kept pulling. So it is a simple failure by the pilot to
monitor airspeed. The people on the ground even could see that it was
slow.

On a winch launch, you can feel and hear the changes in speed as well
as see it on the ASI.

To get back to the question of how to best influence airspeed, the
best answer is don't even try. Just do not try to effect the speed,
let the winch do it for you and if it drops off bellow a certain
point, start shallowing the climb FOR SAFETY REASONS.

The accident report with the DG600 shows what can happen if you don't.

The exact speeds at which you should start shallowing the climb or
even abort and release, depend on glider type and wing loading. Every
pilot launching should know those speeds and the winch driver should
know what glider type he's launching and if it's light or heavy or any
other particulars he should know.

In Germany, even with K-13s we'd give through to the winch driver
"K-13, two pilots, ready for launch".etc......It's the winch driver
that hopefully applies the correct power settings.

Of course sometimes we'd see rocket launches with the sailplane
airborne almost instantly or very high launch speeds that everyone can
hear. Usually the winch driver sees that too and backs off on the
power.

From the beginning, I just wanted to point out here, that winch
launching with a wing low and the pilot trying to influence airspeed
are dangerous practices.

[Marc Ramsey[_2_]]

tommytoyz wrote:
> Marc,
> Let us assume the accident report is accurate,unless you can show why
> is would not be. The winch engine did not respond as anticipated and
> the pilot kept pulling. So it is a simple failure by the pilot to
> monitor airspeed. The people on the ground even could see that it was
> slow.

No, I don't think it is a safe assumption that this report is accurate
in and of itself. What you posted is closer to what we call a
"preliminary report" in the US, a collection of observations without
analysis or probable cause. There may more somewhere, but I don't know
how to find it.

The problem I see is with the sequence of events, did the people on the
ground notice the glider was slow before or after the "winch engine lost
rpm"? It does make a big difference.

> On a winch launch, you can feel and hear the changes in speed as well
> as see it on the ASI.

Yes, I've experienced that in normal winch launches, and experienced and
recognized pre-arranged "power losses" at the winch. I just don't
assume that all such problems are equivalent, and that I or the glider
will always react the same way.

> To get back to the question of how to best influence airspeed, the
> best answer is don't even try. Just do not try to effect the speed,
> let the winch do it for you and if it drops off bellow a certain
> point, start shallowing the climb FOR SAFETY REASONS.

Except in the narrow case of a "tension controlled" winch, I haven't
seen anyone advocate trying to control the speed directly. The question
was "what happens to the airspeed if you pull harder", the correct
answer is "it depends".

> The accident report with the DG600 shows what can happen if you don't.

No, it shows that the glider got slow, stalled, and spun in, which is
possible in any glider under many different circumstances. I can't
reach any conclusions from the report, other than the simple fact that
the pilot allowed the angle of attack to get too high, something that
can be directly sensed with a proper AoA meter.

> The exact speeds at which you should start shallowing the climb or
> even abort and release, depend on glider type and wing loading. Every
> pilot launching should know those speeds and the winch driver should
> know what glider type he's launching and if it's light or heavy or any
> other particulars he should know.

Yes, I just don't assume that I can't stall just because the ASI says
I'm going fast enough.

> In Germany, even with K-13s we'd give through to the winch driver
> "K-13, two pilots, ready for launch".etc......It's the winch driver
> that hopefully applies the correct power settings.

Yes, that is what I've experienced in every winch launch. There is
still the interesting question of what happens at specific moments if
the winch driver gets the power setting wrong, or the engine experiences
a momentary loss of power.

> Of course sometimes we'd see rocket launches with the sailplane
> airborne almost instantly or very high launch speeds that everyone can
> hear. Usually the winch driver sees that too and backs off on the
> power.

Been there, done that, with the rudder waggling all of the way up.

> From the beginning, I just wanted to point out here, that winch
> launching with a wing low and the pilot trying to influence airspeed
> are dangerous practices.

I agree that launching with a wing low, in general, is an undesirable
practice. Now, it just so happens that I flew a number of launches in
that same 2-33 under similar circumstances the weekend before. There
was almost certainly a 10 knot or more crosswind, the glider was a nose
dragger with an offset CG hook, and the winch did not anywhere near the
initial acceleration I experienced at a number of sites in the UK. This
2-33 showed a remarkable tendency to swing into the wind during the
first few seconds of the launch, and people tried various combinations
of rudder, aileron, wing low, etc., to control the swing. Now, one
might argue with certain choices made there, but the glider belonged to
the host club, using their winch and procedures. I found it a bit
disconcerting, but completely controllable.

And, yes, I posted about trying to influence the airspeed once, in a K21
with a qualified instructor, and we were both curious about whether
their Supacat exhibited constant tension behavior as some had described.
We reached the conclusion that the answer was no, without ever
engaging in dangerous practices...

Marc

[tommytoyz]

On Dec 12, 9:39 pm, Marc Ramsey > wrote:
> tommytoyz wrote:
> > Marc,
> > Let us assume the accident report is accurate,unless you can show why
> > is would not be. The winch engine did not respond as anticipated and
> > the pilot kept pulling. So it is a simple failure by the pilot to
> > monitor airspeed. The people on the ground even could see that it was
> > slow.
>
> No, I don't think it is a safe assumption that this report is accurate
> in and of itself. What you posted is closer to what we call a
> "preliminary report" in the US, a collection of observations without
> analysis or probable cause. There may more somewhere, but I don't know
> how to find it.
>
> The problem I see is with the sequence of events, did the people on the
> ground notice the glider was slow before or after the "winch engine lost
> rpm"? It does make a big difference.
>
> > On a winch launch, you can feel and hear the changes in speed as well
> > as see it on the ASI.
>
> Yes, I've experienced that in normal winch launches, and experienced and
> recognized pre-arranged "power losses" at the winch. I just don't
> assume that all such problems are equivalent, and that I or the glider
> will always react the same way.
>
> > To get back to the question of how to best influence airspeed, the
> > best answer is don't even try. Just do not try to effect the speed,
> > let the winch do it for you and if it drops off bellow a certain
> > point, start shallowing the climb FOR SAFETY REASONS.
>
> Except in the narrow case of a "tension controlled" winch, I haven't
> seen anyone advocate trying to control the speed directly. The question
> was "what happens to the airspeed if you pull harder", the correct
> answer is "it depends".
>
> > The accident report with the DG600 shows what can happen if you don't.
>
> No, it shows that the glider got slow, stalled, and spun in, which is
> possible in any glider under many different circumstances. I can't
> reach any conclusions from the report, other than the simple fact that
> the pilot allowed the angle of attack to get too high, something that
> can be directly sensed with a proper AoA meter.
>
> > The exact speeds at which you should start shallowing the climb or
> > even abort and release, depend on glider type and wing loading. Every
> > pilot launching should know those speeds and the winch driver should
> > know what glider type he's launching and if it's light or heavy or any
> > other particulars he should know.
>
> Yes, I just don't assume that I can't stall just because the ASI says
> I'm going fast enough.
>
> > In Germany, even with K-13s we'd give through to the winch driver
> > "K-13, two pilots, ready for launch".etc......It's the winch driver
> > that hopefully applies the correct power settings.
>
> Yes, that is what I've experienced in every winch launch. There is
> still the interesting question of what happens at specific moments if
> the winch driver gets the power setting wrong, or the engine experiences
> a momentary loss of power.
>
> > Of course sometimes we'd see rocket launches with the sailplane
> > airborne almost instantly or very high launch speeds that everyone can
> > hear. Usually the winch driver sees that too and backs off on the
> > power.
>
> Been there, done that, with the rudder waggling all of the way up.
>
> > From the beginning, I just wanted to point out here, that winch
> > launching with a wing low and the pilot trying to influence airspeed
> > are dangerous practices.
>
> I agree that launching with a wing low, in general, is an undesirable
> practice. Now, it just so happens that I flew a number of launches in
> that same 2-33 under similar circumstances the weekend before. There
> was almost certainly a 10 knot or more crosswind, the glider was a nose
> dragger with an offset CG hook, and the winch did not anywhere near the
> initial acceleration I experienced at a number of sites in the UK. This
> 2-33 showed a remarkable tendency to swing into the wind during the
> first few seconds of the launch, and people tried various combinations
> of rudder, aileron, wing low, etc., to control the swing. Now, one
> might argue with certain choices made there, but the glider belonged to
> the host club, using their winch and procedures. I found it a bit
> disconcerting, but completely controllable.
>
> And, yes, I posted about trying to influence the airspeed once, in a K21
> with a qualified instructor, and we were both curious about whether
> their Supacat exhibited constant tension behavior as some had described.
> We reached the conclusion that the answer was no, without ever
> engaging in dangerous practices...
>
> Marc


Marc the full report can be read here:

http://www.google.com/url?sa=t&ct=res&cd=1&url=http%3A%2F%2Fwww.aaib.gov.uk%2Fcms_resources%2 FGlaser%2520Dirks%2520DG600%2520Glider%2C%2520BGA% 25203445%2520(Tail%2520No%2520656).pdf&ei=mfpgR8aqH6WaoQSylYy3Aw&usg=AFQjCNHEGJO-D6tcQA2-lEGNXe7nHJ7SUw&sig2=S1W7ikseMDXYLA2mZvELyA

I don't think you should second guess it unless you have a valid
reason to.

Second, even you say:

"No, it shows that the glider got slow...........' Don't you think an
ASI would show you the slow airspeed? Also, if the pilot is not paying
attention to the ASI, why would you pay attention to an AoA?

Anyway, the report also says that the cause may have been caused by
the pilot shifting position during launch due to acceleration and
particulars of his harness, forcing him to move the stick back. But
the effect, no matter the reason, was that he stalled due to lack of
airspeed or AoA, if that's what you prefer to go by. It doesn't
matter.

You also say:
"I just don't assume that all such problems are equivalent, and that I
or the glider
will always react the same way."

However, you should always react in the same way to remain safe and
not vary it around. If the airspeed or AoA, are going the wrong way,
the reaction must always be the same - gradually lower the nose to
only a shallow climb or even abort if it gets too low - period. If the
winch resumes power before you have to abort, you can gradually resume
normal climb, so long as the power remains sufficient to keep the
airspeed or AoA up.

If the winch power cuts out, even temporarily, this is the only safe
reaction that will maintain enough airspeed or proper AoA to avoid a
stall.

There are no other safe reactions. So I hope you ALWAYS react this
way.

[tommytoyz]

By the way Marc,

The DG 600 in question did have an AoA stall warning device.
Obviously, that didn't help.

"The stall warning system fitted to the glider consisted
of two orifices on either side of the fuselage, one close
to the wing leading edge and one at approximately
mid-chord. The pressure readings from these orifices
are fed into a cockpit mounted variometer. As the
angle of attack of the glider's wing approaches the
stalling angle, the airflow over the wing changes
giving a differential pressure between the forward and
mid-chord orifices. This produces a movement of the
variometer needle, and an audible signal to warn the
pilot of an impending stall."

[Martin Gregorie[_1_]]

Marc Ramsey wrote:
> From a pure
> dynamics point of view, if you have the stick back during the final
> stage of the rotation to climb and the winch looses power, will the
> airspeed necessarily decay to near "stall" speed before the glider
> actually stalls? It's worth thinking about.
>
Fair comment, though some awareness of attitude should have helped too.
My instructors have always tended to discourage pole-bending. As a
result I tend to fly the launch after rotating into full climb with
little or no stick back pressure. I check attitude after rotation by
glancing at the tip to compare its angle to the horizon and correct if
needed.

If our CFI thinks a student is messing up the launch by thrashing the
stick and conditions are calm he demonstrates a complete launch post
rotation in the K-21 with his hands off the stick, slow clapping to show
he isn't cheating.

> Absolutely, but if an effective and inexpensive AoA meter was available,
> I'd want both...
>
It would be interesting to try one, but I do slightly wonder whether the
increased workload of monitoring it as well as the ASI might be
unhelpful. IMO its no substitute for the ASI during lift-off and
rotation: it can't show the acceleration that indicates its safe to
start rotation.

However, an audible AOA warning may be useful because it wouldn't add to
the normal workload: it would be just one more eventuality.


--
martin@ | Martin Gregorie
gregorie. | Essex, UK
org |

[Chris Reed[_1_]]

This is only part of the report. The full report is available at the Air
Accident Investigation Branch website (no time to find reference at the
moment), and the possible causes were quite complex.

I knew the pilot involved, so won't enter this discussion other than to
suggest reading the full report.

Marc Ramsey wrote:
> tommytoyz wrote:
>> Marc,
>> Let us assume the accident report is accurate,unless you can show why
>> is would not be.

[Del C]

With respect to the DG600 accident the shoulder straps
were found to be unfastened after the crash. Therefore
there was at least a possibility that the pilot had
slipped backwards along the very reclined seat on this
type, either due to the ground run acceleration or
entering the climb, as a result, and had pulled the
stick hard back in the process. Hence the unusually
steep climb. Or he could just have been pole bending.

One of our clubs DG1000s has a pneumatic stall warning
device, probably similar to the one in the 600. Problem
is that it goes off anyway during the ground run and
rotation, so people now ignore it. It also keeps going
off in gusty thermals at any speed below about 60 knots
- Not good for our tiny UK thermals!

I don't know what people want from an AoA device; a
stall warning or another dial to look at. If it's just
to warn you of impending instant death, it shouldn't
cry wolf like the one on our DG1000.

As for controlling speed on the winch, this depends
on the winch. I tried out one of the latest Skylaunch
winches yesterday and found that you could vary the
speed by about 5 knots either way by pulling harder
or easing forward. This is almost impossible with our
old Tost winches, despite having very similar engines
and gearboxes to the Skylaunch!

Del Copeland



At 13:06 13 December 2007, Martin Gregorie wrote:
>Marc Ramsey wrote:
>> From a pure
>> dynamics point of view, if you have the stick back
>>during the final
>> stage of the rotation to climb and the winch looses
>>power, will the
>> airspeed necessarily decay to near 'stall' speed before
>>the glider
>> actually stalls? It's worth thinking about.
>>
>Fair comment, though some awareness of attitude should
>have helped too.
>My instructors have always tended to discourage pole-bending.
>As a
>result I tend to fly the launch after rotating into
>full climb with
>little or no stick back pressure. I check attitude
>after rotation by
>glancing at the tip to compare its angle to the horizon
>and correct if
>needed.
>
>If our CFI thinks a student is messing up the launch
>by thrashing the
>stick and conditions are calm he demonstrates a complete
>launch post
>rotation in the K-21 with his hands off the stick,
>slow clapping to show
>he isn't cheating.
>
>> Absolutely, but if an effective and inexpensive AoA
>>meter was available,
>> I'd want both...
>>
>It would be interesting to try one, but I do slightly
>wonder whether the
> increased workload of monitoring it as well as the
>ASI might be
>unhelpful. IMO its no substitute for the ASI during
>lift-off and
>rotation: it can't show the acceleration that indicates
>its safe to
>start rotation.
>
>However, an audible AOA warning may be useful because
>it wouldn't add to
>the normal workload: it would be just one more eventuality.
>
>
>--
>martin@ | Martin Gregorie
>gregorie. | Essex, UK
>org |
>

[Marc Ramsey[_2_]]

tommytoyz wrote:
> By the way Marc,
>
> The DG 600 in question did have an AoA stall warning device.
> Obviously, that didn't help.
>
> "The stall warning system fitted to the glider consisted
> of two orifices on either side of the fuselage, one close
> to the wing leading edge and one at approximately
> mid-chord. The pressure readings from these orifices
> are fed into a cockpit mounted variometer. As the
> angle of attack of the glider's wing approaches the
> stalling angle, the airflow over the wing changes
> giving a differential pressure between the forward and
> mid-chord orifices. This produces a movement of the
> variometer needle, and an audible signal to warn the
> pilot of an impending stall."

My DG-600 had the AoA device installed, too, it was an annoyance since I
could never get it calibrated to any useful degree. I took it out
eventually...

Marc

[HoUdini]

I suppose it is OK to highjack a thread that I started?....HU

Click the link that follows for probably the most unique soaring
calendar of all time. Roller Derby and Sailplanes? Just in time for
holidays, this is a limited print calendar that is sure to be a
soaring collectors item in the future. Unless they sell out of
inventory, I doubt it will be repeated for 2009. To help the team,
please order a few for your buddies as gifts!

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HoUdino


PS- Our glider field helped arrange the photo shoot, but none of us
have a financial interest (but it did make for an interesting day at
Hemet-Ryan).
PSS- Better than Winchfest... ;-)








On Dec 13, 7:54 am, Del C >
wrote:
> With respect to the DG600 accident the shoulder straps
> were found to be unfastened after the crash. Therefore
> there was at least a possibility that the pilot had
> slipped backwards along the very reclined seat on this
> type, either due to the ground run acceleration or
> entering the climb, as a result, and had pulled the
> stick hard back in the process. Hence the unusually
> steep climb. Or he could just have been pole bending.
>
> One of our clubs DG1000s has a pneumatic stall warning
> device, probably similar to the one in the 600. Problem
> is that it goes off anyway during the ground run and
> rotation, so people now ignore it. It also keeps going
> off in gusty thermals at any speed below about 60 knots
> - Not good for our tiny UK thermals!
>
> I don't know what people want from an AoA device; a
> stall warning or another dial to look at. If it's just
> to warn you of impending instant death, it shouldn't
> cry wolf like the one on our DG1000.
>
> As for controlling speed on the winch, this depends
> on the winch. I tried out one of the latest Skylaunch
> winches yesterday and found that you could vary the
> speed by about 5 knots either way by pulling harder
> or easing forward. This is almost impossible with our
> old Tost winches, despite having very similar engines
> and gearboxes to the Skylaunch!
>
> Del Copeland
>
> At 13:06 13 December 2007, Martin Gregorie wrote:
>
>
>
> >Marc Ramsey wrote:
> >> From a pure
> >> dynamics point of view, if you have the stick back
> >>during the final
> >> stage of the rotation to climb and the winch looses
> >>power, will the
> >> airspeed necessarily decay to near 'stall' speed before
> >>the glider
> >> actually stalls? It's worth thinking about.
>
> >Fair comment, though some awareness of attitude should
> >have helped too.
> >My instructors have always tended to discourage pole-bending.
> >As a
> >result I tend to fly the launch after rotating into
> >full climb with
> >little or no stick back pressure. I check attitude
> >after rotation by
> >glancing at the tip to compare its angle to the horizon
> >and correct if
> >needed.
>
> >If our CFI thinks a student is messing up the launch
> >by thrashing the
> >stick and conditions are calm he demonstrates a complete
> >launch post
> >rotation in the K-21 with his hands off the stick,
> >slow clapping to show
> >he isn't cheating.
>
> >> Absolutely, but if an effective and inexpensive AoA
> >>meter was available,
> >> I'd want both...
>
> >It would be interesting to try one, but I do slightly
> >wonder whether the
> > increased workload of monitoring it as well as the
> >ASI might be
> >unhelpful. IMO its no substitute for the ASI during
> >lift-off and
> >rotation: it can't show the acceleration that indicates
> >its safe to
> >start rotation.
>
> >However, an audible AOA warning may be useful because
> >it wouldn't add to
> >the normal workload: it would be just one more eventuality.
>
> >--
> >martin@ | Martin Gregorie
> >gregorie. | Essex, UK
> >org |- Hide quoted text -
>
> - Show quoted text -

[Andreas Maurer]

On Wed, 12 Dec 2007 22:33:24 +0000, Martin Gregorie
> wrote:

>Speaking for myself, I watched the video and saw a succession of
>launches with right wing low. As wing low launching is something that,
>on my field, would earn you a talk with the duty instructor, I was
>unhappy with the description of this being a "best practices" event and
>said so.

I agree, Martin.
I've never seen such a series of really critical winch launches
before. With all due respect - a very serious ground-loop accident is
going to happen rather sooner than later.


>Comment on launch speed. The rules we use are:
>- after lift off, maintain a shallow climb until the ASI passes 50 kts
> with steady acceleration.
>- then and only then rotate slowly. The ideal is to complete rotation
> not less than 5 seconds after lift off.
>- we have a high torque, high inertia, fluid clutch winch. The pilot
> cannot and should not attempt to control its speed except by
> signalling the winch driver.
>- if you're above Vwinch when the launch starts to flatten toward the
> top (i.e. when the angle is below 35 degrees or so), release.
>- if the speed drops toward 50 kts, lower the nose to maintain at least
> 50 kts and monitor the speed.
>- if the speed picks up, resume the climb.
>- if the nose approaches level and the speed doesn't rise, release.

The same rules apply for us. Works like a charm.



Bye
Andreas

[Bill Daniels]

Actually guys, you CAN and SHOULD control airspeed on some winches. There
are few winches that have enough power to prevent a large, heavy glider from
pulling down the drum RPM. Maybe you guys have one - maybe not.

If you are a little too fast, pitch up, load the winch a little and wait to
see what the airspeed does. In most cases, it will ease back down to the
desired airspeed. If you are a bit slow, lower the nose which unloads the
winch a bit and wait for the effect. Once you get the hang of it, it works
sweet.

Many pilots think this won't work becasue they haven't tried it. Give it a
try and get back to us.

Bill Daniels


"Andreas Maurer" > wrote in message
...
> On Wed, 12 Dec 2007 22:33:24 +0000, Martin Gregorie
> > wrote:
>
>>Speaking for myself, I watched the video and saw a succession of
>>launches with right wing low. As wing low launching is something that,
>>on my field, would earn you a talk with the duty instructor, I was
>>unhappy with the description of this being a "best practices" event and
>>said so.
>
> I agree, Martin.
> I've never seen such a series of really critical winch launches
> before. With all due respect - a very serious ground-loop accident is
> going to happen rather sooner than later.
>
>
>>Comment on launch speed. The rules we use are:
>>- after lift off, maintain a shallow climb until the ASI passes 50 kts
>> with steady acceleration.
>>- then and only then rotate slowly. The ideal is to complete rotation
>> not less than 5 seconds after lift off.
>>- we have a high torque, high inertia, fluid clutch winch. The pilot
>> cannot and should not attempt to control its speed except by
>> signalling the winch driver.
>>- if you're above Vwinch when the launch starts to flatten toward the
>> top (i.e. when the angle is below 35 degrees or so), release.
>>- if the speed drops toward 50 kts, lower the nose to maintain at least
>> 50 kts and monitor the speed.
>>- if the speed picks up, resume the climb.
>>- if the nose approaches level and the speed doesn't rise, release.
>
> The same rules apply for us. Works like a charm.
>
>
>
> Bye
> Andreas

[Martin Gregorie[_1_]]

Bill Daniels wrote:
> Actually guys, you CAN and SHOULD control airspeed on some winches. There
> are few winches that have enough power to prevent a large, heavy glider from
> pulling down the drum RPM. Maybe you guys have one - maybe not.
>
> If you are a little too fast, pitch up, load the winch a little and wait to
> see what the airspeed does. In most cases, it will ease back down to the
> desired airspeed. If you are a bit slow, lower the nose which unloads the
> winch a bit and wait for the effect. Once you get the hang of it, it works
> sweet.
>
> Many pilots think this won't work becasue they haven't tried it. Give it a
> try and get back to us.
>
I tried it enough times when I was pre-solo, thanks, in both ASK-21 and
Puchacz. Didn't work with them. The only effect I remember it having was
breaking a weak link with the Puchacz in a gust.

I did experience a small speed drop today, also in the Puchacz as it
happens, but from the rate and amount of the decrease that was the
driver adjusting the power by making a small reduction at around 500 ft.
After that the remainder of the launch was smack on Vwinch (59 kts)
until he chopped power at the top and we floated off at 55 kts.

We have two Supacats. One has a 240 hp Deutz aircooled diesel V8
industrial engine and the second a big diesel straight six, probably
around 180 hp: I think we were using the straight six winch today. Both
winches drive the drums with a custom gearbox, in turn driven through a
fluid clutch. There are no gear changes during a launch. AFAIK the
gearbox does the following:
- reduction gear. Drum speed is less than engine RPM (of course)
- drum selection (its a two drum winch)
- oscillating drive for the pay-on system


--
martin@ | Martin Gregorie
gregorie. | Essex, UK
org |

[Bill Daniels]

"Martin Gregorie" > wrote in message
...
> Bill Daniels wrote:
>> Actually guys, you CAN and SHOULD control airspeed on some winches.
>> There are few winches that have enough power to prevent a large, heavy
>> glider from pulling down the drum RPM. Maybe you guys have one - maybe
>> not.
>>
>> If you are a little too fast, pitch up, load the winch a little and wait
>> to see what the airspeed does. In most cases, it will ease back down to
>> the desired airspeed. If you are a bit slow, lower the nose which
>> unloads the winch a bit and wait for the effect. Once you get the hang
>> of it, it works sweet.
>>
>> Many pilots think this won't work becasue they haven't tried it. Give it
>> a try and get back to us.
>>
> I tried it enough times when I was pre-solo, thanks, in both ASK-21 and
> Puchacz. Didn't work with them. The only effect I remember it having was
> breaking a weak link with the Puchacz in a gust.
>
> I did experience a small speed drop today, also in the Puchacz as it
> happens, but from the rate and amount of the decrease that was the driver
> adjusting the power by making a small reduction at around 500 ft. After
> that the remainder of the launch was smack on Vwinch (59 kts) until he
> chopped power at the top and we floated off at 55 kts.
>
> We have two Supacats. One has a 240 hp Deutz aircooled diesel V8
> industrial engine and the second a big diesel straight six, probably
> around 180 hp: I think we were using the straight six winch today. Both
> winches drive the drums with a custom gearbox, in turn driven through a
> fluid clutch. There are no gear changes during a launch. AFAIK the gearbox
> does the following:
> - reduction gear. Drum speed is less than engine RPM (of course)
> - drum selection (its a two drum winch)
> - oscillating drive for the pay-on system
>
>
> --
> martin@ | Martin Gregorie
> gregorie. | Essex, UK
> org |

Keep trying it. I think you will find you have control over airspeed.
180 - 240 HP isn't nearly enough power to prevent a big 2-seat glider from
slowing the winch.

Bill Daniels

[Marc Ramsey[_2_]]

Bill Daniels wrote:
> "Martin Gregorie" > wrote:
>> I tried it enough times when I was pre-solo, thanks, in both ASK-21 and
>> Puchacz. Didn't work with them. The only effect I remember it having was
>> breaking a weak link with the Puchacz in a gust.
>>
>> I did experience a small speed drop today, also in the Puchacz as it
>> happens, but from the rate and amount of the decrease that was the driver
>> adjusting the power by making a small reduction at around 500 ft. After
>> that the remainder of the launch was smack on Vwinch (59 kts) until he
>> chopped power at the top and we floated off at 55 kts.
>>
>> We have two Supacats. One has a 240 hp Deutz aircooled diesel V8
>> industrial engine and the second a big diesel straight six, probably
>> around 180 hp: I think we were using the straight six winch today. Both
>> winches drive the drums with a custom gearbox, in turn driven through a
>> fluid clutch. There are no gear changes during a launch. AFAIK the gearbox
>> does the following:
>> - reduction gear. Drum speed is less than engine RPM (of course)
>> - drum selection (its a two drum winch)
>> - oscillating drive for the pay-on system
>>
>>
>> --
>> martin@ | Martin Gregorie
>> gregorie. | Essex, UK
>> org |
>
> Keep trying it. I think you will find you have control over airspeed.
> 180 - 240 HP isn't nearly enough power to prevent a big 2-seat glider from
> slowing the winch.

I assume Martin flies at the Cambridge Gliding Centre. Their V8 Supacat
could not be slowed by pulling (and in fact sped up at times) through
multiple attempts by myself and an instructor (both of us in the 200+ lb
range) in one of their ASK-21s. The only otherwise unusual outcome was
a premature back release late in one launch. This was done with prior
knowledge and discussion of the fact that it should theoretically be
possible. I'd guess there is no overcoming gobs of torque...

Marc

[Martin Gregorie[_1_]]

Bill Daniels wrote:
>
> Keep trying it. I think you will find you have control over airspeed.
> 180 - 240 HP isn't nearly enough power to prevent a big 2-seat glider from
> slowing the winch.
>
A big two seater may have a small effect on the straight six - we've
only had that winch a year or two. I did all my training on the V8 and I
know from both experience and instructor verbals that nothing in our
club fleet can slow it down enough to make a detectable difference.

An ASH-25 probably could, but although I've seen them winched I've not
been in the winch or the ASH at the time so can't and won't comment
further about that.

I think you're ignoring torque. The 240 hp Deutz is likely to produce
more torque than an automotive V8 of the same or higher power output.
Its a mining engine and designed for high torque at low rpm. Power =
torque * rpm, so for equal power the slower turning engine has
proportionately higher torque. It is, after all, the torque not the
power of the winch that determines whether a glider can affect its speed.

I've looked for engine specs, but although I know it produces peak power
at 2300 rpm, I can't find figures for max torque or the rpm for max
torque. At a guess max torque will be produced at somewhat below 2000 rpm.


--
martin@ | Martin Gregorie
gregorie. | Essex, UK
org |

[Bill Daniels]

"Marc Ramsey" > wrote in message
et...
> Bill Daniels wrote:
>> "Martin Gregorie" > wrote:
>>> I tried it enough times when I was pre-solo, thanks, in both ASK-21 and
>>> Puchacz. Didn't work with them. The only effect I remember it having was
>>> breaking a weak link with the Puchacz in a gust.
>>>
>>> I did experience a small speed drop today, also in the Puchacz as it
>>> happens, but from the rate and amount of the decrease that was the
>>> driver adjusting the power by making a small reduction at around 500 ft.
>>> After that the remainder of the launch was smack on Vwinch (59 kts)
>>> until he chopped power at the top and we floated off at 55 kts.
>>>
>>> We have two Supacats. One has a 240 hp Deutz aircooled diesel V8
>>> industrial engine and the second a big diesel straight six, probably
>>> around 180 hp: I think we were using the straight six winch today. Both
>>> winches drive the drums with a custom gearbox, in turn driven through a
>>> fluid clutch. There are no gear changes during a launch. AFAIK the
>>> gearbox does the following:
>>> - reduction gear. Drum speed is less than engine RPM (of course)
>>> - drum selection (its a two drum winch)
>>> - oscillating drive for the pay-on system
>>>
>>>
>>> --
>>> martin@ | Martin Gregorie
>>> gregorie. | Essex, UK
>>> org |
>>
>> Keep trying it. I think you will find you have control over airspeed.
>> 180 - 240 HP isn't nearly enough power to prevent a big 2-seat glider
>> from slowing the winch.
>
> I assume Martin flies at the Cambridge Gliding Centre. Their V8 Supacat
> could not be slowed by pulling (and in fact sped up at times) through
> multiple attempts by myself and an instructor (both of us in the 200+ lb
> range) in one of their ASK-21s. The only otherwise unusual outcome was a
> premature back release late in one launch. This was done with prior
> knowledge and discussion of the fact that it should theoretically be
> possible. I'd guess there is no overcoming gobs of torque...
>
> Marc

As I said, try it again with careful observation. You will find it works
though you may have to wait a bit to see the effect.

Bill Daniels

[Marc Ramsey[_2_]]

Bill Daniels wrote:
> "Marc Ramsey" > wrote in message
> et...
>> Bill Daniels wrote:
>>> "Martin Gregorie" > wrote:
>>>> I tried it enough times when I was pre-solo, thanks, in both ASK-21 and
>>>> Puchacz. Didn't work with them. The only effect I remember it having was
>>>> breaking a weak link with the Puchacz in a gust.
>>>>
>>>> I did experience a small speed drop today, also in the Puchacz as it
>>>> happens, but from the rate and amount of the decrease that was the
>>>> driver adjusting the power by making a small reduction at around 500 ft.
>>>> After that the remainder of the launch was smack on Vwinch (59 kts)
>>>> until he chopped power at the top and we floated off at 55 kts.
>>>>
>>>> We have two Supacats. One has a 240 hp Deutz aircooled diesel V8
>>>> industrial engine and the second a big diesel straight six, probably
>>>> around 180 hp: I think we were using the straight six winch today. Both
>>>> winches drive the drums with a custom gearbox, in turn driven through a
>>>> fluid clutch. There are no gear changes during a launch. AFAIK the
>>>> gearbox does the following:
>>>> - reduction gear. Drum speed is less than engine RPM (of course)
>>>> - drum selection (its a two drum winch)
>>>> - oscillating drive for the pay-on system
>>>>
>>>>
>>>> --
>>>> martin@ | Martin Gregorie
>>>> gregorie. | Essex, UK
>>>> org |
>>> Keep trying it. I think you will find you have control over airspeed.
>>> 180 - 240 HP isn't nearly enough power to prevent a big 2-seat glider
>>> from slowing the winch.
>> I assume Martin flies at the Cambridge Gliding Centre. Their V8 Supacat
>> could not be slowed by pulling (and in fact sped up at times) through
>> multiple attempts by myself and an instructor (both of us in the 200+ lb
>> range) in one of their ASK-21s. The only otherwise unusual outcome was a
>> premature back release late in one launch. This was done with prior
>> knowledge and discussion of the fact that it should theoretically be
>> possible. I'd guess there is no overcoming gobs of torque...
>>
>> Marc
>
> As I said, try it again with careful observation. You will find it works
> though you may have to wait a bit to see the effect.
>
As I said, we discussed ahead of time what would happen if we were to
pull harder (for a normal launch, only a small amount of back pressure
was needed). We were observing carefully and tried holding the stick on
the back stop for a good portion of the climb. We obviously didn't have
a huge amount of elevator authority (forward CG from two heavy guys), so
maybe we just couldn't generate enough lift on a cold autumn day to
exceed the power output of the winch. Or, perhaps you are used to
winches that are underpowered...

Marc

[Marc Ramsey[_2_]]

Marc Ramsey wrote:
> As I said, we discussed ahead of time what would happen if we were to
> pull harder (for a normal launch, only a small amount of back pressure
> was needed). We were observing carefully and tried holding the stick on
> the back stop for a good portion of the climb. We obviously didn't have
> a huge amount of elevator authority (forward CG from two heavy guys), so
> maybe we just couldn't generate enough lift on a cold autumn day to
> exceed the power output of the winch. Or, perhaps you are used to
> winches that are underpowered...

By the way, I absolutely do not claim to be any sort of winch launch
expert. I am interested in reviving ground launch locally, was in the
UK on business, and chose a number of clubs to visit based primarily on
their winch launch operations. I trained according to BGA standards,
and was signed off to solo on the winch at a couple of clubs. I also
received some training in winch driving, talked to anyone who would
listen, and was generally impressed with equipment and the procedures used.

I recommend that anyone who is interested in using a winch in the US do
the same, we have a lot to learn here...

Marc

[Del C]

Hi Bill,

With our Chevy big block powered Tost winches at Lasham,
you cannot slow down by pulling back - if anything
it has the opposite effect and risks breaking the weak
link. Easing forwards also makes you go faster, so
the only way to slow down is to signal to the winch
driver by wagging the tail with the rudder.

However we tried out a Skylaunch 2 winch for one day
last week with a very similar engine and gearbox, but
with a sophisticated throttle stop system. With that
I could control the speed from the glider, at least
in a K21, by about 5 knots either side of the mean
speed, which was ideal anyway. Maybe this is because
you are being supplied with just the right amount of
power. Unfortunately I didn't get a chance to try this
out with a lighter glider.

Derek Copeland

At 18:36 16 December 2007, Bill Daniels wrote:
>Actually guys, you CAN and SHOULD control airspeed
>on some winches. There
>are few winches that have enough power to prevent a
>large, heavy glider from
>pulling down the drum RPM. Maybe you guys have one
>- maybe not.
>
>If you are a little too fast, pitch up, load the winch
>a little and wait to
>see what the airspeed does. In most cases, it will
>ease back down to the
>desired airspeed. If you are a bit slow, lower the
>nose which unloads the
>winch a bit and wait for the effect. Once you get
>the hang of it, it works
>sweet.
>
>Many pilots think this won't work becasue they haven't
>tried it. Give it a
>try and get back to us.
>
>Bill Daniels
>
>
>'Andreas Maurer' wrote in message
...
>> On Wed, 12 Dec 2007 22:33:24 +0000, Martin Gregorie
>> wrote:
>>
>>>Speaking for myself, I watched the video and saw a
>>>succession of
>>>launches with right wing low. As wing low launching
>>>is something that,
>>>on my field, would earn you a talk with the duty instructor,
>>>I was
>>>unhappy with the description of this being a 'best
>>>practices' event and
>>>said so.
>>
>> I agree, Martin.
>> I've never seen such a series of really critical winch
>>launches
>> before. With all due respect - a very serious ground-loop
>>accident is
>> going to happen rather sooner than later.
>>
>>
>>>Comment on launch speed. The rules we use are:
>>>- after lift off, maintain a shallow climb until the
>>>ASI passes 50 kts
>>> with steady acceleration.
>>>- then and only then rotate slowly. The ideal is to
>>>complete rotation
>>> not less than 5 seconds after lift off.
>>>- we have a high torque, high inertia, fluid clutch
>>>winch. The pilot
>>> cannot and should not attempt to control its speed
>>>except by
>>> signalling the winch driver.
>>>- if you're above Vwinch when the launch starts to
>>>flatten toward the
>>> top (i.e. when the angle is below 35 degrees or
>>>so), release.
>>>- if the speed drops toward 50 kts, lower the nose
>>>to maintain at least
>>> 50 kts and monitor the speed.
>>>- if the speed picks up, resume the climb.
>>>- if the nose approaches level and the speed doesn't
>>>rise, release.
>>
>> The same rules apply for us. Works like a charm.
>>
>>
>>
>> Bye
>> Andreas
>
>
>

[Andreas Maurer]

On Sun, 16 Dec 2007 11:34:33 -0700, "Bill Daniels"
<bildan@comcast-dot-net> wrote:

>Actually guys, you CAN and SHOULD control airspeed on some winches. There
>are few winches that have enough power to prevent a large, heavy glider from
>pulling down the drum RPM. Maybe you guys have one - maybe not.

>If you are a little too fast, pitch up, load the winch a little and wait to
>see what the airspeed does. In most cases, it will ease back down to the
>desired airspeed. If you are a bit slow, lower the nose which unloads the
>winch a bit and wait for the effect. Once you get the hang of it, it works
>sweet.
>
>Many pilots think this won't work becasue they haven't tried it. Give it a
>try and get back to us.

Hi Bill,

I'm giving this a try since over 20 years and I have to admit that the
influence of pitch attitude on airspeed is negligible with out 280 hp
turbo-diesel winch (even with gliders like ASK-21 and DG-505).

On the other hand - I seldom have the need to control airspeed anyway.
Anything between 90 and 120 kp/h is perfectly ok - if I'm faster or
slower, I decrease pitch attitude. As simple as it gets. :)


Cheers
Andreas


p.s.:
I think it's usually the response of the winch driver that results in
an airspeed increase: If the winch driver notices a sudden
pitch-decrease (or an abnormal low pitch) of the gilder, he assumes
that the gider is too slow and adds power.
We don't have (and don't need) a voice communication between glider
and winch.







Bye
Andreas

[John Galloway[_1_]]

At 13:36 17 December 2007, Del C wrote:
>Hi Bill,
>
>With our Chevy big block powered Tost winches at Lasham,
>you cannot slow down by pulling back - if anything
>it has the opposite effect and risks breaking the weak
>link. Easing forwards also makes you go faster, so
>the only way to slow down is to signal to the winch
>driver by wagging the tail with the rudder.
>
>However we tried out a Skylaunch 2 winch for one day
>last week with a very similar engine and gearbox, but
>with a sophisticated throttle stop system. With that
>I could control the speed from the glider, at least
>in a K21, by about 5 knots either side of the mean
>speed, which was ideal anyway. Maybe this is because
>you are being supplied with just the right amount of
>power. Unfortunately I didn't get a chance to try this
>out with a lighter glider.
>
>Derek Copeland

Derek,

The Skylaunch system works just as well for very light
gliders and it beats me why other designers have not
copied the elegant simplicity and effectiveness of
the concept of using the progressive torque characterstics
of the GM V8 spark ignition engine combined with properly
researched throttle limitation.

When our club had a Skylaunch for a trial I drove it
under the supervision of their super-experienced winch
man, Pete Salisbury. To my surprise the K8 pilots
were just as complimentary about the suitability and
controllability of their launches as were the pilots
of heavier gliders.

John Galloway

[tommytoyz]

Andeas:


> Andreas
>
> p.s.:
> I think it's usually the response of the winch driver that results in
> an airspeed increase: If the winch driver notices a sudden
> pitch-decrease (or an abnormal low pitch) of the gilder, he assumes
> that the gider is too slow and adds power.
> We don't have (and don't need) a voice communication between glider
> and winch.
>
> Bye
> Andreas

Despite the danger that Bill Daniels calling me dangerous or some
other unsubstantiated claim, I post here to agree with you 100%.
Playing around with the airspeed should not be the focus of the
launch. It is the winch driver who controls this to the greatest
degree.

Safety and minimizing risk should be the main focus of the pilot.

The incidents mentioned here, are indicative of an increase in risks
during winch launches when trying to influence airspeed as discussed
in this thread. Weak links breaking as you're pulling back to put
strain on the winch or the premature back releases of the cable as
you're pulling are certainly not desirable nor add to safety.

I am with Andreas that from the pilot's point of view, it should be a
simple matter. The winch driver will also get a clue as to what's
happening by observing the glider. However, by pushing and pulling as
discussed here, the winch driver may not be able to figure out what's
going on and perhaps not respond at all or respond in a way that makes
thing worse.

Since the winch driver is the one who has the most control over speed,
you really don't want to confuse him or her.

[Andreas Maurer[_1_]]

On Mon, 17 Dec 2007 16:40:49 -0800 (PST), tommytoyz
> wrote:


>from the pilot's point of view, it should be a
>simple matter.

I think that's the main point.

@Bill:
I really love the fact that you are trying to promote winch launching
in the US - but (please correct me if I'm wrong) from the comments
here in this newsgroup I get the impression that you US guys regard
the winch launch as something pretty hazardous that needs a lot of
technology to be safe.
Consequently, your approach to a US winch design looks a little
over-engineered to me, I have to admit. Complex and expensive to
build, hard to set up correctly. Possibly prone to mechanical
problems.

Us European guys seem to see things in a more relaxed way - we tend to
advocate training instead of technological devices to achieve safe
winch operations.

Considering the number of accident-free winch launches per year on my
side of the pond, don't you think that it might be useful to stick
more closely to the KISS-principle ("keep it simple, stupid"), forget
all that high-tech stuff and concentrate on correct training?

Nearly all the winches here are basically very simple.
Anything a winch needs is a strong diesel engine, two drums, 3.500 ft
of cable (be it steel or plastic). No rocket science involved.




Bye
Andreas

[Bill Daniels]

"Andreas Maurer" > wrote in message
...
> On Mon, 17 Dec 2007 16:40:49 -0800 (PST), tommytoyz
> > wrote:
>
>
>>from the pilot's point of view, it should be a
>>simple matter.
>
> I think that's the main point.
>
> @Bill:
> I really love the fact that you are trying to promote winch launching
> in the US - but (please correct me if I'm wrong) from the comments
> here in this newsgroup I get the impression that you US guys regard
> the winch launch as something pretty hazardous that needs a lot of
> technology to be safe.
> Consequently, your approach to a US winch design looks a little
> over-engineered to me, I have to admit. Complex and expensive to
> build, hard to set up correctly. Possibly prone to mechanical
> problems.
>
> Us European guys seem to see things in a more relaxed way - we tend to
> advocate training instead of technological devices to achieve safe
> winch operations.
>
> Considering the number of accident-free winch launches per year on my
> side of the pond, don't you think that it might be useful to stick
> more closely to the KISS-principle ("keep it simple, stupid"), forget
> all that high-tech stuff and concentrate on correct training?
>
> Nearly all the winches here are basically very simple.
> Anything a winch needs is a strong diesel engine, two drums, 3.500 ft
> of cable (be it steel or plastic). No rocket science involved.
>
>
>
>
> Bye
> Andreas

Andreas, I have great respect for the long experience you have on that side
of the pond. I have spent years researching just what you do over there.
That's where I got my ideas.

But, there are problems with the very basic KISS principle. If you ask the
winch driver to control the glider's airspeed, you have to give him a way to
to judge how well he does that. If the pilot has an airspeed indicator with
which he judges the quality of a launch but the winch driver has nothing but
"feel", that's unfair to the winch driver since the pilot has MUCH more
information than he does. It's interesting to see that a German company is
now selling an inexpensive airspeed telemetry unit to address this.

If you ask the winch driver to control tension instead of airspeed, he has
several things to help him do that - things like cable sag (if using steel)
throttle setting and the sound and feel of the winch. It's even simpler for
him if there is a tensiometer. It's still better if you can link the
instantaneous cable tension to a throttle control loop so the winch does it
automatically.

The critical point is that neither the pilot or winch driver can control
both airspeed AND tension at the same time. If you tell the pilot to just
"go along for the ride" and task the winch driver with controling both, you
are giving the winch driver an impossible task.

If the winch driver controls only tension, the pilot now has to step up and
control his own airspeed. Once I realized I could do this, launches assumed
a high level of smoothness and consistency. This REALLY works SWEET. The
math shows it works right up to the cable tension that would break the weak
link so winch engine potential power or torque has nothing to do with it.

However, this is a hard concept to teach someone who has been trained
otherwise. I've had people who were jumping up and down with indignation
since they "knew" that pulling harder would make the glider speed up. "Show
me", I said. They lost the bet - every time.

A good analogy is old cars with drum brakes. When they got wet, braking
action vanished until they dried out. There is an almost overpowering
sensation that the car actually speeds up when you step hard on the brakes
and nothing happens.

I'm sure this is what is confusing glider pilots on a winch. As the nose
rises during the rotation, the glider is still accelerating and, since the
airspeed doesn't drop when they pull, they assume pulling on the stick makes
the glider speed up - or at least that they have no control over airspeed.

Once the glider has stabilized in the climb, the old pitch/airspeed
relationship is restored and you can control airspeed. Pitch up to slow and
down to speed up. As the glider nears the top of the launch, the ability to
reduce airspeed is much reduced but releasing back pressure will definitely
make the glider speed up.

There are things that make this hard to see. For one thing, the airspeed
response is not instantaneous - it takes a little time for a pitch input to
result in an airspeed change. For another, if the glider is loaded with the
CG at or even beyond the forward limit, you will likely not have enough up
elevator authority to slow the glider. This is a W&B problem - not a winch
problem. It's is the "two 200+ pounders in a glider with a 380 pound
maximum cockpit load" problem.

So, is this approach unnecessarily complicated? I don't think so. All I am
saying is to give the winch driver the ability to control tension extremely
accurately no matter what. Any driver, any wind, any glider or pilot and
the tension is always exactly right. What's not to like about that?

All you ask of the pilot is to control airspeed with pitch exactly like it
is done in all other flight situations. In other words, "Just fly the
glider". What's complicated about that?

An AOA indicator helps the pilot because his wings are loaded to the
equivalent of 3.5 G's so the "loaded stall airspeed" is much higher than in
1G flight. Glider's have stalled while on the wire with disastrous results.
A safe AOA indication is an absolute guarantee that you won't stall - no ASI
indication gives that level of assurance.


Bill Daniels

[Bert Willing[_2_]]

Bill,

accidents don't happen because somebody is missing a gadget.

Accidents happen because people are not aware about the situation they are
in. On a winch launch, and more so during free flight, you have lots of
indications about what is going on (speed, attitude, feel, sound).

Whenever somebody lacks situational awareness, he is an accident waiting to
happen, and the lack of awareness is the main cause of accidents. It's not
the missing AoA which is fatal..

Somebody who doesn't pay attention to what is going on will not benefit from
an AoA because he obviously doesn't care about all the information he
already gets.

I am a profound believer that you can increase safety only by training (both
mental and on the stick), and by increasing situational awareness. Adding
gadgets is an engineering approach to something which can't be solved by an
engineering approach. Somebody who doesn't get the fact that he is about to
stall will find another way to die, once you've added the AoA (and he cares
to look).

Bert

"Bill Daniels" <bildan@comcast-dot-net> wrote in message > A safe AOA
indication is an absolute guarantee that you won't stall - no ASI
> indication gives that level of assurance.
>
>
> Bill Daniels
>
>
>

[Edward Lockhart[_2_]]

At 17:18 18 December 2007, Bill Daniels wrote:

>All you ask of the pilot is to control airspeed with
>pitch exactly like it
>is done in all other flight situations. In other words,
>'Just fly the
>glider'. What's complicated about that?
>
>An AOA indicator helps the pilot because his wings
>are loaded to the
>equivalent of 3.5 G's so the 'loaded stall airspeed'
>is much higher than in
>1G flight. Glider's have stalled while on the wire
>with disastrous results.
>A safe AOA indication is an absolute guarantee that
>you won't stall - no ASI
>indication gives that level of assurance.
>
>
>Bill Daniels
>
>
A typical winch launch will put up to a 2G load on
the wings. If you're using the proper techniques and
equipment, the load is limited to a maximum of about
2.5G, depending on the glider.

The AoA increases as the glider flies up the wire.
Its therefore easier to use a calculated minimum safe
speed during the full climb which you know will keep
the AoA below the critical angle, even at the top of
the launch. This also ensures that the AoA is comfortably
below the critical angle at low level where a stall/spin
would be particularly dangerous.

Edward

[Bill Daniels]

"Edward Lockhart" > wrote in message
...
> At 17:18 18 December 2007, Bill Daniels wrote:
>
>>All you ask of the pilot is to control airspeed with
>>pitch exactly like it
>>is done in all other flight situations. In other words,
>>'Just fly the
>>glider'. What's complicated about that?
>>
>>An AOA indicator helps the pilot because his wings
>>are loaded to the
>>equivalent of 3.5 G's so the 'loaded stall airspeed'
>>is much higher than in
>>1G flight. Glider's have stalled while on the wire
>>with disastrous results.
>>A safe AOA indication is an absolute guarantee that
>>you won't stall - no ASI
>>indication gives that level of assurance.
>>
>>
>>Bill Daniels
>>
>>
> A typical winch launch will put up to a 2G load on
> the wings. If you're using the proper techniques and
> equipment, the load is limited to a maximum of about
> 2.5G, depending on the glider.
>
> The AoA increases as the glider flies up the wire.
> Its therefore easier to use a calculated minimum safe
> speed during the full climb which you know will keep
> the AoA below the critical angle, even at the top of
> the launch. This also ensures that the AoA is comfortably
> below the critical angle at low level where a stall/spin
> would be particularly dangerous.
>
> Edward
>

From this I assume you would rather fly gliders that weren't designed by
'engineers'.

No one who understand the use of an AOA indicator will call it a "gadget".

Having done winch launches with an AOA indicator, I can assure you that the
AOA does, in fact, remain constant throughout a well flown launch.

Yes, you can use airspeed but only as an abstraction of the real thing which
is AOA. Airspeed and AOA are not the same thing. You can stall a glider at
any airspeed but only at one AOA.

I can also assure you that the maximum loads on the wing is much nearer 3.5G
than 2.5.

Bill Daniels

[tommytoyz]

Bill,
I think the resistance your seeing is due to this:

Pilot Adjusted Airspeed
The acceptable airspeed range on a winch launch for any given wing
loading on practically any glider is fairly wide. Say +/- 30 knots. So
what then is the point of pushing and pulling to change the airspeed
for a few knots here and there, if it is even possible on some set
ups?

If the airspeed is in the acceptable range, there is no point to doing
this. It will only possibly confuse the winch driver creating a
negative feedback loop between pilot/driver actions.

Think about your statement:
"All you ask of the pilot is to control airspeed with pitch exactly
like it
is done in all other flight situations. In other words, "Just fly the
glider". What's complicated about that? "

As has been reported here, different winch set ups react differently.
So you would need to fly and train differently for each set up. That's
not good.

Also, as has been reported here, which you seem not to believe, is
that it is dangerous, such as breaking the weak link, say on a gust,
just as your pulling the most. Think about that situation.

All this just to control airspeed a few knots here and there?

It doesn't sound like a good practice to base standard practices on
and train people that way. If you want to do it yourself after much
experience, that's another matter. But it should not be taught this
way across the board. On some winch setups it might produce the exact
opposite effects for all anyone knows.

Experimenting by experienced pilots is one thing, especially if you're
willing to get closer to the weak link breakage point that necessary
during launch. But it should not be standard practice, IMHO.

[Bill Daniels]

I'm really tempted not to answer but here goes anyway.

"tommytoyz" > wrote in message
...
> Bill,
> I think the resistance your seeing is due to this:
>
> Pilot Adjusted Airspeed
> The acceptable airspeed range on a winch launch for any given wing
> loading on practically any glider is fairly wide. Say +/- 30 knots. So
> what then is the point of pushing and pulling to change the airspeed
> for a few knots here and there, if it is even possible on some set
> ups?

Because being at the optimum airspeed is both safer and results in higher
launches.
>
> If the airspeed is in the acceptable range, there is no point to doing
> this. It will only possibly confuse the winch driver creating a
> negative feedback loop between pilot/driver actions.

If your winch driver get confused so easilly, maybe you need to find another
one.

>
> Think about your statement:
> "All you ask of the pilot is to control airspeed with pitch exactly
> like it
> is done in all other flight situations. In other words, "Just fly the
> glider". What's complicated about that? "

I stand by that.
>
> As has been reported here, different winch set ups react differently.
> So you would need to fly and train differently for each set up. That's
> not good.

The laws of physics are the same everywhere in the universe. Train to the
physics.

>
> Also, as has been reported here, which you seem not to believe, is
> that it is dangerous, such as breaking the weak link, say on a gust,
> just as your pulling the most. Think about that situation.

Breaking a weak link is inconvenient, not dangerous. If you think it's
dangerous, maybe you need more training in emergencies.

>
> All this just to control airspeed a few knots here and there?
>
> It doesn't sound like a good practice to base standard practices on
> and train people that way. If you want to do it yourself after much
> experience, that's another matter. But it should not be taught this
> way across the board. On some winch setups it might produce the exact
> opposite effects for all anyone knows.

I say, train to the physics . That accomodates all differences. If you
train to some standard other than the basic physics, that is REALLY
dangerous.

> Experimenting by experienced pilots is one thing, especially if you're
> willing to get closer to the weak link breakage point that necessary
> during launch. But it should not be standard practice, IMHO.

No one is experimenting, This is how it works.

Bill Daniels

[tommytoyz]

Bill's statement #1
"Breaking a weak link is inconvenient, not dangerous."

My Response
And even this is good? You want to risk incurring a breakage more
often, just to get a slightly higher launch altitude? I don't think
it's a good trade off and at a minimum, it does not add to safety in
any case either.

And being at optimum airspeed is not safer than being slightly outside
but still in the acceptable airspeed range. Only being at the edge is
unsafe, specifically at the low end. That's when everyone advocates
changing the attitude by lowering the nose, in case it continues and
an abort becomes necessary, and as you know, to maintain good AoA.

Bill's statement #2
"The laws of physics are the same everywhere in the universe. Train
to the
physics."

I say:
Your statement is not false all by itself. But it fails to make your
point as winch launch training. It excludes to consider the fact that
not all winch setups are the same. Some have vastly more torque than
others and the weight and type of ship being launched also makes a
difference in how the airspeed will or will not react if you push or
pull. Driver training also matters. You can not assume all these
factors are the same at all times. They're not.

It also matters at what speed you initiate the attitude changes. Lots
a variables. All just to get slightly higher? How much do you think
you'll gain anyway? Experienced winch pilots may play around with this
but is should not be taught as best practices.

I respectfully disagree with your advice that it is good practice. I
think it's bad practice, especially for clubs here in the USA trying
to establish best practices.

If you haven't done so already, I suggest you fly off several winches
in Europe. I hear (since I've never flown winches here) that the
winches in the USA are very different.

[[email protected]]

On Dec 18, 12:36 pm, "Bill Daniels" <bildan@comcast-dot-net> wrote:
>
> I can also assure you that the maximum loads on the wing is much nearer 3.5G
> than 2.5.

Spar bending moment, yes. Aerodynamic load, no.

If the wing loading was 3.5G, the stall speed would be in excess of 60
knots and there would be a lot more dead pole benders.

[Bill Daniels]

So, tommytoys, are you in the USA or Europe? Why is it that you are afraid
to use your real name?


"tommytoyz" > wrote in message
...
> Bill's statement #1
> "Breaking a weak link is inconvenient, not dangerous."
>
> My Response
> And even this is good? You want to risk incurring a breakage more
> often, just to get a slightly higher launch altitude? I don't think
> it's a good trade off and at a minimum, it does not add to safety in
> any case either.

Dont' waffle. You said unsafe and that's BS.

>
> And being at optimum airspeed is not safer than being slightly outside
> but still in the acceptable airspeed range. Only being at the edge is
> unsafe, specifically at the low end. That's when everyone advocates
> changing the attitude by lowering the nose, in case it continues and
> an abort becomes necessary, and as you know, to maintain good AoA.
>
> Bill's statement #2
> "The laws of physics are the same everywhere in the universe. Train
> to the
> physics."
>
> I say:
> Your statement is not false all by itself. But it fails to make your
> point as winch launch training. It excludes to consider the fact that
> not all winch setups are the same. Some have vastly more torque than
> others and the weight and type of ship being launched also makes a
> difference in how the airspeed will or will not react if you push or
> pull. Driver training also matters. You can not assume all these
> factors are the same at all times. They're not.

Physics is the whole enchilada. Winch setups may be different but the
operating physics are the same. Train to the physics and winch setup
differences won't matter.

Are you saying that every 'different' winch operation should have a
different training syllabus? That's really nuts.


>
> It also matters at what speed you initiate the attitude changes. Lots
> a variables. All just to get slightly higher? How much do you think
> you'll gain anyway? Experienced winch pilots may play around with this
> but is should not be taught as best practices.

I can't make any sense of this paragraph. All the variables are simple and
easily exlainable. Which one confuses you?

>
> I respectfully disagree with your advice that it is good practice. I
> think it's bad practice, especially for clubs here in the USA trying
> to establish best practices.

I think it's not that you disagree but that you just don't understand it.

>
> If you haven't done so already, I suggest you fly off several winches
> in Europe. I hear (since I've never flown winches here) that the
> winches in the USA are very different.

I have flown from many winches of many different types but far more
important, I've studied the physics. Go read the papers by Goulthrope and
Moore. Read the information provided by Hydrostart at www.Hydrostart.nl

Winch launch is not an art, it's a science and not a very complicated one.

Bill Daniels

[tommytoyz]

Bill,
I am not confused at all. I don't know why you come off so defensive
and aggressive.

In that vein, have never explained why you said I should ground myself
and that I'm dangerous. Thats was a ridiculous statement and a cop out
to not answer - and you know it. Owning up to it wold be a good start,
IMHO.

Anyway, I am of the KISS school. You advocate the pilot push or pull
to try and oscillate attitude to control airspeed. I say the pilot
should not. Why is that so difficult for you to understand? This is
the only point we disagree on. Does this call for insults and crazy
statements? We mostly agree.

"Train to the physics and winch setup differences won't matter."

You forget that the winch driver is main factor, which you repeatedly
leave out and that's not a physics issue. Having been launched by many
different winch drivers off the same winch, I can tell you there are
differences.

Instructors will often ask who is driving the winch. There is a reason
for this.

So if you think that oscillating by pushing and pulling with
a) different winch set ups
b) different aircraft and
c) different winch drivers
will always give the same results with your technique, be my guest. I
know otherwise.

Your oscillating technique is just not best practices for pilots to
learn to launch with a variety of variables. Perhaps for one
particular set up, yes. But not as general standard.

Premature back releases and tempting weak link breaks with high nose
up attitudes in the name of slightly higher (and even this is
questionable) release altitudes is not best practices. A steady climb
profile when the speed is acceptable and steady is better than pushing
and pulling to supposedly get higher. Perhaps you actually release
lower, if the winch driver doesn't react well to this technique? Ever
thought of that?

But you think different, and I have no problem with that. Be my guest.
Oscillate away on your launches.
Tom Vallarino

[Andreas Maurer[_1_]]

On Tue, 18 Dec 2007 10:14:05 -0700, "Bill Daniels"
<bildan@comcast-dot-net> wrote:


>But, there are problems with the very basic KISS principle. If you ask the
>winch driver to control the glider's airspeed, you have to give him a way to
>to judge how well he does that.

Yup.
Here in Germany we call this training. :)

A new winch driver needs 100 winch launches on 10 different days
(read: different weather situations) to acquire his winch driver
license.
Any winch driver student is able to drive the winch safely after a
dozen launches using his feeling, an RPM meter and a look at the cable
sag.
Driving a winch is pretty simple if you ask me. :)


>If you ask the winch driver to control tension instead of airspeed, he has
>several things to help him do that - things like cable sag (if using steel)
>throttle setting and the sound and feel of the winch. It's even simpler for
>him if there is a tensiometer. It's still better if you can link the
>instantaneous cable tension to a throttle control loop so the winch does it
>automatically.

Nice to have... but we use a much simpler way: We have an RPM meter.

Winch driver accelerates to a certain RPM (depending on glider type).
This RPM is modified according to the wind condition. Once the glider
goes through 45 degrees "winch driver head up", RPM is slowly
decreased.
Works like a charm 99.99 percent of the time.


>The critical point is that neither the pilot or winch driver can control
>both airspeed AND tension at the same time. If you tell the pilot to just
>"go along for the ride" and task the winch driver with controling both, you
>are giving the winch driver an impossible task.

I think you are wrong here. The fact alone that nearly all winches in
Europe operate the way I described above means that this task is easy
to handle, don't you agree?


>If the winch driver controls only tension, the pilot now has to step up and
>control his own airspeed. Once I realized I could do this, launches assumed
>a high level of smoothness and consistency. This REALLY works SWEET. The
>math shows it works right up to the cable tension that would break the weak
>link so winch engine potential power or torque has nothing to do with it.

Who cares?
I can assure you that with the KISS principle we reach the same
altitudes as you do. :)


>However, this is a hard concept to teach someone who has been trained
>otherwise. I've had people who were jumping up and down with indignation
>since they "knew" that pulling harder would make the glider speed up. "Show
>me", I said. They lost the bet - every time.

LOL... here comes the urban legend "pilot controls airspeed" again...


>I'm sure this is what is confusing glider pilots on a winch. As the nose
>rises during the rotation, the glider is still accelerating and, since the
>airspeed doesn't drop when they pull, they assume pulling on the stick makes
>the glider speed up - or at least that they have no control over airspeed.

I don't think so.
Being able to control the airspeed safely by pulling on the stick has
been an urban legend for ages. We sometimes talk about it, have a good
laugh, and return to the standard technique.


>There are things that make this hard to see. For one thing, the airspeed
>response is not instantaneous - it takes a little time for a pitch input to
>result in an airspeed change. For another, if the glider is loaded with the
>CG at or even beyond the forward limit, you will likely not have enough up
>elevator authority to slow the glider. This is a W&B problem - not a winch
>problem. It's is the "two 200+ pounders in a glider with a 380 pound
>maximum cockpit load" problem.

I can ssure you - even a very tail-heavy DG-505 (the glider that can
break *any* weak-link) is unable to slow a winch with halfways
sufficient power down, although its elevator authority is sufficient
to stall it in any phase of the winch launch.
Fly one if you get the chance - it's interesting to see the loss of
aileron authority when you approach the stall during the winch
launch...


>So, is this approach unnecessarily complicated? I don't think so. All I am
>saying is to give the winch driver the ability to control tension extremely
>accurately no matter what. Any driver, any wind, any glider or pilot and
>the tension is always exactly right. What's not to like about that?

The complexity.
The fact that extremely few winch operators feel the need to build a
winch according to yxour ideas points out that there might be other
priorities.


>All you ask of the pilot is to control airspeed with pitch exactly like it
>is done in all other flight situations. In other words, "Just fly the
>glider". What's complicated about that?

It's not how it's done.
Taking the example of the 505 - if I tried to reduce airspeed by
pulling at more than 115 kph, I'd break the strongest weak link *any
time*.

>An AOA indicator helps the pilot because his wings are loaded to the
>equivalent of 3.5 G's so the "loaded stall airspeed" is much higher than in
>1G flight. Glider's have stalled while on the wire with disastrous results.
>A safe AOA indication is an absolute guarantee that you won't stall - no ASI
>indication gives that level of assurance.

I disagree completely. :)

Take a closer look at causes for winch accidents:

Most accidents happen due to ground loops (just look at the video that
started this thread if you want to see some close cases) and badly
executed rope-break procedures.

There's hardly any case (I know of none) where the glider stalled at
an altitude of more than 200 ft. Nearly all stall related accidents
happen due to a too-sudden transition into full climb, followed by an
immediate highspeed stall and cartwheel or spin.
It's extremely simple to avoid this kind of accident: Keep the stick
in the recommended position for their first 150 ft of the winch launch
before pulling back smooooothly to enter the full climb angle.

Usually such a stall occurs extremely quickly - it's nearly impossible
to recover before impact.

These pilots were not able to hold the stick halfways in the correct
position, nor were they able to detect the very sudden transition into
a steep nose-up attitude. Nor, obvously, were they able to perform the
very simple corrective measure: Push the stick forward immediately.

I strongly doubt that these pilots had been able to watch, interpret
and act according to an AoA meter.




Bye
Andreas

[Del C]

Even better, buy a Skylaunch 2 Winch with adjustable
throttle stops for glider type and wind direction.
It isn't even fitted with a RPM meter, because it doesn't
need one. We had one demonstrated at Lasham recently,
and it was very easy to drive and gave great launches:
See the following video:

http://www.youtube.com/watch?v=0qc3U_7_4FY

I wrote a report on the demo day for our club newsgroup,
which I reproduce below:-

Hi,

Mike Groves and the Skylaunch team brought along one
of their latest main winches for a demonstration day
at Lasham on 12th December to coincide with the 'Winter
Wednesdays' flying group, which is a very active and
pro-active instructional team, so there was plenty
of launching to be done. It was a beautiful Winter's
day, with lots of sunshine and a very light South-Easterly
wind. We set up on the Easterly run (semi-crosswind)
with our normal retrieve winch in action, as the grass
was rather too wet, soft and slippery for too much
vehicle retrieving after a period of prolonged rain.

This was the first time I had seen a Skylaunch with
the trim tab throttle setting system, although I have
flown many launches at the Long Mynd on their original
prototype winch, which is not so fitted. With this
system there are two setting tabs, one for glider typerunning
from A+ for DG1000s down to F for vintage gliders,
and a headwind component tab (which we set to 5 knots).
In the cab was a booklet with most glider types listed
with the appropriate settings

After watching a few launches, I was allowed to drive
this winch
under the supervision of their pro winch driver. Compared
with our Tosts it was ridiculously simple, without
all the fiddly bits. The controls are a drum selection
lever on the left, a gearbox drive selector, a console
with the throttle lever and tabs, and just one instrument
(interestingly no rev counter) plus a few warning lights,
and a brake lever on the right.

To launch you select the drum, engage 'drive', and
select the
appropriate throttle tab setting for the type of glider
being
launched (you have to be informed by radio what it
is, particularly as we were launching over a hump so
couldn't quite see the launch point). Then a little
touch on the throttle lever for 'take up slack' and
then push the lever up to the preset and hold it there
for the first 2/3rds of the launch (no need to back
off during rotation),after which you have to start
backing off a bit as normal. You can overide the preset
if you consider this necessary. As the glider gets
nearly overhead, you reduce the throttle to indicate
that the launch is over, and as soon as the glider
releases apply a short burst of power to pull the cable
straight. After that select neutral and allow the retrieve
winch to pull the cable back to the launch point. There
is a automatic tow-out brake, controlled by gas struts,
so no need to wrestle with the handbrake levers as
with the Tost. You just rest your hand on the brake
lever and apply a litle bit of brake as the cable(s)
slows down as the other end reaches the launch point
to prevent the drum over-running.

My first launch was a 'Baby Grob' G102, which we launched
on the Grob Astir setting. This produced a bit of initial
tail wagging (signal for too fast) so I had to back
the power off a touch, after which the rest of the
launch went smoothly. Peter the winch driver said he
had never launched one of these before, and suspected
that it was a bit slower and lighter than the Astir
(which it is) and that we should have used the next
lowest setting down. This probably shows how accurate
the system is!
Then I launched a heavy Grob 2 seater and then a K13
which seemed to be having a very good launch until
the instructor pulled a simulated cable break on his
student. No problem, I just closed the throttle and
let the cable drop and waited until the glider landed.
Then after liasing with the retrieve winch by radio
I pulled a little bit of cable in to straighten things
up, and then the cable was retrieved as normal. I did
a couple more launches which went smoothly with no
signalling from the glider.

Although I am not a current winch driver, I found this
winch very
little more difficult to drive than our retrieve winch.
It was just
winch driving by numbers. Mike pointed out that this
winch is
designed specifically to be driven by ordinary gliding
club members, as opposed to skilled professional drivers.
Compared with the Tost, it is very quiet,comfortable
and user friendly

Later on I a tried a solo launch in a K21 on this winch.
The ground run acceleration was a little bit faster
than we normally get and the glider rotated into an
ideal 65 knots climb. I tried pulling back a bit harder
and it slowed down to 60 knots and then eased forward
and it speeded up to 70 knots. So with this system
you can control the speed. Despite this messing around
I still got a 1400ft launch off a short run (1080 metres)
in a crosswind using steel cables, which is about 100ft
or so higher than I would have expected on the Tost.
Members generally
reported 1300-1400ft launches.

A few interesting points. Mike Groves said that some
clubs with
shorter runs are using rope rather than dyneema, which
is a fraction of the cost, but still much lighter than
steel cables, although somewhat thicker so you can't
get so much onto a drum. No good for really long runs.

He will also re-engineer old Tost winches to modern
standards, which includes turning the axle over so
it is the right way up and properly lubricated, throwing
away the small diameter drums and level wind gear and
fitting Skylaunch narrow large diameter bottom feeding
drums. If you have an old Tost with a decent engine
and gearbox, this could be very cost effective and
will reduce maintenance requirements.

Derek Copeland



At 01:06 19 December 2007, Andreas Maurer wrote:
>On Tue, 18 Dec 2007 10:14:05 -0700, 'Bill Daniels'
> wrote:
>
>
>>But, there are problems with the very basic KISS principle.
>> If you ask the
>>winch driver to control the glider's airspeed, you
>>have to give him a way to
>>to judge how well he does that.
>
>Yup.
>Here in Germany we call this training. :)
>
>A new winch driver needs 100 winch launches on 10 different
>days
>(read: different weather situations) to acquire his
>winch driver
>license.
>Any winch driver student is able to drive the winch
>safely after a
>dozen launches using his feeling, an RPM meter and
>a look at the cable
>sag.
>Driving a winch is pretty simple if you ask me. :)
>
>
>>If you ask the winch driver to control tension instead
>>of airspeed, he has
>>several things to help him do that - things like cable
>>sag (if using steel)
>>throttle setting and the sound and feel of the winch.
>> It's even simpler for
>>him if there is a tensiometer. It's still better if
>>you can link the
>>instantaneous cable tension to a throttle control loop
>>so the winch does it
>>automatically.
>
>Nice to have... but we use a much simpler way: We have
>an RPM meter.
>
>Winch driver accelerates to a certain RPM (depending
>on glider type).
>This RPM is modified according to the wind condition.
>Once the glider
>goes through 45 degrees 'winch driver head up', RPM
>is slowly
>decreased.
>Works like a charm 99.99 percent of the time.
>
>
>>The critical point is that neither the pilot or winch
>>driver can control
>>both airspeed AND tension at the same time. If you
>>tell the pilot to just
>>'go along for the ride' and task the winch driver with
>>controling both, you
>>are giving the winch driver an impossible task.
>
>I think you are wrong here. The fact alone that nearly
>all winches in
>Europe operate the way I described above means that
>this task is easy
>to handle, don't you agree?
>
>
>>If the winch driver controls only tension, the pilot
>>now has to step up and
>>control his own airspeed. Once I realized I could
>>do this, launches assumed
>>a high level of smoothness and consistency. This REALLY
>>works SWEET. The
>>math shows it works right up to the cable tension that
>>would break the weak
>>link so winch engine potential power or torque has
>>nothing to do with it.
>
>Who cares?
>I can assure you that with the KISS principle we reach
>the same
>altitudes as you do. :)
>
>
>>However, this is a hard concept to teach someone who
>>has been trained
>>otherwise. I've had people who were jumping up and
>>down with indignation
>>since they 'knew' that pulling harder would make the
>>glider speed up. 'Show
>>me', I said. They lost the bet - every time.
>
>LOL... here comes the urban legend 'pilot controls
>airspeed' again...
>
>
>>I'm sure this is what is confusing glider pilots on
>>a winch. As the nose
>>rises during the rotation, the glider is still accelerating
>>and, since the
>>airspeed doesn't drop when they pull, they assume pulling
>>on the stick makes
>>the glider speed up - or at least that they have no
>>control over airspeed.
>
>I don't think so.
>Being able to control the airspeed safely by pulling
>on the stick has
>been an urban legend for ages. We sometimes talk about
>it, have a good
>laugh, and return to the standard technique.
>
>
>>There are things that make this hard to see. For one
>>thing, the airspeed
>>response is not instantaneous - it takes a little time
>>for a pitch input to
>>result in an airspeed change. For another, if the
>>glider is loaded with the
>>CG at or even beyond the forward limit, you will likely
>>not have enough up
>>elevator authority to slow the glider. This is a W&B
>>problem - not a winch
>>problem. It's is the 'two 200+ pounders in a glider
>>with a 380 pound
>>maximum cockpit load' problem.
>
>I can ssure you - even a very tail-heavy DG-505 (the
>glider that can
>break *any* weak-link) is unable to slow a winch with
>halfways
>sufficient power down, although its elevator authority
>is sufficient
>to stall it in any phase of the winch launch.
>Fly one if you get the chance - it's interesting to
>see the loss of
>aileron authority when you approach the stall during
>the winch
>launch...
>
>
>>So, is this approach unnecessarily complicated? I
>>don't think so. All I am
>>saying is to give the winch driver the ability to control
>>tension extremely
>>accurately no matter what. Any driver, any wind, any
>>glider or pilot and
>>the tension is always exactly right. What's not to
>>like about that?
>
>The complexity.
>The fact that extremely few winch operators feel the
>need to build a
>winch according to yxour ideas points out that there
>might be other
>priorities.
>
>
>>All you ask of the pilot is to control airspeed with
>>pitch exactly like it
>>is done in all other flight situations. In other words,
>>'Just fly the
>>glider'. What's complicated about that?
>
>It's not how it's done.
>Taking the example of the 505 - if I tried to reduce
>airspeed by
>pulling at more than 115 kph, I'd break the strongest
>weak link *any
>time*.
>
>>An AOA indicator helps the pilot because his wings
>>are loaded to the
>>equivalent of 3.5 G's so the 'loaded stall airspeed'
>>is much higher than in
>>1G flight. Glider's have stalled while on the wire
>>with disastrous results.
>>A safe AOA indication is an absolute guarantee that
>>you won't stall - no ASI
>>indication gives that level of assurance.
>
>I disagree completely. :)
>
>Take a closer look at causes for winch accidents:
>
>Most accidents happen due to ground loops (just look
>at the video that
>started this thread if you want to see some close cases)
>and badly
>executed rope-break procedures.
>
>There's hardly any case (I know of none) where the
>glider stalled at
>an altitude of more than 200 ft. Nearly all stall related
>accidents
>happen due to a too-sudden transition into full climb,
>followed by an
>immediate highspeed stall and cartwheel or spin.
>It's extremely simple to avoid this kind of accident:
>Keep the stick
>in the recommended position for their first 150 ft
>of the winch launch
>before pulling back smooooothly to enter the full climb
>angle.
>
>Usually such a stall occurs extremely quickly - it's
>nearly impossible
>to recover before impact.
>
>These pilots were not able to hold the stick halfways
>in the correct
>position, nor were they able to detect the very sudden
>transition into
>a steep nose-up attitude. Nor, obvously, were they
>able to perform the
>very simple corrective measure: Push the stick forward
>immediately.
>
>I strongly doubt that these pilots had been able to
>watch, interpret
>and act according to an AoA meter.
>
>
>
>
>Bye
>Andreas
>

[Andreas Maurer[_1_]]

On 19 Dec 2007 22:04:13 GMT, Del C
> wrote:

>Even better, buy a Skylaunch 2 Winch with adjustable
>throttle stops for glider type and wind direction.

Hi Derek,

sound pretty good - and as close to the KISS principle as it gets. :)


Just one annotation:
I regard 70 kts for an ASK-21 as a little on the too-fast side (it
will break the weak link if you pull back too much at this speed) - do
you always tow that fast?

Bye
Andreas

[Del C]

I agree with Andreas Maurer that 70 knots is a bit
too fast for winch launching a K21. However flying
a normal launch profile, where the stick is just back
from centre for the full climb,gave a perfect 65 knots
launch on the Skylaunch. I tried pulling back harder
and then easing forward just to see what would happen,
as some people in the winching world seem to believe
that the airspeed should be controlled by the pilot
changing the pitch angle. I found you could vary the
speed by about 5 knots either way, but I can't really
see the point of doing this, as it only gives you poorer
launches than flying at the optimum speed!

BTW, everyone I have spoken to has been very impressed
by the Skylaunch 2 Winch.

Del Copeland

At 23:42 19 December 2007, Andreas Maurer wrote:
>On 19 Dec 2007 22:04:13 GMT, Del C
> wrote:
>
>>Even better, buy a Skylaunch 2 Winch with adjustable
>>throttle stops for glider type and wind direction.
>
>Hi Derek,
>
>sound pretty good - and as close to the KISS principle
>as it gets. :)
>
>
>Just one annotation:
>I regard 70 kts for an ASK-21 as a little on the too-fast
>side (it
>will break the weak link if you pull back too much
>at this speed) - do
>you always tow that fast?
>
>Bye
>Andreas
>

[Dan G]

On Dec 20, 1:32 pm, Del C >
wrote:
> I tried pulling back harder
> and then easing forward just to see what would happen,
> as some people in the winching world seem to believe
> that the airspeed should be controlled by the pilot
> changing the pitch angle. I found you could vary the
> speed by about 5 knots either way

Just out of interest - when pulling back was the 5 knot change one of
increasing or decreasing speed?


Dan

[Del C]

Dan

Can I refer you back to my report on this winch!

For the record, pulling back harder reduced the airspeed
and easing forward increased it.

Cheers and Happy Xmas
Del C

At 18:00 20 December 2007, Dan G wrote:
>On Dec 20, 1:32 pm, Del C
>wrote:
>> I tried pulling back harder
>> and then easing forward just to see what would happen,
>> as some people in the winching world seem to believe
>> that the airspeed should be controlled by the pilot
>> changing the pitch angle. I found you could vary the
>> speed by about 5 knots either way
>
>Just out of interest - when pulling back was the 5
>knot change one of
>increasing or decreasing speed?
>
>
>Dan
>

[tommytoyz]

Pilot controlling speed on Winch Launch:
- Another thing that speaks against pulling to slow down is this that
if the winch driver does nothing when you pull, the speed can only be
slowed temporarily by pulling.

So you may slow down on certain set ups and aircraft, by you have to
ease off on the extra pull over normal pretty soon, at which point
you'll speed up again. So what's the point? You're just slowing down
temporarily only to speed up again, or release prematurely by breaking
the weak link or having the back release release earlier.

Pushing over when to slow should be done anyway, for safety reasons.
So no argument there. But unless the winch driver changes power
settings, nothing will change. He's in charge.

I also am more inclined to believe that oscillating by the pilot to
influence airspeed, the way Bill Daniels advocates, will result in
lower release altitudes than using the KISS method.

[Dan G]

On Dec 20, 6:54 pm, Del C >
wrote:
> Dan
>
> Can I refer you back to my report on this winch!
>
> For the record, pulling back harder reduced the airspeed
> and easing forward increased it.
>
> Cheers and Happy Xmas
> Del C

Sorry, a goldfish brain moment on my part. Your experience with the
speed is the same as mine on a V8 LPG winch.

I think of the winch launch as a little bit like horse-riding - there
are two brains involved in controlling what happens next.... Both
pilot and winch driver control the speed to some degree, with the
winch driver having the ability to induce bigger speed excursions from
the optimum.


Dan