Nimbus 4DT accident 31 July 2000 in Spain.

How long is ACL's runway?

Mike Schumann

"Bill Daniels" wrote in message
...
Good comments, Don.

If the break occurs between the winch and drogue the 'chute will collapse
and pass harmlessly below the glider, releasing automatically from the
glider in most cases.

If the break is between the glider and drogue, (weak link failure) then
the
drogue will be open as long as the winch driver maintains power. In this
case, the winch driver is the key. My driving technique is to cut the
throttle and let the drogue collapse and drop to the ground. Comments?

The worst case that is very rarely seen is that somehow the glider gets in
front of the drogue and it overtakes the glider from behind. This is the
equivalent of getting an air tow rope entangled with the glider. Both are
equally rare. This is why once the drogue is on the ground, the winch
driver must not move the cable until he hears that it is safe to do so.

It is very important to point out that almost all the cable breaks were
using the old steel wire. The new Dyneema winch cables rarely break. The
last I heard, Aero Club Landau in Germany had more than 4000 launches on
their 'plastic' cable without a single break. ACL is also getting more
than
1200 meters AGL with their winch launches.

Bill Daniels

The pilot is trained not to land on the wire if at all possible.
"Don Johnstone" wrote in
message ...
Just to add to what Bill has said, the really low launch
failure 100 is one of the minor problem areas. If
the launch is flown correctly it can be quite safely
handled. The good point is, as Bill has pointed out
that there is a large amount of airfield still in front
of you. The bad news is that by the time the nose has
been lowered the airspeed may be below the minimum
allowed for the deployment of airbrakes. It may not
be possible to lower the nose any further to increase
the speed because of the proximity to the ground and
therefore a touchdown has to be achieved without using
airbrake. Patience is required as most modern gliders
float a long way even at 50 kts in ground effect. (Grob
103 will travel the length of the 10000ft runway at
Marham from 20ft/60kts) Simulating a launch failure
at this height is not recomended as there is a real
danger that the drogue will inflate as the winch driver
cuts the power and drape itself over the cockpit. The
good news is that such breaks are rare as the strain
on the cable is reducing before increasing again. The
procedure can be simulated by carrying out a faster
than normal approach, pulling up and closing the airbrakes
and then recovering from that situation which puts
the glider in the same situation as a low break but
without the cable in the way.


At 04:30 28 June 2005, Bill Daniels wrote:

'Kilo Charlie' wrote in message
news:9D3we.3579$Qo.3471@fed1read01...
Your input re winch launches is appreciated Bill....esp
for those of us
that
have never done one!

Please don't take this as a criticism of winch launches
but through this
thread there has not been any mention of what happens
at the critical low
level altitude when the cable breaks. There is clearly
also a zone of
real
problems with aerotows too.....esp here in the desert
with few, if any
landing options straight ahead. What do you guys
teach re breaks at 100
feet? It seems like landing ahead would be good but
how much altitude
does
it take to regain the necessary speed to be able to
control the glider for
landing when at a high angle of attack? Sorry if
this is too obvious for
those of you that do it all the time!

Casey


Thanks, Casey.

The climb profile must be such that a safe recovery
with generous margins be
possible from any height that a cable break occurs.
Safety is the product
of airspeed, altitude and attitude - and good training.

If the break happens at 100 feet, then 90%+ of the
runway lies ahead to
receive the glider. At 100 feet, the glider will have
full climb airspeed,
approx. 60 knots, but then pitch attitude will only
be 20 - 30 degrees. A
prompt, gentle pushover to a glide at approach airspeed
is all that is
needed to land straight ahead.

If the break occurs higher, say 300 - 400 feet, then
the straight ahead
landing is still possible with spoilers but a tight
360 pattern is also
possible. The two options overlap by a good amount
of height depending on
the airfield. At this height, the climb attitude will
be about 45 degrees
nose up (although from the cockpit it will feel like
60 degrees) so a more
aggressive pushover is needed.

All these situations will be practiced over and over
until the instructor
feels the student reacts instinctively and correctly
to each. The student
must firmly push the nose down until the airspeed is
observed to be at a
safe value and increasing before establishing a glide
for a straight ahead
landing or a turn for an abbreviated pattern.

I must admit that winch launch LOOKS scary and FEELS
scary to the
uninitiated but the procedures worked out over literally
tens of millions of
launches in Europe and elsewhere make it actually safer
than air tow.

As for releasing over the winch instead of wherever
the tow plane takes you,
I see by looking at a lot of On-Line Contest IGC files,
that most air tow
releases happen within a mile of the takeoff point
and the glider is rarely
in a thermal at release but must glide around looking
for one just like with
a winch launch. If you don't find a thermal, a winch
re-light will cost you
less than $10.

The latest European winches are getting even heavy
gliders to over 1000
meters AGL so finding lift shouldn't be a problem.

Bill Daniels

This article makes you want to install a ballistic recovery chute in this
class of glider to handle a worst case scenario.

Mike Schumann

"M B" wrote in message
...
The article was very interesting. The idea of aileron
stiffness at high bending was thought-provoking.

'Abandoning ailerons for a more effective way of starting
and stopping roll...' Perhaps a reference to
full span spoilers for roll?

'the smoking gun was the aircraft's incredibly high
performance.' This is consistent with, but not a proof
of, the things I've written before about USA fatalities
and L/D.
Of course, this was however NOT a ridge flying accident.

The article didn't mention the possibility that the
other
pilot may have popped the airbrakes/two pilots on the
controls working at odds with each other. Of course
there
is absolutely no way to confirm or deny this.

Lastly, I liked the article's end, and the idea of
big bold red letters in the AFM. It also occered to
me that some of the
'seconds to accelerate from stall speed to ...' and
a lot
of the ideas we have, and how we practice spins and
spirals, is in STILL AIR. I generally don't go up
in huge
thermals/turbulence to practice spins, specifically
so I don't exceed Va and gust loads and 1/3 deflection,
etc.

Does a spin turn into a spiral on it's own sometimes
in turbulent air? Can AOAs be changed by turbulence
alone,
with no movement of controls? Oh, yes.

Start throwing in severe turbulence (which we love,
when it
suits us) and I think we are closer to the 'naked edge
of safety'
than is obvious.

The 2-32 accident in Hawaii was anectdotally in 'the
toilet bowl' there in turbulent air, too. Shear 10/20/30
knots in a few
seconds and 1/4 mile vertically or horizontally, and
our
still air analysis can't be done with a pristine slide-rule...
At 17:12 30 June 2005, Don Johnstone wrote:
If Stans analysis is right, and I can see no obvious
flaw, once the spiral dive/spin situation is met then
the chances of a sucessful recovery are slim. The 4DT
would not be unique in this. Perhaps a tail parachute
is an essential item of equipment.

Food for thought


At 15:18 30 June 2005, Bill wrote:

Stan Hall presented his analysis of the Nimbus-4DB
accident in Minden,
NV, 1999. Stan's analysis is scary, to say the least.

The article, Probing for the Smoking Gun, was reprinted
in the Soaring
Association of Canada's free flight, 2/04. Go to the
link below. Click
on free flight on the side bar. Go to free flight back
issues - 2004 -
issue 2. Down load the PDF file.

http://www.sac.ca/

Bill Feldbaumer 09






Mark J. Boyd

"Mike Schumann" wrote in message
hlink.net...
How long is ACL's runway?

I'm not sure but I've heard the figure of 2000 meters.

If you want to see the operation, go to this site and download a movie:
http://www.gliding4life.com/

Nistal Wloczysiak is a young genius with a camera.

Bill Daniels

Agreed, winch launching does require some length, and the more the better.

In the US, there are some soaring sites that reside on BLM patents.

1. You need to form or belong to a 501c(3) organization.
2. You need to find the appropriate patch of federal land and make formal
application.
3. There may be some property taxes and extended costs in acquiring access
roads.

See http://airsailing.org/
and
http://tucsonsoaring.org/
for examples.

For a startup operation or move, winch launching will clearly entertain
fewer NIMBY issues than an aerotow operation.

Frank Whiteley


Mike Schumann wrote:

There are certain points during an air tow, where there are also very
small
margins for error. I also believe that winch launches have major risk
advantages over air tow, particularly due to the elimination of the tow
plane from the risk equation.

Unfortunately, the field I fly out of is too short for winch launching to
be practical.

Mike Schumann

"Stefan" wrote in message
...
Bill Daniels wrote:

I am fighting a lonely battle to convince my fellow USA pilots that
winch launch is a perfectly normal way to launch gliders and not some
invention of
the devil.

Just three things to consider:

A which launch brings you to a certain altitude above the site. At some
places, this gives you enough options to find a thermal, at other sites,
it does not.

A winch operation doesn't mix well with other traffic. It's doable, if
everybody is willing.

And, most important: If done correctly, a winch launch is safe. But there
is an extremely small margin for errors. I love winch launches, but they
are dead serious, literally.

Stefan

Hi,

I suspect that it would be much easier for your typical club to train and
line up qualified winch operators than finding tow pilots.

Where I fly every student is required to start learning how to operate the
winch as soon as he or she goes solo.

As a result we have lots of winch drivers.

And I think it is a good idea anyway. You learn what a good launch looks
and feels like from the other side.

Ciao, MM
--
Marian Aldenhövel, Rosenhain 23, 53123 Bonn. +49 228 624013.
http://www.marian-aldenhoevel.de

At 13:30 01 July 2005, T O D D P A T T I S T wrote:
'Mike Schumann' wrote:

From what I have seen, I doubt that winch launches
require more people than
air tow. One of the biggest problems we have with
air tow is finding tow
pilots who have the necessary hours in type to meet
insurance requirements.

I agree, that is a problem.

I suspect that it would be much easier for your typical
club to train and
line up qualified winch operators than finding tow
pilots.

For a club, particularly one with some members already
trained and comfortable with winch launches, you are
probably right, but at least with aerotowing, you get
pilots
volunteering just because they like to fly, but don't
want
to pay for it. Is running the winch considered to
be a
desirable job similar to flying the tug?

It is for me. Escaping down the winch end is a definite
bonus with the nonsense that can occur at the flying
end. Heater and wall to wall Queen/Dire Straits. Wonderful
way to spend time when soaring is not possible.

T o d d P a t t i s t - 'WH' Ventus C
(Remove DONTSPAMME from address to email reply.)

T o d d P a t t i s t writes
Is running the winch considered to be a desirable job similar to flying
the tug?

Not by most. For our part, all post solo pilots are expected to train to
drive the winch and keep themselves current (except for the instructors,
who are obviously exempt), and we run a rota to ensure everybody takes a
fair turn at it.

In practice, this means that we each have to drive the winch for half a
day once a quarter, so it really isn't a huge burden.

--
Bill Gribble
http://www.scapegoatsanon.demon.co.uk
- Learn from the mistakes of others.
- You won't live long enough to make all of them yourself.

Our club has about 40 members, and about 5 tow pilots. Given that all 40
regular members could be trained as winch operators, my gut feeling is that
it would be a lot easier to get winch drivers than tow pilots on a daily
basis.

Mike Schumann

"T o d d P a t t i s t" wrote in message
...
"Mike Schumann" wrote:

From what I have seen, I doubt that winch launches require more people
than
air tow. One of the biggest problems we have with air tow is finding tow
pilots who have the necessary hours in type to meet insurance
requirements.

I agree, that is a problem.

I suspect that it would be much easier for your typical club to train and
line up qualified winch operators than finding tow pilots.

For a club, particularly one with some members already
trained and comfortable with winch launches, you are
probably right, but at least with aerotowing, you get pilots
volunteering just because they like to fly, but don't want
to pay for it. Is running the winch considered to be a
desirable job similar to flying the tug?

T o d d P a t t i s t - "WH" Ventus C
(Remove DONTSPAMME from address to email reply.)

T o d d P a t t i s t wrote:

"Mike Schumann" wrote:

From what I have seen, I doubt that winch launches require more people
than
air tow. One of the biggest problems we have with air tow is finding tow
pilots who have the necessary hours in type to meet insurance
requirements.

I agree, that is a problem.

1. Because some clubs are usually very conservative about who they let fly
the tow plane, and maybe wisely so, it's a very significant problem to
screen and indoctrinate tow pilots. More so if you insist that they also
have glider time first. We just re-engined and upgraded our Pawnee and
added a new prop. Not cheap as there weren't any significant member
contributed efforts. In the 2400+ hours on the prior mill, there were few
issues, no cracked jugs, and one sticky valve. We did have a main journal
problem when we first bought it, but worked that out early on.

I suspect that it would be much easier for your typical club to train and
line up qualified winch operators than finding tow pilots.

For a club, particularly one with some members already
trained and comfortable with winch launches, you are
probably right, but at least with aerotowing, you get pilots
volunteering just because they like to fly, but don't want
to pay for it. Is running the winch considered to be a
desirable job similar to flying the tug?

2. I know of one operation that recently turned down a young sprog for
towing. He moved to another location and put a Pawnee on its nose in short
order. FWIW, the wooden Hoffman four-bladed prop saved the engine parts.
Volunteers are one thing, quality volunteers are something else. Not too
many younger pilots are working on tail dragger time. Most middle aged
pilots I encounter have 10-15 hours in tail dragger, no high power
endorsement, and may or may not have a commercial.

We have recently trained a few more winch drivers. If we had a better
winch, we'd get a few more. There are some neat things about driving a
winch, especially when trying to get it 'right' each time. A good winch at
the right site is an attractive proposition. Personally I like listening
to the Larks between launches, or spotting wild life. If I'm bored, I'll
also drag the wire also, which really gets it down to two people to manage
the operation, the winch/retrieve driver and the launch marshall/captain.
Actually, if I drive both winch and wire vehicle, I can get higher launch
rates most of the time. There are a couple of drivers that can keep the
wire retrieve moving fast enough to beat what I can do solo. That way we
can keep two training gliders in the air most of the time on a non-soaring
day with a single drum.

Frank

F.L. Whiteley wrote:
T o d d P a t t i s t wrote:


"Mike Schumann" wrote:

From what I have seen, I doubt that winch launches require more people

than
air tow. One of the biggest problems we have with air tow is finding tow
pilots who have the necessary hours in type to meet insurance
requirements.

I agree, that is a problem.


1. Because some clubs are usually very conservative about who they let fly
the tow plane, and maybe wisely so, it's a very significant problem to
screen and indoctrinate tow pilots. More so if you insist that they also
have glider time first. We just re-engined and upgraded our Pawnee and
added a new prop. Not cheap as there weren't any significant member
contributed efforts. In the 2400+ hours on the prior mill, there were few
issues, no cracked jugs, and one sticky valve. We did have a main journal
problem when we first bought it, but worked that out early on.


I suspect that it would be much easier for your typical club to train and
line up qualified winch operators than finding tow pilots.

For a club, particularly one with some members already
trained and comfortable with winch launches, you are
probably right, but at least with aerotowing, you get pilots
volunteering just because they like to fly, but don't want
to pay for it. Is running the winch considered to be a
desirable job similar to flying the tug?


2. I know of one operation that recently turned down a young sprog for
towing. He moved to another location and put a Pawnee on its nose in short
order. FWIW, the wooden Hoffman four-bladed prop saved the engine parts.
Volunteers are one thing, quality volunteers are something else. Not too
many younger pilots are working on tail dragger time. Most middle aged
pilots I encounter have 10-15 hours in tail dragger, no high power
endorsement, and may or may not have a commercial.

We have recently trained a few more winch drivers. If we had a better
winch, we'd get a few more. There are some neat things about driving a
winch, especially when trying to get it 'right' each time. A good winch at
the right site is an attractive proposition. Personally I like listening
to the Larks between launches, or spotting wild life. If I'm bored, I'll
also drag the wire also, which really gets it down to two people to manage
the operation, the winch/retrieve driver and the launch marshall/captain.
Actually, if I drive both winch and wire vehicle, I can get higher launch
rates most of the time. There are a couple of drivers that can keep the
wire retrieve moving fast enough to beat what I can do solo. That way we
can keep two training gliders in the air most of the time on a non-soaring
day with a single drum.

Frank

Might mention that in thirty or so years of winch driving, most line
breaks as I recall happen mostly on initial acceleration and next most
often over the winch when we hit a thermal. I know it’s
counter-intuitive, but the pull-up seems to generate the fewest breaks.
Except for the fact that this is where most instructors of my
observation anyway like to pull the knob on you. This is tricky, since
at this point with maybe 500 ft in hand, you actually have too many
choices -- 360, 180 or straight ahead. So be forewarned, and as usual,
after making a plan stick with it, or do as the IP has previously
briefed you. Most points for that one, no sense getting creative with
Mr. Back Seat.

And for us Schweizer drivers, remember we’re going to have the stick
really honked back on the edge of an elevator stall to compensate for
the download caused by that pesky nose hook. So our nose up excursion is
genuinely going to raise the dirt, but the horizon and airspeed will
return just as they should, especially if you get that stick on the
front stop pronto. The only time this happened to me was over the winch
in a 2-33. After recovery, I thermaled away, saved the day (but not my
shorts).

One last thing, be prepared for winch engine failure. If plenty of line
has been spliced in ahead of the chute, there shouldn’t be too much
chance of a canopy or wing drape. But anyway, I think this is where that
happens mostly. Spectra is so light, I worry that even with a long
snapper, the chute may float out in front of you much longer than it
would otherwise.

Bob