Almost perfect payout winch launch.

[WAVEGURU]

http://www.youtube.com/watch?v=f5WDiHHgua8

Boggs

[WAVEGURU]

If we had slowed down a little, and tightened up the tension a bit, we could have added a couple hundred more feet? What do you think about the "Payout Winch"?

http://www.youtube.com/watch?v=f5WDiHHgua8

Boggs

[Tony[_5_]]

I think I want one!

[WAVEGURU]

Here's the payout launch from the glider end. The launch starts at about 3 minutes in.

http://www.youtube.com/watch?v=M3ga-XJ_cdw

Boggs

[Bill D]

On Monday, May 6, 2013 10:46:40 PM UTC-6, Waveguru wrote:
> If we had slowed down a little, and tightened up the tension a bit, we could have added a couple hundred more feet? What do you think about the "Payout Winch"?
>
>
>
> http://www.youtube.com/watch?v=f5WDiHHgua8
>
>
>
> Boggs

I think if you had a real winch and learned how to use it safely, you'd get a lot higher.

[Don Johnstone[_4_]]

At 14:07 07 May 2013, Bill D wrote:
>On Monday, May 6, 2013 10:46:40 PM UTC-6, Waveguru wrote:
>> If we had slowed down a little, and tightened up the tension a bit, we
>could have added a couple hundred more feet? What do you think about the
>"Payout Winch"?
>>
>>
>>
>> http://www.youtube.com/watch?v=f5WDiHHgua8
>>
>>
>>
>> Boggs
>
>I think if you had a real winch and learned how to use it safely, you'd
get
>a lot higher.

I think that is the most complicated and potentially dangerous method of
winch launching that I have ever seen.
I am completely sold on winching, having made over 10000 launches on many
types of winch over the years. I have to say that some of the winches I
have used, including a converted Rover car have been less than ideal, and
perhaps a little unwise, but this has to be the most foolhardy version I
have ever come across.
I would be the first to admit that there are several potential hazards in
winch launching but a system as complex as that is an accident just waiting
to happen. Please stop it guys, get a proper conventional winch if that is
the way you want to go, or go to a straight forward auto tow.

[Tony[_5_]]

On Tuesday, May 7, 2013 11:02:14 AM UTC-5, Don Johnstone wrote:
> At 14:07 07 May 2013, Bill D wrote: >On Monday, May 6, 2013 10:46:40 PM UTC-6, Waveguru wrote: >> If we had slowed down a little, and tightened up the tension a bit, we >could have added a couple hundred more feet? What do you think about the >"Payout Winch"? >> >> >> >> http://www.youtube.com/watch?v=f5WDiHHgua8 >> >> >> >> Boggs > >I think if you had a real winch and learned how to use it safely, you'd get >a lot higher. I think that is the most complicated and potentially dangerous method of winch launching that I have ever seen. I am completely sold on winching, having made over 10000 launches on many types of winch over the years. I have to say that some of the winches I have used, including a converted Rover car have been less than ideal, and perhaps a little unwise, but this has to be the most foolhardy version I have ever come across. I would be the first to admit that there are several potential hazards in winch launching but a system as complex as that is an accident just waiting to happen. Please stop it guys, get a proper conventional winch if that is the way you want to go, or go to a straight forward auto tow.

i'm interested to hear more about your opinion. Gary's payout winch basically has built in tension control in that if, say, the glider hits a thermal on the climb, instead of the line loading up and breaking, it just lets out more line so you get to use that thermal to climb higher.

hang glider guys use payout winches a lot to launch in the flat lands.

[Greg Arnold]

On 5/7/2013 9:23 AM, Tony wrote:
> On Tuesday, May 7, 2013 11:02:14 AM UTC-5, Don Johnstone wrote:
>> At 14:07 07 May 2013, Bill D wrote: >On Monday, May 6, 2013 10:46:40 PM UTC-6, Waveguru wrote: >> If we had slowed down a little, and tightened up the tension a bit, we >could have added a couple hundred more feet? What do you think about the >"Payout Winch"? >> >> >> >> http://www.youtube.com/watch?v=f5WDiHHgua8 >> >> >> >> Boggs > >I think if you had a real winch and learned how to use it safely, you'd get >a lot higher. I think that is the most complicated and potentially dangerous method of winch launching that I have ever seen. I am completely sold on winching, having made over 10000 launches on many types of winch over the years. I have to say that some of the winches I have used, including a converted Rover car have been less than ideal, and perhaps a little unwise, but this has to be the most foolhardy version I have ever come across. I would be the first to admit that there are several potential hazards in winch launching but a system as complex as that is an accident ju
st waiting to happen. Please stop it guys, get a proper conventional winch if that is the way you want to go, or go to a straight forward auto tow.
>
> i'm interested to hear more about your opinion. Gary's payout winch basically has built in tension control in that if, say, the glider hits a thermal on the climb, instead of the line loading up and breaking, it just lets out more line so you get to use that thermal to climb higher.
>
> hang glider guys use payout winches a lot to launch in the flat lands.
>

Their stall speed is a lot slower. I am not sure that I understand how
you could use a payout winch with a glider unless the truck is driving
at a tremendous speed.

[GM]

On Tuesday, May 7, 2013 12:46:40 AM UTC-4, Waveguru wrote:
> If we had slowed down a little, and tightened up the tension a bit, we could have added a couple hundred more feet? What do you think about the "Payout Winch"?
>
>
>
> http://www.youtube.com/watch?v=f5WDiHHgua8
>
>
>
> Boggs

How long is the runway? With a well-built conventional winch, you can typically achieve a release height of 45-50% of the line length.

Uli
Winchmeister of the Carolina Soaring Assoc.

[Morgan[_2_]]

My limited experience with launching a hang glider via a payout winch was that we only got about 1/3 of the runway length and that was with good headwind. About 900ft on a 2800ft or so runway.

Most issues and accidents with hang gliders and payout winches happen due to "lockout" when you get turned and can't recover. Without control surfaces it gets bad in a hurry.

Vehicle speeds were about the same as with a static line. 20-30mph depending on the headwind.

The launch is crazy exciting though. You're laying in your harness, on the back of a pickup racing down a runway/road. At 35mph airspeed or so (I don't remember specifics) you hit a release and pop off the truck instantly to about 20 ft, then slowly start winding out. Just like a glider ground launch, once high enough you maximize your climb angle.

When you hit thermals, the tension was pretty constant so you just surged higher as the drum let more line out.

We are working on getting our glider winch going. I will let you know how I think they compare once we have our ducks in a row and are launching with it.

Morgan

On Tuesday, May 7, 2013 9:52:21 AM UTC-7, GM wrote:
> On Tuesday, May 7, 2013 12:46:40 AM UTC-4, Waveguru wrote:
>
> > If we had slowed down a little, and tightened up the tension a bit, we could have added a couple hundred more feet? What do you think about the "Payout Winch"?
>
> >
>
> >
>
> >
>
> > http://www.youtube.com/watch?v=f5WDiHHgua8
>
> >
>
> >
>
> >
>
> > Boggs
>
>
>
> How long is the runway? With a well-built conventional winch, you can typically achieve a release height of 45-50% of the line length.
>
>
>
> Uli
>
> Winchmeister of the Carolina Soaring Assoc.

[Bill D]

On Tuesday, May 7, 2013 10:26:31 AM UTC-6, Greg Arnold wrote:
> On 5/7/2013 9:23 AM, Tony wrote:
>
> > On Tuesday, May 7, 2013 11:02:14 AM UTC-5, Don Johnstone wrote:
>
> >> At 14:07 07 May 2013, Bill D wrote: >On Monday, May 6, 2013 10:46:40 PM UTC-6, Waveguru wrote: >> If we had slowed down a little, and tightened up the tension a bit, we >could have added a couple hundred more feet? What do you think about the >"Payout Winch"? >> >> >> >> http://www.youtube.com/watch?v=f5WDiHHgua8 >> >> >> >> Boggs > >I think if you had a real winch and learned how to use it safely, you'd get >a lot higher. I think that is the most complicated and potentially dangerous method of winch launching that I have ever seen. I am completely sold on winching, having made over 10000 launches on many types of winch over the years. I have to say that some of the winches I have used, including a converted Rover car have been less than ideal, and perhaps a little unwise, but this has to be the most foolhardy version I have ever come across. I would be the first to admit that there are several potential hazards in winch launching but a system as complex as that is an accident ju
>
> st waiting to happen. Please stop it guys, get a proper conventional winch if that is the way you want to go, or go to a straight forward auto tow.
>
> >
>
> > i'm interested to hear more about your opinion. Gary's payout winch basically has built in tension control in that if, say, the glider hits a thermal on the climb, instead of the line loading up and breaking, it just lets out more line so you get to use that thermal to climb higher.
>
> >
>
> > hang glider guys use payout winches a lot to launch in the flat lands.
>
> >
>
>
>
> Their stall speed is a lot slower. I am not sure that I understand how
>
> you could use a payout winch with a glider unless the truck is driving
>
> at a tremendous speed.

That's the basic problem. Payout winches are less a winch launch than auto-tow with a variable rope length and a built-in rope management system. In a traditional auto-tow, you must set aside enough distance for the tow vehicle to accelerate to tow speed and then stop at the far end plus the rope length - what's left is used for the launch.

The payout scheme helps with the acceleration phase in that the tow vehicle can accelerate while paying out rope so the acceleration distance and rope length requirements overlap then at the departure end, the tow vehicle can stop as fast as possible while the on-board winch pulls in the slack rope. All this is much easier with a slow hang glider.

The takeoff roll seemed slow and the climb angle seemed shallow similar to auto-tow indicating the height achieved was lower than traditional winches where the takeoff roll is very short and the climb angle is around 45 degrees.

Low achieved height can be a safety issue. I call it the "end trap" where the glider reaches the departure end without enough height to safely turn back and nowhere to land ahead. This doesn't mean I think what Gary is doing is unsafe. That depends on the options available to the pilot in the event of a launch failure.

[Bill D]

On Tuesday, May 7, 2013 11:07:58 AM UTC-6, Morgan wrote:

> We are working on getting our glider winch going. I will let you know how I think they compare once we have our ducks in a row and are launching with it.

> Morgan

As part of "getting your ducks in a row" please plan on some formal winch training.

[Don Johnstone[_4_]]

At 17:27 07 May 2013, Bill D wrote:
>On Tuesday, May 7, 2013 11:07:58 AM UTC-6, Morgan wrote:
>
>> We are working on getting our glider winch going. I will let you know
>how I think they compare once we have our ducks in a row and are
launching
>with it.
>
>> Morgan
>
>As part of "getting your ducks in a row" please plan on some formal winch
>training.

AMEN to that, not only have I been on the receiving end of 10000 lauches
but I have probably done even more as a winch driver.
I have driven converted WW2 balloon wiches, converted bus, rover car and
combine harvester winches and others up to the Munster Van Gelder and
Skylaunch. They are all inherently hazardous but with properly trained
drivers and correct procedures the risks can be minimised. The key is the
simpler the better.
A few dollars spent in getting the expertise and proper training will save
money and more importantly lives.
Even with the expertise we have over here we still get caught out from time
to time and we are still learning, well some of us are.

[Bart[_4_]]

On May 7, 10:27*am, Bill D > wrote:
> > We are working on getting our glider winch going. *I will let you know how I think they compare once we have our ducks in a row and are launching with it.
> As part of "getting your ducks in a row" please plan on some formal winch training.

We have several members (including instructors) with winch launching
experience AND are planning on bringing in a winch-current CFI-G.

Bart

[Bill T]

Thanks Bill!
After many auto tow launches, I just completed the winch course with AGCSC at Jucumba CA and will add these documents to my reference library.

Bill T

[Bill D]

On Tuesday, May 7, 2013 8:42:15 PM UTC-6, Bill T wrote:
> Thanks Bill!
>
> After many auto tow launches, I just completed the winch course with AGCSC at Jucumba CA and will add these documents to my reference library.
>
>
>
> Bill T

Apparently I linked to the PPT twice (funny how there URL's start to look alike) Here's the one I intended to link to.
https://dl.dropboxusercontent.com/u/79580374/Winch%20operations.pdf

[Nigel Pocock[_2_]]

A few safety issues safety issues.
The strop. i.e. the rope between the rings and the parachute appears to be
very flexible. If the glider roles forward when taking up slack and overuns
the cable it can easily get caught in the wheel box meaning the glider
cannot release at the top of the launch. Encasing this bit of rope in a
plastic tube (garden hose) should aleviate the problem.

This strop should also be quite long. We were using a short one at Lasham
for years until we had a winch failure just as the glider left the ground.
The chute opened and draped itself over the cockpit when the glider was a a
few feet in the air. A wonderful cure for constipation.

The payout winch does not appear to have any form of guilotine.
If the glider cannot release you need to have some way of freeing it from
the winch so it has a chance to make a landing.

The BGA advice on winch launching can be found here_
http://www.gliding.co.uk/bgainfo/safety/safewinchlaunching.htm

[WAVEGURU]

Here's another video of our payout winch in operation at the Alvord Desert:

http://www.youtube.com/watch?v=oP8bVgG8xJc

Boggs

[Brian[_1_]]

Just a few notes on Gary's Payout winch System.

I have done Winch Launches, Auto Tows and have had the privilege of launching with Gary's payout winch.

It has been a few years since I have launched with it, and it appears Gary has perfected the technique and winch some since I have used it. He has been using the system for quite a few years now. He was using an electric rewinder and less payout at the start of the tow when I did it. But he may have modified the technique from what I am going to describe.

From the glider end when I was towing with it seems like a normal Auto Tow to start with, However once nearing the top of the climb for the rope he had payed out, he would start paying out more rope. This was easy to determine from the glider end and we just lowered the nose to maintain airspeed while he payed out more rope. He would then increase the tension and we would go back into a steep climb.

I was doing it on a very long dry lake, but was getting 2200 feet or more on a tow. I am sure we could have gone higher if we wanted to. It is a bit different in that it is a stepped climb, as opposed to the constant climb you get with an auto tow or winch launch, but still very easy do.

Some advantages of the system are that...
it probably cost 1/10 what a winch would cost
It is entirely portable, no equipment is left on the field or needs to be setup
It retrieves the rope and resets almost as quickly as you can return to the staging area.

I am sure he has a guillotine in the system, I probably wouldn't have towed with it if he didn't.

Since I haven't used it on a shorter runway, I can't comment on how it compares to an auto tow for launch height.

The initial climb is identical to an auto tow and will get the glider high enough for a 180 or even a 360 degree turn back to the runway typically before he starts paying out line.

Thanks Gary, I enjoyed towing behind your system, Perhaps will do it again someday.

Brian
CFIIG/ASEL

[WAVEGURU]

I replaced the electric retrieve motor with a 6hp Honda. The electric just didn't have enough poop to pull the chute back well. We've been using this payout winch for years now, and it works very well. It is simple and safe.. We are continuing to improve our technique tho. We used to start with the brake set, and accelerate the truck and glider together. But we changed that to accelerating the truck with the brake off, and the line paying out, and after the truck is up to speed, we then set the brake to the proper tension. This worked much better. The glider gets up to flying speed, and off the ground, much quicker, and therefor has control sooner, and gets higher.
The payout winch has several advantages over a conventional winch or auto tow in that when the glider hits lift, the line simply pays out faster. We almost never have any rope breaks because the tension on the brake is never supposed to be set above the breaking strength of the weak link.

It's too bad that some people, that have no idea what we are doing, immediately label it as bad and dangerous. It must be nice to be such a know it all, eh? I figured that it would bring out some of the idiots here when I posted the video. It's just so easy to be a dick online these days, isn't it?

Boggs

[Bill D]

On Wednesday, May 8, 2013 8:53:23 AM UTC-6, Waveguru wrote:
> I replaced the electric retrieve motor with a 6hp Honda. The electric just didn't have enough poop to pull the chute back well. We've been using this payout winch for years now, and it works very well. It is simple and safe. We are continuing to improve our technique tho. We used to start with the brake set, and accelerate the truck and glider together. But we changed that to accelerating the truck with the brake off, and the line paying out, and after the truck is up to speed, we then set the brake to the proper tension. This worked much better. The glider gets up to flying speed, and off the ground, much quicker, and therefor has control sooner, and gets higher.
>
> The payout winch has several advantages over a conventional winch or auto tow in that when the glider hits lift, the line simply pays out faster. We almost never have any rope breaks because the tension on the brake is never supposed to be set above the breaking strength of the weak link.
>
>
>
> It's too bad that some people, that have no idea what we are doing, immediately label it as bad and dangerous. It must be nice to be such a know it all, eh? I figured that it would bring out some of the idiots here when I posted the video. It's just so easy to be a dick online these days, isn't it?
>
>
>
> Boggs

Gary,

How are you measuring rope tension?

[WAVEGURU]

>How are you measuring rope tension?>

All we have is a pressure gauge on the hydraulics of the disc brake.
A tentiometer would be better, but we are trying to KISS.

Boggs

[Bob Kuykendall]

Don, I can respect that you have reservations about the method in
question. But it would be a lot more constructive if you'd provide
specific examples of why the method in question is inadvisable, and
are prepared to tell us how it can go wrong. Otherwise, when you call
people "foolhardy" and tell them flat out to "stop it," you mostly
just come across as a disagreeable curmudgeon.

Furthermore, I think that anybody who has used a winch but decries the
"complexity" of other ground launch methods does not really understand
how complex a good winch is, and how many points of failure there
really are.

Thanks, Bob K.

On May 7, 9:02*am, Don Johnstone > wrote:

> I think that is the most complicated and potentially dangerous method of
> winch launching that I have ever seen.
> I am completely sold on winching, having made over 10000 launches on many
> types of winch over the years. I have to say that some of the winches I
> have used, including a converted Rover car have been less than ideal, and
> perhaps a little unwise, but this has to be the most foolhardy version I
> have ever come across.
> I would be the first to admit that there are several potential hazards in
> winch launching but a system as complex as that is an accident just waiting
> to happen. Please stop it guys, get a proper conventional winch if that is
> the way you want to go, or go to a straight forward auto tow.

[Don Johnstone[_4_]]

At 02:45 10 May 2013, Bob Kuykendall wrote:
>Don, I can respect that you have reservations about the method in
>question. But it would be a lot more constructive if you'd provide
>specific examples of why the method in question is inadvisable, and
>are prepared to tell us how it can go wrong. Otherwise, when you call
>people "foolhardy" and tell them flat out to "stop it," you mostly
>just come across as a disagreeable curmudgeon.
>
>Furthermore, I think that anybody who has used a winch but decries the
>"complexity" of other ground launch methods does not really understand
>how complex a good winch is, and how many points of failure there
>really are.
>
>Thanks, Bob K.
>
Fair point Bob

If we consider the simplest winch where the engine is connected to a
transmission via a gearbox of some kind. In this type of winch the driver
is seated and controls the throttle to control the speed of cable
retrieval.

What can go wrong? Three basic things as regards the operation of the
winch.

1. A break in the cable
2. A mechanical failure of the winch
3. Winch driver error or incapitation.

All of these eventualities are dealt with by practising launch failures or
launch abandonment. As far as mechanical failure of the winch is concerned
there are only two main components to fail, the engine (Uncommon but not
unknown) and the transmission. In all cases the winch driver is seated with
a good view of what is going on and can react to problems as they arise, in
particular using the guillotine if required in a timely manner.
The first winch I drove was of this time, a 3 litre petrol engine driving a
winch drum through a conventional 4 speed gearbox.
The most complex winch I have driven was a Munster Van Gelder winch with a
ginormous turbo diesel engine providing power for 6 seperate drums through
a torque converter. The engine control, transmission and drum select
functions were complex but once the transmission was connected to the power
module the principle was the same as for the simple Eagle winch described
above. Failure of either winch by mechanical failure of the
engine/transmission during launching was very rare. The MVG winch was
however less reliable in that faults within the more complex system meant
that it was U/s far more often than the simple winch, and took longer to
fix. Having said that the components making up the MVG winch were of top
quality and specifcally designed or adapted to provide the proper function,
it was just that there were more components to go wrong. In both cases the
winch was fixed, the driver had control and could see the glider at all
times and take the appropriate action.

The payout winch provides an additional level of complexity and reduces the
ability of the operator to control the launch. Some aspects of the launch
rely totally on unsupervised mechanical/electrical operations, the payout
part of the operation. The system is really a combination of two launch
methods, an auto tow and a winch launch and is just one level of complexity
too much when the proven technology already exists to provide a good
launch without introducing more complex procedures, especially ones which
rely totally on a mechanical/electrical function with no human input or
control.
During an auto tow the driver is facing the wrong way or is peering over
his shoulder so his ability to offer proper control or reaction to an
emergency is compromised, add to that the fact that cable payout is taking
place while the vehicle is moving in the opposite direction and while the
glider is on the cable and the things that can go wrong increases
exponentially.
Winch launching has hazards, no denying that, some of them completely
outside the control of the winch operator. A fixed winch with the operator
in a good position to observe the launch provides the best and safest
solution.
I have of course assumed that the launch is contolled by one person, the
implications of having two people controlling a launch (or not) are too
horrible to consider. I cannot see that anyone would be daft enough to do
that.
I can see that the payout winch launch is dangerous, I have said so. I may
or may not be believed. Like all human activity it will continue until
something goes wrong. If god forbid someone is killed then many people will
pipe up saying they knew it was dangerous, I am just saying it in the vain
hope that people will look at what they are doing and see that however
attractive it might seem it is not woth the risks, before it ends in
tears.
Bottom line, a vehicle driving down a runway with a glider on tow and a
winch paying out cable while the launch is taking place is not something
that I would ever be involved in. Been gliding and winching for 50 years
and would like to continue for a few more years.

[son_of_flubber]

On Friday, May 10, 2013 8:11:07 AM UTC-4, Don Johnstone wrote:
>The system is really a combination of two launch
> methods, an auto tow and a winch launch and is just one level of complexity
> too much when the proven technology already exists to provide a good
> launch without introducing more complex procedures, especially ones which
> rely totally on a mechanical/electrical function with no human input or
> control.

The opposite of Don, I have ZERO experience with winch launches, so I look at the approach with a completely naive perspective. If you think that my inexperience means that I should not comment on what I see, then stop reading now. I have no opinion, but I have a few questions.

>The system is really a combination of two launch
> methods, an auto tow and a winch launch...

From my naive point of view, this launch starts out as an autotow. How is this phase of the launch different than a traditional autotow? Waveguru depends on the clutch on the payout winch to modulate the tension on the line.. What are the failure modes for this clutch and what are the consequences? Would it be safer to lock the clutch and start the tow with the line under tension (rather than the truck taking the "running start"? Is a traditional autotow more failure prone and/or dangerous than a winch launch?

Once the autotow phase of the launch is completed, the glider is several hundred feet in the air. All of the bad things that can happen with a winch launch close to the ground have been sidestepped.

>(waveguru's method introduces) more complex procedures, especially ones which
> rely totally on a mechanical/electrical function with no human input or
> control.

Again, naively, in a rapidly developing situation, whenever "time is of the essence" and extremely short, I would generally trust a properly designed and constructed mechanical or electrical mechanism to effect the correct response much more than I would trust a human operator. Is there a reason why a human operator would be more trustworthy in this situation?

Okay. I do have a few observations/opinions:

1)That the payout winch payouts more line and keeps line tension constant when the glider hits lift seems an inherent advantage of this approach when compared to a traditional winch launch.

2)Don's suggestion that traditional winch launching is proven and that there is therefore no reason to experiment with payout winching misses the point. In a country where beefy pickup trucks are common, the start-up costs for payout winching are much lower than traditional winching. Secondly, far fewer humans need to be deployed and coordinated to run a payout winch. The relevant question is "Which is better to use on a dry lake bed, 1)autotow with payout winch or 2)traditional autotow? What are the tradeoffs?

[[email protected]]

On Friday, May 10, 2013 7:11:07 AM UTC-5, Don Johnstone wrote:
> At 02:45 10 May 2013, Bob Kuykendall wrote:
>
> >Don, I can respect that you have reservations about the method in
>
> >question. But it would be a lot more constructive if you'd provide
>
> >specific examples of why the method in question is inadvisable, and
>
> >are prepared to tell us how it can go wrong. Otherwise, when you call
>
> >people "foolhardy" and tell them flat out to "stop it," you mostly
>
> >just come across as a disagreeable curmudgeon.
>
> >
>
> >Furthermore, I think that anybody who has used a winch but decries the
>
> >"complexity" of other ground launch methods does not really understand
>
> >how complex a good winch is, and how many points of failure there
>
> >really are.
>
> >
>
> >Thanks, Bob K.
>
> >
>
> Fair point Bob
>
>
>
> If we consider the simplest winch where the engine is connected to a
>
> transmission via a gearbox of some kind. In this type of winch the driver
>
> is seated and controls the throttle to control the speed of cable
>
> retrieval.
>
>
>
> What can go wrong? Three basic things as regards the operation of the
>
> winch.
>
>
>
> 1. A break in the cable
>
> 2. A mechanical failure of the winch
>
> 3. Winch driver error or incapitation.
>
>
>
> All of these eventualities are dealt with by practising launch failures or
>
> launch abandonment. As far as mechanical failure of the winch is concerned
>
> there are only two main components to fail, the engine (Uncommon but not
>
> unknown) and the transmission. In all cases the winch driver is seated with
>
> a good view of what is going on and can react to problems as they arise, in
>
> particular using the guillotine if required in a timely manner.
>
> The first winch I drove was of this time, a 3 litre petrol engine driving a
>
> winch drum through a conventional 4 speed gearbox.
>
> The most complex winch I have driven was a Munster Van Gelder winch with a
>
> ginormous turbo diesel engine providing power for 6 seperate drums through
>
> a torque converter. The engine control, transmission and drum select
>
> functions were complex but once the transmission was connected to the power
>
> module the principle was the same as for the simple Eagle winch described
>
> above. Failure of either winch by mechanical failure of the
>
> engine/transmission during launching was very rare. The MVG winch was
>
> however less reliable in that faults within the more complex system meant
>
> that it was U/s far more often than the simple winch, and took longer to
>
> fix. Having said that the components making up the MVG winch were of top
>
> quality and specifcally designed or adapted to provide the proper function,
>
> it was just that there were more components to go wrong. In both cases the
>
> winch was fixed, the driver had control and could see the glider at all
>
> times and take the appropriate action.
>
>
>
> The payout winch provides an additional level of complexity and reduces the
>
> ability of the operator to control the launch. Some aspects of the launch
>
> rely totally on unsupervised mechanical/electrical operations, the payout
>
> part of the operation. The system is really a combination of two launch
>
> methods, an auto tow and a winch launch and is just one level of complexity
>
> too much when the proven technology already exists to provide a good
>
> launch without introducing more complex procedures, especially ones which
>
> rely totally on a mechanical/electrical function with no human input or
>
> control.
>
> During an auto tow the driver is facing the wrong way or is peering over
>
> his shoulder so his ability to offer proper control or reaction to an
>
> emergency is compromised, add to that the fact that cable payout is taking
>
> place while the vehicle is moving in the opposite direction and while the
>
> glider is on the cable and the things that can go wrong increases
>
> exponentially.
>
> Winch launching has hazards, no denying that, some of them completely
>
> outside the control of the winch operator. A fixed winch with the operator
>
> in a good position to observe the launch provides the best and safest
>
> solution.
>
> I have of course assumed that the launch is contolled by one person, the
>
> implications of having two people controlling a launch (or not) are too
>
> horrible to consider. I cannot see that anyone would be daft enough to do
>
> that.
>
> I can see that the payout winch launch is dangerous, I have said so. I may
>
> or may not be believed. Like all human activity it will continue until
>
> something goes wrong. If god forbid someone is killed then many people will
>
> pipe up saying they knew it was dangerous, I am just saying it in the vain
>
> hope that people will look at what they are doing and see that however
>
> attractive it might seem it is not woth the risks, before it ends in
>
> tears.
>
> Bottom line, a vehicle driving down a runway with a glider on tow and a
>
> winch paying out cable while the launch is taking place is not something
>
> that I would ever be involved in. Been gliding and winching for 50 years
>
> and would like to continue for a few more years.

Interesting dichotomy between the European and American viewpoint. Being trained on the winch learning to soar and having 3,000 winch launches done from the winch driver seat I tend to agree with Don. To add to his points: A winch launch (1 km cable length) gets you to 1,300 - 1,600' altitude safely and cheaply. You learn to climb away from that altitude even in poor weather, or you land and do it again. I just don't see the need for winching to 2-3k feet in a glider and if you disagree you probably have some thermaling to learn. I witnessed a hang glider accident with a payout winch on a pick-up truck and it was not pretty. We asked the hang glider group to not fly from our site any more...
Herb

[Bill D]

On Friday, May 10, 2013 7:21:55 AM UTC-6, wrote:
I just don't see the need for winching to 2-3k feet in a glider and if you disagree you probably have some thermaling to learn.
>
> Herb

Depends on the purpose of the flight. Early morning or late evening student training flights can benefit from higher launches.

[Bill D]

On Friday, May 10, 2013 7:19:27 AM UTC-6, son_of_flubber wrote:

> Okay. I do have a few observations/opinions:

> 1)That the payout winch payouts more line and keeps line tension constant when the glider hits lift seems an inherent advantage of this approach when compared to a traditional winch launch.

If a glider can hit at thermal, it can also hit sink. A conventional winch can call on huge reserves of power to pull the glider through sink but the payout winch is more limited in this ability.


> 2)Don's suggestion that traditional winch launching is proven and that there is therefore no reason to experiment with payout winching misses the point. In a country where beefy pickup trucks are common, the start-up costs for payout winching are much lower than traditional winching. Secondly, far fewer humans need to be deployed and coordinated to run a payout winch. The relevant question is "Which is better to use on a dry lake bed, 1)autotow with payout winch or 2)traditional autotow? What are the tradeoffs?

If space is essentially unlimited, as is sometimes the case on dry lakes, a traditional auto-tow is both simpler and safer. When space is limited, as on a runway, conventional winches will prove more efficient and, I think, safer. I've run the numbers several times and a conventional winch will always get you higher than a payout winch given a limited runway length. Don's point that a conventional winch is simpler is valid. In the extreme it only requires as many people as aero tow.

The conventional winch is a very mature technology with an enormous body of safety data. In the 7 or 8 decades of its history, the potentially dangerous aspects have been found and procedures developed to minimize them. Germans manage 180,000 winch launches or so between accidents where we have an aero tow accident roughly every 26,000 tows. Unfortunately, the Brits suffer a winch accident every 16,000 launches which calls their methods into question. No one knows what the accident rate with payout winches would be, but until everyone climbs the learning curve, I suspect it won't be stellar.

[Peter F[_2_]]

Don is right in thinking that there should be one person in charge of the
launch.

Unfortunately the person he thinks should be in charge is at the wrong end
of the cable.

With high powered winches driving through auto transmission (Skylaunch) the
pilot has little control over the speed of launch, he just has to accept
what the winch driver gives him.

With a launch system that provides cable tension, by whatever control
system
is used, the speed is under control of the pilot. Ease off on the stick
speed increases, ease back speed reduces, just like in normal flight.

I've launched on both in the UK & I know which I prefer

PF

At 13:52 10 May 2013, Bill D wrote:
>On Friday, May 10, 2013 7:21:55 AM UTC-6, wrote:
> I just don't see the need for winching to 2-3k feet in a glider and if
>you disagree you probably have some thermaling to learn.
>>
>> Herb
>
>Depends on the purpose of the flight. Early morning or late evening
>student training flights can benefit from higher launches.
>
>

[Bill D]

On Friday, May 10, 2013 8:42:39 AM UTC-6, Peter F wrote:
> Don is right in thinking that there should be one person in charge of the launch.

> Unfortunately the person he thinks should be in charge is at the wrong end of the cable.

You are correct, it's much better to have the pilot control airspeed with pitch. However, for this to happen, the winch has to control rope tension accurately as a percentage of glider weight. Control is divided where pilot controls airspeed and winch controls tension. This means Gary is right to control rope tension with his payout winch.

[WAVEGURU]

One of the most important things we teach all glider pilots is that it is there responsibility to keep themselves safe at all times, no matter what happens with the launch vehicle, be it winch, or aerotow. At no time should the pilot put himself in a position that he can't recover from in the event of a launch failure. That means you don't climb until you have sufficient airspeed, you limit the climb angle below 200', you abort the tow with enough runway to land straight ahead if you aren't climbing. No matter what happens to the launch vehicle, it is up to the glider pilot to keep himself in a safe place at all times, with safe options. Maybe you guys train differently? Even if my truck blew up, it just means the glider doesn't get as high as he would have. If the brake fails, it just means the glider doesn't get as high as he might. If my truck fails to get up to speed, the truck goes to the left and the glider lands straight ahead. Our payout system has been very dependable, but we train for launch failures just the same. Contrary to your assumptions, our operation is innovative, simple, safe, and really fun, and it doesn't cost a boat load of money.

Boggs

[Don Johnstone[_4_]]

At 14:55 10 May 2013, Bill D wrote:
>On Friday, May 10, 2013 8:42:39 AM UTC-6, Peter F wrote:
>> Don is right in thinking that there should be one person in charge of
>the=
> launch.
>
>> Unfortunately the person he thinks should be in charge is at the wrong
>en=
>d of the cable.
>
>You are correct, it's much better to have the pilot control airspeed with
>p=
>itch. However, for this to happen, the winch has to control rope tension
>a=
>ccurately as a percentage of glider weight. Control is divided where
>pilot=
> controls airspeed and winch controls tension. This means Gary is right
>to=
> control rope tension with his payout winch.

No, I said there should be one person with total control of the winch, just
the same as the number of people in command of a glider. Would you fly an
airplane where one pilot had control of the stick pulling back and another
pilot was in control of pushing it forwards? The person in charge of the
launch is always the pilot of the glider who has absolute control of the
airspeed at all times via the stick and yellow knob.

From a 2500' run we get 1000 ft winch launches in still air. We are cleared
and capable of winching to 3000ft but seldom do, using a standard Skylaunch
winch.
Average winch launch at our site using the standard runs is 1500ft.

[Bill D]

On Friday, May 10, 2013 8:59:22 AM UTC-6, Waveguru wrote:
> One of the most important things we teach all glider pilots is that it is there responsibility to keep themselves safe at all times, no matter what happens with the launch vehicle, be it winch, or aerotow. At no time should the pilot put himself in a position that he can't recover from in the event of a launch failure. That means you don't climb until you have sufficient airspeed, you limit the climb angle below 200', you abort the tow with enough runway to land straight ahead if you aren't climbing. No matter what happens to the launch vehicle, it is up to the glider pilot to keep himself in a safe place at all times, with safe options. Maybe you guys train differently? Even if my truck blew up, it just means the glider doesn't get as high as he would have. If the brake fails, it just means the glider doesn't get as high as he might. If my truck fails to get up to speed, the truck goes to the left and the glider lands straight ahead. Our payout system has been very dependable, but we train for launch failures just the same. Contrary to your assumptions, our operation is innovative, simple, safe, and really fun, and it doesn't cost a boat load of money.
>
>
>
> Boggs

I have no doubt Gary is a highly responsible pilot and instructor who trains pilots to the best of his ability. He is absolutely correct in describing the pilot's responsibility for his own safety.

That said, I think it may be instructive to examine some of the German DAeC Technical Commission's requirements for winches. (I have a copy translated for me by Ulrich Newmann and I can provide a copy to anyone who requested it.) It's a satisfyingly practical document clearly developed from their vast experience and the results show in their absolutely stellar safety record.

Lets start with power,tension and rope speeds where the DAeC sets minimums.


"In dead calm air, the glider has to be controllable around it's longitudinal axis after less than 15 meters and must reach it's takeoff speed after a maximum of 45 meters."

I think Gary's payout winch can meet this requirement since it only depends on how fast the drum brake is engaged.

Now, here's a tough one - minimum rope speed. This is important because a glider launched in thermic conditions can encounter unexpected tailwind gusts or tailwind layers aloft.

"The drum speed (RPM) has to be chosen such that using the drum core diameter and the power to accelerate the glider according to (above), a rope speed of no less than 1.2 x Va is achievable."

Va on many gliders is in excess of 100 knots so let's say 1.2 x Vw which is typically 70% - 75% of Va but this still may require rope speeds near 100 knots. In the case of a payout winch, one has to add whatever the payout speed is to get the truck speed. I think Gary's pickup truck may have some difficulty with this one since it could mean tow vehicle speeds in excess of 100mph.

Here's a crucial one - minimum release height.

"The power of the winch has to be such that at MTOW in dead calm air, a glider launched at maximum permissible (Vw) airspeed for winch launching can achieve a release altitude of at least 25% of the initial rope length. This must assure safe execution of a normal pattern."

While it's possible Gary's payout winch could achieve this, there may be issues with tow vehicle traction when launching the heaviest gliders. Rope tensions up to a ton may be required at tow speeds.

There are a lot more requirements in the DAeC technical documents on winch design which make good reading.

[Tony[_5_]]

On Friday, May 10, 2013 11:01:53 AM UTC-5, Bill D wrote:
> On Friday, May 10, 2013 8:59:22 AM UTC-6, Waveguru wrote: > One of the most important things we teach all glider pilots is that it is there responsibility to keep themselves safe at all times, no matter what happens with the launch vehicle, be it winch, or aerotow. At no time should the pilot put himself in a position that he can't recover from in the event of a launch failure. That means you don't climb until you have sufficient airspeed, you limit the climb angle below 200', you abort the tow with enough runway to land straight ahead if you aren't climbing. No matter what happens to the launch vehicle, it is up to the glider pilot to keep himself in a safe place at all times, with safe options. Maybe you guys train differently? Even if my truck blew up, it just means the glider doesn't get as high as he would have. If the brake fails, it just means the glider doesn't get as high as he might. If my truck fails to get up to speed, the truck goes to the left and the glider lands straight ahead. Our payout system has been very dependable, but we train for launch failures just the same. Contrary to your assumptions, our operation is innovative, simple, safe, and really fun, and it doesn't cost a boat load of money. > > > > Boggs I have no doubt Gary is a highly responsible pilot and instructor who trains pilots to the best of his ability. He is absolutely correct in describing the pilot's responsibility for his own safety. That said, I think it may be instructive to examine some of the German DAeC Technical Commission's requirements for winches. (I have a copy translated for me by Ulrich Newmann and I can provide a copy to anyone who requested it.) It's a satisfyingly practical document clearly developed from their vast experience and the results show in their absolutely stellar safety record. Lets start with power,tension and rope speeds where the DAeC sets minimums. "In dead calm air, the glider has to be controllable around it's longitudinal axis after less than 15 meters and must reach it's takeoff speed after a maximum of 45 meters." I think Gary's payout winch can meet this requirement since it only depends on how fast the drum brake is engaged. Now, here's a tough one - minimum rope speed. This is important because a glider launched in thermic conditions can encounter unexpected tailwind gusts or tailwind layers aloft. "The drum speed (RPM) has to be chosen such that using the drum core diameter and the power to accelerate the glider according to (above), a rope speed of no less than 1.2 x Va is achievable." Va on many gliders is in excess of 100 knots so let's say 1.2 x Vw which is typically 70% - 75% of Va but this still may require rope speeds near 100 knots. In the case of a payout winch, one has to add whatever the payout speed is to get the truck speed. I think Gary's pickup truck may have some difficulty with this one since it could mean tow vehicle speeds in excess of 100mph. Here's a crucial one - minimum release height. "The power of the winch has to be such that at MTOW in dead calm air, a glider launched at maximum permissible (Vw) airspeed for winch launching can achieve a release altitude of at least 25% of the initial rope length. This must assure safe execution of a normal pattern." While it's possible Gary's payout winch could achieve this, there may be issues with tow vehicle traction when launching the heaviest gliders. Rope tensions up to a ton may be required at tow speeds. There are a lot more requirements in the DAeC technical documents on winch design which make good reading.

if a 100 knot rope speed was required, any auto tow, payout or not, would be impossible.

[Bill D]

On Friday, May 10, 2013 9:36:02 AM UTC-6, Don Johnstone wrote:
> At 14:55 10 May 2013, Bill D wrote:
>
> >On Friday, May 10, 2013 8:42:39 AM UTC-6, Peter F wrote:
>
> >> Don is right in thinking that there should be one person in charge of
>
> >the=
>
> > launch.
>
> >
>
> >> Unfortunately the person he thinks should be in charge is at the wrong
>
> >en=
>
> >d of the cable.
>
> >
>
> >You are correct, it's much better to have the pilot control airspeed with
>
> >p=
>
> >itch. However, for this to happen, the winch has to control rope tension
>
> >a=
>
> >ccurately as a percentage of glider weight. Control is divided where
>
> >pilot=
>
> > controls airspeed and winch controls tension. This means Gary is right
>
> >to=
>
> > control rope tension with his payout winch.
>
>
>
> No, I said there should be one person with total control of the winch, just
>
> the same as the number of people in command of a glider. Would you fly an
>
> airplane where one pilot had control of the stick pulling back and another
>
> pilot was in control of pushing it forwards? The person in charge of the
>
> launch is always the pilot of the glider who has absolute control of the
>
> airspeed at all times via the stick and yellow knob.
>
>
>
> From a 2500' run we get 1000 ft winch launches in still air. We are cleared
>
> and capable of winching to 3000ft but seldom do, using a standard Skylaunch
>
> winch.
>
> Average winch launch at our site using the standard runs is 1500ft.


That's a fuzzy analogy. A better analogy is an airplane with a flight engineer controlling the power of the engines. The engineer (think winch operator) applies whatever power the pilot asks for. The pilot then takes that power and controls airspeed with pitch attitude.

[WAVEGURU]

Please describe to us a winch accident that would be the fault of the winch and not the pilot.

Boggs

[Bill D]

On Friday, May 10, 2013 10:08:48 AM UTC-6, Tony wrote:

> if a 100 knot rope speed was required, any auto tow, payout or not, would be impossible.

Not impossible, just not as safe as it could be. Those are German DAeC rules and you simply can't argue with their safety record.

[Bill D]

On Friday, May 10, 2013 10:25:24 AM UTC-6, Waveguru wrote:
> Please describe to us a winch accident that would be the fault of the winch and not the pilot.
>
>
>
> Boggs

First, Gary, let me say again I agree with your position on pilot responsibility and I would be perfectly willing to take a tow behind your payout winch. However, here's a couple of scenarios where a powerful winch can be safer than auto tow.

On a calm but strongly thermic day, a tailwind gust is encountered just as the glider begins rotation into the climb. If the winch has substantial reserve power, and is controlling rope tension, it will instantly add power to help the glider maintain a safe margin over stall in the critical rotation phase. In this case, the pilot has less control over his fate than the winch. If the winch or tow car power is marginal, the glider may stall in this situation.

This is why the DAeC Technical Committee guidelines set minimum power and rope speed requirements.

Another scenario is a winch which balks just after the glider is airborne leaving the glider momentarily gliding at minimum controllable airspeed. The winch then "catches" and applies full power. Without the runway surface supporting the tail wheel, and if the glider's CG is well above its hook, the inertial couple effect may cause a dangerous uncommanded pitch-up.

This is why the DAeC Technical Committee, in another paragraph, requires absolute smoothness in winch power without any tension oscillations or spikes in rope tension.

[Tony[_5_]]

On Friday, May 10, 2013 11:50:21 AM UTC-5, Bill D wrote:
> On Friday, May 10, 2013 10:08:48 AM UTC-6, Tony wrote: > if a 100 knot rope speed was required, any auto tow, payout or not, would be impossible. Not impossible, just not as safe as it could be. Those are German DAeC rules and you simply can't argue with their safety record.

sure but there are differences between auto and winch tow. notably that the rope is not getting shorter. any idea how the auto tow accident rate compares to winch? i don't recall ever reading about an auto tow accident but that is probably because its not very common.

[Bart[_4_]]

On May 10, 10:17*am, Tony > wrote:
> i don't recall ever reading about an auto tow accident but that is probably because its not very common.

The "Cadillac commercial" accident comes to mind. That, of course, was
hardly a typical auto tow.

Bart

[Ventus_a]

On Friday, May 10, 2013 8:59:22 AM UTC-6, Waveguru wrote:
One of the most important things we teach all glider pilots is that it is there responsibility to keep themselves safe at all times, no matter what happens with the launch vehicle, be it winch, or aerotow. At no time should the pilot put himself in a position that he can't recover from in the event of a launch failure. That means you don't climb until you have sufficient airspeed, you limit the climb angle below 200', you abort the tow with enough runway to land straight ahead if you aren't climbing. No matter what happens to the launch vehicle, it is up to the glider pilot to keep himself in a safe place at all times, with safe options. Maybe you guys train differently? Even if my truck blew up, it just means the glider doesn't get as high as he would have. If the brake fails, it just means the glider doesn't get as high as he might. If my truck fails to get up to speed, the truck goes to the left and the glider lands straight ahead. Our payout system has been very dependable, but we train for launch failures just the same. Contrary to your assumptions, our operation is innovative, simple, safe, and really fun, and it doesn't cost a boat load of money.



Boggs

I have no doubt Gary is a highly responsible pilot and instructor who trains pilots to the best of his ability. He is absolutely correct in describing the pilot's responsibility for his own safety.

That said, I think it may be instructive to examine some of the German DAeC Technical Commission's requirements for winches. (I have a copy translated for me by Ulrich Newmann and I can provide a copy to anyone who requested it.) It's a satisfyingly practical document clearly developed from their vast experience and the results show in their absolutely stellar safety record.

Lets start with power,tension and rope speeds where the DAeC sets minimums.


"In dead calm air, the glider has to be controllable around it's longitudinal axis after less than 15 meters and must reach it's takeoff speed after a maximum of 45 meters."

I think Gary's payout winch can meet this requirement since it only depends on how fast the drum brake is engaged.

Now, here's a tough one - minimum rope speed. This is important because a glider launched in thermic conditions can encounter unexpected tailwind gusts or tailwind layers aloft.

"The drum speed (RPM) has to be chosen such that using the drum core diameter and the power to accelerate the glider according to (above), a rope speed of no less than 1.2 x Va is achievable."

Va on many gliders is in excess of 100 knots so let's say 1.2 x Vw which is typically 70% - 75% of Va but this still may require rope speeds near 100 knots. In the case of a payout winch, one has to add whatever the payout speed is to get the truck speed. I think Gary's pickup truck may have some difficulty with this one since it could mean tow vehicle speeds in excess of 100mph.

Here's a crucial one - minimum release height.

"The power of the winch has to be such that at MTOW in dead calm air, a glider launched at maximum permissible (Vw) airspeed for winch launching can achieve a release altitude of at least 25% of the initial rope length. This must assure safe execution of a normal pattern."

While it's possible Gary's payout winch could achieve this, there may be issues with tow vehicle traction when launching the heaviest gliders. Rope tensions up to a ton may be required at tow speeds.

There are a lot more requirements in the DAeC technical documents on winch design which make good reading.

Hi all

Doing a quick search of the DAeC website to find the document Bill is referencing gives the following information translated by Google

"The speed of the drum must be such that, for
Rated power of the motor to the drum core diameter a
Rope speed in the amount of 1.2 times the lift-off speed
is reached to slow aircraft.
When calculating the drum speed is a surcharge of 10% (for
Operating conditions and weather conditions) to consider.
With more than 1000 m elevation sites of the winds is another
Surcharge of 5% per thousand meters of altitude required."

Even with my imperfect understanding of German or of this translation I don't think they are referring to Va when setting rope speed requirements

:-) Colin

[gb]

Hangglider and Paraglider pilots have been using payout winches for decades.. Payout winches are a viable, proven way to get horseless flying machines up in the sky. This isn't a singular redneck with a rope and spool, the Germans payout winch launch their paragliders. Nothing new here folks, no witches to burn, you can come out from under your glider trailers now.

[Bill D]

On Friday, May 10, 2013 6:09:17 PM UTC-6, gb wrote:
> Hangglider and Paraglider pilots have been using payout winches for decades. Payout winches are a viable, proven way to get horseless flying machines up in the sky. This isn't a singular redneck with a rope and spool, the Germans payout winch launch their paragliders. Nothing new here folks, no witches to burn, you can come out from under your glider trailers now.

There is a huge difference in speed between sailplanes and paragliders. So much so there is really no comparison.

[Bill D]

On Friday, May 10, 2013 5:11:43 PM UTC-6, Ventus_a wrote:
> Bill D;837692 Wrote:
>
> > On Friday, May 10, 2013 8:59:22 AM UTC-6, Waveguru wrote:-
>
> > One of the most important things we teach all glider pilots is that it
>
> > is there responsibility to keep themselves safe at all times, no matter
>
> > what happens with the launch vehicle, be it winch, or aerotow. At no
>
> > time should the pilot put himself in a position that he can't recover
>
> > from in the event of a launch failure. That means you don't climb until
>
> > you have sufficient airspeed, you limit the climb angle below 200', you
>
> > abort the tow with enough runway to land straight ahead if you aren't
>
> > climbing. No matter what happens to the launch vehicle, it is up to the
>
> > glider pilot to keep himself in a safe place at all times, with safe
>
> > options. Maybe you guys train differently? Even if my truck blew up,
>
> > it just means the glider doesn't get as high as he would have. If the
>
> > brake fails, it just means the glider doesn't get as high as he might.
>
> > If my truck fails to get up to speed, the truck goes to the left and the
>
> > glider lands straight ahead. Our payout system has been very
>
> > dependable, but we train for launch failures just the same. Contrary to
>
> > your assumptions, our operation is innovative, simple, safe, and really
>
> > fun, and it doesn't cost a boat load of money.
>
> >
>
> >
>
> >
>
> > Boggs-
>
> >
>
> > I have no doubt Gary is a highly responsible pilot and instructor who
>
> > trains pilots to the best of his ability. He is absolutely correct in
>
> > describing the pilot's responsibility for his own safety.
>
> >
>
> > That said, I think it may be instructive to examine some of the German
>
> > DAeC Technical Commission's requirements for winches. (I have a copy
>
> > translated for me by Ulrich Newmann and I can provide a copy to anyone
>
> > who requested it.) It's a satisfyingly practical document clearly
>
> > developed from their vast experience and the results show in their
>
> > absolutely stellar safety record.
>
> >
>
> > Lets start with power,tension and rope speeds where the DAeC sets
>
> > minimums.
>
> >
>
> >
>
> > "In dead calm air, the glider has to be controllable around it's
>
> > longitudinal axis after less than 15 meters and must reach it's takeoff
>
> > speed after a maximum of 45 meters."
>
> >
>
> > I think Gary's payout winch can meet this requirement since it only
>
> > depends on how fast the drum brake is engaged.
>
> >
>
> > Now, here's a tough one - minimum rope speed. This is important because
>
> > a glider launched in thermic conditions can encounter unexpected
>
> > tailwind gusts or tailwind layers aloft.
>
> >
>
> > "The drum speed (RPM) has to be chosen such that using the drum core
>
> > diameter and the power to accelerate the glider according to (above), a
>
> > rope speed of no less than 1.2 x Va is achievable."
>
> >
>
> > Va on many gliders is in excess of 100 knots so let's say 1.2 x Vw which
>
> > is typically 70% - 75% of Va but this still may require rope speeds near
>
> > 100 knots. In the case of a payout winch, one has to add whatever the
>
> > payout speed is to get the truck speed. I think Gary's pickup truck may
>
> > have some difficulty with this one since it could mean tow vehicle
>
> > speeds in excess of 100mph.
>
> >
>
> > Here's a crucial one - minimum release height.
>
> >
>
> > "The power of the winch has to be such that at MTOW in dead calm air, a
>
> > glider launched at maximum permissible (Vw) airspeed for winch launching
>
> > can achieve a release altitude of at least 25% of the initial rope
>
> > length. This must assure safe execution of a normal pattern."
>
> >
>
> > While it's possible Gary's payout winch could achieve this, there may be
>
> > issues with tow vehicle traction when launching the heaviest gliders.
>
> > Rope tensions up to a ton may be required at tow speeds.
>
> >
>
> > There are a lot more requirements in the DAeC technical documents on
>
> > winch design which make good reading.
>
>
>
> Hi all
>
>
>
> Doing a quick search of the DAeC website to find the document Bill is
>
> referencing gives the following information translated by Google
>
>
>
> "The speed of the drum must be such that, for
>
> Rated power of the motor to the drum core diameter a
>
> Rope speed in the amount of 1.2 times the lift-off speed
>
> is reached to slow aircraft.
>
> When calculating the drum speed is a surcharge of 10% (for
>
> Operating conditions and weather conditions) to consider.
>
> With more than 1000 m elevation sites of the winds is another
>
> Surcharge of 5% per thousand meters of altitude required."
>
>
>
> Even with my imperfect understanding of German or of this translation I
>
> don't think they are referring to Va when setting rope speed
>
> requirements
>
>
>
> :-) Colin
>

Your translation doesn't even remotely make sense. 1.2 x liftoff speed wouldn't even allow a safe rotation into climb. Have a professional translate it.

[GM]

> Hi all
>
>
>
> Doing a quick search of the DAeC website to find the document Bill is
>
> referencing gives the following information translated by Google
>
>
>
> "The speed of the drum must be such that, for
>
> Rated power of the motor to the drum core diameter a
>
> Rope speed in the amount of 1.2 times the lift-off speed
>
> is reached to slow aircraft.
>
> When calculating the drum speed is a surcharge of 10% (for
>
> Operating conditions and weather conditions) to consider.
>
> With more than 1000 m elevation sites of the winds is another
>
> Surcharge of 5% per thousand meters of altitude required."
>
>
>
> Even with my imperfect understanding of German or of this translation I
>
> don't think they are referring to Va when setting rope speed
>
> requirements
>
>
>
> :-) Colin
>
> Ventus_a

Long live the machine translator - barf.....
Please check Bill's post on that subject - he is referencing the correct translation.

Ulrich Neumann

[Martin Gregorie[_5_]]

On Fri, 10 May 2013 06:19:27 -0700, son_of_flubber wrote:

> Okay. I do have a few observations/opinions:
>
> 1)That the payout winch payouts more line and keeps line tension
> constant when the glider hits lift seems an inherent advantage of this
> approach when compared to a traditional winch launch.
>
As Bill says, a payout winch can't easily compensate for sink or a rear
gust at the start of a launch in calm conditions.

> 2)Don's suggestion that traditional winch launching is proven and that
> there is therefore no reason to experiment with payout winching misses
> the point. In a country where beefy pickup trucks are common, the
> start-up costs for payout winching are much lower than traditional
> winching. Secondly, far fewer humans need to be deployed and
> coordinated to run a payout winch. The relevant question is "Which is
> better to use on a dry lake bed, 1)autotow with payout winch or
> 2)traditional autotow? What are the tradeoffs?
>
As Don mentioned, we've been shown videos of payout winches with *no
gillotine fitted*. Its relatively rare, but cases of failures to release
have happened and are highly liable to be fatal without prompt use of the
guillotine. Even with a guillotine, what are the chances of a solo payout
winch driver noticing the problem in time? Even if he does notice, how
fast can he get to the guillotine's release and operate it?

I wouldn't accept a winch or auto-tow launch if there wasn't a functional
guillotine installed so that its release was instantly accessible to the
driver and/or the person monitoring the launch.


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

[Dan Marotta]

Guillotine? How about simply mounting a release mechanism to the back of
the tow vehicle with the release cable within reach of the driver or
observer? That's the way they do it on the dry lake in Nevada and I was not
the least concerned about accepting ground launches. And, of course,
there's always the weak link at the glider end...


"Martin Gregorie" > wrote in message
...
> On Fri, 10 May 2013 06:19:27 -0700, son_of_flubber wrote:
>
>> Okay. I do have a few observations/opinions:
>>
>> 1)That the payout winch payouts more line and keeps line tension
>> constant when the glider hits lift seems an inherent advantage of this
>> approach when compared to a traditional winch launch.
>>
> As Bill says, a payout winch can't easily compensate for sink or a rear
> gust at the start of a launch in calm conditions.
>
>> 2)Don's suggestion that traditional winch launching is proven and that
>> there is therefore no reason to experiment with payout winching misses
>> the point. In a country where beefy pickup trucks are common, the
>> start-up costs for payout winching are much lower than traditional
>> winching. Secondly, far fewer humans need to be deployed and
>> coordinated to run a payout winch. The relevant question is "Which is
>> better to use on a dry lake bed, 1)autotow with payout winch or
>> 2)traditional autotow? What are the tradeoffs?
>>
> As Don mentioned, we've been shown videos of payout winches with *no
> gillotine fitted*. Its relatively rare, but cases of failures to release
> have happened and are highly liable to be fatal without prompt use of the
> guillotine. Even with a guillotine, what are the chances of a solo payout
> winch driver noticing the problem in time? Even if he does notice, how
> fast can he get to the guillotine's release and operate it?
>
> I wouldn't accept a winch or auto-tow launch if there wasn't a functional
> guillotine installed so that its release was instantly accessible to the
> driver and/or the person monitoring the launch.
>
>
> --
> martin@ | Martin Gregorie
> gregorie. | Essex, UK
> org |

[Martin Gregorie[_5_]]

On Sat, 18 May 2013 10:03:48 -0600, Dan Marotta wrote:

> Guillotine? How about simply mounting a release mechanism to the back
> of the tow vehicle with the release cable within reach of the driver or
> observer? That's the way they do it on the dry lake in Nevada and I was
> not the least concerned about accepting ground launches. And, of
> course, there's always the weak link at the glider end...
>
The guillotine *is* the winch-end release mechanism. What else can you do
but cut the rope if the glider can't release? Jettisoning the drum and
guides, leaving them swinging beneath the glider isn't a good solution!

And, as others have pointed out, if you're not using a stiff 2-3 metre
strop (4.5mm steel cable inside plastic hose) on the glider's end of the
shock rope, then a hesitation or snatch as the take-off run starts can
wrap the cable round your wheel. That's something that's known to prevent
the glider from releasing its end of the cable.

I've just reviewed the video that started this thread and can't see any
sign that such a strop is in use or any indication that the weak link, if
there is one, at the glider end is correct for the glider. In the UK the
weak link housing is an integral part of the strop and the plastic hose
is colour coded to match the weak link: hence the pilot, or anybody else
at the launch point, can visually check that the correct weak is being
used when the cable is accepted prior to launch.


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

[Bill D]

The rope on a payout winch is on a drum not simply attached to the rear of a truck. Straight auto-tow uses a release. A payout winch needs a guillotine.

On Saturday, May 18, 2013 10:03:48 AM UTC-6, Dan Marotta wrote:
> Guillotine? How about simply mounting a release mechanism to the back of
>
> the tow vehicle with the release cable within reach of the driver or
>
> observer? That's the way they do it on the dry lake in Nevada and I was not
>
> the least concerned about accepting ground launches. And, of course,
>
> there's always the weak link at the glider end...
>
>
>
>
>
> "Martin Gregorie" > wrote in message
>
> ...
>
> > On Fri, 10 May 2013 06:19:27 -0700, son_of_flubber wrote:
>
> >
>
> >> Okay. I do have a few observations/opinions:
>
> >>
>
> >> 1)That the payout winch payouts more line and keeps line tension
>
> >> constant when the glider hits lift seems an inherent advantage of this
>
> >> approach when compared to a traditional winch launch.
>
> >>
>
> > As Bill says, a payout winch can't easily compensate for sink or a rear
>
> > gust at the start of a launch in calm conditions.
>
> >
>
> >> 2)Don's suggestion that traditional winch launching is proven and that
>
> >> there is therefore no reason to experiment with payout winching misses
>
> >> the point. In a country where beefy pickup trucks are common, the
>
> >> start-up costs for payout winching are much lower than traditional
>
> >> winching. Secondly, far fewer humans need to be deployed and
>
> >> coordinated to run a payout winch. The relevant question is "Which is
>
> >> better to use on a dry lake bed, 1)autotow with payout winch or
>
> >> 2)traditional autotow? What are the tradeoffs?
>
> >>
>
> > As Don mentioned, we've been shown videos of payout winches with *no
>
> > gillotine fitted*. Its relatively rare, but cases of failures to release
>
> > have happened and are highly liable to be fatal without prompt use of the
>
> > guillotine. Even with a guillotine, what are the chances of a solo payout
>
> > winch driver noticing the problem in time? Even if he does notice, how
>
> > fast can he get to the guillotine's release and operate it?
>
> >
>
> > I wouldn't accept a winch or auto-tow launch if there wasn't a functional
>
> > guillotine installed so that its release was instantly accessible to the
>
> > driver and/or the person monitoring the launch.
>
> >
>
> >
>
> > --
>
> > martin@ | Martin Gregorie
>
> > gregorie. | Essex, UK
>
> > org |

[Dan Marotta]

Oops! I was thinking of a straight auto tow. I forgot about the payout
winch part.

You are, of course, correct in the need for a guillotine in this
application.


"Martin Gregorie" > wrote in message
...
> On Sat, 18 May 2013 10:03:48 -0600, Dan Marotta wrote:
>
>> Guillotine? How about simply mounting a release mechanism to the back
>> of the tow vehicle with the release cable within reach of the driver or
>> observer? That's the way they do it on the dry lake in Nevada and I was
>> not the least concerned about accepting ground launches. And, of
>> course, there's always the weak link at the glider end...
>>
> The guillotine *is* the winch-end release mechanism. What else can you do
> but cut the rope if the glider can't release? Jettisoning the drum and
> guides, leaving them swinging beneath the glider isn't a good solution!
>
> And, as others have pointed out, if you're not using a stiff 2-3 metre
> strop (4.5mm steel cable inside plastic hose) on the glider's end of the
> shock rope, then a hesitation or snatch as the take-off run starts can
> wrap the cable round your wheel. That's something that's known to prevent
> the glider from releasing its end of the cable.
>
> I've just reviewed the video that started this thread and can't see any
> sign that such a strop is in use or any indication that the weak link, if
> there is one, at the glider end is correct for the glider. In the UK the
> weak link housing is an integral part of the strop and the plastic hose
> is colour coded to match the weak link: hence the pilot, or anybody else
> at the launch point, can visually check that the correct weak is being
> used when the cable is accepted prior to launch.
>
>
> --
> martin@ | Martin Gregorie
> gregorie. | Essex, UK
> org |

[Wallace Berry[_2_]]

In article >,
Martin Gregorie > wrote:

>
>
> I wouldn't accept a winch or auto-tow launch if there wasn't a functional
> guillotine installed so that its release was instantly accessible to the
> driver and/or the person monitoring the launch.



We used to do a lot of ground launching via the "pulley method". We
always had an observer in the tow car watching the launch. Our
"guillotine" was a sharp machete in the hands of the observer. Of course
we were also taught to immediately bank into a tight turn and circle the
tow vehicle if we could not release. I always had my doubts about
recognizing the release failure in time to cut the line or to turn and
get tension off the line before things got out of hand.

All the pulley launch rigs I have seen are just a bare pulley, usually a
truck rim mounted an a trailer hitch. No fairleads or other structure. I
guess a guillotine could be mounted to such a rig. Would be a good Idea,
I think.

[Tony[_5_]]

On Monday, May 20, 2013 9:19:03 AM UTC-5, WB wrote:
> In article >, Martin Gregorie > wrote: > > > I wouldn't accept a winch or auto-tow launch if there wasn't a functional > guillotine installed so that its release was instantly accessible to the > driver and/or the person monitoring the launch. We used to do a lot of ground launching via the "pulley method". We always had an observer in the tow car watching the launch. Our "guillotine" was a sharp machete in the hands of the observer. Of course we were also taught to immediately bank into a tight turn and circle the tow vehicle if we could not release. I always had my doubts about recognizing the release failure in time to cut the line or to turn and get tension off the line before things got out of hand. All the pulley launch rigs I have seen are just a bare pulley, usually a truck rim mounted an a trailer hitch. No fairleads or other structure. I guess a guillotine could be mounted to such a rig. Would be a good Idea, I think.

If you're using a pulley why not just have a release on the tow vehicle?

[Wallace Berry[_2_]]

In article >,
Tony > wrote:

>
>
> If you're using a pulley why not just have a release on the tow vehicle?

Hi Tony,

I was unclear about the pulley launch. The pulley is on the tow vehicle.
One end of the line is anchored, the line goes over the pulley to the
glider. The tow vehicle is pulling from the middle of the rope, going in
the same direction as the glider. The advantages are that acceleration
at the glider is almost as fast as a winch launch and the tow car only
has to go 25-30 mph maximum to launch the glider. No gear changes
required, and the low vehicle speed means it can be done on less than
paved surfaces. Launching with 4000 feet of dacron rope and an old LTD
with 500 lbs of bricks in the trunk used to get our Ka-8 to 2000' if we
had a bit of headwind.

A release can be put at the anchor point, but that's a long way from
where the action is.

There are some other disadvantages to this type of ground launch as
well. Turn around time is fairly long. Switching ends of the rope after
each launch can speed things up especially if the anchor point is
another vehicle. Rope recovery can be problematic since a chute is
usually not part of the rope end hardware, so the rope tends to fall a
ways downwind.

[Tony[_5_]]

On Monday, May 20, 2013 9:52:58 AM UTC-5, WB wrote:
> In article >, Tony > wrote: > > > If you're using a pulley why not just have a release on the tow vehicle? Hi Tony, I was unclear about the pulley launch. The pulley is on the tow vehicle. One end of the line is anchored, the line goes over the pulley to the glider. The tow vehicle is pulling from the middle of the rope, going in the same direction as the glider. The advantages are that acceleration at the glider is almost as fast as a winch launch and the tow car only has to go 25-30 mph maximum to launch the glider. No gear changes required, and the low vehicle speed means it can be done on less than paved surfaces. Launching with 4000 feet of dacron rope and an old LTD with 500 lbs of bricks in the trunk used to get our Ka-8 to 2000' if we had a bit of headwind. A release can be put at the anchor point, but that's a long way from where the action is. There are some other disadvantages to this type of ground launch as well. Turn around time is fairly long. Switching ends of the rope after each launch can speed things up especially if the anchor point is another vehicle. Rope recovery can be problematic since a chute is usually not part of the rope end hardware, so the rope tends to fall a ways downwind.

ah i see, i was thinking of a fixed pulley.

[[email protected]]

On Monday, May 20, 2013 11:00:54 AM UTC-4, Tony wrote:
> On Monday, May 20, 2013 9:52:58 AM UTC-5, WB wrote:
>
> > In article >, Tony > wrote: > > > If you're using a pulley why not just have a release on the tow vehicle? Hi Tony, I was unclear about the pulley launch. The pulley is on the tow vehicle. One end of the line is anchored, the line goes over the pulley to the glider. The tow vehicle is pulling from the middle of the rope, going in the same direction as the glider. The advantages are that acceleration at the glider is almost as fast as a winch launch and the tow car only has to go 25-30 mph maximum to launch the glider. No gear changes required, and the low vehicle speed means it can be done on less than paved surfaces. Launching with 4000 feet of dacron rope and an old LTD with 500 lbs of bricks in the trunk used to get our Ka-8 to 2000' if we had a bit of headwind. A release can be put at the anchor point, but that's a long way from where the action is. There are some other disadvantages to this type of ground launch as well. Turn around time is fairly long. Switching ends of the rope after each launch can speed things up especially if the anchor point is another vehicle. Rope recovery can be problematic since a chute is usually not part of the rope end hardware, so the rope tends to fall a ways downwind.
>
>
>
> ah i see, i was thinking of a fixed pulley.

Yes, fixed pulley has some advantages: quick turnaround, can use a chute, driver
is facing the action. The disadvantage is that you drag the whole rope the
length of the field at speed. I would think that would wear out Spectra
pretty fast. There's some places that use multiple pulleys that can
mitigate some of that. Check out the pulleylaunch Yahoo group for that.

Matt

[Bill D]

On Monday, May 20, 2013 10:02:54 AM UTC-6, wrote:
> On Monday, May 20, 2013 11:00:54 AM UTC-4, Tony wrote:
>
> > On Monday, May 20, 2013 9:52:58 AM UTC-5, WB wrote:
>
> >
>
> > > In article >, Tony > wrote: > > > If you're using a pulley why not just have a release on the tow vehicle? Hi Tony, I was unclear about the pulley launch. The pulley is on the tow vehicle. One end of the line is anchored, the line goes over the pulley to the glider. The tow vehicle is pulling from the middle of the rope, going in the same direction as the glider. The advantages are that acceleration at the glider is almost as fast as a winch launch and the tow car only has to go 25-30 mph maximum to launch the glider. No gear changes required, and the low vehicle speed means it can be done on less than paved surfaces. Launching with 4000 feet of dacron rope and an old LTD with 500 lbs of bricks in the trunk used to get our Ka-8 to 2000' if we had a bit of headwind. A release can be put at the anchor point, but that's a long way from where the action is. There are some other disadvantages to this type of ground launch as well. Turn around time is fairly long.. Switching ends of the rope after each launch can speed things up especially if the anchor point is another vehicle. Rope recovery can be problematic since a chute is usually not part of the rope end hardware, so the rope tends to fall a ways downwind.
>
> >
>
> >
>
> >
>
> > ah i see, i was thinking of a fixed pulley.
>
>
>
> Yes, fixed pulley has some advantages: quick turnaround, can use a chute, driver
>
> is facing the action. The disadvantage is that you drag the whole rope the
>
> length of the field at speed. I would think that would wear out Spectra
>
> pretty fast. There's some places that use multiple pulleys that can
>
> mitigate some of that. Check out the pulleylaunch Yahoo group for that.
>
>
>
> Matt

Yes, dragging a rope will wear it out. The car doing the dragging will also wear out fairly quickly. Auto tow is like drag racing - it puts a lot of strain on a car.

Of course, start-up costs for auto tow are lower than a winch which makes it attractive but in the medium term (Say two years) a winch is much cheaper to operate. There are about 1500 clubs worldwide which use ground launch but only a handful use auto tow. They've found a winch is quicker, cheaper, safer and gets the glider higher using less space.

By the time you've replaced a few ropes and tow cars, a winch starts looking pretty cheap.

[Wallace Berry[_2_]]

In article >,
Bill D > wrote:

> > Matt
>
> Yes, dragging a rope will wear it out. The car doing the dragging will also
> wear out fairly quickly. Auto tow is like drag racing - it puts a lot of
> strain on a car.
>
> Of course, start-up costs for auto tow are lower than a winch which makes it
> attractive but in the medium term (Say two years) a winch is much cheaper to
> operate. There are about 1500 clubs worldwide which use ground launch but
> only a handful use auto tow. They've found a winch is quicker, cheaper,
> safer and gets the glider higher using less space.
>
> By the time you've replaced a few ropes and tow cars, a winch starts looking
> pretty cheap.

Yep, we did that. We did the pulley ground launch until the club's
founder, Glen Lawler, built the "Eagle Winch". We happily used it for
several years before a change if airfield made winch use untenable
(crossing runway, not enough runway length). Last I heard, the winch was
at Philly Gliding Council. I miss it. We once launched half a contest
grid with it. The other poor, benighted sods without a ground launch
endorsement had to suffer aerotow.


Speaking of Glen's winch, it had a wide drum requiring an active level
wind mechanism to lay the line on evenly. Glen's level wind was a neat
bit of engineering involving a slotted bar that cammed the guide back
and forth across the drum. Have seen some pretty expensive winches that
had level winds mechanisms that did the job, but were clearly not as
precise as Glen's. Given that, if designing a winch, I'd go for simple
with a large diameter drum that would not need an active level wind.

[Chris Nicholas[_2_]]

It is possible and highly desirable to fit a guillotine to a pulley system. My club had considerable experience with reverse pulley for many years when we had a hard runway, and developed it to a great degree.

Method: We had 2 pulley wheels in a frame which pivoted about a horizontal axis, and also mounted so that it could swing sideways. This enabled the cable to run true from glider to one pulley, and from the other pulley to the tow vehicle. Both pulleys were framed in lead-in guards. The horizontal pivot was hollow. A spring loaded chisel-edged cutter ran through it. This could be released from the cab of the truck on which the pulley system was mounted. It would hit the cable, against an anvil mounted between the two pulleys. It worked.

Reason: Cable hang-ups at the glider end are not unknown. One fatal accident in the UK in the 1970’s arose from this (either release hook did not work, or cable wrapped round wheel, on a winch launch). With the cable taut, the glider described an arc from nearly above the winch to the ground. A non-fatal accident from a similar cause was addressed by the pilot circling over the winch while descending, straightening up with slack in the cable near the ground and landing downwind.

Mitigation: Plastic hose round the strop from weak link/drogue to glider prevents hang-up round the wheel/axle, but faulty cable release in the glider still needs the safety of a guillotine.

Chris N

[Wallace Berry[_2_]]

> > Matt
>
> Yes, dragging a rope will wear it out. The car doing the dragging will also
> wear out fairly quickly. Auto tow is like drag racing - it puts a lot of
> strain on a car.
>
> Of course, start-up costs for auto tow are lower than a winch which makes it
> attractive but in the medium term (Say two years) a winch is much cheaper to
> operate. There are about 1500 clubs worldwide which use ground launch but
> only a handful use auto tow. They've found a winch is quicker, cheaper,
> safer and gets the glider higher using less space.
>
> By the time you've replaced a few ropes and tow cars, a winch starts looking
> pretty cheap.


We shortened the life of a Nissan Pathfinder transmission autolaunching
at remote locations. Our primary launch car at home was straight out of
a scrap yard. It was an old LTD with a big motor, maybe a 460. I think
it actually only ran on 5 cylinders though. The transmission was crap
but it worked in low gear and reverse. That was all we needed. Oh, and
the 500 lbs of salvaged brick wall that we put into the trunk to hold
the back end down when the glider was at the top of the climb.

[Wallace Berry[_2_]]

In article >,
Chris Nicholas > wrote:

> It is possible and highly desirable to fit a guillotine to a pulley system.
> My club had considerable experience with reverse pulley for many years when
> we had a hard runway, and developed it to a great degree.
>
> Method: We had 2 pulley wheels in a frame which pivoted about a horizontal
> axis, and also mounted so that it could swing sideways. This enabled the
> cable to run true from glider to one pulley, and from the other pulley to the
> tow vehicle. Both pulleys were framed in lead-in guards. The horizontal pivot
> was hollow. A spring loaded chisel-edged cutter ran through it. This could be
> released from the cab of the truck on which the pulley system was mounted. It
> would hit the cable, against an anvil mounted between the two pulleys. It
> worked.
>

Sounds like an excellent setup. If we ever do groundlaunch again, we
will have to put together a guillotine system like that. Your guillotine
sounds almost identical to the one Glen Lawler put on the Eagle Winch.
It was a spring loaded chisel firing against an anvil. A hydraulic jack
was used to cock the thing. Made a heck of bang when fired. It would
shear steel rope like it was made of air. Not sure how well it worked on
Spectra, but I would expect that it had no trouble with it, especially
with any tension on the line.

[Bill D]

On Tuesday, May 21, 2013 8:10:22 AM UTC-6, WB wrote:
> In article >,
>
> Chris Nicholas > wrote:
>
>
>
> > It is possible and highly desirable to fit a guillotine to a pulley system.
>
> > My club had considerable experience with reverse pulley for many years when
>
> > we had a hard runway, and developed it to a great degree.
>
> >
>
> > Method: We had 2 pulley wheels in a frame which pivoted about a horizontal
>
> > axis, and also mounted so that it could swing sideways. This enabled the
>
> > cable to run true from glider to one pulley, and from the other pulley to the
>
> > tow vehicle. Both pulleys were framed in lead-in guards. The horizontal pivot
>
> > was hollow. A spring loaded chisel-edged cutter ran through it. This could be
>
> > released from the cab of the truck on which the pulley system was mounted. It
>
> > would hit the cable, against an anvil mounted between the two pulleys. It
>
> > worked.
>
> >
>
>
>
> Sounds like an excellent setup. If we ever do groundlaunch again, we
>
> will have to put together a guillotine system like that. Your guillotine
>
> sounds almost identical to the one Glen Lawler put on the Eagle Winch.
>
> It was a spring loaded chisel firing against an anvil. A hydraulic jack
>
> was used to cock the thing. Made a heck of bang when fired. It would
>
> shear steel rope like it was made of air. Not sure how well it worked on
>
> Spectra, but I would expect that it had no trouble with it, especially
>
> with any tension on the line.

I suggest a cheaper and safer guillotine is a simple air cylinder powered by a portable air tank. I bought a new 2" bore Bimba cylinder on eBay for $15 and an air tank with pressure gauge from Harbor Freight for $25. A "pop-open" push-button air valve and some air hose completes the system.

A 2" cylinder produces exactly 3.1316 pounds-force for every PSI. The tank holds over 100 PSI so the cylinder can drive a chisel blade with at least 313 Lbs-F which WILL cut a rope. Checking the gauge on the tank assures you have air pressure. If necessary, refill with any shop air compressor. Unlike a steel spring, compressed air doesn't rust or lose strength with age..

Why is it safer? You can de-energize by just removing the air hose to the guillotine so there's no chance of losing a finger. Spring powered guillotines resemble bear traps and have to be relaxed VERY CAREFULLY to work on them.

[Frank Whiteley]

On Tuesday, May 21, 2013 8:10:22 AM UTC-6, WB wrote:
> In article >,
>
> Chris Nicholas > wrote:
>
>
>
> > It is possible and highly desirable to fit a guillotine to a pulley system.
>
> > My club had considerable experience with reverse pulley for many years when
>
> > we had a hard runway, and developed it to a great degree.
>
> >
>
> > Method: We had 2 pulley wheels in a frame which pivoted about a horizontal
>
> > axis, and also mounted so that it could swing sideways. This enabled the
>
> > cable to run true from glider to one pulley, and from the other pulley to the
>
> > tow vehicle. Both pulleys were framed in lead-in guards. The horizontal pivot
>
> > was hollow. A spring loaded chisel-edged cutter ran through it. This could be
>
> > released from the cab of the truck on which the pulley system was mounted. It
>
> > would hit the cable, against an anvil mounted between the two pulleys. It
>
> > worked.
>
> >
>
>
>
> Sounds like an excellent setup. If we ever do groundlaunch again, we
>
> will have to put together a guillotine system like that. Your guillotine
>
> sounds almost identical to the one Glen Lawler put on the Eagle Winch.
>
> It was a spring loaded chisel firing against an anvil. A hydraulic jack
>
> was used to cock the thing. Made a heck of bang when fired. It would
>
> shear steel rope like it was made of air. Not sure how well it worked on
>
> Spectra, but I would expect that it had no trouble with it, especially
>
> with any tension on the line.

http://www.coloradosoaring.org/thinking_pages/ground_launching/reverse_pulley/default.htm

No guillotine, wire and tackle pulled through the 'pulley' apparently.

[Frank Whiteley]

On Monday, May 20, 2013 8:26:41 AM UTC-6, Tony wrote:
> On Monday, May 20, 2013 9:19:03 AM UTC-5, WB wrote:
>
> > In article >, Martin Gregorie > wrote: > > > I wouldn't accept a winch or auto-tow launch if there wasn't a functional > guillotine installed so that its release was instantly accessible to the > driver and/or the person monitoring the launch. We used to do a lot of ground launching via the "pulley method". We always had an observer in the tow car watching the launch. Our "guillotine" was a sharp machete in the hands of the observer. Of course we were also taught to immediately bank into a tight turn and circle the tow vehicle if we could not release. I always had my doubts about recognizing the release failure in time to cut the line or to turn and get tension off the line before things got out of hand. All the pulley launch rigs I have seen are just a bare pulley, usually a truck rim mounted an a trailer hitch. No fairleads or other structure. I guess a guillotine could be mounted to such a rig. Would be a good Idea, I think.
>
>
>
> If you're using a pulley why not just have a release on the tow vehicle?

http://framework.latimes.com/2013/05/21/horse-launched-sailplane/

[Bill D]

On Tuesday, May 21, 2013 5:20:21 PM UTC-6, Frank Whiteley wrote:

> http://framework.latimes.com/2013/05/21/horse-launched-sailplane/

Bad Photoshop job. You can see the real rope going past the horse to something out of the frame that's really launching the glider. However, it would have to be a gentile something - that's a Baby Albatross with a, IIRC, 65mph Vne.

[Tom Gardner[_2_]]

Bill D wrote:
> On Tuesday, May 21, 2013 5:20:21 PM UTC-6, Frank Whiteley wrote:
>
>> http://framework.latimes.com/2013/05/21/horse-launched-sailplane/
>
> Bad Photoshop job. You can see the real rope going past the horse to something out of the frame that's really launching the glider. However, it would have to be a gentile something - that's a Baby Albatross with a, IIRC, 65mph Vne.

http://www.youtube.com/watch?v=86rOfjhsIIM

[Wallace Berry[_2_]]

> I suggest a cheaper and safer guillotine is a simple air cylinder powered by
> a portable air tank. I bought a new 2" bore Bimba cylinder on eBay for $15
> and an air tank with pressure gauge from Harbor Freight for $25. A
> "pop-open" push-button air valve and some air hose completes the system.
>
> A 2" cylinder produces exactly 3.1316 pounds-force for every PSI. The tank
> holds over 100 PSI so the cylinder can drive a chisel blade with at least 313
> Lbs-F which WILL cut a rope. Checking the gauge on the tank assures you have
> air pressure. If necessary, refill with any shop air compressor. Unlike a
> steel spring, compressed air doesn't rust or lose strength with age.
>
> Why is it safer? You can de-energize by just removing the air hose to the
> guillotine so there's no chance of losing a finger. Spring powered
> guillotines resemble bear traps and have to be relaxed VERY CAREFULLY to work
> on them.

I don't think we had to worry about the spring losing strength. It took
around 500 lbs to compress it IIRC so it had some margin. Valve springs
on cars sit compressed for long periods without losing strength. Might
get rusty, but the winch was only outside when being used. No argument
about the bear trap. We did not put our fingers anywhere near that thing.
We "relaxed" ours by firing it. Not a gentle process, but worth it in
entertainment value! We never fired it in anger, not sure about
subsequent users.

I drove about 2000 launches with that winch and I miss it!