Ground launch payout winch systems...Are they suitable for gliders?

[[email protected]]

It seems that a payout winch similar to those used for hang gliders
might be useful as a more efficient alternative to auto tows. You can
make better use of the runway length and have perhaps a safer launch
with proper calibration. Is anyone using such systems? Are they
practical? Are they in fact better than a straight auto tow?

[BT]

Gary Boggs uses a payout winch system http://www.nwskysports.com/


> wrote in message
...
> It seems that a payout winch similar to those used for hang gliders
> might be useful as a more efficient alternative to auto tows. You can
> make better use of the runway length and have perhaps a safer launch
> with proper calibration. Is anyone using such systems? Are they
> practical? Are they in fact better than a straight auto tow?

[Bill Daniels]

> wrote in message
...
> It seems that a payout winch similar to those used for hang gliders
> might be useful as a more efficient alternative to auto tows. You can
> make better use of the runway length and have perhaps a safer launch
> with proper calibration. Is anyone using such systems? Are they
> practical? Are they in fact better than a straight auto tow?

It comes down to how much room you have and how fast you are willing to
drive. The typical glider will need about 60kts from a tow car on a
straight auto tow. That sixty knots will cover 6000 feet of runway in a
minute.

To that 60 kts, you have to add whatever speed you intend to use for rope
payout. If you intend to pay out 2000 feet of rope in that minute, the car
will have to go a third faster or 80 kts or 92mph. 92mph cuts your climb
time to 39 seconds on a 6000' runway not allowing for acceleration and
stopping distances. Of course you have to iterate these number again since
you'll need to pay out that 2000 feet in only 39 seconds. You'll also need
to add distance for accelerating and stopping the tow car.

Ninty is already getting kinda fast for me but there's more. To that 92mph,
you will need to add about 2% for each thousand feet of density altitude.
Say your DA is 5000 feet then you need to drive the car at 101mph on a calm
day (Don't even think about 10,000' DA's). Of course, if you have a 15 knot
headwind, that drops it to 'only' 85 or so.

So, if you are willing to drive that fast and have that much room, will it
result in a usable release height? Probably. 39 seconds is enough to reach
about 1800 feet AGL on a 2000' rope.

Most people who have worked this out have a winch. A winch with 6000 feet
of rope can deliver 3000 feet AGL and use only about a quart of fuel doing
it.

Bill D

[Brian[_1_]]

I have done a few launches behind Gary's payout system.

it is on awesome system from a functionality stand point in that you
launch, wind up the rope and drive back to the starting point to set
up for the next launch. The rope drags very little and setting up for
the next launch is quick.

I didn't see any advantage in runway length required. But then I was
doing it on a 3 mile plus dry lake so it wasn't an issue and 2000 ft +
tows were no problem.

I suspect that on a 5000 foot runway it would be comparable to a
straight auto tow in launch height.

Brian
HP16T

[Ian Burgin]

Reciprocal auto tow works better the cable is pulled through a pulley at
the other end. as each launch is finished the car returns to the pulley
end and picks up the other end of the cable ready for next launch.
Some British clubs use a "Skylaunch" commercially built retrieve launch
system see their web site.

At 02:24 22 September 2008, Bill Daniels wrote:
>
> wrote in message
...
>> It seems that a payout winch similar to those used for hang gliders
>> might be useful as a more efficient alternative to auto tows. You can
>> make better use of the runway length and have perhaps a safer launch
>> with proper calibration. Is anyone using such systems? Are they
>> practical? Are they in fact better than a straight auto tow?
>
>It comes down to how much room you have and how fast you are willing to
>drive. The typical glider will need about 60kts from a tow car on a
>straight auto tow. That sixty knots will cover 6000 feet of runway in a

>minute.
>
>To that 60 kts, you have to add whatever speed you intend to use for rope

>payout. If you intend to pay out 2000 feet of rope in that minute, the
>car
>will have to go a third faster or 80 kts or 92mph. 92mph cuts your climb

>time to 39 seconds on a 6000' runway not allowing for acceleration and
>stopping distances. Of course you have to iterate these number again
>since
>you'll need to pay out that 2000 feet in only 39 seconds. You'll also
>need
>to add distance for accelerating and stopping the tow car.
>
>Ninty is already getting kinda fast for me but there's more. To that
>92mph,
>you will need to add about 2% for each thousand feet of density altitude.

>Say your DA is 5000 feet then you need to drive the car at 101mph on a
>calm
>day (Don't even think about 10,000' DA's). Of course, if you have a
15
>knot
>headwind, that drops it to 'only' 85 or so.
>
>So, if you are willing to drive that fast and have that much room, will
it
>
>result in a usable release height? Probably. 39 seconds is enough to
>reach
>about 1800 feet AGL on a 2000' rope.
>
>Most people who have worked this out have a winch. A winch with 6000
feet
>
>of rope can deliver 3000 feet AGL and use only about a quart of fuel
doing
>
>it.
>
>Bill D
>
>
>
>

[Ian Burgin]

Reciprocal auto tow works better the cable is pulled through a pulley at
the other end. as each launch is finished the car returns to the pulley
end and picks up the other end of the cable ready for next launch.
Some British clubs use a "Skylaunch" commercially built retrieve launch
system see their web site.

At 02:24 22 September 2008, Bill Daniels wrote:
>
> wrote in message
...
>> It seems that a payout winch similar to those used for hang gliders
>> might be useful as a more efficient alternative to auto tows. You can
>> make better use of the runway length and have perhaps a safer launch
>> with proper calibration. Is anyone using such systems? Are they
>> practical? Are they in fact better than a straight auto tow?
>
>It comes down to how much room you have and how fast you are willing to
>drive. The typical glider will need about 60kts from a tow car on a
>straight auto tow. That sixty knots will cover 6000 feet of runway in a

>minute.
>
>To that 60 kts, you have to add whatever speed you intend to use for rope

>payout. If you intend to pay out 2000 feet of rope in that minute, the
>car
>will have to go a third faster or 80 kts or 92mph. 92mph cuts your climb

>time to 39 seconds on a 6000' runway not allowing for acceleration and
>stopping distances. Of course you have to iterate these number again
>since
>you'll need to pay out that 2000 feet in only 39 seconds. You'll also
>need
>to add distance for accelerating and stopping the tow car.
>
>Ninty is already getting kinda fast for me but there's more. To that
>92mph,
>you will need to add about 2% for each thousand feet of density altitude.

>Say your DA is 5000 feet then you need to drive the car at 101mph on a
>calm
>day (Don't even think about 10,000' DA's). Of course, if you have a
15
>knot
>headwind, that drops it to 'only' 85 or so.
>
>So, if you are willing to drive that fast and have that much room, will
it
>
>result in a usable release height? Probably. 39 seconds is enough to
>reach
>about 1800 feet AGL on a 2000' rope.
>
>Most people who have worked this out have a winch. A winch with 6000
feet
>
>of rope can deliver 3000 feet AGL and use only about a quart of fuel
doing
>
>it.
>
>Bill D
>
>
>
>

[Ian Burgin]

Reciprocal auto tow works better the cable is pulled through a pulley at
the other end. as each launch is finished the car returns to the pulley
end and picks up the other end of the cable ready for next launch.
Some British clubs use a "Skylaunch" commercially built retrieve launch
system see their web site.

At 02:24 22 September 2008, Bill Daniels wrote:
>
> wrote in message
...
>> It seems that a payout winch similar to those used for hang gliders
>> might be useful as a more efficient alternative to auto tows. You can
>> make better use of the runway length and have perhaps a safer launch
>> with proper calibration. Is anyone using such systems? Are they
>> practical? Are they in fact better than a straight auto tow?
>
>It comes down to how much room you have and how fast you are willing to
>drive. The typical glider will need about 60kts from a tow car on a
>straight auto tow. That sixty knots will cover 6000 feet of runway in a

>minute.
>
>To that 60 kts, you have to add whatever speed you intend to use for rope

>payout. If you intend to pay out 2000 feet of rope in that minute, the
>car
>will have to go a third faster or 80 kts or 92mph. 92mph cuts your climb

>time to 39 seconds on a 6000' runway not allowing for acceleration and
>stopping distances. Of course you have to iterate these number again
>since
>you'll need to pay out that 2000 feet in only 39 seconds. You'll also
>need
>to add distance for accelerating and stopping the tow car.
>
>Ninty is already getting kinda fast for me but there's more. To that
>92mph,
>you will need to add about 2% for each thousand feet of density altitude.

>Say your DA is 5000 feet then you need to drive the car at 101mph on a
>calm
>day (Don't even think about 10,000' DA's). Of course, if you have a
15
>knot
>headwind, that drops it to 'only' 85 or so.
>
>So, if you are willing to drive that fast and have that much room, will
it
>
>result in a usable release height? Probably. 39 seconds is enough to
>reach
>about 1800 feet AGL on a 2000' rope.
>
>Most people who have worked this out have a winch. A winch with 6000
feet
>
>of rope can deliver 3000 feet AGL and use only about a quart of fuel
doing
>
>it.
>
>Bill D
>
>
>
>

[Frank Whiteley]

http://www.coloradosoaring.org/thinking_pages/ground_launching/reverse_pulley/default.htm
On Sep 22, 10:37*am, Ian Burgin > wrote:
> Reciprocal auto tow works better the cable is pulled through a pulley at
> the other end. as each launch is finished the car returns to the pulley
> end and picks up the other end of the cable ready for next launch.
> Some British clubs use a "Skylaunch" commercially built retrieve launch
> system see their web site.
>
> At 02:24 22 September 2008, Bill Daniels wrote:
>
>
>
>
>
> > wrote in message
> ....
> >> It seems that a payout winch similar to those used for hang gliders
> >> might be useful as a more efficient alternative to auto tows. You can
> >> make better use of the runway length and have perhaps a safer launch
> >> with proper calibration. Is anyone using such systems? Are they
> >> practical? Are they in fact better than a straight auto tow?
>
> >It comes down to how much room you have and how fast you are willing to
> >drive. *The typical glider will need about 60kts from a tow car on a
> >straight auto tow. *That sixty knots will cover 6000 feet of runway in a
> >minute.
>
> >To that 60 kts, you have to add whatever speed you intend to use for rope
> >payout. *If you intend to pay out 2000 feet of rope in that minute, the
> >car
> >will have to go a third faster or 80 kts or 92mph. *92mph cuts your climb
> >time to 39 seconds on a 6000' runway not allowing for acceleration and
> >stopping distances. *Of course you have to iterate these number again
> >since
> >you'll need to pay out that 2000 feet in only 39 seconds. *You'll also
> >need
> >to add distance for accelerating and stopping the tow car.
>
> >Ninty is already getting kinda fast for me but there's more. To that
> >92mph,
> >you will need to add about 2% for each thousand feet of density altitude..
> >Say your DA is 5000 feet then you need to drive the car at 101mph on a
> >calm
> >day (Don't even think about 10,000' DA's). *Of course, if you have a
> 15
> >knot
> >headwind, that drops it to 'only' 85 or so.
>
> >So, if you are willing to drive that fast and have that much room, will
> it
>
> >result in a usable release height? *Probably. *39 seconds is enough to
> >reach
> >about 1800 feet AGL on a 2000' *rope.
>
> >Most people who have worked this out have a winch. *A winch with 6000
> feet
>
> >of rope can deliver 3000 feet AGL and use only about a quart of fuel
> doing
>
> >it.
>
> >Bill D

[Pete Brown]

BT, Bill, Ian, and Frank

Thanks for the comments. At our site, I am fairly certain that we could
never use a reverse pulley because airport management wouldn't permit
it. We might get away with a payout winch with a retrieve system so we
could exit the runway quickly after the launch.

I may be forced to visit Gary for a peak at his system.

Pete



BT wrote:
> Gary Boggs uses a payout winch system http://www.nwskysports.com/
>
>
> > wrote in message
> ...
>> It seems that a payout winch similar to those used for hang gliders
>> might be useful as a more efficient alternative to auto tows. You can
>> make better use of the runway length and have perhaps a safer launch
>> with proper calibration. Is anyone using such systems? Are they
>> practical? Are they in fact better than a straight auto tow?
>
>

[Pete Brown]

Gents:

I have assumed, perhaps incorrectly, that a payout winch would have an
advantage. If I have 2000 ft of cable on a spool and a 6,000 ft runway,
the car with a payout winch use almost all of the 6,000ft runway length.

Were we to do a regular auto tow, the car could only use 4,000ft of the
runway to lift the glider. A reverse pulley would also give us the full
6,000 ft but, in our case, we can't use it because of runway management
issues, not aerodynamics.


Pete

Brian wrote:
> I have done a few launches behind Gary's payout system.
>
> it is on awesome system from a functionality stand point in that you
> launch, wind up the rope and drive back to the starting point to set
> up for the next launch. The rope drags very little and setting up for
> the next launch is quick.
>
> I didn't see any advantage in runway length required. But then I was
> doing it on a 3 mile plus dry lake so it wasn't an issue and 2000 ft +
> tows were no problem.
>
> I suspect that on a 5000 foot runway it would be comparable to a
> straight auto tow in launch height.
>
> Brian
> HP16T
>

[Frank Whiteley]

On Sep 22, 11:53*pm, Pete Brown > wrote:
> Gents:
>
> I have assumed, perhaps incorrectly, that a payout winch *would have an
> advantage. If I have 2000 ft of cable on a spool and a 6,000 ft runway,
> the car with a payout winch use almost all of the *6,000ft runway length.
>
> Were we to do a regular auto tow, the car *could only use 4,000ft of the
> runway to lift the glider. A reverse pulley would also give us the full
> 6,000 ft but, in our case, we can't use it because of runway management
> issues, not aerodynamics.
>
> Pete
>
Your airport designator?

Frank Whiteley

[Gary Boggs]

We've done thousands of payout winch launches at our airport, 4S2.
Even in no wind, we never have to drive over about 65mph. Fortunately
though, the wind is always blowing here in the wind capitol of the
world, Hood River, Oregon. Our winch works very well and has several
safety advantages over a conventional winch.

Airport management continues to be our biggest problem.

Feel free to call me with any questions. My phone numbers are on my
web site, along with some links to videos of our winch in action on
YouTube.

www.nwskysports.com

[Gilbert Smith]

GARY BOGGS > wrote:

>We've done thousands of payout winch launches at our airport, 4S2.
>Even in no wind, we never have to drive over about 65mph. Fortunately
>though, the wind is always blowing here in the wind capitol of the
>world, Hood River, Oregon. Our winch works very well and has several
>safety advantages over a conventional winch.
>
>Airport management continues to be our biggest problem.
>
>Feel free to call me with any questions. My phone numbers are on my
>web site, along with some links to videos of our winch in action on
>YouTube.
>
>www.nwskysports.com

Stunning.
How much cable is let out before starting the launch ?
How far does the tow car travel ?
What height does the glider reach ?
How much height is gained with the tow car stopped ?

Gilbert
UK

[[email protected]]

On Sunday, September 21, 2008 4:06:19 PM UTC-8, wrote:
> It seems that a payout winch similar to those used for hang gliders
> might be useful as a more efficient alternative to auto tows. You can
> make better use of the runway length and have perhaps a safer launch
> with proper calibration. Is anyone using such systems? Are they
> practical? Are they in fact better than a straight auto tow?

I've done payout winch tows on Gary's system. Start out with 100 ft at the glider. vs 1,500 or 2,000 ft on a straight auto tow. Once the tension is set at the truck the pilot does not worry about over-stressing the line. When you pitch up the line is payed out, hit headwind or lift the line is payed out more. (vice versa if you hit sink or tailwind) After the climb is established the truck drivers slows down and the glider can pitch up more for speed/climb. 900 foot pattern tows from a 3,000 ft taxiway. As compared to the same on a 5,000 ft run w 1,500 foot recently at Ephrata WA
There is no cable to drop as it is rewound on the payout drum.
I think http://www.romansdesign.com/ has a project on this, although I have not heard anything in awhile.