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

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?

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?

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

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

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

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

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

http://www.coloradosoaring.org/think...ey/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

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?

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