Wanting to start a new glider club

John,

I hope you can get this operation off the ground. I did some power plane flying in that area some years back and it looks spectacular for glider flying. Montana's nickname is "big sky country" after all.....

Best of luck,

Ron Clark
LS3
Evergreen Soaring Club

Some useful links. I was a member of a club that did straight reverse
pulley autotow off grass, just a pulley on a rotating shackle on a chain
staked into the grass, and we used to launch a 22M Kestrel with that
system. You have to be carefull with initial rotation as acceleration is
not as fast as a winch - using a 2:1 and 3:1 pulley system might help
with that.



http://www.ukmsg.co.uk/wp-content/up.../SG-Dec-2013.-
Expedition-pilots-guide-to-aunching.pdf

https://www.youtube.com/watch?v=Q0rv1zOmyWg

http://www.pas.rochester.edu/~cline/...und-launch.pdf

http://www.coloradosoaring.org/think...launching/reve
rse_pulley/default.htm

I did most of my ab initio training and learning to be an instructor on
autotow.

I'd suggest avoiding reverse pulley because it's difficult for both the tow
car driver and pilot to know when to finish the launch. With straight
autotow it's easy, stop sufficiently before the end of the runway that you
can drive forward and lay the cable out.

Another issue is cross winds. The cable will drift downwind and looking at
Ronan on Google Earth there are fields with irrigation equipment there. The
farmers will take a dim view of the launch cable being dragged through
their irrigation kit.

Chris

At 15:14 28 April 2018, Paul T wrote:
Some useful links. I was a member of a club that did straight reverse
pulley autotow off grass, just a pulley on a rotating shackle on a chain
staked into the grass, and we used to launch a 22M Kestrel with that
system. You have to be carefull with initial rotation as acceleration is
not as fast as a winch - using a 2:1 and 3:1 pulley system might help
with that.



http://www.ukmsg.co.uk/wp-content/up.../SG-Dec-2013.-
Expedition-pilots-guide-to-aunching.pdf

https://www.youtube.com/watch?v=Q0rv1zOmyWg

http://www.pas.rochester.edu/~cline/...und-launch.pdf

http://www.coloradosoaring.org/think...launching/reve
rse_pulley/default.htm

At 20:43 28 April 2018, Chris Rowland wrote:
I did most of my ab initio training and learning to be an instructor
o
autotow.

I'd suggest avoiding reverse pulley because it's difficult for both
the to
car driver and pilot to know when to finish the launch. With
straigh
autotow it's easy, stop sufficiently before the end of the runway
that yo
can drive forward and lay the cable out.

Another issue is cross winds. The cable will drift downwind and
looking a
Ronan on Google Earth there are fields with irrigation equipment
there. Th
farmers will take a dim view of the launch cable being dragged
throug
their irrigation kit.

Chris



Don't see what the problem is at all with reverse pulley - had many
launches that way - the other end of the runway is just as easily
visible to the tow car driver and as speed decays the glider pilot
pulls off - think you creating an issue where none exists.

If you have a straight reverse pulley system and set it up properly,
with removable strops t both ends the cable is waiting for the next
glider, the car drives back and connects to the other end of the cable
and your ready to launch again.

Some reverse pulley systems where just way over the top -KISS is
the answer. Doubt these guys will be doing hundreds of launches a
day.

Crosswinds are something every ground launching site has to
contend with and 1000's of sites around the world seem to manage
ok with proper training - seem to remember the advice was to have
at least 80m width of clear land to launch from.

On Sunday, April 29, 2018 at 3:30:06 AM UTC-6, Paul T wrote:
At 20:43 28 April 2018, Chris Rowland wrote:
I did most of my ab initio training and learning to be an instructor
o
autotow.

I'd suggest avoiding reverse pulley because it's difficult for both
the to
car driver and pilot to know when to finish the launch. With
straigh
autotow it's easy, stop sufficiently before the end of the runway
that yo
can drive forward and lay the cable out.

Another issue is cross winds. The cable will drift downwind and
looking a
Ronan on Google Earth there are fields with irrigation equipment
there. Th
farmers will take a dim view of the launch cable being dragged
throug
their irrigation kit.

Chris



Don't see what the problem is at all with reverse pulley - had many
launches that way - the other end of the runway is just as easily
visible to the tow car driver and as speed decays the glider pilot
pulls off - think you creating an issue where none exists.

If you have a straight reverse pulley system and set it up properly,
with removable strops t both ends the cable is waiting for the next
glider, the car drives back and connects to the other end of the cable
and your ready to launch again.

Some reverse pulley systems where just way over the top -KISS is
the answer. Doubt these guys will be doing hundreds of launches a
day.

Crosswinds are something every ground launching site has to
contend with and 1000's of sites around the world seem to manage
ok with proper training - seem to remember the advice was to have
at least 80m width of clear land to launch from.

http://coloradosoaring.org/thinking_...ey/default.htm

I've had a couple of chats with John Foster. There are raised runway lights. Reverse pulley allows a lot more control of the line than direct auto tow, so could be an option. Today, UHMWPE ropes, spectra, dyneema, or polyolefin drag line might work for reverse pulley, though I'm unaware of an operation doing so.

Frank Whiteley

On Sunday, April 29, 2018 at 4:22:59 PM UTC-6, Frank Whiteley wrote:
On Sunday, April 29, 2018 at 3:30:06 AM UTC-6, Paul T wrote:
At 20:43 28 April 2018, Chris Rowland wrote:
I did most of my ab initio training and learning to be an instructor
o
autotow.

I'd suggest avoiding reverse pulley because it's difficult for both
the to
car driver and pilot to know when to finish the launch. With
straigh
autotow it's easy, stop sufficiently before the end of the runway
that yo
can drive forward and lay the cable out.

Another issue is cross winds. The cable will drift downwind and
looking a
Ronan on Google Earth there are fields with irrigation equipment
there. Th
farmers will take a dim view of the launch cable being dragged
throug
their irrigation kit.

Chris



Don't see what the problem is at all with reverse pulley - had many
launches that way - the other end of the runway is just as easily
visible to the tow car driver and as speed decays the glider pilot
pulls off - think you creating an issue where none exists.

If you have a straight reverse pulley system and set it up properly,
with removable strops t both ends the cable is waiting for the next
glider, the car drives back and connects to the other end of the cable
and your ready to launch again.

Some reverse pulley systems where just way over the top -KISS is
the answer. Doubt these guys will be doing hundreds of launches a
day.

Crosswinds are something every ground launching site has to
contend with and 1000's of sites around the world seem to manage
ok with proper training - seem to remember the advice was to have
at least 80m width of clear land to launch from.

http://coloradosoaring.org/thinking_...ey/default.htm

I've had a couple of chats with John Foster. There are raised runway lights. Reverse pulley allows a lot more control of the line than direct auto tow, so could be an option. Today, UHMWPE ropes, spectra, dyneema, or polyolefin drag line might work for reverse pulley, though I'm unaware of an operation doing so.

Frank Whiteley

Sorry to dig up this old thread, but now that winter has set in, I'm starting to think and plan more on this project. Do you happen to know where one could get one of these "polyolefin drag lines"? I've looked around a bit, but haven't seen any links for such. I'm also considering various designs for the pulley system. The one that you have linked from the Cotswold GC in Great Britain looks like it would take some effort to build. I've wondered about conscripting an old motorcycle wheel for this purpose and welding up a frame with guides for it to attach to a tow hitch of a pick-up truck. Any proven designs out there like this?

On Friday, December 28, 2018 at 8:33:58 PM UTC-7, John Foster wrote:
On Sunday, April 29, 2018 at 4:22:59 PM UTC-6, Frank Whiteley wrote:
On Sunday, April 29, 2018 at 3:30:06 AM UTC-6, Paul T wrote:
At 20:43 28 April 2018, Chris Rowland wrote:
I did most of my ab initio training and learning to be an instructor
o
autotow.

I'd suggest avoiding reverse pulley because it's difficult for both
the to
car driver and pilot to know when to finish the launch. With
straigh
autotow it's easy, stop sufficiently before the end of the runway
that yo
can drive forward and lay the cable out.

Another issue is cross winds. The cable will drift downwind and
looking a
Ronan on Google Earth there are fields with irrigation equipment
there. Th
farmers will take a dim view of the launch cable being dragged
throug
their irrigation kit.

Chris



Don't see what the problem is at all with reverse pulley - had many
launches that way - the other end of the runway is just as easily
visible to the tow car driver and as speed decays the glider pilot
pulls off - think you creating an issue where none exists.

If you have a straight reverse pulley system and set it up properly,
with removable strops t both ends the cable is waiting for the next
glider, the car drives back and connects to the other end of the cable
and your ready to launch again.

Some reverse pulley systems where just way over the top -KISS is
the answer. Doubt these guys will be doing hundreds of launches a
day.

Crosswinds are something every ground launching site has to
contend with and 1000's of sites around the world seem to manage
ok with proper training - seem to remember the advice was to have
at least 80m width of clear land to launch from.

http://coloradosoaring.org/thinking_...ey/default.htm

I've had a couple of chats with John Foster. There are raised runway lights. Reverse pulley allows a lot more control of the line than direct auto tow, so could be an option. Today, UHMWPE ropes, spectra, dyneema, or polyolefin drag line might work for reverse pulley, though I'm unaware of an operation doing so.

Frank Whiteley

Sorry to dig up this old thread, but now that winter has set in, I'm starting to think and plan more on this project. Do you happen to know where one could get one of these "polyolefin drag lines"? I've looked around a bit, but haven't seen any links for such. I'm also considering various designs for the pulley system. The one that you have linked from the Cotswold GC in Great Britain looks like it would take some effort to build. I've wondered about conscripting an old motorcycle wheel for this purpose and welding up a frame with guides for it to attach to a tow hitch of a pick-up truck. Any proven designs out there like this?

The Essex GC one had a reverse pulley set up. However the rig had a lot of stored energy in the pulley wheels. So a wire break could involve quite a mess. I launched on this rig a few times. I think the Cotswold rig was better. In both iterations, solid wire needs considerably more safety area than other methods.

The Cotswold GC was 200 members and 70 gliders. They also owned tow planes, mostly for wave days.

Now, they did pack in the reverse-pulley for a winch. Not sure exactly why, but cost was not the first consideration.

Frank Whiteley

At 03:33 29 December 2018, John Foster wrote:

Sorry to dig up this old thread, but now that winter has set in, I'm
starti=
ng to think and plan more on this project. Do you happen to know where
one=
could get one of these "polyolefin drag lines"? I've looked around a
bit,=
but haven't seen any links for such. I'm also considering various
designs=
for the pulley system. The one that you have linked from the Cotswold
GC
=
in Great Britain looks like it would take some effort to build. I've
wonde=
red about conscripting an old motorcycle wheel for this purpose and
welding=
up a frame with guides for it to attach to a tow hitch of a pick-up
truck.=
Any proven designs out there like this?

Don't underestimate the loads involved - I doubt if a motorcycle wheel
could cope! The load on the rope from pulley to glider could be up to the

weak link strength and the same load will be in the rope from the pulley to

the towcar. This means that the pulley frame and the anchor point (or
anchor truck) has to withstand twice the weak link break load.