Winching - Reverse Auto Tow

On Tuesday, July 26, 2016 at 8:38:31 AM UTC-6, Steve Leonard wrote:
I would get a 15 to 17 inch rim from a junk yard. Cheap, steel, plain. Then, get a stub axle and hub from Tractor Supply or the like with at least a 2000 lb load rating. No need for guides. No need for swivels. Axis of rotation for the wheel to be horizontal, running side to side. Your pull off angles to the side (for the anchor, or the glider while climbing) will never be more than a few degrees, and the rope will not want to climb out of the deepest part of the wheel. Don't add more complication than is needed. With 8000 feet of ramp, you probably don't need much more than 6000 feet of rope.

If you are anchoring the pulley (say, to a parked car), still no need for a swivel. Keep your life simple!

Just my two cents worth.

Steve Leonard

Steve, that is exactly what I was planning to do at first. As I looked at other applications, I began to think that I was making it too simple, and needed more precision. Maybe some other designs are overly complex.

On Tuesday, July 26, 2016 at 1:51:14 AM UTC-6, Peter Whitehead wrote:
On Tuesday, 26 July 2016 02:12:58 UTC+1, wrote:
Does anyone have particularly bad experiences with pulleys used like this. I am talking about the pulleys themselves. Has someone found a particular diameter that is too small. Obviously larger is better for both bearing speed and rope bending, but there are limitations on cost and availability...particular for the trial run I'm thinking about. I am considering a trial run with a swiveling pulley on the receiver hitch of a pickup, no guides, just the pulley, with around 8,000' of 1/4" poly hollow braid, flying a 1-26. That should prove the launch height, assuming the rope doesn't break on the first launch. I'm not sure what to expect at the pulley end, and don't want the rope jumping out of the sheave, catching and breaking. I doubt it will, but have no experience to back it up.

Hi, I wrote an article "The Expedition Pilot's guide to launching" in the Dec2013/Jan 2014 edition of the UK Sailplane and Gliding magazine. It may be of interest. I use 12mm diameter high density polypropylene rope (Skyrope from Skylaunch) on snatch blocks with, initally steel pulleys on plain bearings 110mm dia. The bearings cooked in spite of lots of grease! These have been modified for regular use to nylon pulleys with steel ball bearings. The steel flaps or cheeks of the snatch blocks keep the rope where it should be. I use either a 2 to 1 or 3 to one system to keep the tow speed down ( we use some rough fields). If you are serious then I can send you a copy of the article and details of the kit, as well as the links to YouTube videos of some launches in the Lake District (UK) using 2 to 1 pulley system, with one pulley on a ground anchor and the other on the car's tow hitch (with the rope tail to another ground anchor). Everything used is inexpensive, and it works. Pete Whitehead

Pete, I watched your videos, and those look like strong launches! Much better acceleration than we typically see. If you could send me an electronic copy of your article, I would love to read it.

On Wednesday, July 27, 2016 at 3:28:38 AM UTC+12, wrote:
On Tuesday, July 26, 2016 at 1:51:14 AM UTC-6, Peter Whitehead wrote:
On Tuesday, 26 July 2016 02:12:58 UTC+1, wrote:
Does anyone have particularly bad experiences with pulleys used like this. I am talking about the pulleys themselves. Has someone found a particular diameter that is too small. Obviously larger is better for both bearing speed and rope bending, but there are limitations on cost and availability...particular for the trial run I'm thinking about. I am considering a trial run with a swiveling pulley on the receiver hitch of a pickup, no guides, just the pulley, with around 8,000' of 1/4" poly hollow braid, flying a 1-26. That should prove the launch height, assuming the rope doesn't break on the first launch. I'm not sure what to expect at the pulley end, and don't want the rope jumping out of the sheave, catching and breaking. I doubt it will, but have no experience to back it up.

Hi, I wrote an article "The Expedition Pilot's guide to launching" in the Dec2013/Jan 2014 edition of the UK Sailplane and Gliding magazine. It may be of interest. I use 12mm diameter high density polypropylene rope (Skyrope from Skylaunch) on snatch blocks with, initally steel pulleys on plain bearings 110mm dia. The bearings cooked in spite of lots of grease! These have been modified for regular use to nylon pulleys with steel ball bearings.. The steel flaps or cheeks of the snatch blocks keep the rope where it should be. I use either a 2 to 1 or 3 to one system to keep the tow speed down ( we use some rough fields). If you are serious then I can send you a copy of the article and details of the kit, as well as the links to YouTube videos of some launches in the Lake District (UK) using 2 to 1 pulley system, with one pulley on a ground anchor and the other on the car's tow hitch (with the rope tail to another ground anchor). Everything used is inexpensive, and it works. Pete Whitehead

Pete, I watched your videos, and those look like strong launches! Much better acceleration than we typically see. If you could send me an electronic copy of your article, I would love to read it.

Yes, the launches shown here look like normal launches from a pretty powerful winch, not the average rather anaemic direct-pull car launch. Sadly, we don't see anything of the vehicle or launch setup

https://www.youtube.com/channel/UC_G...WaGdMMduefDVAg

On 7/26/2016 9:28 AM, wrote:
Snip If you could send me an electronic copy of your article, I would love to read it.

Or post it on Dropbox or similar so we can all read it!
--
Dan, 5J

On Tuesday, July 26, 2016 at 9:44:26 AM UTC-6, Bruce Hoult wrote:
On Wednesday, July 27, 2016 at 3:28:38 AM UTC+12, wrote:
On Tuesday, July 26, 2016 at 1:51:14 AM UTC-6, Peter Whitehead wrote:
On Tuesday, 26 July 2016 02:12:58 UTC+1, wrote:
Does anyone have particularly bad experiences with pulleys used like this. I am talking about the pulleys themselves. Has someone found a particular diameter that is too small. Obviously larger is better for both bearing speed and rope bending, but there are limitations on cost and availability...particular for the trial run I'm thinking about. I am considering a trial run with a swiveling pulley on the receiver hitch of a pickup, no guides, just the pulley, with around 8,000' of 1/4" poly hollow braid, flying a 1-26. That should prove the launch height, assuming the rope doesn't break on the first launch. I'm not sure what to expect at the pulley end, and don't want the rope jumping out of the sheave, catching and breaking. I doubt it will, but have no experience to back it up.

Hi, I wrote an article "The Expedition Pilot's guide to launching" in the Dec2013/Jan 2014 edition of the UK Sailplane and Gliding magazine. It may be of interest. I use 12mm diameter high density polypropylene rope (Skyrope from Skylaunch) on snatch blocks with, initally steel pulleys on plain bearings 110mm dia. The bearings cooked in spite of lots of grease! These have been modified for regular use to nylon pulleys with steel ball bearings. The steel flaps or cheeks of the snatch blocks keep the rope where it should be. I use either a 2 to 1 or 3 to one system to keep the tow speed down ( we use some rough fields). If you are serious then I can send you a copy of the article and details of the kit, as well as the links to YouTube videos of some launches in the Lake District (UK) using 2 to 1 pulley system, with one pulley on a ground anchor and the other on the car's tow hitch (with the rope tail to another ground anchor). Everything used is inexpensive, and it works. Pete Whitehead

Pete, I watched your videos, and those look like strong launches! Much better acceleration than we typically see. If you could send me an electronic copy of your article, I would love to read it.

Yes, the launches shown here look like normal launches from a pretty powerful winch, not the average rather anaemic direct-pull car launch. Sadly, we don't see anything of the vehicle or launch setup

https://www.youtube.com/channel/UC_G...WaGdMMduefDVAg

This one gives a little more detail of the mechanical set-up. Surprising they are able to get that kind of acceleration from such a small vehicle.

On Tuesday, July 26, 2016 at 9:44:26 AM UTC-6, Bruce Hoult wrote:
On Wednesday, July 27, 2016 at 3:28:38 AM UTC+12, wrote:
On Tuesday, July 26, 2016 at 1:51:14 AM UTC-6, Peter Whitehead wrote:
On Tuesday, 26 July 2016 02:12:58 UTC+1, wrote:
Does anyone have particularly bad experiences with pulleys used like this. I am talking about the pulleys themselves. Has someone found a particular diameter that is too small. Obviously larger is better for both bearing speed and rope bending, but there are limitations on cost and availability...particular for the trial run I'm thinking about. I am considering a trial run with a swiveling pulley on the receiver hitch of a pickup, no guides, just the pulley, with around 8,000' of 1/4" poly hollow braid, flying a 1-26. That should prove the launch height, assuming the rope doesn't break on the first launch. I'm not sure what to expect at the pulley end, and don't want the rope jumping out of the sheave, catching and breaking. I doubt it will, but have no experience to back it up.

Hi, I wrote an article "The Expedition Pilot's guide to launching" in the Dec2013/Jan 2014 edition of the UK Sailplane and Gliding magazine. It may be of interest. I use 12mm diameter high density polypropylene rope (Skyrope from Skylaunch) on snatch blocks with, initally steel pulleys on plain bearings 110mm dia. The bearings cooked in spite of lots of grease! These have been modified for regular use to nylon pulleys with steel ball bearings. The steel flaps or cheeks of the snatch blocks keep the rope where it should be. I use either a 2 to 1 or 3 to one system to keep the tow speed down ( we use some rough fields). If you are serious then I can send you a copy of the article and details of the kit, as well as the links to YouTube videos of some launches in the Lake District (UK) using 2 to 1 pulley system, with one pulley on a ground anchor and the other on the car's tow hitch (with the rope tail to another ground anchor). Everything used is inexpensive, and it works. Pete Whitehead

Pete, I watched your videos, and those look like strong launches! Much better acceleration than we typically see. If you could send me an electronic copy of your article, I would love to read it.

Yes, the launches shown here look like normal launches from a pretty powerful winch, not the average rather anaemic direct-pull car launch. Sadly, we don't see anything of the vehicle or launch setup

https://www.youtube.com/channel/UC_G...WaGdMMduefDVAg

This one gives a little more detail of the mechanical set-up. Surprising they are able to get that kind of acceleration from such a small vehicle.

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

On Sunday, December 30, 2018 at 8:17:58 PM UTC-7, John Foster wrote:
On Tuesday, July 26, 2016 at 9:44:26 AM UTC-6, Bruce Hoult wrote:
On Wednesday, July 27, 2016 at 3:28:38 AM UTC+12, wrote:
On Tuesday, July 26, 2016 at 1:51:14 AM UTC-6, Peter Whitehead wrote:
On Tuesday, 26 July 2016 02:12:58 UTC+1, wrote:
Does anyone have particularly bad experiences with pulleys used like this. I am talking about the pulleys themselves. Has someone found a particular diameter that is too small. Obviously larger is better for both bearing speed and rope bending, but there are limitations on cost and availability...particular for the trial run I'm thinking about. I am considering a trial run with a swiveling pulley on the receiver hitch of a pickup, no guides, just the pulley, with around 8,000' of 1/4" poly hollow braid, flying a 1-26. That should prove the launch height, assuming the rope doesn't break on the first launch. I'm not sure what to expect at the pulley end, and don't want the rope jumping out of the sheave, catching and breaking. I doubt it will, but have no experience to back it up.

Hi, I wrote an article "The Expedition Pilot's guide to launching" in the Dec2013/Jan 2014 edition of the UK Sailplane and Gliding magazine. It may be of interest. I use 12mm diameter high density polypropylene rope (Skyrope from Skylaunch) on snatch blocks with, initally steel pulleys on plain bearings 110mm dia. The bearings cooked in spite of lots of grease! These have been modified for regular use to nylon pulleys with steel ball bearings. The steel flaps or cheeks of the snatch blocks keep the rope where it should be. I use either a 2 to 1 or 3 to one system to keep the tow speed down ( we use some rough fields). If you are serious then I can send you a copy of the article and details of the kit, as well as the links to YouTube videos of some launches in the Lake District (UK) using 2 to 1 pulley system, with one pulley on a ground anchor and the other on the car's tow hitch (with the rope tail to another ground anchor). Everything used is inexpensive, and it works. Pete Whitehead

Pete, I watched your videos, and those look like strong launches! Much better acceleration than we typically see. If you could send me an electronic copy of your article, I would love to read it.

Yes, the launches shown here look like normal launches from a pretty powerful winch, not the average rather anaemic direct-pull car launch. Sadly, we don't see anything of the vehicle or launch setup

https://www.youtube.com/channel/UC_G...WaGdMMduefDVAg

This one gives a little more detail of the mechanical set-up. Surprising they are able to get that kind of acceleration from such a small vehicle.

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

Anchored plus reverse pulley, so mechanical advantage of 2 plus speed reduction of 2, so the launch vehicle probably weighes 3,000lb or more so it can provide a 60mph rope speed at 30mph and not break traction on grass. Thus it can give a snappy launch. Slow turn around but better than just anchor pulley for short fields. Appears they can snap onto a working ridge nearby.

Frank Whiteley

On Sunday, December 30, 2018 at 8:17:58 PM UTC-7, John Foster wrote:
On Tuesday, July 26, 2016 at 9:44:26 AM UTC-6, Bruce Hoult wrote:
On Wednesday, July 27, 2016 at 3:28:38 AM UTC+12, wrote:
On Tuesday, July 26, 2016 at 1:51:14 AM UTC-6, Peter Whitehead wrote:
On Tuesday, 26 July 2016 02:12:58 UTC+1, wrote:
Does anyone have particularly bad experiences with pulleys used like this. I am talking about the pulleys themselves. Has someone found a particular diameter that is too small. Obviously larger is better for both bearing speed and rope bending, but there are limitations on cost and availability...particular for the trial run I'm thinking about. I am considering a trial run with a swiveling pulley on the receiver hitch of a pickup, no guides, just the pulley, with around 8,000' of 1/4" poly hollow braid, flying a 1-26. That should prove the launch height, assuming the rope doesn't break on the first launch. I'm not sure what to expect at the pulley end, and don't want the rope jumping out of the sheave, catching and breaking. I doubt it will, but have no experience to back it up.

Hi, I wrote an article "The Expedition Pilot's guide to launching" in the Dec2013/Jan 2014 edition of the UK Sailplane and Gliding magazine. It may be of interest. I use 12mm diameter high density polypropylene rope (Skyrope from Skylaunch) on snatch blocks with, initally steel pulleys on plain bearings 110mm dia. The bearings cooked in spite of lots of grease! These have been modified for regular use to nylon pulleys with steel ball bearings. The steel flaps or cheeks of the snatch blocks keep the rope where it should be. I use either a 2 to 1 or 3 to one system to keep the tow speed down ( we use some rough fields). If you are serious then I can send you a copy of the article and details of the kit, as well as the links to YouTube videos of some launches in the Lake District (UK) using 2 to 1 pulley system, with one pulley on a ground anchor and the other on the car's tow hitch (with the rope tail to another ground anchor). Everything used is inexpensive, and it works. Pete Whitehead

Pete, I watched your videos, and those look like strong launches! Much better acceleration than we typically see. If you could send me an electronic copy of your article, I would love to read it.

Yes, the launches shown here look like normal launches from a pretty powerful winch, not the average rather anaemic direct-pull car launch. Sadly, we don't see anything of the vehicle or launch setup

https://www.youtube.com/channel/UC_G...WaGdMMduefDVAg

This one gives a little more detail of the mechanical set-up. Surprising they are able to get that kind of acceleration from such a small vehicle.

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

It's a anchor/reverse pulley, thus different from the old Cotswold setup. 2x pull advantage and 2x rope acceleration, so a 2600-3000lb launch vehicle could provide adequate power and not break traction on turf using 4WD.

IMVHO,

Frank Whiteley

On Sunday, December 30, 2018 at 11:18:12 PM UTC-5, Frank Whiteley wrote:
On Sunday, December 30, 2018 at 8:17:58 PM UTC-7, John Foster wrote:
On Tuesday, July 26, 2016 at 9:44:26 AM UTC-6, Bruce Hoult wrote:
On Wednesday, July 27, 2016 at 3:28:38 AM UTC+12, wrote:
On Tuesday, July 26, 2016 at 1:51:14 AM UTC-6, Peter Whitehead wrote:
On Tuesday, 26 July 2016 02:12:58 UTC+1, wrote:
Does anyone have particularly bad experiences with pulleys used like this. I am talking about the pulleys themselves. Has someone found a particular diameter that is too small. Obviously larger is better for both bearing speed and rope bending, but there are limitations on cost and availability...particular for the trial run I'm thinking about. I am considering a trial run with a swiveling pulley on the receiver hitch of a pickup, no guides, just the pulley, with around 8,000' of 1/4" poly hollow braid, flying a 1-26. That should prove the launch height, assuming the rope doesn't break on the first launch. I'm not sure what to expect at the pulley end, and don't want the rope jumping out of the sheave, catching and breaking.. I doubt it will, but have no experience to back it up.

Hi, I wrote an article "The Expedition Pilot's guide to launching" in the Dec2013/Jan 2014 edition of the UK Sailplane and Gliding magazine. It may be of interest. I use 12mm diameter high density polypropylene rope (Skyrope from Skylaunch) on snatch blocks with, initally steel pulleys on plain bearings 110mm dia. The bearings cooked in spite of lots of grease! These have been modified for regular use to nylon pulleys with steel ball bearings. The steel flaps or cheeks of the snatch blocks keep the rope where it should be. I use either a 2 to 1 or 3 to one system to keep the tow speed down ( we use some rough fields). If you are serious then I can send you a copy of the article and details of the kit, as well as the links to YouTube videos of some launches in the Lake District (UK) using 2 to 1 pulley system, with one pulley on a ground anchor and the other on the car's tow hitch (with the rope tail to another ground anchor). Everything used is inexpensive, and it works. Pete Whitehead

Pete, I watched your videos, and those look like strong launches! Much better acceleration than we typically see. If you could send me an electronic copy of your article, I would love to read it.

Yes, the launches shown here look like normal launches from a pretty powerful winch, not the average rather anaemic direct-pull car launch. Sadly, we don't see anything of the vehicle or launch setup

https://www.youtube.com/channel/UC_G...WaGdMMduefDVAg

This one gives a little more detail of the mechanical set-up. Surprising they are able to get that kind of acceleration from such a small vehicle..

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

Anchored plus reverse pulley, so mechanical advantage of 2 plus speed reduction of 2, so the launch vehicle probably weighes 3,000lb or more so it can provide a 60mph rope speed at 30mph and not break traction on grass. Thus it can give a snappy launch. Slow turn around but better than just anchor pulley for short fields. Appears they can snap onto a working ridge nearby.

Frank Whiteley

The 2x speed advantage means a 1/2x force disadvantage, no? The car has to accelerate its own weight, plus twice the tension of the rope. Better have a big engine. After it reaches the needed speed (say 30mph for the car - 60mph for the glider) then no further acceleration is needed, so the car's own mass no longer matters and the engine only has to keep the 2x rope tension going (which gradually reduces towards 1x as the angle of airborne part of the rope increaes). Assuming 1000 pounds tension, 2000 pounds pull, at 30 mph, that's a delivered mechanical power of about 150 HP.

On Monday, December 31, 2018 at 10:19:17 AM UTC-6, wrote:
On Sunday, December 30, 2018 at 11:18:12 PM UTC-5, Frank Whiteley wrote:
On Sunday, December 30, 2018 at 8:17:58 PM UTC-7, John Foster wrote:
On Tuesday, July 26, 2016 at 9:44:26 AM UTC-6, Bruce Hoult wrote:
On Wednesday, July 27, 2016 at 3:28:38 AM UTC+12, wrote:
On Tuesday, July 26, 2016 at 1:51:14 AM UTC-6, Peter Whitehead wrote:
On Tuesday, 26 July 2016 02:12:58 UTC+1, wrote:
Does anyone have particularly bad experiences with pulleys used like this. I am talking about the pulleys themselves. Has someone found a particular diameter that is too small. Obviously larger is better for both bearing speed and rope bending, but there are limitations on cost and availability...particular for the trial run I'm thinking about. I am considering a trial run with a swiveling pulley on the receiver hitch of a pickup, no guides, just the pulley, with around 8,000' of 1/4" poly hollow braid, flying a 1-26. That should prove the launch height, assuming the rope doesn't break on the first launch. I'm not sure what to expect at the pulley end, and don't want the rope jumping out of the sheave, catching and breaking. I doubt it will, but have no experience to back it up.

Hi, I wrote an article "The Expedition Pilot's guide to launching" in the Dec2013/Jan 2014 edition of the UK Sailplane and Gliding magazine. It may be of interest. I use 12mm diameter high density polypropylene rope (Skyrope from Skylaunch) on snatch blocks with, initally steel pulleys on plain bearings 110mm dia. The bearings cooked in spite of lots of grease! These have been modified for regular use to nylon pulleys with steel ball bearings. The steel flaps or cheeks of the snatch blocks keep the rope where it should be. I use either a 2 to 1 or 3 to one system to keep the tow speed down ( we use some rough fields). If you are serious then I can send you a copy of the article and details of the kit, as well as the links to YouTube videos of some launches in the Lake District (UK) using 2 to 1 pulley system, with one pulley on a ground anchor and the other on the car's tow hitch (with the rope tail to another ground anchor). Everything used is inexpensive, and it works. Pete Whitehead

Pete, I watched your videos, and those look like strong launches! Much better acceleration than we typically see. If you could send me an electronic copy of your article, I would love to read it.

Yes, the launches shown here look like normal launches from a pretty powerful winch, not the average rather anaemic direct-pull car launch. Sadly, we don't see anything of the vehicle or launch setup

https://www.youtube.com/channel/UC_G...WaGdMMduefDVAg

This one gives a little more detail of the mechanical set-up. Surprising they are able to get that kind of acceleration from such a small vehicle.

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

Anchored plus reverse pulley, so mechanical advantage of 2 plus speed reduction of 2, so the launch vehicle probably weighes 3,000lb or more so it can provide a 60mph rope speed at 30mph and not break traction on grass. Thus it can give a snappy launch. Slow turn around but better than just anchor pulley for short fields. Appears they can snap onto a working ridge nearby.

Frank Whiteley

The 2x speed advantage means a 1/2x force disadvantage, no? The car has to accelerate its own weight, plus twice the tension of the rope. Better have a big engine. After it reaches the needed speed (say 30mph for the car - 60mph for the glider) then no further acceleration is needed, so the car's own mass no longer matters and the engine only has to keep the 2x rope tension going (which gradually reduces towards 1x as the angle of airborne part of the rope increaes). Assuming 1000 pounds tension, 2000 pounds pull, at 30 mph, that's a delivered mechanical power of about 150 HP.

The SES tow car we used for pulley launch was a late 70's Ford LTD out of a junkyard. It had the 460 cubic inch engine, but it appeared to be running on only 5 cylinders or so. That worked in our favor. Had just the right amount of horsepower to launch a loaded 2 seater. Put it in low gear, floor it and keep the pedal on the floor and accelerate up to 28 mph. As the glider loaded up the line, the car would gradually decelerate to around 18 mph at which time the glider would be at the top of the launch. Launching single seaters or launching with much headwind required backing off the throttle some during the launch, but all-in-all, it was stupid simple and worked very well. We did have to put some bricks in the trunk to weight the rear end for traction. That was on asphalt. We did operate a few times on grass strips and used a Nissan 4 wheel drive SUV for that.

WB