Self Retracting Aero Tow Rope?

On TV they have been selling a garden hose that shrinks in length when it is not in use. On TV they advertise that that it will not kink or tangle. The hose is constructed of two parts. The outer cover is a canvas like material that is flat and sealed on the edges. The inner material is a elastic hose.

I am wondering if aero tow rope might constructed to shrink to about 1/4 its length when it is not under load. The outer tube would designed to pull the glider and take the dragging wear. In the center would be a slick elastic material (like a model glider high start).

A retracting rope would allow the tow plane to make lower approaches and be easier to handle on the ground. It might also keep slack out of the rope on tow.

Anyone for a garden hose tow?

Bill Snead
6W

Am 07.04.2014 05:29, wrote:
On TV they have been selling a garden hose that shrinks in length when it is not in use. On TV they advertise that that it will not kink or tangle. The hose is constructed of two parts. The outer cover is a canvas like material that is flat and sealed on the edges. The inner material is a elastic hose.

I am wondering if aero tow rope might constructed to shrink to about 1/4 its length when it is not under load. The outer tube would designed to pull the glider and take the dragging wear. In the center would be a slick elastic material (like a model glider high start).

A retracting rope would allow the tow plane to make lower approaches and be easier to handle on the ground. It might also keep slack out of the rope on tow.

Anyone for a garden hose tow?

Bill Snead
6W


TOST offers a tow cable retractor winch, much better than a garden hose...

http://www.tost.de/Esekd.html


--
Peter Scholz
ASW24 JE

On 4/7/2014 3:25 AM, Peter Scholz wrote:
Am 07.04.2014 05:29, wrote:
On TV they have been selling a garden hose that shrinks in length when
it is not in use. .........
Anyone for a garden hose tow?


TOST offers a tow cable retractor winch, much better than a garden hose...

http://www.tost.de/Esekd.html


--
Peter Scholz
ASW24 JE


We (Greater Boston Soaring Club) have one on each of our 2 Pawnees. We
found them to be unsatisfactory and now only use the Tost release that
is part of that system.

Tony LS6-b 6N

It's a very good idea.

On Monday, April 7, 2014 3:25:02 AM UTC-4, Peter Scholz wrote:
TOST offers a tow cable retractor winch, much better than a garden hose...
http://www.tost.de/Esekd.html

Many sites operate these winches happily in their Pawnees.
However, these sites:
- operate the winches exactly per Tost recommendations
- use only rope known to work with Tost reel
- keep a few spare parts on hand
- have knowledgeable individuals *always* available to
fix the occasional problems that do arise

Sites not meeting the above criteria will be unhappy...

Hope that helps Bill!
Best Regards, Dave

On Sunday, April 6, 2014 9:29:22 PM UTC-6, wrote:
On TV they have been selling a garden hose that shrinks in length when it is not in use. On TV they advertise that that it will not kink or tangle. The hose is constructed of two parts. The outer cover is a canvas like material that is flat and sealed on the edges. The inner material is a elastic hose.



I am wondering if aero tow rope might constructed to shrink to about 1/4 its length when it is not under load. The outer tube would designed to pull the glider and take the dragging wear. In the center would be a slick elastic material (like a model glider high start).



A retracting rope would allow the tow plane to make lower approaches and be easier to handle on the ground. It might also keep slack out of the rope on tow.



Anyone for a garden hose tow?



Bill Snead

6W

Last night I was trying to remember back to the 1950's when some of the tow ropes were made of woven nylon. I think these ropes were somewhat elastic, but I do not remember if having some give and spring back in the rope caused problems on tow. Also, am I right to assume that the tension on an aero tow rope pulling a 700 pound glider up at 600 feet per minute would be about 60 pounds? Further, would I be correct to guess that the tension on a tow rope towing through moderate turbulence would probably vary from 0 to 150 pounds?

Bill Snead

On Monday, April 7, 2014 7:20:38 PM UTC-5, wrote:
Also, am I right to assume that the tension on an aero tow rope pulling a 700 pound glider up at 600 feet per minute would be about 60 pounds? Further, would I be correct to guess that the tension on a tow rope towing through moderate turbulence would probably vary from 0 to 150 pounds? Bill Snead

Need to know a few more things. L/D of the glider, and tow speed. If I assumed 40:1 and 60 MPH, I came up with roughly 100 lbs line tension at 60 MPH, 600 ft/min climb rate, 700 lb glider. But, that was without going back to verify anything other than cancelation of units. Calculation was made up of two parts. Tension due to drag of the glider, and HP to climb converted back into line tension.

Your math may vary. Don't take this as gospel yet. :-)

Steve

I think it is a lousy idea to have an artificially shortening and lengthening tow rope, because as the glider pulls hard and the tow rope reaches the maximum length of the non elastic jacket, the resulting yank is likely to break the weak link and give you an entirely new adventure. Why are you trying to reinvent the wheel? Or are you just "rediscovering the infinigon?"

Need to know a few more things. L/D of the glider, and tow speed. If I assumed 40:1 and 60 MPH, I came up with roughly 100 lbs line tension at 60 MPH, 600 ft/min climb rate, 700 lb glider. But, that was without going back to verify anything other than cancelation of units. Calculation was made up of two parts. Tension due to drag of the glider, and HP to climb converted back into line tension.

Barring any unusual flight maneuvers, the highest line tension will generally occur during initial acceleration on the ground, which is why this is when most rope breaks happen.

On tow, the line tension may be higher than the lower theoretical limits if there is higher drag, for example from lowered gear or a tow hook that is offset from the center of mass or drag.

Mike

On Sunday, April 6, 2014 9:29:22 PM UTC-6, wrote:
On TV they have been selling a garden hose that shrinks in length when it is not in use. On TV they advertise that that it will not kink or tangle. The hose is constructed of two parts. The outer cover is a canvas like material that is flat and sealed on the edges. The inner material is a elastic hose.



I am wondering if aero tow rope might constructed to shrink to about 1/4 its length when it is not under load. The outer tube would designed to pull the glider and take the dragging wear. In the center would be a slick elastic material (like a model glider high start).



A retracting rope would allow the tow plane to make lower approaches and be easier to handle on the ground. It might also keep slack out of the rope on tow.



Anyone for a garden hose tow?



Bill Snead

6W

I appreciate the help. I agree that a rope system that combines an elastic element and non elastic element is not a good system for production towing.. I have always thought that tost winches in the Pawnees were a really a good system.

I am more worried about the thrust of the fully extend rope tending to make the glider over fly the rope in turbulence than breaking the rope when hitting the end of the stretch. If the proposed rope system works at all, it probably should only used by skillful glider pilots.

When gliders are operated off of a typical rual general aviation airport, tow ropes (both auto and aero tows) do not mix well with runway lights and other signage. I have both bought runway lights and been run off airports because of rope damage to runway lights.

At Prievidza a couple of years ago many of the towplanes were equipped with tow line take up reels. They would taxi by about a wing span in front of the glider, the wing runner would grab the tow ring from the tail of the towplane, and hook up the glider as the towplane taxied to the end of the rope. Dangerous to the wing runner, but very fast.

My thought was that a short - non tangling - tow rope might helpful when operating a glider from a public airport.

Bill Snead