Auto-Towing - why is this not more popular?

Thanks, Bill.

I only did a couple of pulley tows for the filming of the ESPN thing.
Some of the raw footage (not shown on TV) shows the rear end of the car
being lifted sufficiently that the driver lost control of the car.
Fortunately the passenger/observer was Emerson Fittipaldi and he reached
across, took the wheel, and straightened out the car. When I released,
it was quite a sight seeing the rope literally slamming down on the
runway. I can easily imagine the tangles this caused in the pulley
system. =-O

Dan

On 10/5/2015 6:18 PM, wrote:


Dan, a pulley tow launches a glider just fine - but then you need to reset for the next launch. Often, this means untangling the rope. Straight auto tow or winch launch rarely tangles the rope.

There are very few pulley tow operations in the world and cycle time is the usual reason why they gave up on pulleys and moved on to winch launch.


On Monday, October 5, 2015 at 9:16:28 AM UTC-6, Dan Marotta wrote:
I once flew for an ESPN video on flying (Secrets of Speed). One of
the launch methods used was an auto pulley tow wherein the pulley
was mounted to the receiver on the back of the car and the cable was
staked to the ground near mid field. The car drove in the takeoff
direction during the launch and, with the 2:1 advantage of the
pulley, it was every bit as exciting as a winch. The car drove at
about 1/2 the speed of the glider. We were using a 3,400' runway
and I don't recall the release height, though it was not as high as
a winch with a full runway length of cable.




On 10/5/2015 5:01 AM, GB wrote:



Good question. Seems to me reverse car tows(fixed pulley windward car drives toward the glider) would be the way to go. Has there been any sailplane work with car mounted pay out winches? Pay out winches are what the hangglider and paraglider community have mostly settled on using. Both of these solutions somewhat mitigate the space needed to auto tow.






--

Dan, 5J

--
Dan, 5J

....
I have the raw footage on DVD. Perhaps I can find a "free" video editor
program and pull out the car pulley sequence and upload to google
drive. We'll see...

Dan

On 10/6/2015 9:21 AM, Dan Marotta wrote:
Thanks, Bill.

I only did a couple of pulley tows for the filming of the ESPN thing.
Some of the raw footage (not shown on TV) shows the rear end of the
car being lifted sufficiently that the driver lost control of the
car. Fortunately the passenger/observer was Emerson Fittipaldi and he
reached across, took the wheel, and straightened out the car. When I
released, it was quite a sight seeing the rope literally slamming down
on the runway. I can easily imagine the tangles this caused in the
pulley system. =-O

Dan

On 10/5/2015 6:18 PM, wrote:


Dan, a pulley tow launches a glider just fine - but then you need to reset for the next launch. Often, this means untangling the rope. Straight auto tow or winch launch rarely tangles the rope.

There are very few pulley tow operations in the world and cycle time is the usual reason why they gave up on pulleys and moved on to winch launch.


On Monday, October 5, 2015 at 9:16:28 AM UTC-6, Dan Marotta wrote:
I once flew for an ESPN video on flying (Secrets of Speed). One of
the launch methods used was an auto pulley tow wherein the pulley
was mounted to the receiver on the back of the car and the cable was
staked to the ground near mid field. The car drove in the takeoff
direction during the launch and, with the 2:1 advantage of the
pulley, it was every bit as exciting as a winch. The car drove at
about 1/2 the speed of the glider. We were using a 3,400' runway
and I don't recall the release height, though it was not as high as
a winch with a full runway length of cable.




On 10/5/2015 5:01 AM, GB wrote:



Good question. Seems to me reverse car tows(fixed pulley windward car drives toward the glider) would be the way to go. Has there been any sailplane work with car mounted pay out winches? Pay out winches are what the hangglider and paraglider community have mostly settled on using. Both of these solutions somewhat mitigate the space needed to auto tow.






--

Dan, 5J

--
Dan, 5J

--
Dan, 5J

Wonder if they would be interested in upsizing to full on sailplane size?
http://cloudstreetwinch.com/

Pay out winch works great! Our airport manager here won't let me use it here tho...
Enjoy this video from our Alvord Desert Safari:

https://www.youtube.com/watch?v=oP8bVgG8xJc

Boggs

Here's another pay out winch video from the other end:

https://www.youtube.com/watch?v=OWPbB2hxPKo

Boggs

And another next to the tow:
https://www.youtube.com/watch?v=gB1KUrgAu58

Here one that's a little long, 13 minutes, but gives you the view from the glider. The tow starts at about 3 minutes. We get more height when the truck gets up to speed before setting the brake:
https://www.youtube.com/watch?v=M3ga-XJ_cdw

Boggs

On Tuesday, October 6, 2015 at 6:45:08 AM UTC-6, Nigel Pocock wrote:
The former Enstone GC in the UK used autotow for several years.
Parafil
wa=
s used as it could be dragged along the tarmac without
appreciable wear.
P=
arafil is not pulley friendly (they tried). It was easily spliced.
Case study,
http://linearcomposites.net/media/pa...e_study_13.pdf

The club moved on to winches before we wore out the parafil.
1500ft plus
l=
aunches were done on a 500m length using an XJ-6 Jaguar with
275hp. We
jus=
t pulled it back to the launch point at 65mph. Near tangled
though we did
=
snag a couple of things in the tall grass on the north side of the
runway.

That engine replaced the 150hp Bedford diesel in one of the ex-
ATC
winches.=
Another winch was refitted with the motor and transmission from
a stolen
=
Rolls Royce that was burned on the airfield one night.

I don't think the third ex-ATC winch was ever put into service
before the
c=
lub folded.

Maybe some lurker knows the fate of those winches.

Frank Whiteley

I learned to fly at Enstone in the late 70s but my recollections of
parafil are very different. Once the outer sheath had been worn
through on retrieves the cable broke on about 1 in 5 launches.
Since we were using scrapper cars we mounted the cable
attatchment in the middle of the roof. This solved the problem of
lifting the weight off the rear wheels when towing.
We also built a special which used a Ford Transit pickup with a mid
mounted 4.2litre Jaguar engine. We retained the original axle which
gave us very good acceleration but a top speed of about 60mph.

I now fly at Lasham which used to use Autotow. We now use
modern winches which give better and safer launches to 1700-
2000ft on a normal day. The cost of buying, maintaining and
running costs of autotow were much higher than the winch in the
UK. Gasoline about $7.50 a gallon here. Winch runs on LPG.


Interesting. I can only recall 2-3 repairs. We knotted the dacron in a protective rubber bumper. We did move in winches within a year, so I really only had a single season with the parafil. Enjoyed the Jag though.

Frank Whiteley

On Tuesday, October 6, 2015 at 11:17:37 AM UTC-6, Waveguru wrote:
Pay out winch works great! Our airport manager here won't let me use it here tho...
Enjoy this video from our Alvord Desert Safari:

https://www.youtube.com/watch?v=oP8bVgG8xJc

Boggs

A payout winch can be forced to work with a low speed glider like a 2-33 but don't try to launch a heavy composite that way. If you do the math you'll see that the tow car will have to hit nearly 100mph.

When one looks at all the alternatives, it's clear that the cheapest, quickest, simplest way to ground launch a glider is with a winch. Auto tow in all its variations just can't compete.

All of these objections to winch launch have been put to rest. If you want to see small field winch operations, use Google Earth to look at European, particularly German, glider airports. Many are as short as 1000m and surrounded by trees. Just pick club names from OLC and enter them in the GE search field.

Winch launch will never drop the rope anywhere except right in front of the winch unless the rope breaks which is getting very rare with ultra-strong ropes.

If a pilot really thinks a distant tow is necessary, then use a sustainer from a winch launch.

SSA group insurance offers winch coverage for traveling to and operating at any airfield.


I would not classify a 1000m field as particularly short. I have operated winch and auto launch off of shorter fields, but it is not too good for anything but pattern practice. I would say that in some ways winching can do something that aerotow would not do as well: With a winch you only need 1000 feet (or less) of launching/landing area if the winch can be placed a sufficient distance beyond the "runway" end. That opens up a lot of possibilities for flying from non-airports. I agree that when everything works correctly the winch line will not end up in the trees. However, there's always the pilot who forgets to correct for crosswind and drops the rope too far downwind or the line breaks and falls into the trees. Even the synthetics break occasionally. Timely replacement when worn makes breaks unlikely. And with synthetics we no longer have the problem of a highly conductive steel cable on power lines.

Glad to hear that SSA group plan covers winch transport. That may not have always been the case. Or, it might have just been the case that our self mobile winch was not insured for over the road. That winch left us a long time ago. Wish we had it back.

the tow car will have to hit nearly 100mph.

I guess you didn't bother to watch the videos, eh Bill? We launched many glass ships to thousands of feet.

Boggs