Auto-Towing - why is this not more popular?

At 04:29 06 October 2015, Frank Whiteley wrote:
On Monday, October 5, 2015 at 7:32:02 PM UTC-6, Sean Fidler wrote:
From the guy who ran the Cadilac auto-tow camp last year...
=20
"Auto-tow pointers" - Cadillac, MI camp
=20
Gliders: ASW12, ASK21, ASW15, RS15, and some others =20
Tow vehicle: Late model Ford Fairmont, V8, 305 cubic inch=20
Tow rope: Initially, dacron 1500 ft The next year spectra 1500ft
Runway length 5200 ft (field elevation - 800 msl)
Average altitude gain 1000 to 1200 ft (occasionally 1500ft)=20
Get away rate for cross country: 75%
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Highlights: =20
Six pilots auto-tow launch endorsed in one day and a 12-year annual
(Than=
k you Stan & Carol)
Over 100 hours of XC in the 12 from auto-tow in 1 yr=20
=20
Lowlights: introduced to a club with many solo pilots, not many tow
pilo=
ts, and left the unit with them for a year. They never used it!
=20
Auto-Tow unit description: 1500 ft.rope on a reel powered by a Ford
star=
ter motor 1950's vintage (exposed shaft beyond motor housing)
controlled
by=
a dead man type switch. Reel in time about 1 minute. Easily fits in
trun=
k. The emergency release mechanism is a larger copy of Schweizer tow
relea=
se mounted to a hitch with a rope to the driver. The driver has radio
comm=
unication to glider. The driver is any person that is willing. The
driver=
is instructed to accelerate smoothly until glider lifts off and then add
5=
mph unless told otherwise. Normally, this meant (after glider lift off)
fu=
ll to the floorboard (and to remember that the runway does have an
end!). =
=20
=20
=20
=20
For those of you that think this technique is not proper well, ok. For
t=
hose that are willing, this is a way to launch sailplane with: 1) less
cost=
and 2) no need for a tow pilot or tow aircraft. This auto-towing
techniqu=
e is ideal for any "club" with a willing group of two or more. Oh yes,
the=
safety checks were performed on all gliders used. They all had properly
f=
unctioning, carefully inspected tow releases. =20
=20

=20
Sean (still shaking my head at the sidenote).
7T

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


For info
The winch with RR engine is at north wales gliding club,
our other winch destroyed it,s gearbox on sunday so the Rolls Royce is to
be put back to work this weekend with some luck.
KF

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.

On Tue, 06 Oct 2015 13:38:01 -0700, WB wrote:

I would not classify a 1000m field as particularly short.

Agreed. With a remotely placed winch, all you need is a launch and
landing area that's about 350-400m square.

In a southwesterly, pretty much our usual wind direction, we operate off
the 'diamond' in front of our club house. This is 390m on the SW axis and
300m across. We set up the launch point halfway along the southerly edge.
The winch is 1200m away at the far end of 22, a grass run 175m wide that
extends out of the diamond.

With this arrangement almost everybody, including many ab-initios, can
land in the first half of the 'diamond' and stop more or less in line
with the launch point, so a landed glider doesn't block the next winch
launch. In this wind the remainder of 22 is only used for aero-tows,
cable breaks and cable break training, though its available as a huge
safety margin if an ab-initio overshoots his first few landings.

Our Robins can easily launch the Puchacz or an ASK-21 from the diamond,
though this is normally only done for the first aero-tow of the day.


--
martin@ | Martin Gregorie
gregorie. | Essex, UK
org |

WB, I 'm glad you like winch launching. However, I do have just one tiny nit to pick just for the benefit of those not familiar with winch launch. Pilots don't "drop" the rope, they release it (or more likely, it auto-releases). Then the parachute opens preventing the rope from dropping too fast. That gives the winch operator plenty of time to wind in the rope all the way to the winch before it can hit the ground. There's usually less than 100' of rope left out when the winch stops.

If a winch is capable of it, the transmission can be shifted to overdrive and the 'chute ripped out of the sky at more than 100mph to minimize drift. Of course, the operator has to be absolutely certain he can stop the drum before the 'chute is pulled through the fairlead.




On Tuesday, October 6, 2015 at 2:38:05 PM UTC-6, WB wrote:

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.

On Tuesday, October 6, 2015 at 8:25:43 PM UTC-5, wrote:
WB, I 'm glad you like winch launching. However, I do have just one tiny nit to pick just for the benefit of those not familiar with winch launch. Pilots don't "drop" the rope, they release it (or more likely, it auto-releases). Then the parachute opens preventing the rope from dropping too fast. That gives the winch operator plenty of time to wind in the rope all the way to the winch before it can hit the ground. There's usually less than 100' of rope left out when the winch stops.

If a winch is capable of it, the transmission can be shifted to overdrive and the 'chute ripped out of the sky at more than 100mph to minimize drift.. Of course, the operator has to be absolutely certain he can stop the drum before the 'chute is pulled through

Yes, most of the time we did just let it back release. I would often shift our winch (the Eagle Winch, now at Philadelphia) into second gear to recover the line. Usually could lay it down right in front of the winch. Worked even better after the steel cable was replaced with Spectra.

On Monday, October 5, 2015 at 1:27:24 PM UTC-4, Sean Fidler wrote:
Anyway...back to work.

Aaarrggg! Stuff like that gives us nightmares Sean...

One reason winch or auto tows are not more popular is that you are released over the airpark. In an aero tow you can be towed to the lift before releasing. Yes, I know usually on soft days there is a thermal just as one turns downwind to base, but that is not the best place to thermal.

One reason winch or auto tows are not more popular is that you are released
over the airpark. In an aero tow you can be towed to the lift before
releasing. Yes, I know usually on soft days there is a thermal just as one
turns downwind to base, but that is not the best place to thermal.

Hmmm...

I suspect this "truth" is more a statement of "the way aerotows normally are"
than "the realities of usable lift distribution." Reality as a self-fulfilling
prophecy, maybe?

In any event, BTDT insofar as brain-picking for "local knowledge" and
"locations of house thermals," but my experience throughout launch sites
(mostly aerotow) in the intermountain west (mostly Colorado and New Mexico)
has me concluding I can't think of one locale where it's *necessary* to "tow
over there" in order to find usable lift. Sure, some plains sites along the
east slope of the Colorado Rockies tend to start later than a tow into nearby
uplands, but my observation has been very few of the locals routinely take
advantage of that fact when time of launch is considered as a function of
release point. IOW, many tows "go to the hills" just because they can, and not
because it's necessary. Every single one of my launch sites has had convective
lift with easy reach of "above pattern height" releases, for ships of the
ubiquitous 2-33-35:1 performance range.

As for auto towing (exposed to that before winching, I was), popularity (or
lack thereof) has to do - so I reckon - with lack of familiarity; neither auto
towing or winching have been "popular" ("common" is probably a better
descriptor) in the U.S. because whatever critical mass may once have existed
disappeared when "cheap towplanes" became the norm after WW-II. Where they
exist(ed), my experience has been both were "hugely popular."

Bob W.

When I started ground launching, I was told that the glider taking off
often kicks off a thermal is there was a bubble of warm air that the
glider passed through. Because of that, on my ground launch safaris, I
always made a U-turn after release and flew back down the runway. I got
away every time from about 700'. Maybe I was just lucky...

On 10/9/2015 4:30 PM, BobW wrote:
One reason winch or auto tows are not more popular is that you are
released
over the airpark. In an aero tow you can be towed to the lift before
releasing. Yes, I know usually on soft days there is a thermal just
as one
turns downwind to base, but that is not the best place to thermal.

Hmmm...

I suspect this "truth" is more a statement of "the way aerotows
normally are" than "the realities of usable lift distribution."
Reality as a self-fulfilling prophecy, maybe?

In any event, BTDT insofar as brain-picking for "local knowledge" and
"locations of house thermals," but my experience throughout launch
sites (mostly aerotow) in the intermountain west (mostly Colorado and
New Mexico) has me concluding I can't think of one locale where it's
*necessary* to "tow over there" in order to find usable lift. Sure,
some plains sites along the east slope of the Colorado Rockies tend to
start later than a tow into nearby uplands, but my observation has
been very few of the locals routinely take advantage of that fact when
time of launch is considered as a function of release point. IOW, many
tows "go to the hills" just because they can, and not because it's
necessary. Every single one of my launch sites has had convective lift
with easy reach of "above pattern height" releases, for ships of the
ubiquitous 2-33-35:1 performance range.

As for auto towing (exposed to that before winching, I was),
popularity (or lack thereof) has to do - so I reckon - with lack of
familiarity; neither auto towing or winching have been "popular"
("common" is probably a better descriptor) in the U.S. because
whatever critical mass may once have existed disappeared when "cheap
towplanes" became the norm after WW-II. Where they exist(ed), my
experience has been both were "hugely popular."

Bob W.

--
Dan, 5J

On Friday, October 9, 2015 at 10:05:15 AM UTC-6, Jonathan St. Cloud wrote:
One reason winch or auto tows are not more popular is that you are released over the airpark. In an aero tow you can be towed to the lift before releasing. Yes, I know usually on soft days there is a thermal just as one turns downwind to base, but that is not the best place to thermal.

If you can get 2000' - 2500' over the airport, there's no need for a distant tow. If you disagree, get a turbo.

If you can find a thermal, why aero tow? If you can't, there probably aren't any so why aero tow?