Winch launch clinic at Faribault, Minnesota

Frank Whiteley and I spent the first three days of this week training the
folks at Cross Country Soaring (
http://www.crosscountrysoaring.com/index.html ) to use their new winch.
Frank trained the winch drivers and I trained pilots.

I lost track of the number of launches but it was probably over 80.
Faribault is a fairly busy GA airport but we were able to use their main
runway without causing any problems for the 'power' traffic by making radio
calls on the CTAF frequency like, "Faribault traffic, Glider 37M position
and hold runway 30 at taxiway Bravo, winch launch to 1500 AGL in one minute.
Arriving traffic please advise"

Every day offered thermic conditions allowing for sustained flight whenever
needed to accomodate arriving or departing 'power traffic'. "Glider 37M
holding 2 miles NW Faribault for arriving Cessna."

We pulled out the rope on the ten foot wide strip of grass between the edge
of the asphalt and the edge lights on the side opposite the taxiways. This
kept the rope off the runway surface until needed. No aircraft could taxi
over the rope.

Simultaineously training winch drivers and pilots can lead to chaotic
results but occasional glitches by newbie drivers gave just the right level
of emergiency training to the pilots. In addition to driver glitches, we
suffered a few rope breaks, mostly knots made by the previous owner giving
way, but since we were using Spectra rope, these led to minimum delay.
There were no tangles. Spectra allows convincing simulations of rope breaks
since pulling the release under high tension causes no tangles.

We gave one of the local mechanics a ride. Afterwards I asked him how he
liked it. "Kinda nice", he said but he was having trouble enunciating the
words through an enormous ear to ear grin. To allow Don to stay at the
winch for more training, I took one of his scheduled students who told me he
was having trouble with landings. Four quick winch launches for landing
practice had him much improved. Three or four more would have him ready for
solo.

At the end, no one questioned whether winch launch can co-exist with GA
traffic. I chatted with some of the airplane owners at the fuel pump.
Their main question was, "How much gas does that thing use?" My answer was,
"About a quart of Unleaded per launch". That made them look wistfully at
the $200 figure on the pump.

What type of winch was being used?

John Scott

"John Scott" wrote in message
.. .
What type of winch was being used?

John Scott



It was an ex-Canadian Gerhlein style single drum winch with a Chevy 350 V8
and a GM TH400 series transmission. It's a well maintained example of a
1960's style winch. It's not ideal but cheap enough to get started with
winch launch. The ~1500' AGL launches it delivered were just fine for
contacting thermals. Had we not been in training mode, I could have
thermalled away on almost every launch.

The power was just right to allow the glider pilot to control airspeed with
pitch inputs but it did exhibit tension oscillations whenever the launch was
disturbed by a rough gear change or thermals as is typical with this type of
winch. We were able to reduce oscillations by using 2nd gear. 2nd gear
also eliminates the tendency for the TH400 to make a 3 - 2 downshift near
the top of the launch.

A modern tension controlled winch would probably increase the release
heights to 2000' AGL by holding rope tension nearly perfect.

Bill Daniels

On May 23, 9:45*am, "Bill Daniels" bildan@comcast-dot-net wrote:
Frank Whiteley and I spent the first three days of this week training the
folks at Cross Country Soaring (http://www.crosscountrysoaring.com/index.html) to use their new winch.
Frank trained the winch drivers and I trained pilots.

I lost track of the number of launches but it was probably over 80.
Faribault is a fairly busy GA airport but we were able to use their main
runway without causing any problems for the 'power' traffic by making radio
calls on the CTAF frequency like, "Faribault traffic, Glider 37M position
and hold runway 30 at taxiway Bravo, winch launch to 1500 AGL in one minute.
Arriving traffic please advise"

Every day offered thermic conditions allowing for sustained flight whenever
needed to accomodate arriving or departing 'power traffic'. *"Glider 37M
holding 2 miles NW Faribault for arriving Cessna."

We pulled out the rope on the ten foot wide strip of grass between the edge
of the asphalt and the edge lights on the side opposite the taxiways. *This
kept the rope off the runway surface until needed. *No aircraft could taxi
over the rope.

Simultaineously training winch drivers and pilots can lead to chaotic
results but occasional glitches by newbie drivers gave just the right level
of emergiency training to the pilots. *In addition to driver glitches, we
suffered a few rope breaks, mostly knots made by the previous owner giving
way, but since we were using Spectra rope, *these led to minimum delay.
There were no tangles. *Spectra allows convincing simulations of rope breaks
since pulling the release under high tension causes no tangles.

We gave one of the local mechanics a ride. *Afterwards I asked him how he
liked it. *"Kinda nice", he said but he was having trouble enunciating the
words through an enormous ear to ear grin. *To allow Don to stay at the
winch for more training, I took one of his scheduled students who told me he
was having trouble with landings. *Four quick winch launches for landing
practice had him much improved. *Three or four more would have him ready for
solo.

At the end, no one questioned whether winch launch can co-exist with GA
traffic. *I chatted with some of the airplane owners at the fuel pump.
Their main question was, "How much gas does that thing use?" *My answer was,
"About a quart of Unleaded per launch". *That made them look wistfully at
the $200 figure on the pump.

Awesome, I wish I could've made it, but darn work got in the way. A
couple people from my club were there though so I look forward to
debriefing with them. And I just may have to get up there with Don
now and take some launches!

As a long time booster of soaring in the upper midwest I want to thank
Bill and Frank for making the trip and doing the great training and
promotion that I'm sure has motivated many here. And to Don at CC
Soaring for taking a chance and making it work. You guys ROCK! Sorry
I couldn't be there. Matt Michael Ames Iowa

Coupla' questions;

1) What was the highest release?
2) What was the lowest release?
3) Was it skill/training/experience of the pilot/operator/both that
allowed you to get to the highest release?
4) What types of line was used? Steel? Spectra? How long was the
line?

Thanks.

"ContestID67" wrote in message
...
Coupla' questions;

1) What was the highest release?
A little over 1700 feet AGL with the ASK21 (K21's always seem to come out
on top)

2) What was the lowest release?
~50 feet (rope break). But I think what you meant was lowest release when
nothing went wrong and that was about 1400 feet with the G103 Twin II.

3) Was it skill/training/experience of the pilot/operator/both that
allowed you to get to the highest release?
Nope, just following standard winch launch protocol.

This winch allowed a fairly simple technique of just "capturing" the
airspeed and holding it at 60 knots with the 103 and 65 knots with the K21.
If you didn't let the airspeed get high it was easy to control it with
elevator inputs.

I just let the glider float off the runway and climb gently with rapidly
increasing airspeed until 50 knots and then smoothly pitched up to "capture"
the airspeed at the pre-selected "target". All the pilots found this easy
to master.

4) What types of line was used? Steel? Spectra? How long was the
line?

We were .25" diameter double braid (Kermantle?) Spectra. There was a 5/32"
12 strand load bearing core of Spectra (UHMWPE) and a braided cover. The
cover was probably polyester and was suffering from the rollers. I think we
were using about 3700 feet according to Google Earth.

The 1//4" diameter meant that the winch drum wouldn't hold a runway length
of rope so we used a taxiway intersection as the launch point. 1/4" also
meant that the aerodynamic drag was high which limited the achieved release
height. Don will probably switch to 3/16" 12-strand single braid Spectra
when this stuff wears out. Using the full runway length and thinner rope
should permit 2000' launches.

Bill Daniels.

We don't seem to get 'tension oscillations' using basically similar
winches in the UK! Deliberately launching in second gear sounds like a
good way of over-reving the winch engine or running out of available cable
speed, unless there is a reasonable headwind. Perhaps Bill should have a
word with our gearbox supplier? We just launch in 'Drive' without
experiencing any of these problems!

We weren't told how long the winch run was, but I note that Bill felt
that 1500ft launches were usually high enough for contacting thermals.
That also mirrors our finding on this side of the pond. More height is
alway welcome though!

Derek Copeland


At 15:39 23 May 2008, Bill Daniels wrote:

"John Scott" wrote in message
. ..
What type of winch was being used?

John Scott


It was an ex-Canadian Gerhlein style single drum winch with a Chevy 350
V8

and a GM TH400 series transmission. It's a well maintained example of a

1960's style winch. It's not ideal but cheap enough to get started
with
winch launch. The ~1500' AGL launches it delivered were just fine for

contacting thermals. Had we not been in training mode, I could have
thermalled away on almost every launch.

The power was just right to allow the glider pilot to control airspeed
with
pitch inputs but it did exhibit tension oscillations whenever the launch
was
disturbed by a rough gear change or thermals as is typical with this
type
of
winch. We were able to reduce oscillations by using 2nd gear. 2nd gear

also eliminates the tendency for the TH400 to make a 3 - 2 downshift near

the top of the launch.

A modern tension controlled winch would probably increase the release
heights to 2000' AGL by holding rope tension nearly perfect.

Bill Daniels

On May 24, 12:25 am, ContestID67 wrote:
Coupla' questions;

1) What was the highest release?
2) What was the lowest release?
3) Was it skill/training/experience of the pilot/operator/both that
allowed you to get to the highest release?
4) What types of line was used? Steel? Spectra? How long was the
line?

Thanks.

1. 1800agl (private K21), ~3900ft run.
2. Aborted launch. There were variations due to pilot training,
winch driver training, wind, so there a few may have been 1300ft.
Average with the Grob seemed to be about 1500agl. Bill will have to
comment further.
3. Actually, the K21 just seemed to perform better than the G103, but
a very small sample. Again Bill will have to comment.
4. The rope used was 1/4" Amsteel II type (not clear which type, see
www.samsonrope.com), rated at nominally 3800-5300lbs minimum
strength. This is a 12-strand Dyneema 75 core with a double braided
polyester cover. 2.2 times the weight of uncovered rope. No specific
knowledge of how well used the rope was. The is a temporary splice
that can be made using a double fisherman knot and duct tape, but we
found those failed after about 20 launches. The knots didn't fail,
but the knot appeared to cause damage near the end of the knotted
area. A better repair was to slide back the covering, tuck splice the
12-strand, then work the covering back over the splice. I suspect the
rope had been pretty well used before we used it. I make a good field
fid from the tip of a 10 1/2 (6.5mm) knitting needle and aluminum
tube that greatly accelerate the splicing process. Don had a large
fid that was a chore to use and a plastic fid that just wouldn't work.

We figured the final drive ratio at 2.92, which is too tall. The
winch came with instructions to only launch in 3rd, but after the
first launch, I used and trained on 2nd (1-2 upshift) for the rest of
the clinic. 3.55-4.11 final would probably allow use of 3rd, depending
on engine torque/hp/redline. This appears to be an LT-4 350/330hp 4-
bolt, with Holley 4bbl. 340lbs@4500 and 330hp@5800. Redline 6300.
There were tags riveted on the winch indicated the transmission was a
TH400 installed in 1999 and engine an LT-4 installed in 2003. There
are some tweaks that could make this a better winch, but it wasn't bad
and fairly easy to drive and train on.

Frank Whiteley

Some additional comments:

The grass overruns are 500ft to the NW and 700ft to the SE. The winch
can be parked at the end of either. The runway is 4200ft paved.
Winching there is a compromise of staging from the taxiways and shared
use with power traffic. Parking the winch 400-500ft beyond the
lights allows the driver to 'fly' the chute and strop back without
issues. If you park too close to the lights, you complicate this and
stand a much bigger risk of snagging a light or pulling the tackle
into the winch.

The runway end lights could all be removed in about 15 minutes if
there was any desire to extend the winch run to a mile or so. We only
removed two on the rope side for retrieves and used the runway and
parallel grass for landing back and staging. As this is a commercial
operation, manpower is not a luxury. Don has a nice rig on one person
staging and movement of the Grobs.

The capacity of the drum with Amsteel II is about 4000ft. 3/16"
spectra/dyneema would allow for a lot more capacity. The retrieve
drag is such that the winch driver could also retrieve the rope. The
drag braking did heat up and cause some increased drag when we were
launching/retrieving at a high rate. Couldn't find a way to adjust
this in the short time we were there.

Frank