Where to get Winched?

On 7/06/2012 02:45, Chris wrote:

We in europe do winch launching as the standard procedure. Our airfield has
1200m (~4000 feet) paid out cable and we get release height of about 400m
(~1300 feet). With strong headwind we even get 600m, sometimes more. Our
club charges 4,- ? for a launch.

Yes. Bill Daniels seems optimistic to me. 1 for 3 is about what I'd
expect with a nil to light wind.

It depends on lots of factors: engine power, pilot skills, wind direction
and strength, cable (steel or dyneema), lenght of cable, glider type... and
certainly more. The above numbers are for a double seater like ASK21, steel
cable and moderate headwind.

There have been launches with dyneema cable of 3000m length and release
heights of 1200m. This is a really cost effective way to do aerobatics.

To answer your question: I would think 3000 feet is the minimun for a
reasonable winch operation. However, I have seen fields with only 2000 feet.

The length you need is wire length - not runway length. The ground run
for a launch is barely 100 yards. Any more is for landing, launch
emergencies, etc. Winches are also commonly sited well beyond the
upwind runway threshold. It's a very flexible launching system.

GC
Chris

If you're only getting 33% of the rope length, yours is a low
performance winch operation. If you optimize it, 45% or so is
achievable in no-wind conditions. A 10 knot wind can boost that over
50%. Again, I'm saying this is for gliders with better than 30:1 and
rope tensions equal to the weight of the glider. Below 30:1, achieved
height falls off a lot.

On Jun 7, 7:51*am, GC wrote:
On 7/06/2012 02:45, Chris wrote:

We in europe do winch launching as the standard procedure. Our airfield has
1200m (~4000 feet) paid out cable and we get release height of about 400m
(~1300 feet). With strong headwind we even get 600m, sometimes more. Our
club charges 4,- ? for a launch.

Yes. *Bill Daniels seems optimistic to me. *1 for 3 is about what I'd
expect with a nil to light wind.

It depends on lots of factors: engine power, pilot skills, wind direction
and strength, cable (steel or dyneema), lenght of cable, glider type... and
certainly more. The above numbers are for a double seater like ASK21, steel
cable and moderate headwind.

There have been launches with dyneema cable of 3000m length and release
heights of 1200m. This is a really cost effective way to do aerobatics.

To answer your question: I would think 3000 feet is the minimun for a
reasonable winch operation. However, I have seen fields with only 2000 feet.

The length you need is wire length - not runway length. *The ground run
for a launch is barely 100 yards. *Any more is for landing, launch
emergencies, etc. *Winches are also commonly sited well beyond the
upwind runway threshold. *It's a very flexible launching system.

GC







Chris

On 8/06/2012 00:37, Bill D wrote:
If you're only getting 33% of the rope length, yours is a low
performance winch operation. If you optimize it, 45% or so is
achievable in no-wind conditions. A 10 knot wind can boost that over
50%. Again, I'm saying this is for gliders with better than 30:1 and
rope tensions equal to the weight of the glider. Below 30:1, achieved
height falls off a lot.

I didn't say it was "my" operation and I don't mind your 'low
performance' putdown, Bill. I've been involved in eight different winch
operations and my judgment overall is, like Chris said - 400m from
1200m, about 1:3 is a normal nil to light wind figure. I've read
previous posts on this from you. I think your 45% minimum is optimistic
and you do winching no favours making those promises.

1. The vast majority of winch operations are hand to mouth. Old
winches launching old gliders. Most of us can't afford professional
winches costing the price of 2 Pawnees. Most winches (outside Europe)
are medium- to low-powered. About 1:3 is what they'll get. An aerotow
operation converting to a winch probably won't be a prosperous, thriving
club setting out buy a $100,000 Skylaunch.

2. The vast majority (ALL, in my experience) of winch operations are
optimistic in their claimed launch heights. "He's not a very
experienced driver". "There must be a tailwind at height". "This is
not our best launching direction". "The engine is due to be serviced".
"The wire's a bit shorter than we usually have". I've heard them all
- including (just now) "...if you optimize it...".

I believe YOUR operation will routinely achieve a little better than 1:3
but will rarely exceed 2:5.

GC

On Jun 7, 7:51*am, GC wrote:
On 7/06/2012 02:45, Chris wrote:

We in europe do winch launching as the standard procedure. Our airfield has
1200m (~4000 feet) paid out cable and we get release height of about 400m
(~1300 feet). With strong headwind we even get 600m, sometimes more. Our
club charges 4,- ? for a launch.

Yes. *Bill Daniels seems optimistic to me. *1 for 3 is about what I'd
expect with a nil to light wind.

It depends on lots of factors: engine power, pilot skills, wind direction
and strength, cable (steel or dyneema), lenght of cable, glider type... and
certainly more. The above numbers are for a double seater like ASK21, steel
cable and moderate headwind.

There have been launches with dyneema cable of 3000m length and release
heights of 1200m. This is a really cost effective way to do aerobatics.

To answer your question: I would think 3000 feet is the minimun for a
reasonable winch operation. However, I have seen fields with only 2000 feet.

The length you need is wire length - not runway length. *The ground run
for a launch is barely 100 yards. *Any more is for landing, launch
emergencies, etc. *Winches are also commonly sited well beyond the
upwind runway threshold. *It's a very flexible launching system.

GC







Chris

100 yards for acceleration is way too long. A 1G acceleration will
get a glider to 40 knots liftoff speed in 71 feet.

I have read that the insurance is much higher for winch operations.
Anyone have a comment or tips on reducing this?

On Thursday, June 7, 2012 12:26:55 PM UTC-4, soartech wrote:
I have read that the insurance is much higher for winch operations.
Anyone have a comment or tips on reducing this?

We have not experienced this at PGC, however, we do not have SSA insurance. I suspect that the carrier's knowledge--or should I say lack of knowledge--may have a lot to do with this.

Skip

On Thursday, June 7, 2012 10:26:55 AM UTC-6, soartech wrote:
I have read that the insurance is much higher for winch operations.
Anyone have a comment or tips on reducing this?

Winch liability insurance was split off from premises liability under the SSA plan. Winch hull insurance is also a separate product. The advantage is that the 3rd party liability now allows operation away from home base. So yes, it did increase the fixed cost of operating a winch and included a restriction against using steel wire or steel wire rope.

GC wrote:

The length you need is wire length - not runway length. The ground run
for a launch is barely 100 yards. Any more is for landing, launch
emergencies, etc. Winches are also commonly sited well beyond the
upwind runway threshold. It's a very flexible launching system.

While this is true, there is another reason for a 3000 feet runway: safety.
You need to be prepared for a cable break at any time. Up to 300 feet you
can land straight ahead, if there is enough runway left. If the cable breaks
at a higher altitude, you can do a full circle or a short pattern. If the
runway is too short, you can get in a situation where both options do not
apply.

I guess that you refer to this scenario when you talk about launch
emergency. My opinion is that a cable break is no emergency, but is part of
the procedure. It must be trained well, but if the pilot is prepared for a
break, this is no emergency. You can expect a cable break in one of 100
launches.

BTW, my last break on the winch was in 120m. Too high to land straight, so I
initiated a 180 for a short pattern. After that turn, my altimeter showed
150m. I decided to do a full circle and got 200m. Now I continued and got
1300m in the end. This was fun while the guys below had to fix the cable :-)
Chris

On 8/06/2012 03:50, Chris wrote:
GC wrote:

The length you need is wire length - not runway length. The ground run
for a launch is barely 100 yards. Any more is for landing, launch
emergencies, etc. Winches are also commonly sited well beyond the
upwind runway threshold. It's a very flexible launching system.

While this is true, there is another reason for a 3000 feet runway: safety.
You need to be prepared for a cable break at any time. Up to 300 feet you
can land straight ahead, if there is enough runway left. If the cable breaks
at a higher altitude, you can do a full circle or a short pattern. If the
runway is too short, you can get in a situation where both options do not
apply.

I guess that you refer to this scenario when you talk about launch
emergency.

Well, yes I do.

My opinion is that a cable break is no emergency, but is part of
the procedure. It must be trained well, but if the pilot is prepared for a
break, this is no emergency. You can expect a cable break in one of 100
launches.

Ok, call it 'launch failures'. Whatever floats your boat.

My actual point was that winching is very flexible. On Long Mynd, a
launch emergency (or failure) high enough for a circuit sometimes means
landing at right angles to the takeoff direction. The actual length
requirement is ONLY for ground over which the wire can be laid out. A
winch operation - unlike aerotow - doesn't necessarily require a single
continuous runway.

GC

BTW, my last break on the winch was in 120m. Too high to land straight, so I
initiated a 180 for a short pattern. After that turn, my altimeter showed
150m. I decided to do a full circle and got 200m. Now I continued and got
1300m in the end. This was fun while the guys below had to fix the cable :-)
Chris