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#51
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Auto-Towing - why is this not more popular?
On Tuesday, October 6, 2015 at 2:37:30 PM UTC-7, Waveguru wrote:
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 Gary, what were your typical truck speeds? Thanks, Craig |
#52
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Auto-Towing - why is this not more popular?
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 | |
#53
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Auto-Towing - why is this not more popular?
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. |
#54
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Auto-Towing - why is this not more popular?
Bill....at best, not accurate.
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#55
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Auto-Towing - why is this not more popular?
On Tuesday, October 6, 2015 at 3:37:30 PM UTC-6, Waveguru wrote:
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 Yeah, I watched your video. |
#56
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Auto-Towing - why is this not more popular?
Out in the prairies, trees and power lines
are less prevalent than center pivot irrigators and barbed wire fences. The neighboring farmers might let us put in gates to run the winch line another 3000' +, but I'm wondering if we could mount high pulleys at the fence lines to avoid rubbing against fence posts etc. If we could get a drone with PowerFLARM to pull the line back, life would be really good except for the pipeline patrol guy. |
#57
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Auto-Towing - why is this not more popular?
We figured the truck speed as stall speed plus 10 or 15 minus the wind speed. At the Alvord we had to add five or 10 for density altitude. I don't think we ever went more than 75mph, usually 60-65 We never launched any ships with water. The slower you can go and still get the job done the better. It's really important for there to be good three way communication between pilot, driver, and winch operator. Having the cable pressure set so that in lift the glider just climbs faster and in sink it doesn't pay out at all takes out the wild fluctuations in airspeed we used to get with the solid wire auto tow. It's much safer and the cable rarely breaks. Only when you get a nick in it some how.
Boggs |
#58
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Auto-Towing - why is this not more popular?
On Tuesday, October 6, 2015 at 8:45:05 PM UTC-6, George Haeh wrote:
Out in the prairies, trees and power lines are less prevalent than center pivot irrigators and barbed wire fences. The neighboring farmers might let us put in gates to run the winch line another 3000' +, but I'm wondering if we could mount high pulleys at the fence lines to avoid rubbing against fence posts etc. If we could get a drone with PowerFLARM to pull the line back, life would be really good except for the pipeline patrol guy. Would take a bit more time to retrieve the rope, but an wheel rim on a shaft on top of a fence topping frame would probably work if done properly, though a gate would be better and much more desireable. Retrieve drivers would have to be able to drive in a straight line. Not too hard on a flat surface. There was a club that reportedly used a wheel rim of some sort on a post to guide the rope around a runway dogleg during the start of the launch. It may have been in the UK. Frank Whiteley |
#59
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Auto-Towing - why is this not more popular?
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. |
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