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#71
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New winch height record
Del C wrote:
John, With the Tost winches we use at Lasham, the pilot has no control over the speed, unlike the torque or tension controlled Supacat or MEL winches. Exactly the same applies to a V-8 diesel Supacat with its high torque output - an Ash-25 might control the winch speed but a K-21 has no chance. -- martin@ | Martin Gregorie gregorie. | Essex, UK org | |
#72
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New winch height record
Del C wrote:
With the Tost winches we use at Lasham, the pilot has no control over the speed, We have a Tost winch, too, and the pilot has definitely some degree of control over the speed. The winch driver gives the tension depending on how much the pilots pulls. But then the winch driver holds that tension and the pilot makes the fine adjustments. No way a winch driver could adjust precisely and quickly enough. It's like a dialogue between the winch driver and the pilot. It requires a certain experience and feeling from both to yield good results. But having winched at many sites, I know that there are huge differences among the "winch cultures". A pilot must be able to immediately feel how he is winched and to adopt accordingly. |
#73
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New winch height record
"John Smith" wrote in message ... Del C wrote: With the Tost winches we use at Lasham, the pilot has no control over the speed, We have a Tost winch, too, and the pilot has definitely some degree of control over the speed. The winch driver gives the tension depending on how much the pilots pulls. But then the winch driver holds that tension and the pilot makes the fine adjustments. No way a winch driver could adjust precisely and quickly enough. It's like a dialogue between the winch driver and the pilot. It requires a certain experience and feeling from both to yield good results. But having winched at many sites, I know that there are huge differences among the "winch cultures". A pilot must be able to immediately feel how he is winched and to adopt accordingly. Winch culltures and varying winch driver techniques is one reason computer controlled cable tension is such a good idea. It puts the airspeed control firmly in the hands of the pilot. You get a near perfect launch every time in every glider pretty much regardless of conditions. Bill Daniels |
#74
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New winch height record
You don't say what engine you have in your Tost winch
John, but ours are fitted with powerful 8.2 litre, 410hp Chevy marine engines. Except for the very heaviest two seater gliders, pulling back harder on the stick will not reduce the airspeed and may even have the opposite effect due to increasing the vertical speed vector - the so called 'water skier' effect. Easing the stick forward may momentarily reduce the speed for the same reason (reduces the vertical speed component) but will signal to the driver that more power is required so you will still speed up again! The only way to slow down if the launch gets too fast is to signal to the winch driver by wagging the tail with the rudder. Having said all that, we have very well trained winch drivers who nearly always provide correctly speeded launches. I have launched on a number of low powered, 'torque controlled' diesel engined winches where speed is supposed to be controllable from the glider end, but I wonder if this is just because pulling back harder slows the winch engine down and easing forward allows it to speed up again? These winches seem to become less easily controllable by the glider when re-fitted with more powerful engines, as has been confirmed by another correspondent. Maybe the answer is to provide just the right amount of power to launch the specific glider type in the prevailing wind conditions. In this respect throttle tabs as found on the latest Skylaunch winches may be the KISS (Keep It Simple Stupid) way to go, rather than very expensive and complicated tension controlled diesel-hydraulic or electric winches. Del Copeland At 20:24 01 December 2007, John Smith wrote: Del C wrote: With the Tost winches we use at Lasham, the pilot has no control over the speed, We have a Tost winch, too, and the pilot has definitely some degree of control over the speed. The winch driver gives the tension depending on how much the pilots pulls. But then the winch driver holds that tension and the pilot makes the fine adjustments. No way a winch driver could adjust precisely and quickly enough. It's like a dialogue between the winch driver and the pilot. It requires a certain experience and feeling from both to yield good results. But having winched at many sites, I know that there are huge differences among the 'winch cultures'. A pilot must be able to immediately feel how he is winched and to adopt accordingly. |
#75
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New winch height record
Del C wrote:
You don't say what engine you have in your Tost winch John, but ours are fitted with powerful 8.2 litre, 410hp Chevy marine engines. Except for the very heaviest Frankly, I don't know. It's a gas engine with I guess something like 300 or 350hp. We can definitely slow down the engine when pulling the stick hard back in a two seater. With a single seater, the winch driver must winch with reduced power, but then the pilot has some control again, slowing down the winch when pulling. |
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