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I thought that was exactly the point I was trying to
make! Stick position is type dependent. Where you hold the stick and how much you have to pull back, or push forward, may be different to what you are used to, if you fly a different type of glider. It depends on the hook position, the exact c of g and centre of pressure, and the trim position. The advice I gave was to hold the stick in a position that gives the optimum angle of climb for your type of winch. Full stop, period! Real life winch launching takes place using different types of gliders in differing wind strengths. No one throttle setting can cover all cases. If you launched a slow glider (e.g. a K8) into a 45 knot headwind, you could stop the winch altogether once it has got airborne and allow it to launch like a kite. The wind would be providing the energy while the winch would just act as an anchor point on the ground. Conversely launching a heavy two seater on a still day with a moderately powerful winch might require absolutely full throttle. Derek Copeland At 18:12 16 December 2006, Ian wrote: Dan G wrote: Ian wrote: And that was a surprise? Find yourself another club, man, because if headwinds on a winch launch are unexpected your current lot are going to damage someone one day. Easy now, my club has a long safety record any would be proud of. AFAIK there's never been a winch launch accident. In that particular example there was a very strong wind gradient. I was using as an illustration of the belief that K21s can take everything the winch gives. I am glad to hear about the safety record. I only hope they can keep it. No. I think it's bad advice. Yes, you should aim to have a proper climb angle and air speed, but the stick position is irrelevant. Just use enough to do what's needed. Well, 'find what stick position will hold them at about 45 degrees to the horizon AND give a safe speed' and 'you should aim to have a proper climb angle and air speed' seems to be the same thing... No, they are completely different. Stick position is irrelevant. All that matters is whether you need to move it. Let me give a simple example. The exact position of the temperature lever on a shower doesn't matter, does it? If it's too hot you move it 'cold' a bit and if it's too cold you move it 'hot' a bit. You don't say 'I'll have a position 5 shower, no matter how hot that is'. Same with the stick. Ian |
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On Saturday, December 16, 2006 at 3:33:08 PM UTC-8, Derek Copeland wrote:
I thought that was exactly the point I was trying to make! Stick position is type dependent. Where you hold the stick and how much you have to pull back, or push forward, may be different to what you are used to, if you fly a different type of glider. It depends on the hook position, the exact c of g and centre of pressure, and the trim position. The advice I gave was to hold the stick in a position that gives the optimum angle of climb for your type of winch. Full stop, period! Real life winch launching takes place using different types of gliders in differing wind strengths. No one throttle setting can cover all cases. If you launched a slow glider (e.g. a K8) into a 45 knot headwind, you could stop the winch altogether once it has got airborne and allow it to launch like a kite. The wind would be providing the energy while the winch would just act as an anchor point on the ground. Conversely launching a heavy two seater on a still day with a moderately powerful winch might require absolutely full throttle. Derek Copeland At 18:12 16 December 2006, Ian wrote: Dan G wrote: Ian wrote: And that was a surprise? Find yourself another club, man, because if headwinds on a winch launch are unexpected your current lot are going to damage someone one day. Easy now, my club has a long safety record any would be proud of. AFAIK there's never been a winch launch accident. In that particular example there was a very strong wind gradient. I was using as an illustration of the belief that K21s can take everything the winch gives. I am glad to hear about the safety record. I only hope they can keep it. No. I think it's bad advice. Yes, you should aim to have a proper climb angle and air speed, but the stick position is irrelevant. Just use enough to do what's needed. Well, 'find what stick position will hold them at about 45 degrees to the horizon AND give a safe speed' and 'you should aim to have a proper climb angle and air speed' seems to be the same thing... No, they are completely different. Stick position is irrelevant. All that matters is whether you need to move it. Let me give a simple example. The exact position of the temperature lever on a shower doesn't matter, does it? If it's too hot you move it 'cold' a bit and if it's too cold you move it 'hot' a bit. You don't say 'I'll have a position 5 shower, no matter how hot that is'. Same with the stick. Ian looking for a used winch or plans for making one. thank you ray |
#3
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![]() looking for a used winch or plans for making one. thank you ray Ray - join the Yahoo forum 'Winchdesign'. There you will find probably the most concentrated winch related knowledge in the world. Where in the world are you located? There are a good number of winches for sale on the German server: http://www.segelflug.de/osclass/inde...&sCategory=107 Uli Winchmeister of the Carolina Soaring Association |
#4
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At 23:33 16 December 2006, Derek Copeland wrote:
I thought that was exactly the point I was trying to make! Stick position is type dependent. Where you hold the stick and how much you have to pull back, or push forward, may be different to what you are used to, if you fly a different type of glider. It depends on the hook position, the exact c of g and centre of pressure, and the trim position. The advice I gave was to hold the stick in a position that gives the optimum angle of climb for your type of winch. Full stop, period! Real life winch launching takes place using different types of gliders in differing wind strengths. No one throttle setting can cover all cases. If you launched a slow glider (e.g. a K8) into a 45 knot headwind, you could stop the winch altogether once it has got airborne and allow it to launch like a kite. The wind would be providing the energy while the winch would just act as an anchor point on the ground. Conversely launching a heavy two seater on a still day with a moderately powerful winch might require absolutely full throttle. Derek Copeland Yep, what he said. If you take a winch launch with a really skilled winch driver you will experience a constant speed all the way up the launch. How is that done? There are a combination of things that can give clues to the winch driver, the bow in the cable, if it is wire, does not work so well with dynema/sky rope. Marked throttle settings as on a Skylaunch winch can help but it really is a matter of feel and experience. For most glass gliders 55-65kts seems to work best. I always reduce power at the top, back to idle once the glider gets near to the max angle, instigating a back release, this avoids the possibility of a loop if the cable is released under tension. It is absolutely essential to ensure that the power is cut, before the glider is vertically over the winch in nil/very low headwind conditions, it is very unpleasant to have 1000ftl of cable drop on top of the winch, it it can take a bit of time to get it off as well. |
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On Tuesday, December 20, 2016 at 3:00:06 PM UTC-7, Don Johnstone wrote:
At 23:33 16 December 2006, Derek Copeland wrote: I thought that was exactly the point I was trying to make! Stick position is type dependent. Where you hold the stick and how much you have to pull back, or push forward, may be different to what you are used to, if you fly a different type of glider. It depends on the hook position, the exact c of g and centre of pressure, and the trim position. The advice I gave was to hold the stick in a position that gives the optimum angle of climb for your type of winch. Full stop, period! Real life winch launching takes place using different types of gliders in differing wind strengths. No one throttle setting can cover all cases. If you launched a slow glider (e.g. a K8) into a 45 knot headwind, you could stop the winch altogether once it has got airborne and allow it to launch like a kite. The wind would be providing the energy while the winch would just act as an anchor point on the ground. Conversely launching a heavy two seater on a still day with a moderately powerful winch might require absolutely full throttle. Derek Copeland Yep, what he said. If you take a winch launch with a really skilled winch driver you will experience a constant speed all the way up the launch. How is that done? There are a combination of things that can give clues to the winch driver, the bow in the cable, if it is wire, does not work so well with dynema/sky rope. Marked throttle settings as on a Skylaunch winch can help but it really is a matter of feel and experience. For most glass gliders 55-65kts seems to work best. I always reduce power at the top, back to idle once the glider gets near to the max angle, instigating a back release, this avoids the possibility of a loop if the cable is released under tension. It is absolutely essential to ensure that the power is cut, before the glider is vertically over the winch in nil/very low headwind conditions, it is very unpleasant to have 1000ftl of cable drop on top of the winch, it it can take a bit of time to get it off as well. If you know how to fly you can have exactly the airspeed you want all the way up the launch. The winch does not and, in fact, cannot control glider airspeed. The pilot is the only one who can do that. The winch merely controls power (think thrust). It works exactly as with airplanes, pitch controls airspeed and power (thrust) controls rate of climb. The pilot merely adjusts pitch attitude as necessary to maintain the desired airspeed. Reduce winch power and the rate of climb (angle) decreases but the airspeed is unchanged. Reduce it all the way to zero and the glider is left in a glide at the desired airspeed. Increase power and the rate of climb (angle) increases but the airspeed stays the same. Increase it too much and the weak link breaks - at exactly the desired airspeed - or the glider runs out of up elevator and the pilot must then ask for less power. It's really very simple. |
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#8
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Actually if we had better designed winches Bill would be correct.
Unfortunately the gliding movement certainly in the UK, but also in Europe, seems to have taken the "Easy" option of Skylaunch winches. 400hp and auto Transmission mean that the pilot has little control of the airspeed during the launch. Too fast? ease back, go even faster! PF At 13:01 21 December 2016, Andreas Maurer wrote: On Tue, 20 Dec 2016 16:59:34 -0800 (PST), wrote: If you know how to fly you can have exactly the airspeed you want all the way up the launch. The winch does not and, in fact, cannot control glider airspeed. The pilot is the only one who can do that. The winch merely controls power (think thrust). It works exactly as with airplanes, pitch controls airspeed and power (thrust) controls rate of climb. The pilot merely adjusts pitch attitude as necessary to maintain the desired airspeed. Reduce winch power and the rate of climb (angle) decreases but the airspeed is unchanged. Reduce it all the way to zero and the glider is left in a glide at the desired airspeed. Increase power and the rate of climb (angle) increases but the airspeed stays the same. Increase it too much and the weak link breaks - at exactly the desired airspeed - or the glider runs out of up elevator and the pilot must then ask for less power. It's really very simple. Hi Bill, unfortunately it's not that simple. Your description does not even remotely match the experiences I made I made in the last couple of thousand winch launches. Best regards Andreas |
#9
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On Wednesday, December 21, 2016 at 8:15:04 AM UTC-6, Peter F wrote:
Actually if we had better designed winches Bill would be correct. Unfortunately the gliding movement certainly in the UK, but also in Europe, seems to have taken the "Easy" option of Skylaunch winches. 400hp and auto Transmission mean that the pilot has little control of the airspeed during the launch. Too fast? ease back, go even faster! PF Ah, so you took the American Approach. Nothing Exceeds like Excess! Or, there is nothing that cannot be improved with application of more cubic inches. Steve Leonard |
#10
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On Wednesday, December 21, 2016 at 7:15:04 AM UTC-7, Peter F wrote:
Actually if we had better designed winches Bill would be correct. Unfortunately the gliding movement certainly in the UK, but also in Europe, seems to have taken the "Easy" option of Skylaunch winches. 400hp and auto Transmission mean that the pilot has little control of the airspeed during the launch. Too fast? ease back, go even faster! PF 400HP is good. Automatic transmissions are evil. |
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