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#161
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How long is ACL's runway?
Mike Schumann "Bill Daniels" wrote in message ... Good comments, Don. If the break occurs between the winch and drogue the 'chute will collapse and pass harmlessly below the glider, releasing automatically from the glider in most cases. If the break is between the glider and drogue, (weak link failure) then the drogue will be open as long as the winch driver maintains power. In this case, the winch driver is the key. My driving technique is to cut the throttle and let the drogue collapse and drop to the ground. Comments? The worst case that is very rarely seen is that somehow the glider gets in front of the drogue and it overtakes the glider from behind. This is the equivalent of getting an air tow rope entangled with the glider. Both are equally rare. This is why once the drogue is on the ground, the winch driver must not move the cable until he hears that it is safe to do so. It is very important to point out that almost all the cable breaks were using the old steel wire. The new Dyneema winch cables rarely break. The last I heard, Aero Club Landau in Germany had more than 4000 launches on their 'plastic' cable without a single break. ACL is also getting more than 1200 meters AGL with their winch launches. Bill Daniels The pilot is trained not to land on the wire if at all possible. "Don Johnstone" wrote in message ... Just to add to what Bill has said, the really low launch failure 100 is one of the minor problem areas. If the launch is flown correctly it can be quite safely handled. The good point is, as Bill has pointed out that there is a large amount of airfield still in front of you. The bad news is that by the time the nose has been lowered the airspeed may be below the minimum allowed for the deployment of airbrakes. It may not be possible to lower the nose any further to increase the speed because of the proximity to the ground and therefore a touchdown has to be achieved without using airbrake. Patience is required as most modern gliders float a long way even at 50 kts in ground effect. (Grob 103 will travel the length of the 10000ft runway at Marham from 20ft/60kts) Simulating a launch failure at this height is not recomended as there is a real danger that the drogue will inflate as the winch driver cuts the power and drape itself over the cockpit. The good news is that such breaks are rare as the strain on the cable is reducing before increasing again. The procedure can be simulated by carrying out a faster than normal approach, pulling up and closing the airbrakes and then recovering from that situation which puts the glider in the same situation as a low break but without the cable in the way. At 04:30 28 June 2005, Bill Daniels wrote: 'Kilo Charlie' wrote in message news:9D3we.3579$Qo.3471@fed1read01... Your input re winch launches is appreciated Bill....esp for those of us that have never done one! Please don't take this as a criticism of winch launches but through this thread there has not been any mention of what happens at the critical low level altitude when the cable breaks. There is clearly also a zone of real problems with aerotows too.....esp here in the desert with few, if any landing options straight ahead. What do you guys teach re breaks at 100 feet? It seems like landing ahead would be good but how much altitude does it take to regain the necessary speed to be able to control the glider for landing when at a high angle of attack? Sorry if this is too obvious for those of you that do it all the time! Casey Thanks, Casey. The climb profile must be such that a safe recovery with generous margins be possible from any height that a cable break occurs. Safety is the product of airspeed, altitude and attitude - and good training. If the break happens at 100 feet, then 90%+ of the runway lies ahead to receive the glider. At 100 feet, the glider will have full climb airspeed, approx. 60 knots, but then pitch attitude will only be 20 - 30 degrees. A prompt, gentle pushover to a glide at approach airspeed is all that is needed to land straight ahead. If the break occurs higher, say 300 - 400 feet, then the straight ahead landing is still possible with spoilers but a tight 360 pattern is also possible. The two options overlap by a good amount of height depending on the airfield. At this height, the climb attitude will be about 45 degrees nose up (although from the cockpit it will feel like 60 degrees) so a more aggressive pushover is needed. All these situations will be practiced over and over until the instructor feels the student reacts instinctively and correctly to each. The student must firmly push the nose down until the airspeed is observed to be at a safe value and increasing before establishing a glide for a straight ahead landing or a turn for an abbreviated pattern. I must admit that winch launch LOOKS scary and FEELS scary to the uninitiated but the procedures worked out over literally tens of millions of launches in Europe and elsewhere make it actually safer than air tow. As for releasing over the winch instead of wherever the tow plane takes you, I see by looking at a lot of On-Line Contest IGC files, that most air tow releases happen within a mile of the takeoff point and the glider is rarely in a thermal at release but must glide around looking for one just like with a winch launch. If you don't find a thermal, a winch re-light will cost you less than $10. The latest European winches are getting even heavy gliders to over 1000 meters AGL so finding lift shouldn't be a problem. Bill Daniels |
#162
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This article makes you want to install a ballistic recovery chute in this
class of glider to handle a worst case scenario. Mike Schumann "M B" wrote in message ... The article was very interesting. The idea of aileron stiffness at high bending was thought-provoking. 'Abandoning ailerons for a more effective way of starting and stopping roll...' Perhaps a reference to full span spoilers for roll? 'the smoking gun was the aircraft's incredibly high performance.' This is consistent with, but not a proof of, the things I've written before about USA fatalities and L/D. Of course, this was however NOT a ridge flying accident. The article didn't mention the possibility that the other pilot may have popped the airbrakes/two pilots on the controls working at odds with each other. Of course there is absolutely no way to confirm or deny this. Lastly, I liked the article's end, and the idea of big bold red letters in the AFM. It also occered to me that some of the 'seconds to accelerate from stall speed to ...' and a lot of the ideas we have, and how we practice spins and spirals, is in STILL AIR. I generally don't go up in huge thermals/turbulence to practice spins, specifically so I don't exceed Va and gust loads and 1/3 deflection, etc. Does a spin turn into a spiral on it's own sometimes in turbulent air? Can AOAs be changed by turbulence alone, with no movement of controls? Oh, yes. Start throwing in severe turbulence (which we love, when it suits us) and I think we are closer to the 'naked edge of safety' than is obvious. The 2-32 accident in Hawaii was anectdotally in 'the toilet bowl' there in turbulent air, too. Shear 10/20/30 knots in a few seconds and 1/4 mile vertically or horizontally, and our still air analysis can't be done with a pristine slide-rule... At 17:12 30 June 2005, Don Johnstone wrote: If Stans analysis is right, and I can see no obvious flaw, once the spiral dive/spin situation is met then the chances of a sucessful recovery are slim. The 4DT would not be unique in this. Perhaps a tail parachute is an essential item of equipment. Food for thought At 15:18 30 June 2005, Bill wrote: Stan Hall presented his analysis of the Nimbus-4DB accident in Minden, NV, 1999. Stan's analysis is scary, to say the least. The article, Probing for the Smoking Gun, was reprinted in the Soaring Association of Canada's free flight, 2/04. Go to the link below. Click on free flight on the side bar. Go to free flight back issues - 2004 - issue 2. Down load the PDF file. http://www.sac.ca/ Bill Feldbaumer 09 Mark J. Boyd |
#163
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"Mike Schumann" wrote in message hlink.net... How long is ACL's runway? I'm not sure but I've heard the figure of 2000 meters. If you want to see the operation, go to this site and download a movie: http://www.gliding4life.com/ Nistal Wloczysiak is a young genius with a camera. Bill Daniels |
#164
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Agreed, winch launching does require some length, and the more the better.
In the US, there are some soaring sites that reside on BLM patents. 1. You need to form or belong to a 501c(3) organization. 2. You need to find the appropriate patch of federal land and make formal application. 3. There may be some property taxes and extended costs in acquiring access roads. See http://airsailing.org/ and http://tucsonsoaring.org/ for examples. For a startup operation or move, winch launching will clearly entertain fewer NIMBY issues than an aerotow operation. Frank Whiteley Mike Schumann wrote: There are certain points during an air tow, where there are also very small margins for error. I also believe that winch launches have major risk advantages over air tow, particularly due to the elimination of the tow plane from the risk equation. Unfortunately, the field I fly out of is too short for winch launching to be practical. Mike Schumann "Stefan" wrote in message ... Bill Daniels wrote: I am fighting a lonely battle to convince my fellow USA pilots that winch launch is a perfectly normal way to launch gliders and not some invention of the devil. Just three things to consider: A which launch brings you to a certain altitude above the site. At some places, this gives you enough options to find a thermal, at other sites, it does not. A winch operation doesn't mix well with other traffic. It's doable, if everybody is willing. And, most important: If done correctly, a winch launch is safe. But there is an extremely small margin for errors. I love winch launches, but they are dead serious, literally. Stefan |
#165
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Hi,
I suspect that it would be much easier for your typical club to train and line up qualified winch operators than finding tow pilots. Where I fly every student is required to start learning how to operate the winch as soon as he or she goes solo. As a result we have lots of winch drivers. And I think it is a good idea anyway. You learn what a good launch looks and feels like from the other side. Ciao, MM -- Marian Aldenhövel, Rosenhain 23, 53123 Bonn. +49 228 624013. http://www.marian-aldenhoevel.de |
#166
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At 13:30 01 July 2005, T O D D P A T T I S T wrote:
'Mike Schumann' wrote: From what I have seen, I doubt that winch launches require more people than air tow. One of the biggest problems we have with air tow is finding tow pilots who have the necessary hours in type to meet insurance requirements. I agree, that is a problem. I suspect that it would be much easier for your typical club to train and line up qualified winch operators than finding tow pilots. For a club, particularly one with some members already trained and comfortable with winch launches, you are probably right, but at least with aerotowing, you get pilots volunteering just because they like to fly, but don't want to pay for it. Is running the winch considered to be a desirable job similar to flying the tug? It is for me. Escaping down the winch end is a definite bonus with the nonsense that can occur at the flying end. Heater and wall to wall Queen/Dire Straits. Wonderful way to spend time when soaring is not possible. T o d d P a t t i s t - 'WH' Ventus C (Remove DONTSPAMME from address to email reply.) |
#167
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T o d d P a t t i s t writes
Is running the winch considered to be a desirable job similar to flying the tug? Not by most. For our part, all post solo pilots are expected to train to drive the winch and keep themselves current (except for the instructors, who are obviously exempt), and we run a rota to ensure everybody takes a fair turn at it. In practice, this means that we each have to drive the winch for half a day once a quarter, so it really isn't a huge burden. -- Bill Gribble http://www.scapegoatsanon.demon.co.uk - Learn from the mistakes of others. - You won't live long enough to make all of them yourself. |
#168
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Our club has about 40 members, and about 5 tow pilots. Given that all 40
regular members could be trained as winch operators, my gut feeling is that it would be a lot easier to get winch drivers than tow pilots on a daily basis. Mike Schumann "T o d d P a t t i s t" wrote in message ... "Mike Schumann" wrote: From what I have seen, I doubt that winch launches require more people than air tow. One of the biggest problems we have with air tow is finding tow pilots who have the necessary hours in type to meet insurance requirements. I agree, that is a problem. I suspect that it would be much easier for your typical club to train and line up qualified winch operators than finding tow pilots. For a club, particularly one with some members already trained and comfortable with winch launches, you are probably right, but at least with aerotowing, you get pilots volunteering just because they like to fly, but don't want to pay for it. Is running the winch considered to be a desirable job similar to flying the tug? T o d d P a t t i s t - "WH" Ventus C (Remove DONTSPAMME from address to email reply.) |
#169
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T o d d P a t t i s t wrote:
"Mike Schumann" wrote: From what I have seen, I doubt that winch launches require more people than air tow. One of the biggest problems we have with air tow is finding tow pilots who have the necessary hours in type to meet insurance requirements. I agree, that is a problem. 1. Because some clubs are usually very conservative about who they let fly the tow plane, and maybe wisely so, it's a very significant problem to screen and indoctrinate tow pilots. More so if you insist that they also have glider time first. We just re-engined and upgraded our Pawnee and added a new prop. Not cheap as there weren't any significant member contributed efforts. In the 2400+ hours on the prior mill, there were few issues, no cracked jugs, and one sticky valve. We did have a main journal problem when we first bought it, but worked that out early on. I suspect that it would be much easier for your typical club to train and line up qualified winch operators than finding tow pilots. For a club, particularly one with some members already trained and comfortable with winch launches, you are probably right, but at least with aerotowing, you get pilots volunteering just because they like to fly, but don't want to pay for it. Is running the winch considered to be a desirable job similar to flying the tug? 2. I know of one operation that recently turned down a young sprog for towing. He moved to another location and put a Pawnee on its nose in short order. FWIW, the wooden Hoffman four-bladed prop saved the engine parts. Volunteers are one thing, quality volunteers are something else. Not too many younger pilots are working on tail dragger time. Most middle aged pilots I encounter have 10-15 hours in tail dragger, no high power endorsement, and may or may not have a commercial. We have recently trained a few more winch drivers. If we had a better winch, we'd get a few more. There are some neat things about driving a winch, especially when trying to get it 'right' each time. A good winch at the right site is an attractive proposition. Personally I like listening to the Larks between launches, or spotting wild life. If I'm bored, I'll also drag the wire also, which really gets it down to two people to manage the operation, the winch/retrieve driver and the launch marshall/captain. Actually, if I drive both winch and wire vehicle, I can get higher launch rates most of the time. There are a couple of drivers that can keep the wire retrieve moving fast enough to beat what I can do solo. That way we can keep two training gliders in the air most of the time on a non-soaring day with a single drum. Frank |
#170
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F.L. Whiteley wrote:
T o d d P a t t i s t wrote: "Mike Schumann" wrote: From what I have seen, I doubt that winch launches require more people than air tow. One of the biggest problems we have with air tow is finding tow pilots who have the necessary hours in type to meet insurance requirements. I agree, that is a problem. 1. Because some clubs are usually very conservative about who they let fly the tow plane, and maybe wisely so, it's a very significant problem to screen and indoctrinate tow pilots. More so if you insist that they also have glider time first. We just re-engined and upgraded our Pawnee and added a new prop. Not cheap as there weren't any significant member contributed efforts. In the 2400+ hours on the prior mill, there were few issues, no cracked jugs, and one sticky valve. We did have a main journal problem when we first bought it, but worked that out early on. I suspect that it would be much easier for your typical club to train and line up qualified winch operators than finding tow pilots. For a club, particularly one with some members already trained and comfortable with winch launches, you are probably right, but at least with aerotowing, you get pilots volunteering just because they like to fly, but don't want to pay for it. Is running the winch considered to be a desirable job similar to flying the tug? 2. I know of one operation that recently turned down a young sprog for towing. He moved to another location and put a Pawnee on its nose in short order. FWIW, the wooden Hoffman four-bladed prop saved the engine parts. Volunteers are one thing, quality volunteers are something else. Not too many younger pilots are working on tail dragger time. Most middle aged pilots I encounter have 10-15 hours in tail dragger, no high power endorsement, and may or may not have a commercial. We have recently trained a few more winch drivers. If we had a better winch, we'd get a few more. There are some neat things about driving a winch, especially when trying to get it 'right' each time. A good winch at the right site is an attractive proposition. Personally I like listening to the Larks between launches, or spotting wild life. If I'm bored, I'll also drag the wire also, which really gets it down to two people to manage the operation, the winch/retrieve driver and the launch marshall/captain. Actually, if I drive both winch and wire vehicle, I can get higher launch rates most of the time. There are a couple of drivers that can keep the wire retrieve moving fast enough to beat what I can do solo. That way we can keep two training gliders in the air most of the time on a non-soaring day with a single drum. Frank Might mention that in thirty or so years of winch driving, most line breaks as I recall happen mostly on initial acceleration and next most often over the winch when we hit a thermal. I know it’s counter-intuitive, but the pull-up seems to generate the fewest breaks. Except for the fact that this is where most instructors of my observation anyway like to pull the knob on you. This is tricky, since at this point with maybe 500 ft in hand, you actually have too many choices -- 360, 180 or straight ahead. So be forewarned, and as usual, after making a plan stick with it, or do as the IP has previously briefed you. Most points for that one, no sense getting creative with Mr. Back Seat. And for us Schweizer drivers, remember we’re going to have the stick really honked back on the edge of an elevator stall to compensate for the download caused by that pesky nose hook. So our nose up excursion is genuinely going to raise the dirt, but the horizon and airspeed will return just as they should, especially if you get that stick on the front stop pronto. The only time this happened to me was over the winch in a 2-33. After recovery, I thermaled away, saved the day (but not my shorts). One last thing, be prepared for winch engine failure. If plenty of line has been spliced in ahead of the chute, there shouldn’t be too much chance of a canopy or wing drape. But anyway, I think this is where that happens mostly. Spectra is so light, I worry that even with a long snapper, the chute may float out in front of you much longer than it would otherwise. Bob |
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