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#11
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SAFE Winch Launching
In all this discussion of winches, and the building thereof, no one has
mentioned auto towing. The 'reverse auto tow' is the most efficient launch method I have ever encountered. We used it at the Essex Club at North Weald while I instructed there. You need a nice long runway, about 6000ft is ideal but shorter will do. The ingredients a 1) Two large automatic cars of about 100BHP - we used retired V6 Ford Zephyrs - we will call them car1 and car2. A driver and observer (who watches the glider) are required. 2) A large grooved pulley about six feet in diameter on a rotatable gimbal and anchored firmly to the ground. The pulley is at the opposite end of the runway to the launch point. 3) A piece of single strand piano wire the length of the runway. 4) Gliders with pilots. The wire is passed over the pulley and attached to car 1 which is sitting at the pulley and the other end to the glider via the usual rope, parachute, and weak link. Car 2 is sitting at the launch point. Slack is taken up, and at the all out signal car 1 sets off down the runway towards the glider which most obligingly lifts off, and sets off up what is now effectively a winch launch. Meanwhile car 2 sets off following the glider towards the pulley avoiding car 1, of course, which is driving at about 35- 40 mph towards the launch point. Glider releases, (we often got nearly 2000ft on a good day), and car 1 carries on the launch point while car 2 arrives at the pulley. The cable has launching tackle on both ends, so the next glider is coupled on and car 2 is connected to the cable and does the next launch ... need I go on? We used to get 20 launches an hour using this method. No time is wasted retrieving cables. No need to buy an expensive winch, and the cheap cable lasted a long time. Ford Zephyrs were also fairly cheap from the scrap yard, and we had people in the club adept at fixing them. As quite of lot of American clubs seem to have access to runways I cannot see why they cannot try this method of launching. I recommend it. Alistair Wright |
#12
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SAFE Winch Launching
On Jul 5, 7:50*am, "Alistair Wright" wrote:
In all this discussion of winches, and the building thereof, no one has mentioned auto towing. The 'reverse auto tow' is the most efficient launch method I have ever encountered. We used it at the Essex Club at North Weald while I instructed there. You need a nice long runway, about 6000ft is ideal but shorter will do. The ingredients a 1) Two large automatic cars of about 100BHP - we used retired V6 Ford Zephyrs - we will call them car1 and car2. A driver and observer (who watches the glider) are required. 2) A large grooved pulley about six feet in diameter on a rotatable gimbal and anchored firmly to the ground. The pulley is at the opposite end of the runway to the launch point. 3) A piece of single strand piano wire the length of the runway. 4) Gliders with pilots. The wire is passed over the pulley and attached to car 1 which is sitting at the pulley and the other end to the glider via the usual rope, parachute, and weak link. Car 2 is sitting at the launch point. Slack is taken up, and at the all out signal car 1 sets off down the runway towards the glider which most obligingly lifts off, and sets off up what is now effectively a winch launch. Meanwhile car 2 sets off following the glider towards the pulley avoiding car 1, of course, which is driving at about 35- 40 mph towards the launch point. Glider releases, (we often got nearly 2000ft on a good day), and car 1 carries on the launch point while car 2 arrives at the pulley. The cable has launching tackle on both ends, so the next glider is coupled on and car 2 is connected to the cable and does the next launch .... need I go on? *We used to get 20 launches an hour using this method. No time is wasted retrieving cables. No need to buy an expensive winch, and the cheap cable lasted a long time. Ford Zephyrs were also fairly cheap from the scrap yard, and we had people in the club adept at fixing them. *As quite of lot of American clubs seem to have access to runways I cannot see why they cannot try this method of launching. I recommend it. Alistair Wright Having launched with EGC at North Weald a couple of occasions many years ago, my experience was a bit different. We got maybe 800ft in the K13, but I think the normal launch cars were broken down and a manually shifted Vauxhall was in use. Each time it shifted, the drogue chute was over the nose of the glider. I got 1200ft in the SHK on the other day. IIRC, airspace was limited to 2200ft until about five miles north. (Have to dig out an old chart that's archived somewhere). On the days I was there, only one vehicle was in use and on the first day, there was a wire snarl up on the pulley system (two big wheels) that delayed things for well over an hour. However, I do agree that the system may be very efficient. To that end, the old Cotswold GC system was, IMVHO, more elegant and required less people to operate http://www.coloradosoaring.org/think...ey/default.htm In addition to the long runway, CGC insisted on a lateral 2000ft clear zone around the pulley. Piano wire is nasty stuff when it breaks under tension. They also used rather more substantial tow vehicles and you couldn't launch modern K-21's, DG-50X's and 1000's and single seaters with Zephyr's. You can't discount the cost of powerful tow vehicles. We did okay at Enstone GC with an XJ6 Jag on auto tow. After many years, Cotswold GC reverted to winching. http://www.cotswoldgliding.co.uk/ They formerly had a history page about the reverse pulley, but I don't find anything on their web site now. They do mention that learning to glide is cheaper than learning to drive though;^) We do have some long runways in the US, but few are lacking runway lights or other obstacles that are too close to entertain reverse pulley launching. On these same runways, it's quite feasible to winch using the UHMWPE ropes. Regards, Frank Whiteley |
#13
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SAFE Winch Launching
On 5 July, 02:38, bildan wrote:
On Jul 4, 5:15*pm, Derek Copeland wrote: To all my friends in the United States of America. You may have got the impression from some recent correspondence on this site that winch launchings is about as risky as bungey jumping or joining a Kamikaze squadron! In fact we do many tens of thousands, if not hundreds of thousands, of winch launches in Europe with only the very occasional accident. Even the ones we do have are largely avoidable. Most of the serious winch launching accidents come into the following categories: 1) Ground loop or cartwheel after catching a wingtip on the ground. 2) Flick spin due to over-rotating after lift off. 3) Stall/spin after a cable break or other launch failure. These can be avoided respectively by: a) Pulling the cable release knob if a wing drops. b) Monitoring the airspeed and controlling the rate of rotation to not more than 10 degrees/second. c) Lowering the nose to the recovery attitude and regaining a safe airspeed before attempting any further manoeuvres. Also learning the most suitable options for landing safely from various heights. Things happen much more quickly during a winch launch than they do during an aerotow, so you do need to engage your brain before you start moving, not halfway up the launch. There is starting to be more interest in winch launching in the States, due to rising fuel and maintenance costs for tug aircraft. However I have found it somewhat disappointing that some of the leading US protagonists seem to want to ignore any advice from European clubs and winch builders, who have a wealth of experience in this method. It's the 'good ol' US of A always knows best' syndrome. As a result you have already suffered a fatality and two serious injuries this year from a fraction of the number of launches that we would do in Europe in the same period. You already have the most of the basics for winch launching in the US. You have many vehicles fitted with large and powerful V8 engines and good automatic gearboxes that can be cannibalised to make decent winches. Please note that you must disable any kick down arrangement on the automatic gearboxes. If you join a Yahoo group called 'Winch Design' you will find a document written by the BGA winching advisor called 'Proven UK specification' which gives you most of the information needed to build a good winch. You don't need very fancy and expensive, but as yet unproven, diesel-hydraulic or electric winches that the above protagonists seem to think are essential. Derek Copeland Written by someone who thinks British automobiles with Lucas electrics are reliable transportation. Seems to be a non sequitor considering that Derek was advocating US not UK engines for winches. |
#14
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SAFE Winch Launching
On Jul 4, 8:00*pm, Brian Goodspeed
wrote: Written by someone who thinks British automobiles with Lucas electrics are reliable transportation. Written by someone who always claims to know everything about everything - except that Lucas no longer exist. *They were taken over and bankrupted by a U.S. company! Written by someone who actually knows how to use Google. BTW, I think Lucas was bought by DARPA who was looking for the secret of light bulbs that emit darkness. See: www.hermit.cc/mania/tmc/articles/lucas.htm |
#15
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SAFE Winch Launching
At 18:17 05 July 2009, johngalloway wrote:
Seems to be a non sequitor considering that Derek was advocating US not UK engines for winches. Well I would, but most UK cars do not have huge gas guzzling V8 engines that are big and powerful enough to power a winch, due to our Government's excessiveand historical taxation of road vehicle fuels. Possibly V12 Jaguar or Rolls Royce engines would do. if you can find them cheaply enough second hand. If you want a new engine, then the GM Marine engines, as used by Skylaunch, are as good and cheap as anything. Derek Copeland P.S. Lucas made their initial fortune by selling reversing lights for Italian tanks in WW2. They worked perfectly! |
#16
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SAFE Winch Launching
On Jul 5, 5:30*pm, Del C wrote:
At 18:17 05 July 2009, johngalloway wrote: Seems to be a non sequitor *considering that Derek was advocating US not UK engines for winches. Well I would, but most UK cars do not have huge gas guzzling V8 engines that are big and powerful enough to power a winch, due to our Government's excessiveand historical taxation of road vehicle fuels. Possibly V12 Jaguar or Rolls Royce engines would do. if you can find them cheaply enough second hand. If you want a new engine, then the GM Marine engines, as used by Skylaunch, are as good and cheap as anything. Derek Copeland P.S. Lucas made their initial fortune by selling reversing lights for Italian tanks in WW2. They worked perfectly! My understanding is that Lucas, Prince of Darkness, was also responsible for the invention of intermittent windshield wipers. I couldn't resist............. Chip F. - who loves a good winch launch. |
#17
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SAFE Winch Launching
"chipsoars" wrote in message ... My understanding is that Lucas, Prince of Darkness, was also responsible for the invention of intermittent windshield wipers. Well, sort of. They just weren't supposed to be intermittent at the time. History seems to assign the invention of true intermittent windshield washers to Robert Kearns. http://www.theautochannel.com/news/2...25/005398.html I seem to remember a movie... Vaughn |
#18
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SAFE Winch Launching
Just to put the record straight about pulley launching at North Weald
(UK): There were at least three different generations of Ford trucks used for launching at North Weald, with the Ford Zodiac cars as a brief interlude. The Vauxhall that Frank mentions must have been on a day during the old generations of second hand vehicles which were certainly not the best. Somebody must have used their own private car for launching – I do not recall the club ever had a Vauxhall between 1970 when I started and 1991 or thereabouts when we had to stop wire launches at North weald. For anyone to judge the capability of reverse pulley launching by a sight of one off day in the 1970’s is not a fair comparison. I joined the club in 1970, and they were using ex-US or Canadian service Ford F100 trucks. A few years later, the second-hand supply of these ran out, and old Mark IV Ford Zodiac’s were tried as an affordable alternative with sufficient power. In 1978 we undertook a major re-equipment. As well as two K13s and a tug, we bought two brand new Ford F100 trucks. They had 5.8 L V8 engines and propane gas tanks. (We still have one of the engines. It went on for a life after death, as a replacement engine in an ex-ATC Eagle-type winch, which we still have as a backup winch at Ridgewell.) In 1988, these were wearing out. We and Lasham ordered new Ford F250 trucks. We had two, but I can’t remember how many Lasham ordered at that time. They had 7.5 L V8 engines, supercooling, LPG conversion, and cost £10,251.25 each including delivery and VAT. This was the net price after I was able to arrange a healthy discount through my connections with Ford at that time, which included from time to time arranging publicity photographs at North Weald with gliders in the background when they wanted to launch a marketing campaign for a new vehicle. These were the last tow trucks we used for launching at North Weald. (In the early 1990s, the council which had bought the aerodrome banned wire launching at the request of powered aircraft operators at the aerodrome. They had concerns about mixing wire and their aircraft at the same time.) The last version of the “pulley” that we used had two wheels on a pivoting frame, with a short straight between them which formed an anvil. A Guillotine arrangement ran through the horizontal pivot, so we could meet the requirement to be able to chop the cable during a launch if necessary. As far as I know, the Aston Down device did not permit such a safety arrangement. As a general comment on life, launching, and the universe, I would add that there are two ways (at least) to contemplate a technique that you have not used before. 1. Invent it from the beginning yourself and make the same mistakes as everybody else did. 2. Learn from people who eventually got it right and do it similarly. Yours in a spirit of friendship and cooperation. Chris N. |
#19
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SAFE Winch Launching
I am not quite sure why this thread has turned into a discussion about the
merits of tasty warm British beer against that cold p*ss water the Yanks drink, an attack on the late lamented Lucas car component company, and the merits or otherwise of reverse pulley autotowing. In the same period as Chris describes below, we did straight autotowing at Lasham using various models of US Ford F series pick up trucks. This was mainly because the winches available at the time were so poor. Once Tost, Supacat and Skylaunch started building decent quality winches, it was realised that you could get get much higher and safer launches, so the changeover was made in the mid 1980's. I believe that only two UK clubs still autotow in any form. Derek Copeland At 12:04 06 July 2009, Chris Nicholas wrote: Just to put the record straight about pulley launching at North Weald (UK): There were at least three different generations of Ford trucks used for launching at North Weald, with the Ford Zodiac cars as a brief interlude. The Vauxhall that Frank mentions must have been on a day during the old generations of second hand vehicles which were certainly not the best. Somebody must have used their own private car for launching =96 I do not recall the club ever had a Vauxhall between 1970 when I started and 1991 or thereabouts when we had to stop wire launches at North weald. For anyone to judge the capability of reverse pulley launching by a sight of one off day in the 1970=92s is not a fair comparison. I joined the club in 1970, and they were using ex-US or Canadian service Ford F100 trucks. A few years later, the second-hand supply of these ran out, and old Mark IV Ford Zodiac=92s were tried as an affordable alternative with sufficient power. In 1978 we undertook a major re-equipment. As well as two K13s and a tug, we bought two brand new Ford F100 trucks. They had 5.8 L V8 engines and propane gas tanks. (We still have one of the engines. It went on for a life after death, as a replacement engine in an ex-ATC Eagle-type winch, which we still have as a backup winch at Ridgewell.) In 1988, these were wearing out. We and Lasham ordered new Ford F250 trucks. We had two, but I can=92t remember how many Lasham ordered at that time. They had 7.5 L V8 engines, supercooling, LPG conversion, and cost =A310,251.25 each including delivery and VAT. This was the net price after I was able to arrange a healthy discount through my connections with Ford at that time, which included from time to time arranging publicity photographs at North Weald with gliders in the background when they wanted to launch a marketing campaign for a new vehicle. These were the last tow trucks we used for launching at North Weald. (In the early 1990s, the council which had bought the aerodrome banned wire launching at the request of powered aircraft operators at the aerodrome. They had concerns about mixing wire and their aircraft at the same time.) The last version of the =93pulley=94 that we used had two wheels on a pivoting frame, with a short straight between them which formed an anvil. A Guillotine arrangement ran through the horizontal pivot, so we could meet the requirement to be able to chop the cable during a launch if necessary. As far as I know, the Aston Down device did not permit such a safety arrangement. As a general comment on life, launching, and the universe, I would add that there are two ways (at least) to contemplate a technique that you have not used before. 1. Invent it from the beginning yourself and make the same mistakes as everybody else did. 2. Learn from people who eventually got it right and do it similarly. Yours in a spirit of friendship and cooperation. Chris N. |
#20
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SAFE Winch Launching
Pros and Cons of winch launching:
PROS: 1) A new professionally built winch will probably cost less than a new towing aircraft. If you build your own from scrap automobile/truck parts it will cost considerably less. 2) A winch doesn't require a highly qualified and certificated driver, Certificates of Airworthiness, 50 hour checks, etc, etc. Some routine maintenance is required though. 3) Low carbon footprint. A winch launch consumes less than a fifth of the fuel required for an aerotow 4) No aircraft noise complaints. 5) Given proper training and pilot awareness, it's pretty safe. 6) Winch launching is cheap; at our club less than a third of the cost of a 2000ft aerotow, even with professional winch drivers. So ideal for training and circuit bashing. A decent soaring pilot can usually get away from the sort of heights achieved, in the right conditions. 7) You don't have to learn accurate formation flying behind a tug. 8) You are unlikely to kill the winch operator, as opposed to a tug pilot who can be killed if you get too high or too out of position. 9) Above all IT'S FUN. CONS: 1) Launch height is limited by by the length of the cable run and the headwind component. On a still day you will at best get about 45% of the cable run. Launching directly into a headwind will improve this. 2) You can't get towed to a source of lift, such as a cumulus cloud or a ridge. You always end up right over the winch. 3) Pilots need to be fairly well trained and switched on to deal with launch failures and cable breaks. 4) Winch Cables may conflict with power flying at a mixed operation site. Derek Copeland |
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