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#11
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At Lasham in the uk we use powerful winchea(450hp). A couple of makes of glider
have problems if the acceleration is too fierce initially.Typically they have a Cof G hook mounted well aft, a high glider Cof G, high mounted wing (or the main drag being relatively high), nose wheel or skid,and light weight. If you watch them as the cable tighten the tail will bang down (sometimes harder than you would like) This gives the wings a high angle of attack and the glider will lift off with the tail skid still on the ground, straight into a full climb. Quite often the pilot is just a passenger whilst this happens. Once in the air and sufficient flying speed is reached the elevator will start to become effective and he can regain control. The two makes that I have flown that have this problem are the K8 and PW5. We now teach pilots in the K8 to start the winch with full forward stick until flying speed has been reached. A couple of other factor that can make the problem worse. Strong headwind and my pet hate, soft cushions. If a soft cushion is being used as a backrest in these circumstances the acceleration and attitude will thow you back compressing the cushion and not allowing full forward movement of the stick. Also in the report it mentions a type of tow hook that sometimes jams under tension, lethal in my opinion, change it. |
#12
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"OscarCVox" wrote in message ... At Lasham in the uk we use powerful winchea(450hp). A couple of makes of glider have problems if the acceleration is too fierce initially.Typically they have a Cof G hook mounted well aft, a high glider Cof G, high mounted wing (or the main drag being relatively high), nose wheel or skid,and light weight. If you watch them as the cable tighten the tail will bang down (sometimes harder than you would like) This gives the wings a high angle of attack and the glider will lift off with the tail skid still on the ground, straight into a full climb. Quite often the pilot is just a passenger whilst this happens. Once in the air and sufficient flying speed is reached the elevator will start to become effective and he can regain control. The two makes that I have flown that have this problem are the K8 and PW5. We now teach pilots in the K8 to start the winch with full forward stick until flying speed has been reached. A couple of other factor that can make the problem worse. Strong headwind and my pet hate, soft cushions. If a soft cushion is being used as a backrest in these circumstances the acceleration and attitude will thow you back compressing the cushion and not allowing full forward movement of the stick. Also in the report it mentions a type of tow hook that sometimes jams under tension, lethal in my opinion, change it. Oly 463 is another tail stander. I thought soft cushions were banned within the BGA after a fatality attributed to them. Frank Whiteley |
#13
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If a soft cushion is being used as a backrest
in these circumstances the acceleration and attitude will thow you back compressing the cushion and not allowing full forward movement of the stick. I thought soft cushions were banned within the BGA after a fatality attributed to them. I believe that they are, but you still see the occasional idiot using them for "comfort". I mentioned it because this is an international newsgroup. |
#14
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#15
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On Fri, 3 Dec 2004 23:21:46 UTC, "Bill Daniels"
wrote: : A very FEW older gliders exhibit a behavior where the nose will pitch up : uncontrollably if the winch acceleration is too strong. These gliders : usually have high CG's, low CG hooks and small tail surfaces and/or all : moving tails that limit down elevator authority. Good winch drivers know : about them and reduce acceleration accordingly. Given an over enthusiastic launch, the Pirat will happily take off, fly level and then rotate into a full climb, and there is absolutely nothing the pilot can do about it. Except attend to the education of the winch driver... One of my pets hates is the belief that it's a good thing to hold down the tail of some gliders for a winch launch. It isn't. All that happens is that as soon as the tail holder lets go, the nose slams down, then the tail slams down even more violently on the rebound. Ian -- |
#16
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Holding the tail down works very well with an SGS 2-33 in any situation
where the initial pull is strong. We use that technique in all our ground launches when we have an extra person. It might not work well with other ships but it is definitely the preferred method with the 2-33. One of my pets hates is the belief that it's a good thing to hold down the tail of some gliders for a winch launch. It isn't. All that happens is that as soon as the tail holder lets go, the nose slams down, then the tail slams down even more violently on the rebound. Ian -- |
#17
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Right. It works with a 2-33 but it's disaster with a Grob 103. A G103
seems to fly the launch just fine without pilot input as does the L23. Bill Daniels "Gary Boggs" wrote in message ... Holding the tail down works very well with an SGS 2-33 in any situation where the initial pull is strong. We use that technique in all our ground launches when we have an extra person. It might not work well with other ships but it is definitely the preferred method with the 2-33. One of my pets hates is the belief that it's a good thing to hold down the tail of some gliders for a winch launch. It isn't. All that happens is that as soon as the tail holder lets go, the nose slams down, then the tail slams down even more violently on the rebound. Ian -- |
#18
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"Andre Volant" wrote in message om... http://www.glidingmagazine.com/NewsArticle.asp?id=1371 http://www.glidingmagazine.com/ I was told that PW5 has front and rear ballast weights, how complicated is it? The PW5 has compartments for lead shot ballast under the seat pan. I don't believe there's any official rear ballast position, but I do know of pilots who have put a pound or two of lead sheets in the flat area where the horizontal stabilizer attaches. It's not a complicated arrangement, but any addition of ballast in either position would be specific to the pilot and should be done by the pilot IMHO. I've been flying for about 7 years and in my estimation there's good news and bad news in answer to the question "can low time student pilot be blamed?" The bad news is yes, in most every accident I've read about the pilot _in_command_ could have done something to prevent the accident. The good news is we have in our own hands and heads the ability to prevent the accident that will kill us. Brent |
#19
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As a low time pilot myself - but most of it on winch starts - I can
perhaps offer the following (not having read the reports - just this thread): - in the "action" of a fast winch launch - compared to tow - it can be easy to fixate on rotation into (too steep) climb and airspeed and not to check simple things like are my wings level. Sounds like to the pilot too far off level and "fell off the side" of the climb into a stall - some correction for crosswind is usually only initated above 100m check (300 ft AGL) - at least that it what I've been taught Andrew goneill wrote: I belong to the club where this happened . The inquiry is still going on but from comments made by people actually there when it happened. The pilot had already flown earlier in the day in the same glider. The witnesses said the pilot rotated early and was a bit steep in the initial climb but then started to turn right when in full climb at around 300 ft, the deviation to the right continued until back release occurred when the PW5 promptly rolled into a spin. Partial recovery seemed to happen and the PW5 landed straddling a driveway. The farm type 7 wire fences on either side of that driveway acted like arrestor wires.The pilot has 2 broken ankles a broken arm and other minor injuries.The pilot I think is from Hong Kong and I believe has already been flown home. The PW5 is known to want to go to full climb quickly if not prevented but I know a Nimbus 2 will do exactly the same if winched a bit quick so don't blame the glider ,this accident has the look of pilot error. A lot of the training here is on the 2 seat PW6 so type conversion problems are likely not an issue. gary "Andre Volant" wrote in message om... http://www.glidingmagazine.com/NewsArticle.asp?id=1371 http://www.glidingmagazine.com/ Correct "CG" release was used, which on PW5 is offsett forward of the CG. I was told that the nose hook is not allowed for winch towing of PW5. That's what manual sais, but who knows why? Which other gliders are not allowed to be winched by the nose? I was told that PW5 has front and rear ballast weights, how complicated is it? Who is resposible for checking weight and ballance, if for example student pilot has 3 hours (40 flights X 5min) of flight experience? When does resposibility of flight instructor end? Andre |
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