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Too-slow tows are a constant problem at contests. Not being a tow
pilot, I can only guess a the problem, but I suspect that tow pilots used to pulling 2-33s can't seem to adjust to what happens with heavily ballasted gliders on a hot day. The radio is full of radio calls, wing rocking, (yes, contest pilots know the signals) and more radio calls to no effect. It happened to me last summer. The big problem was not "more speed" on a well-balanced tow. My towplane simply took off for the sky while I was still rolling on the ground! Towing a fully ballasted glider requires the towplane to gain speed while low, and make sure the glider has taken off before climbing. The contest rules say 70 mph, and that means gain speed to 70 while still in ground effect. Most hilarious radio exchange: Lubbock, standard class nationals. Full water, slight cross and downwind. The same towplane is always too slow. "Towplane X, 70 mph please. ...(no answer) TOWPLANE X, MORE SPEED (no answer) .... TOWPLANE X, I NEED MORE SPEED NOW!" (pause) "all right, all right, ... but what do y'all want to fly so fast for anyhow?" Of course many seasoned contest tow pilots provide excellent and dedicated servce, for little reward, and we're very thankful for them. John Cochrane |
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On Nov 16, 8:01 pm, BB wrote:
Too-slow tows are a constant problem at contests. Not being a tow pilot, I can only guess a the problem, Snip glider has taken off before climbing. The contest rules say 70 mph, and that means gain speed to 70 while still in ground effect. Snip "all right, all right, ... but what do y'all want to fly so fast for anyhow?" Of course many seasoned contest tow pilots provide excellent and dedicated servce, for little reward, and we're very thankful for them. On thread -- I encourage labeling all vehicles largely on multiple surfaces in contest environments. Then -- dangling from the thread.... Oh, how I laugh. It must be about time that the list of ranked pilots is now jonesing for a contest.... in the northern hemisphere (specifically USA) , at least. Thanks for publicly thanking tow pilots. For starters, 70 mph is 60.8 knots (or 112 kph for the entertained Continental pilots avoiding this rant). BB says 70 mph is the rule, so I won't go check the units of measure. 70 mph would do for me. A wet glider won't stall at 60.8 knots in under 30 degrees (aerotowing) bank angle in moderately convective flight conditions, without some other provocation. I do believe most of you will spend hours of the day thermalling at or less than that same 60 knots, wet, at significantly more bank angle than you used while being towed. Have you managed to leave your flaps forward from that moment of initial roll, when you wanted that enhanced aileron effectiveness? So why do those repetitive radio pleas for speed recur? Simply, that the glider pilot is used to spending his day looking at the horizon line with his nose BELOW the reference, and when he spends a scant five to seven minutes with his nose above the horizon, his little peasized hypothalamus is screaming to "normalize" things. Especially since he is aleady adrenalined up, with anticipation of fear or reward in the midst of his peers. Let's holler at the only socially acceptable outlet, the towpilot. Or, if we really don't like the picture, draw on some more positive flap to change lift and the forward view. I didn't say this was rational, in fact, I strongly believe it is an emotional moment. Truly, that heavy, draggy towplane has a seriously higher stall speed than your glider has, and if he is flying, you are/ can be flying. (Unless you happen to be blessed with a Cessna Wren conversion or something else particularly tug exotic.) I heard tales of climbing behind the Italian turbine Bird Dog at Uvalde years ago. Speed was fine, but the climb rate and pitch attitude had eyeballs rolling. I often require pilots in field checks or flight reviews to make the tug slow to 50 knots with signals (not radios). Most folks whine and wallow, when they are learning how much pitch change that requires from them to hold level position behind the tug. Then they must use the speed-up(down?) signal to get back to "regular" speed. Since so few US operations require the use of signals in initial training, flight tests, or recurrent training, few towpilots keep sharp on them, and become lazy/complacent in monitoring the customer. Few glider pilots will practice them voluntarily. And yet, what else improves airmanship during those available minutes behind the tug? Burt's post implies there are a potload of signals to remember (eighteen). But while airborn, there are only seven. And only four originate from the glider pilot, three from the tug. I'd bet everyone reading here can tell me the three hand signals for use bicycling or driving antiques in road traffic. And you used those how recently? Why can't we get glider folks to practice, remember and use something which is so frequently relevant? I want my customers to be "in command" of their towing experience, both in heading and speed, and encourage visual signals to the tug. Radios are helpful, but don't need to be the primary form of "convenience" communication, to save bandwidth for urgent calls, or to be polite in a high traffic environment. And, what do you want to fly so fast for anyway? I know a towpilot who responds to the ground discussion later, "You can tow fast or climb fast, which one do you want?" Because the call after speeding up was frequently, "Can't you get me to those guys any quicker?" My favorite tow speed call from years ago was a complaint . . . "That Pawnee is towing me at ninety knots. Slow down !!!!" When asked later, the glider pilot told me that yes, they were climbing at the time. I withdrew from the discussion at that moment, knowing that those two factors were in complete opposition to each other and not possible in reality. It was a 235 Pawnee and a wet Open Class glider. I just told him I would "talk" to the tow pilot. Discuss, think, learn, practice. Fly with a CFI every spring, and ask to really work on something. Don't take the easy way out; improve. Safe soaring, Cindy B www.caracolesoaring.com |
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![]() "CindyB" wrote in message ... On Nov 16, 8:01 pm, BB wrote: Too-slow tows are a constant problem at contests. Not being a tow pilot, I can only guess a the problem, Snip glider has taken off before climbing. The contest rules say 70 mph, and that means gain speed to 70 while still in ground effect. Snip "all right, all right, ... but what do y'all want to fly so fast for anyhow?" Of course many seasoned contest tow pilots provide excellent and dedicated servce, for little reward, and we're very thankful for them. On thread -- I encourage labeling all vehicles largely on multiple surfaces in contest environments. Then -- dangling from the thread.... Oh, how I laugh. It must be about time that the list of ranked pilots is now jonesing for a contest.... in the northern hemisphere (specifically USA) , at least. Thanks for publicly thanking tow pilots. For starters, 70 mph is 60.8 knots (or 112 kph for the entertained Continental pilots avoiding this rant). BB says 70 mph is the rule, so I won't go check the units of measure. 70 mph would do for me. A wet glider won't stall at 60.8 knots in under 30 degrees (aerotowing) bank angle in moderately convective flight conditions, without some other provocation. I do believe most of you will spend hours of the day thermalling at or less than that same 60 knots, wet, at significantly more bank angle than you used while being towed. Have you managed to leave your flaps forward from that moment of initial roll, when you wanted that enhanced aileron effectiveness? So why do those repetitive radio pleas for speed recur? Simply, that the glider pilot is used to spending his day looking at the horizon line with his nose BELOW the reference, and when he spends a scant five to seven minutes with his nose above the horizon, his little peasized hypothalamus is screaming to "normalize" things. Especially since he is aleady adrenalined up, with anticipation of fear or reward in the midst of his peers. Let's holler at the only socially acceptable outlet, the towpilot. Or, if we really don't like the picture, draw on some more positive flap to change lift and the forward view. I didn't say this was rational, in fact, I strongly believe it is an emotional moment. Truly, that heavy, draggy towplane has a seriously higher stall speed than your glider has, and if he is flying, you are/ can be flying. (Unless you happen to be blessed with a Cessna Wren conversion or something else particularly tug exotic.) I heard tales of climbing behind the Italian turbine Bird Dog at Uvalde years ago. Speed was fine, but the climb rate and pitch attitude had eyeballs rolling. I often require pilots in field checks or flight reviews to make the tug slow to 50 knots with signals (not radios). Most folks whine and wallow, when they are learning how much pitch change that requires from them to hold level position behind the tug. Then they must use the speed-up(down?) signal to get back to "regular" speed. Since so few US operations require the use of signals in initial training, flight tests, or recurrent training, few towpilots keep sharp on them, and become lazy/complacent in monitoring the customer. Few glider pilots will practice them voluntarily. And yet, what else improves airmanship during those available minutes behind the tug? Burt's post implies there are a potload of signals to remember (eighteen). But while airborn, there are only seven. And only four originate from the glider pilot, three from the tug. I'd bet everyone reading here can tell me the three hand signals for use bicycling or driving antiques in road traffic. And you used those how recently? Why can't we get glider folks to practice, remember and use something which is so frequently relevant? I want my customers to be "in command" of their towing experience, both in heading and speed, and encourage visual signals to the tug. Radios are helpful, but don't need to be the primary form of "convenience" communication, to save bandwidth for urgent calls, or to be polite in a high traffic environment. And, what do you want to fly so fast for anyway? I know a towpilot who responds to the ground discussion later, "You can tow fast or climb fast, which one do you want?" Because the call after speeding up was frequently, "Can't you get me to those guys any quicker?" My favorite tow speed call from years ago was a complaint . . . "That Pawnee is towing me at ninety knots. Slow down !!!!" When asked later, the glider pilot told me that yes, they were climbing at the time. I withdrew from the discussion at that moment, knowing that those two factors were in complete opposition to each other and not possible in reality. It was a 235 Pawnee and a wet Open Class glider. I just told him I would "talk" to the tow pilot. Discuss, think, learn, practice. Fly with a CFI every spring, and ask to really work on something. Don't take the easy way out; improve. Safe soaring, Cindy B www.caracolesoaring.com While the SSA signals are important to know, as a practical matter, they are insufficient. I have experience as a towpilot, CFIG, and contestant pilot. Our club Pawnee is festooned with mirrors-4 in all. One is dedicated to watching the "funnel" for the rope in a Tost reel-We have dyed the last 10 ft of rope with red rings to tell when it is "all out" and in flight to tell when it has finished retracting. The switch doesn't always cut off when fully retracted, and some pilots "forget" to reel in the rope, so it can be checked before landing. One is dedicated to seeing the wing runner and his signals. It is mounted outboard on the strut. The other two give a pretty good view of the glider in flight, but the cowl mounted mirrors do vibrate, and the glider doesn't always stay where it belongs. As a result, recognition of signals would not be immediate, to say the least! Radio is IMHO essential communication, with signals as backup. We should, of course, be "currernt" on all backup systems. I have, on a few occasions, been towed "too slow" at a contest. Less frequently now since the CD &CM and Chief TP have agreed that all tows are at 80mph (70kt) unless requested otherwise. Lately, we have been specifying "heavy" by radio during hookup if ballasted, in a contest with FAI and Sports classses. The "too slow" is more of a sensation than a ASI reading, which is often not accurate on tow. I only have a limited range of make and model experience with ballast (ASW20B, ASW27B, DG800B) They all feel solid at thermalling speed in the 55-60 kt range. When the same glider feels "mushy" and wallowing at tow speed, it is worrisome, no matter what the cause. A request for "Pawnee 23L 5 kt faster please" takes 5-6 sec. The increased speed cures the feeling and solidity returns. On one occasion, behind a "sick" Call Aire, I released at 1200 ft over the airport, in a good thermal--preferring a relight to enduring the feeling any longer. A quick look at the ASI showed a hair under 50kt! I was able to climb out but was in a position to join a downwind if needed. The last 3 characters of the towplane call sign on the flaps make it easy to call the correct towplane. That would eliminate a lot of confusion. As far as saving bandwidth, except for an imminent mid-air collision, what could be more urgent than a mushy, heavy glider close to the ground on tow? How would a glider stall and recovery while on tow affect the towplane? Would there be time to recognize a "speed up" signal? Accidents and fatalities have occurred on tow due to a too-slow tow. It is not a trivial problem. Hartley Falbaum USA "KF" |
#4
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Cindy:
Although there may be lots of truth in what you say, I know that many standard class ships are unhappy at low tow speeds. I also know the nose of my Discus 2 is high on tow and can live with it - I just fly a little to the side and peer round the nose. All I can tell you is that below 70 knots when fully ballasted, I lose enough control to be seriously worrying. At 60 knots, I have several times dropped into low tow with full up elevator. For some reason, reaching for the flap handle doesn't seem to help, so I yell for more speed. I know my ship thermals at speeds lower than that, but the handling becomes definitely marginal at similar speeds on tow. Maybe it's the dynamics of the tow and the angle of incidence of the wing, but this behavior is real and not imaginary. Mike |
#5
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![]() "all right, all right, ... but what do y'all want to fly so fast for anyhow?" Of course many seasoned contest tow pilots provide excellent and dedicated servce, for little reward, and we're very thankful for them. On thread -- I encourage labeling all vehicles largely on multiple surfaces in contest environments. Then -- dangling from the thread.... Oh, how I laugh. It must be about time that the list of ranked pilots is now jonesing for a contest.... in the northern hemisphere (specifically USA) , at least. Thanks for publicly thanking tow pilots. For starters, 70 mph is 60.8 knots (or 112 kph for the entertained Continental pilots avoiding this rant). BB says 70 mph is the rule, so I won't go check the units of measure. 70 mph would do for me. A wet glider won't stall at 60.8 knots in under 30 degrees (aerotowing) bank angle in moderately convective flight conditions, without some other provocation. I do believe most of you will spend hours of the day thermalling at or less than that same 60 knots, wet, at significantly more bank angle than you used while being towed. Have you managed to leave your flaps forward from that moment of initial roll, when you wanted that enhanced aileron effectiveness? So why do those repetitive radio pleas for speed recur? Simply, that the glider pilot is used to spending his day looking at the horizon line with his nose BELOW the reference, and when he spends a scant five to seven minutes with his nose above the horizon, his little peasized hypothalamus is screaming to "normalize" things. Especially since he is aleady adrenalined up, with anticipation of fear or reward in the midst of his peers. Let's holler at the only socially acceptable outlet, the towpilot. Or, if we really don't like the picture, draw on some more positive flap to change lift and the forward view. I didn't say this was rational, in fact, I strongly believe it is an emotional moment. Truly, that heavy, draggy towplane has a seriously higher stall speed than your glider has, and if he is flying, you are/ can be flying. (Unless you happen to be blessed with a Cessna Wren conversion or something else particularly tug exotic.) I heard tales of climbing behind the Italian turbine Bird Dog at Uvalde years ago. Speed was fine, but the climb rate and pitch attitude had eyeballs rolling. I often require pilots in field checks or flight reviews to make the tug slow to 50 knots with signals (not radios). Most folks whine and wallow, when they are learning how much pitch change that requires from them to hold level position behind the tug. Then they must use the speed-up(down?) signal to get back to "regular" speed. Since so few US operations require the use of signals in initial training, flight tests, or recurrent training, few towpilots keep sharp on them, and become lazy/complacent in monitoring the customer. Few glider pilots will practice them voluntarily. And yet, what else improves airmanship during those available minutes behind the tug? Burt's post implies there are a potload of signals to remember (eighteen). But while airborn, there are only seven. And only four originate from the glider pilot, three from the tug. I'd bet everyone reading here can tell me the three hand signals for use bicycling or driving antiques in road traffic. And you used those how recently? Why can't we get glider folks to practice, remember and use something which is so frequently relevant? I want my customers to be "in command" of their towing experience, both in heading and speed, and encourage visual signals to the tug. Radios are helpful, but don't need to be the primary form of "convenience" communication, to save bandwidth for urgent calls, or to be polite in a high traffic environment. And, what do you want to fly so fast for anyway? I know a towpilot who responds to the ground discussion later, "You can tow fast or climb fast, which one do you want?" Because the call after speeding up was frequently, "Can't you get me to those guys any quicker?" My favorite tow speed call from years ago was a complaint . . . "That Pawnee is towing me at ninety knots. Slow down !!!!" When asked later, the glider pilot told me that yes, they were climbing at the time. I withdrew from the discussion at that moment, knowing that those two factors were in complete opposition to each other and not possible in reality. It was a 235 Pawnee and a wet Open Class glider. I just told him I would "talk" to the tow pilot. Discuss, think, learn, practice. Fly with a CFI every spring, and ask to really work on something. Don't take the easy way out; improve. Safe soaring, Cindy B www.caracolesoaring.com[/quote][/i][/color] Nice, Ms B, I love a good rant. Here in Oz, we low tow. This improves the feel of a nose high attitude in a full slippery ship, you are always just below the slipstream, getting it slightly wrong only gets you further down, not further in trouble. The towplane is always fully in the canopy, easy to see. Tug upsets are minimised, the tuggie will let you know fairly smartly if he runs out of down elevator, but even so, he will not be greatly alarmed. Run him out of up elevator and there is trouble, almost instantly. Your notation that the tug will stall before the glider is pertinant, it follows that the problem is usually one of sensation rather than actual danger, although I welcome being corrected on this. When the tug is always above you, you feel like you are being pulled up, as opposed to flying behind it. Perhaps Hartley or some of the other posters have tried both and can add? Bagger |
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it.
Perhaps Hartley or some of the other posters have tried both and can add? Bagger Here in the USA, they not only fly high tow, but require the glider to make a right turn off release. Why do they do everything backwards? They even drive on the wrong side of the road here! Anyway..... They also fly low tow in South Africa where I did all my early flying and I have to say I have always preferred it. There are just too many accidents where the glider gets too high on tow and the towplane can't recover, which is much less likely to occur on low tow. Having said that, I prefer to be in low tow of my own volition and not because I am so slow that I have lost elevator control. Below 65 knots, my fully-ballasted Discus 2 gets very wallowy and at 60 is unable to maintain high tow. As others have said, it's essential that the towplane and glider pilot agree on speed, signals and maneuvers. I wouldn't want to be towed too fast in a lightweight fragile wooden ship just as much as I hate slow tows in fast glass. Mike |
#7
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![]() www.caracolesoaring.com Nice, Ms B, I love a good rant. Here in Oz, we low tow. This improves the feel of a nose high attitude in a full slippery ship, you are always just below the slipstream, getting it slightly wrong only gets you further down, not further in trouble. The towplane is always fully in the canopy, easy to see. Tug upsets are minimised, the tuggie will let you know fairly smartly if he runs out of down elevator, but even so, he will not be greatly alarmed. Run him out of up elevator and there is trouble, almost instantly. Your notation that the tug will stall before the glider is pertinant, it follows that the problem is usually one of sensation rather than actual danger, although I welcome being corrected on this. When the tug is always above you, you feel like you are being pulled up, as opposed to flying behind it. Perhaps Hartley or some of the other posters have tried both and can add? Bagger -- bagmaker[/i][/color] I have flown low tow in our trainiing gliders and tried it on aerotow retrieves. I have not tried it fully ballasted. I didn't like the rope rubbing on the fuselage from the CG hook (no nose hook installed), and really didn't find it less fatiguing. So, except to teach that it can be done, I don't use it. I agree that we fly just fine in thermals at a slower speed, and that a Pawnee will stall before the glider. Therefore there must be some other factor in the equation that we are not considering. My suspicion is that the glider on tow is flying in disturbed air behind the towplane. This causes the controls to be less effective. Perhaps laminar flow cannot be established. Perhaps an Aerodynamicist could help us out here. In any event the phenomenon is real, for sure. Hartley Falbaum USA "KF" |
#8
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![]() I agree that we fly just fine in thermals at a slower speed, and that a Pawnee will stall before the glider. Therefore there must be some other factor in the equation that we are not considering. My suspicion is that the glider on tow is flying in disturbed air behind the towplane. This causes the controls to be less effective. Perhaps laminar flow cannot be established. Perhaps an Aerodynamicist could help us out here. In any event the phenomenon is real, for sure. Hartley Falbaum USA "KF" Yes, it's real. I also find it when I am in clean air out of the towplane wake. I suspect non-flapped modern racing sailplanes like the LS-8, ASW-28 and Discus 2 have a low angle of incidence of the wing that requires a nose-up attitude to maintain the proper angle of attack at low speeds. When in high tow with a nosehook, the towline exerts a downward force that reduces the angle of attack. To maintain stable flight in such conditions requires more speed. Mike |
#9
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![]() BB wrote: Too-slow tows are a constant problem at contests. Not being a tow pilot, I can only guess a the problem, but I suspect that tow pilots used to pulling 2-33s can't seem to adjust to what happens with heavily ballasted gliders on a hot day. The radio is full of radio calls, wing rocking, (yes, contest pilots know the signals) and more radio calls to no effect. And the converse is also true. A couple of my less pleasant tows have been at contests where the tuggie failed to compensate for the transition from the heavies to club class unballasted ships. The local tuggies often aim for 80, because of high density altitudes and heavy ships - and sometimes overshoot - 160kmh (85kt) with the tug still on the ground tends to be somewhat hectic in an unballasted Std Cirrus. (at least for the average experience of the guys in club class - including me) It happened to me last summer. The big problem was not "more speed" on a well-balanced tow. My towplane simply took off for the sky while I was still rolling on the ground! Towing a fully ballasted glider requires the towplane to gain speed while low, and make sure the glider has taken off before climbing. The contest rules say 70 mph, and that means gain speed to 70 while still in ground effect. Most hilarious radio exchange: Lubbock, standard class nationals. Full water, slight cross and downwind. The same towplane is always too slow. "Towplane X, 70 mph please. ...(no answer) TOWPLANE X, MORE SPEED (no answer) .... TOWPLANE X, I NEED MORE SPEED NOW!" (pause) "all right, all right, ... but what do y'all want to fly so fast for anyhow?" Of course many seasoned contest tow pilots provide excellent and dedicated servce, for little reward, and we're very thankful for them. John Cochrane |
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