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#1
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We want to install a tow hitch on a recently acquired Husky in
preparation for the contest season. Is a Tost hitch required or preferred for SSA sanctioned events? Is the venerable Schweitzer hitch still OK ? If so, for how long? Tost is the standard in Europe. Is the US moving toward that standard? Has anyone used the Husky/Super Cub Tost hitch kit offered on Wings and Wheels? |
#2
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On Mar 14, 8:19*pm, jim wrote:
We want to install a tow hitch on a recently acquired Husky in preparation for the contest season. *Is a Tost hitch required or preferred for SSA sanctioned events? Not required. *Is the venerable Schweitzer hitch still OK ? Yes *If so, for how long? No end of life specified at this time? *Tost is the standard in Europe. *Is the US moving toward that standard? Yes, but voluntarily due to the benifits of the tost hitch. *Has anyone used the Husky/Super Cub Tost hitch kit offered on Wings and Wheels? I don't know anyone on RAS that has one, I believe the Seattle Glider Council has Tost hitch's on their Super cub and Pawnee's. Brian |
#3
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On Mar 14, 7:19*pm, jim wrote:
We want to install a tow hitch on a recently acquired Husky in preparation for the contest season. *Is a Tost hitch required or preferred for SSA sanctioned events? *Is the venerable Schweitzer hitch still OK ? *If so, for how long? *Tost is the standard in Europe. *Is the US moving toward that standard? *Has anyone used the Husky/Super Cub Tost hitch kit offered on Wings and Wheels? If you are going to be the one flying the Husky perhaps you should make your decision based on whether you hope to be able to release the rope in the event of an upset. My preference, if on the front end of the rope, would be to have a Tost hook. I don't know how many tow pilots we need to kill or maim before the Schweizer hook is eliminated from tugs. If you decide to go for the Schweizer hook you may want to consider the inverted installation which some believe provides a better chance of release. Andy |
#4
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Andy wrote:
On Mar 14, 7:19 pm, jim wrote: We want to install a tow hitch on a recently acquired Husky in preparation for the contest season. Is a Tost hitch required or preferred for SSA sanctioned events? Is the venerable Schweitzer hitch still OK ? If so, for how long? Tost is the standard in Europe. Is the US moving toward that standard? Has anyone used the Husky/Super Cub Tost hitch kit offered on Wings and Wheels? If you are going to be the one flying the Husky perhaps you should make your decision based on whether you hope to be able to release the rope in the event of an upset. My preference, if on the front end of the rope, would be to have a Tost hook. I don't know how many tow pilots we need to kill or maim before the Schweizer hook is eliminated from tugs. If you decide to go for the Schweizer hook you may want to consider the inverted installation which some believe provides a better chance of release. Andy We had a world class pilot write off an ASW20 in December. The schweizer hook turned 180 degrees and sold him the rope at 50 feet... An anthill saw to the rest. Get a Tost... --- news://freenews.netfront.net/ - complaints: --- |
#5
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There is a frustrating side to these discussions that seem to come up
every few months. The schweizer hook works well enough to justify not removing a serviceable one. Tost has not applied for STC's in the US that would allow trouble free approval. I have heard that it is tough to get a Tost hook approved with a 337. The above reasons have prevented a flood of Tost installations. It is hard to spend $2,000 on a hook that may take a year to get approved if your FSDO will even approve it at all. It really isn't just a matter of negligence when someone continues using a schweizer hook but rather the proverbial "between a rock and a hard place". Maybe Tost will step up one day and apply for an STC. I hear that a new and improved schweizer hook may be on the horizon. XF |
#6
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On Mar 16, 4:57*am, Bruce wrote:
Andy wrote: On Mar 14, 7:19 pm, jim wrote: We want to install a tow hitch on a recently acquired Husky in preparation for the contest season. *Is a Tost hitch required or preferred for SSA sanctioned events? *Is the venerable Schweitzer hitch still OK ? *If so, for how long? *Tost is the standard in Europe. *Is the US moving toward that standard? *Has anyone used the Husky/Super Cub Tost hitch kit offered on Wings and Wheels? If you are going to be the one flying the Husky perhaps you should make your decision based on whether you hope to be able to release the rope in the event of an upset. *My preference, if on the front end of the rope, would be to have a Tost hook. I don't know how many tow pilots we need to kill or maim before the Schweizer hook is eliminated from tugs. If you decide to go for the Schweizer hook you may want to consider the inverted installation which some believe provides a better chance of release. Andy We had a world class pilot write off an ASW20 in December. The schweizer hook turned 180 degrees and sold him the rope at 50 feet... An anthill saw to the rest. Seems strange. Unless the field is grossly too small you should have multiple options from 50 ft and 60+ knots -- quite probably there is still room to land straight ahead, a 90 degree turn and crosswind landing is easy if you're still in the vicinity of the boundary fence and the field is wide (or has a suitable other runway), and a 180 and downwind landing should be well within the capabilities of a world class pilot in a 20. We don't know the wind of course, but a headwind strong enough to preclude landing downwind generally makes a lot more space available straight ahead... Perhaps you can explain the situation a bit more fully? |
#7
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"
We had a world class pilot write off an ASW20 in December. The schweizer hook turned 180 degrees and sold him the rope at 50 feet... An anthill saw to the rest. How can a tow hook on the tow plane rotate (turn) 180 degrees, do you mean it was mounted "inverted"? And if mounted upright or inverted, the SGS hook, if properly installed and maintained would not just, "sell him the rope". Just because it was "inverted" means nothing.. they are all "inverted" when installed on the glider. Something was not maintained. I noticed once between flights and I was out of the cockpit that the tow plane end of the rope (hook) seemed to be almost "1/2" way to the release point. I reset it, did a tow and got out and looked again. It had moved again on it's own. So now I start looking to see what would have happened to cause that. The release cable rides in a plastic casing inside the Pawnee, zip tied to fuselage formers. Some ties had aged and broke, the cable was free to sag. So bouncing in turbulence on the way down, the cable bounced in the aft fuselage, no "pressure" on the hook and it was pulling the release lever. There is more to towing than inspecting the rope and the release system... Check ALL of the airplane and it's parts. The SGS hook failure is no different than if TOST springs were broken and not caught on preflight inspection or checked during the day. No different than a weak link failure.. No different than the engine coughing and the tow purposefully releasing the rope. Had a Stearman blow a jug, the glider pilot saw the puff of smoke and then saw the rope release within a second of the puff. Those are the chances you take... don't blame the hook, blame the preflight. BT (Pawnee Tow Pilot on an SGS Upright Hook) |
#8
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Anecdotes make poor proof of thesis.
However - you are correct that the ultimate cause of the accident was poor maintenance of the hook. But - the failure mode is one the Tost/Ottfur does not have. They cannot rotate in a horizontal plane around the mounting bolt. If yours is welded on - good, if it is inverted - better. If not, as on the Cessnas - your daily checks should include whether there is enough friction to prevent rotation around the mount bolt. If it does rotate it will back release. It is unlikely to do this at a peaceful, stable moment in the tow. One near miss - does someone have to die before we accept there is a risk? This means there are at least two situations where the Schweizer hook is unsafe. The other is failure to release under high lateral angle - which can be overcome by inverted mounting. ref - http://www.jdburch.com/Towstudy.htm The Tost is safer - if you have the option I can't see why you would fit an obsolete design that is no longer in production and is known to be unsafe under circumstances that have killed a number of pilots - time to move on. Bruce BT wrote: " We had a world class pilot write off an ASW20 in December. The schweizer hook turned 180 degrees and sold him the rope at 50 feet... An anthill saw to the rest. How can a tow hook on the tow plane rotate (turn) 180 degrees, do you mean it was mounted "inverted"? And if mounted upright or inverted, the SGS hook, if properly installed and maintained would not just, "sell him the rope". Just because it was "inverted" means nothing.. they are all "inverted" when installed on the glider. Something was not maintained. I noticed once between flights and I was out of the cockpit that the tow plane end of the rope (hook) seemed to be almost "1/2" way to the release point. I reset it, did a tow and got out and looked again. It had moved again on it's own. So now I start looking to see what would have happened to cause that. The release cable rides in a plastic casing inside the Pawnee, zip tied to fuselage formers. Some ties had aged and broke, the cable was free to sag. So bouncing in turbulence on the way down, the cable bounced in the aft fuselage, no "pressure" on the hook and it was pulling the release lever. There is more to towing than inspecting the rope and the release system... Check ALL of the airplane and it's parts. The SGS hook failure is no different than if TOST springs were broken and not caught on preflight inspection or checked during the day. No different than a weak link failure.. No different than the engine coughing and the tow purposefully releasing the rope. Had a Stearman blow a jug, the glider pilot saw the puff of smoke and then saw the rope release within a second of the puff. Those are the chances you take... don't blame the hook, blame the preflight. BT (Pawnee Tow Pilot on an SGS Upright Hook) --- news://freenews.netfront.net/ - complaints: --- |
#9
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On Mar 16, 4:09*am, Bruce wrote:
Anecdotes make poor proof of thesis. However - you are correct that the ultimate cause of the accident was poor maintenance of the hook. But - the failure mode is one the Tost/Ottfur does not have. They cannot rotate in a horizontal plane around the mounting bolt. If yours is welded on - good, if it is inverted - better. If not, as on the Cessnas - your daily checks should include whether there is enough friction to prevent rotation around the mount bolt. If it does rotate it will back release. It is unlikely to do this at a peaceful, stable moment in the tow. I've never heard of this happening, until now. Can you elaborate. Was the towhook rotated around backwards before the tow started? |
#10
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We are welded... but not inverted..
A strong pull to the side will not allow an SGS hook to intentionally release, but yes a TOST can release under any directional pull. I say intentional release, not inadvertant release. BT "Bruce" wrote in message ... Anecdotes make poor proof of thesis. However - you are correct that the ultimate cause of the accident was poor maintenance of the hook. But - the failure mode is one the Tost/Ottfur does not have. They cannot rotate in a horizontal plane around the mounting bolt. If yours is welded on - good, if it is inverted - better. If not, as on the Cessnas - your daily checks should include whether there is enough friction to prevent rotation around the mount bolt. If it does rotate it will back release. It is unlikely to do this at a peaceful, stable moment in the tow. One near miss - does someone have to die before we accept there is a risk? This means there are at least two situations where the Schweizer hook is unsafe. The other is failure to release under high lateral angle - which can be overcome by inverted mounting. ref - http://www.jdburch.com/Towstudy.htm The Tost is safer - if you have the option I can't see why you would fit an obsolete design that is no longer in production and is known to be unsafe under circumstances that have killed a number of pilots - time to move on. Bruce BT wrote: " We had a world class pilot write off an ASW20 in December. The schweizer hook turned 180 degrees and sold him the rope at 50 feet... An anthill saw to the rest. How can a tow hook on the tow plane rotate (turn) 180 degrees, do you mean it was mounted "inverted"? And if mounted upright or inverted, the SGS hook, if properly installed and maintained would not just, "sell him the rope". Just because it was "inverted" means nothing.. they are all "inverted" when installed on the glider. Something was not maintained. I noticed once between flights and I was out of the cockpit that the tow plane end of the rope (hook) seemed to be almost "1/2" way to the release point. I reset it, did a tow and got out and looked again. It had moved again on it's own. So now I start looking to see what would have happened to cause that. The release cable rides in a plastic casing inside the Pawnee, zip tied to fuselage formers. Some ties had aged and broke, the cable was free to sag. So bouncing in turbulence on the way down, the cable bounced in the aft fuselage, no "pressure" on the hook and it was pulling the release lever. There is more to towing than inspecting the rope and the release system... Check ALL of the airplane and it's parts. The SGS hook failure is no different than if TOST springs were broken and not caught on preflight inspection or checked during the day. No different than a weak link failure.. No different than the engine coughing and the tow purposefully releasing the rope. Had a Stearman blow a jug, the glider pilot saw the puff of smoke and then saw the rope release within a second of the puff. Those are the chances you take... don't blame the hook, blame the preflight. BT (Pawnee Tow Pilot on an SGS Upright Hook) --- news://freenews.netfront.net/ - complaints: --- |
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