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Hook-In Alarm

Postby Harry » Tue Jul 21, 2015 3:41 pm

Back in 1992, I wrote an article for Hang Gliding Magazine about my hook-In alarm that I created for myself. I'm happy to report that it still works. After all these years, it finally gave out when the Lithium battery finally wore out. Which reminds me, I need to replace the battery before I go flying again.

For those interested in how it works, it consists of a level sensor, metal contacts sewn into the hang strap, a 9V lithium battery, buzzer, and an arming pin. It attaches to the keel and remains on the glider when put away.

When armed, if the glider is lifted up without the pilot being hooked in, the alarm emits an obnoxious sound. As soon as the carabiner is detected in the strap, the alarm is disabled.

The alarm was not accepted by the hang gliding community. I actually met another pilot who managed to invent his own and spent thousands of dollars getting it patented. It never made it to market.

I'm probably the only pilot in the world with this gadget. :mrgreen:
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Re: Hook-In Alarm

Postby JoeF » Tue Jul 21, 2015 8:56 pm

https://www.google.com/patents/US4776530
Stephen M. Mansfield
and
https://www.google.com/patents/US4688022
John R. Gray
and
https://www.google.com/patents/US4272039
Thomas C. Hollingsworth

and we are honored to have present the apparent only user of such alarm ... right here in U.S. Hawks !
There must be a cartoon concept in this story, I bet.
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Re: Hook-In Alarm

Postby Harry » Wed Jul 22, 2015 11:46 am

John Gray is the fellow I ran into so many years ago. He contacted me after reading my article. His design was flawed by the fact that the sensor was very dependent upon gravity. Vibration and dirt would trouble the pilot with false alarms. The other two inventions are overly complicated and difficult to maintain. I don't know if they were invented by pilots or not.

My alarm system was designed to be maintenance free. Other than having to swap out the battery every 5 to 10 years, it has performed flawlessly. Over the years, there was only one incident where I failed to hook into the main strap, but the alarm alerted me to hook into the backup strap, where the sensor is located.
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Re: Hook-In Alarm

Postby Harry » Tue Dec 22, 2015 8:33 pm

I just finished reading Tad Eareckson's review of my hook-in alarm on his forum.
Here: http://www.kitestrings.org/post8270.html#p8270

He spends a great deal of time ripping my article (from 1992) to pieces. That's okay. Nothing wrong with that. I'm just puzzled why it took so long. At the time I wrote that article, I was exploring electronic ways to reduce the possibility of FTHI, as were other pilots. He quite rightly stresses again and again the process of lifting the glider and feeling the leg loops, what I erroneously called the hang straps. Hang straps, leg loops, it's all part of the harness suspension. Something I have always done without thinking much about. If I couldn't feel the leg loops, I didn't launch. Quite right and the correct practice that has never failed me. Flying a Fledge 2 teaches you to do that because for me, it's damn near impossible to launch a Fledge as it is VERY tail heavy. If you can't feel the leg loops tugging at your legs, crotch, and butt, the glider won't launch because as you start your run, the tail will drop and you will just be dragging a stalled dead glider behind you. You stop dead in your tracks. I always did anyway. Feeling the leg loops, the Fledge is easier to balance as you start your run. Plain and simple. I never installed the hook-in alarm on my Fledge because I knew it wouldn't make any difference, but on my WW, I figured it might. Also, on the Fledge, you don't hook into a hang strap. There is none, only a bracket and a bolt. It never had a backup strap either.

The practice of lifting my glider and feeling the leg loops has always worked for me, even while flying other gliders. Enough said there.

Had I read FTHI.pdf by Tad Eareckson, I probably would have never built the device. It was a curiosity to me back then. In all the years I've had it and used it, it actually prevented only one FTHI. In this case, I lifted the glider and the alarm started wailing. I hadn't fully lifted the glider yet to test the leg loops, but I did pause before launching because of the alarm. It could have been that one time I didn't test my straps. Since the sensor was installed in the backup strap, I set the glider down and hooked into the backup and missed the main. I lifted the glider, felt the leg loops, then performed a successful launch. The glider was a WW Sport 150, much easier to launch than a Fledge. Easier to pickup and launch even when not hooked in.

Also, at the time, it was common to have backup straps and I can't remember why, other than maybe there was hang strap failures leading up to folks adding multiple straps and extra carabiners. I remember when there were carabiner failures.

Anyway, I'm posting this because others have tried to design similar devices and they might like to know a bit more about it's history and whether it was a failure or a success. After reading Tad's essay, I'm more inclined to remove the device and the extra hang strap. The device continues to work, but it does add complexity to the glider.
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Re: Hook-In Alarm

Postby Bob Kuczewski » Mon Dec 28, 2015 7:41 pm

People have been wrestling with the hook in problem for a long time.

I like the idea of an alarm, and I considered a simple LED at the nose plate that would have wires running to a battery mounted near the hang loops. The closing of the circuit (lighting the LED) would be accomplished with a jumper attached to the harness. If that jumper didn't close the circuit, then the LED would be off. Never launch with the LED off. Pretty simple.

I never actually built it, but I pictured the design many times. I now do a hook in check immediately before launch. If enough seconds have ticked by since doing it, I do it again ... and again.

It also helps to ask myself before every launch ... "What is the worst thing that could happen at this instant?" ... the answer is always ... "not being hooked in - better be sure."

I like the idea of launching with a tight hang strap, and if the conditions are mild enough, it's a very good technique. At some of the rowdy cliff launches I've flown, it doesn't feel safe to be compromising my launch technique by combining it with a "preflight" item.
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Re: Hook-In Alarm

Postby Rick Masters » Sat Jun 10, 2017 12:12 pm

Image
Mr. Tourette makes the point that a hook-in alarm or even a hang check might not be enough to save you if you haven't stepped into or fastened your leg straps. The hang glider pilot who died yesterday at Emberger Alm had "forgotten to put on his leg loops." After launching from 1750 meters, the man's torso slipped out the bottom of his harness and he hung upright from the bar of his Atos with only his arms passing through the harness openings. Although he could control roll, his weight was far forward in pitch and "he flew at high speed toward the valley" at a steep rate of descent. Those at launch watched helplessly as he approached the village of Greifenburg, where "he could no longer hold on" and fell "from a high altitude into the forest."
http://www.krone.at/oesterreich/auf-beinschlaufen-vergessen-hobby-pilot-54-tot-dramatische-szenen-story-573438
______________________
If you should ever find yourself in this situation, your only chance of survival is to do what my good friend Dave Butz did when he launched unhooked from La Cumbre back in the early 1980s. Quickly, before your strength ebbs from hanging on to the bar, make the decision. Tell yourself, "I am not going to die like this," and pull your legs up in front of you, pass your heels up over your head and behind the bar, then pull your legs up and lock your knees over the bar. Keep yourself centered! Now reach up to the down tubes and pull yourself up onto the bar, pull higher, put your feet on the bar and stand up. You can fly that thing all day like that.
    I don't know what they teach these days but when I learned, we would go to the sand dunes, pick up an old single surface glider without a harness, run and jump up on the bar and practice flying like this. It was part of becoming a hang glider pilot.
    In my opinion, if you can't perform this simple gymnastic trick, you have no business flying a hang glider. Practice it on a suspended glider until it becomes second nature.
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