[Bill Cummings]

If a crash can't be extended in time and distance it seems to me that a restraint system that does all it can in the event of a sudden full stop is all we should strive for.
Wheels are icing on the cake in the event movement is allowed to happen.
The test car crashing into a immovable object have the wheels doing nothing but making black smoke during the fire.
If the crash isn't head on we will get a stop like Rick is talking about.
Jim a test crash with a line tied to the middle of the downtube is going to take out the downtube folding up your protective cage.
That test should be scheduled after the 200 pound pilot/sandbags crash with the rear restraint system.

[Rick Masters]

Going to take out a downtube for sure...

Not necessarily.
The pilot always weighs more than the glider.
That's more than half the mass of the hang glider / pilot combination.
If you can manage to slam that mass against the sail in a way that distributes the force of impact evenly across the glider's sail and frame, you will discover that often little damage results.
This is because damage is a result of pinpoint force concentration.
A death grip on the downtubes, held improperly, is the most common cause of bending them.
Think of 100 pounds x velocity concentrated on 5 square inches for 200 milliseconds.
(And you guys who hold onto your base tube in a crash should think about 170 pounds x velocity concentrated on 3 centimeters of your neck vertebrae.)
But in a more powerful crash, the kind where the pilot's momentum is too strong for him to hold on to the upright, the pilot will lose his grip after he has rotated about 90-degrees.
He will hurl forward and slam against the sail.
As he does, the force will be distributed laterally by the sail and absorbed by many points across the airframe without any damage at all to the structure.
If you can get your body rotated to the point where it will swing forward against the sail at impact, hanging onto the downtube becomes much less important.
(Don't worry about hitting the keel. You'll be knocking it out of column from the side. They bend when you do that, absorbing impact. That's good.)

Look at the pilot with the yellow helmet in the video at 0:52.
https://www.youtube.com/watch?feature=player_embedded&v=Q06HS4eiQ54
This pilot does everything right.
Note the condition of the downtubes.

Also, I'm not trying to discourage compression devices at all.
I'm only saying they should be viewed as a compliment to the primary defense against injury, the pilot applying his skill and knowledge to survive a crash.

[Bill Cummings]

It works 1.JPG (24.45 KiB) Viewed 4928 times

Good outcome.

[reluctantsparrow]

Wow...Great job sluething out that particular crash from the video Rick......OKay....
I still want to see the sidewinder done on my zip line but it might destroy a tube I cant replace from Kenny Richardsons hang glider boneyard ( Kenny must have twenty gliders in that pile).

so the next test will be the showstopper.....Your video, physic lesson, and personal experience Rick has already convinced me the sidewinder , or whatever you think it should be called, is a winner..
I already shared that idea with Steve Danielson today on the phone before he went flying today....just in conversation....then I realized....you never know when a tidbit of shared info like that is going to save a buddys life...or your own...thanks for sharing Rick.

The showstopper restraint line hasnt really tried to break anything significant even when I put 120 pounds on it and even when I did not put the reinforced keel back together properly and the keel twisted out of column (only one item broke though, the small, pivoting fitting in the top of the left downtube and i had an extra one of those in mY hang glider boneyard.)

I will take time to do a better video....I know my videos have been half a**. Never did claim any skills in that area...but I will give more thought to the video this time.

I will not guess at the line length, I will get in the harness and make sure the showstopper is rigged for full range of motion.
I am going to use the trolley....that was kick a**...but I am going to re-attach base tube restraint lines to bring the test rig to a halt after the test rig has dropped away from the trolley but I think the sudden stop thing is not not actually the most ordinary whack either...Lots of times, actually most of the time, some sliding is taking place as a pilot is swinging through....any ideas on how to simulate a short sliding action? say about three feet?

I am going to load it with another sandbag....180 pounds total. and looking at the harness I am using I do believe that it is not going to zip up with three sandbags placed in the torso region....no...i dont think it will...
so I am going to make a longer board to go inside the harness and distribute the 180 pounds as if it was an actual pilot....one sandbag for the hip and leg region and two sandbags for the torso.....
Going to go out and seriously buy a nice balloon for the pilots head this time.....now thats entertainment.

[Bill Cummings]

Diagonal for crash swing through.
Go to 2:34 for slow motion.
https://www.youtube.com/watch?v=gFvTht9gL70

go to 2.34.JPG (59.45 KiB) Viewed 4918 times

[reluctantsparrow]

The diagonal swing through is exactly what I did to save my arse after mid-air shoulder dislocation at chelan. took a full speed whack into about 6 inches of dirt powder. My head ended up closer to the nose than the above video but I WAS sideways and my head WAS clear (although so close to the leading edge I coulda licked it with my tongue)....
I was also flying a moyes SX. Maybe one of strongest gliders ever made but also some of the worst geometry for the head meets noseplate scenario.
The showstopper line is not going to allow a pilot to go diagonal or grab onto a basetube (the sidewinder).
The showstopper is not going to allow the mass of the pilots body to rotate around as it swings through the A-frame to soak up most of the G force of impact.
I am still going to test it and I am re-thinking it..I am now thinking the showstopper IS going to work, especially if I remove the extra forward motion that is being allowed by the two main suspension points in the harness I am using from squeezing together.....I am getting a lot of extra forward motion as those two attach points squeeze together so I am just going to zip tie them together before adjusting the line for the test.....
The results are going to more closely reflect the showstopper attached to s single point main suspension type harness.
However,
The showstopper straightens a pilot out and creates a symetrical swing through while going sideways (diagonal) or grabbing aluminum (downtube) creates asymetrical swing through and I dont see how we are going to have it both ways.....a pilot is going to have to choose between one or the other unless I am missing something.
I dont think a pilot flying with a showstopper type line is going to have the option to get sideways.
We already know diagonal works works very well to keep the pilots head out of harms way....right?
but sometimes a pilot does not have time to grab aluminum or does not think to do so or maybe the pilot has suffered a heart attack and is nothing but a sack of potatoes coming in on final...etc.etc....
so....how about....ONE HALF of an Arpr style line?.....only one half tied off to only one side?....with plenty of slack for normal range of motion....thats a lot of slack required for a line that now no longer slides freely through the harness but is tied directly to say, the tow loop on one shoulder to the downtube/basetube junction.....what is the geometry on that?
If the geometry is workable maybe that would allow a pilot to swing through then be flipped sideways....or
What about changing the geometry?
we can do that....
mount a line to one tow loop on one side of the shoulders....mount the other end of the line to one clamp mounted on one of the rear flying wires.....find the sweet spot that allows full range of motion yet still turns the pilots body sideways at that crucial moment....hmmmm
Do not mount the line to just one tow loop....mount the line to left tow loop....line runs over to right tow loop...firmly attach to right tow loop as well, then route line to attach to right hand lower flying wire wherever the sweet spot that allows full range of motion determines that sweet spot to be.......this will allow the pilots body to initially swing through, then rotate the pilot to one side but keep shoulder straps in place on the pilots shoulders
side of attachment should be determined as opposite whichever side the pilots parachute is pulled and thrown from to avoid possible entanglements.....????????
now I am getting a little excited I must admit....we already know sideways works....and it will reduce the cost of such a safety system to about $5.47 with only one line on one side flapping in the breeze.
unfortunatly that line will not be out of sight, out of mind like the showstopper line unless???????
If I didnt already promise to build a new door for the greenhouse today to keep out the chickens I would test this idea TODAY....cant do it today because I keep my promises (my only virtue).....tomorrow looks good though.....I can rig it today after work to test range of motion and find the sweet spot......
the tie off to only one rear flying wire should be way strong as the line is only being used for a pivoting motion instead of a full stop motion....
If this thing works I am lighting up a really fat doobie tomorrow evening. (its legal in Washington)

[reluctantsparrow]

Not going to attach on rear flying wire.....from shoulder tow straps route line with breakaway velcro along back of harness to where mains meet harness....then one single line running back and up to the rear flying wire/keel junction.....leaves glider totally unaltered and wires untouched....and leaves the single line out of sight, out of mind as the pilot takes off, manuevers, flares, etc....
leaves nothing dangling except one single line running from harness mains back to keel....shouldnt even cause a problem with tow operation....
Got the day off from building a new greenhouse door.....going to test it today...RS

[Rick Masters]

I've mentioned this before but it is worth repeating.
The few hang glider manufacturers that are left try really hard to make great gliders that pilots will buy.
I think they do this really well.

Modern hang gliders are fantastic.
If pilots demand gliders that fly fast, they'll do that.
If pilots want gliders that land like snowflakes, they'll do that.
I don't fault them for their market-based decisions.
The one thing, and about the only thing, that bothers me, is when they design a high-aspect ratio glider that can slam it's nose or leading edge down on top of the pilot's helmet or neck in a crash.
That should not ever be allowed to happen.
It is a bad or incomplete design.
This could easily be prevented with, say, a short bowsprit extension.

But reluctantsparrow may be onto something else here.
If somehow a compressible device in the keel could be made to work with the standard hook-in arrangement
and it could, as well, prevent the pilot's head from reaching the danger zone of the nose impact point,
now that would be interesting and useful.
You have to have a simple and effective and lightweight and easy-to-install and cheap device for it to be adopted.
It will have to be easily retrofitted, then forgotten about and still work perfectly when it is needed.

I do not like the idea AT ALL of any extra lines that could be caught in feet or the legs of the pilot or the tail of the harness.
The challenge is to design a compressible safety device that requires NO EXTRA STEPS, IS NOT IN THE WAY, and is so generic that it can be fitted to virtually any hang glider.
AND it must be effective in off-forward-vector crashes such as wingtip impacts.
I actually think it could be done.
I would look at a compressible foam cartridge that could be inserted in the rear of the keel and secured to the rear keel bolt.
A line running forward through the keel would exit the keel aft of the suspension point through a slider tube (no pulleys) to connect to the harness suspension.
In a crash, the pilot would swing through the downtubes while hanging on to one downtube and the line would go tight as he swung through.
The foam would compress and the line would stop.
This would swing the pilot up into impact with the sail.

[reluctantsparrow]

You have to have a simple and effective and lightweight and easy-to-install and cheap device for it to be adopted.
It will have to be easily retrofitted, then forgotten about and still work perfectly when it is needed.

I do not like the idea AT ALL of any extra lines that could be caught in feet or the legs of the pilot or the tail of the harness.
The challenge is to design a compressible safety device that requires NO EXTRA STEPS, IS NOT IN THE WAY, and is so generic that it can be fitted to virtually any hang glider.
AND it must be effective in off-forward-vector crashes such as wingtip impacts.
I actually think it could be done.
I would look at a compressible foam cartridge that could be inserted in the rear of the keel and secured to the rear keel bolt.
A line running forward through the keel would exit the keel aft of the suspension point through a slider tube (no pulleys) to connect to the harness suspension.
In a crash, the pilot would swing through the downtubes while hanging on to one downtube and the line would go tight as he swung through.
The foam would compress and the line would stop.
This would swing the pilot up into impact with the sail.

Okay Rick, check out this line which I think meets most of the criteria you outlined above...simple, cheap, easy to install, lightweight.....whether it is effective or not will be determined in the testing.....as far as attachment to a device with a compressible foam cartridge.....I am resurrecting the keel piston and fitting it with compressible foam today....which is cheap, generic, and an aftermarket device that will simply replace or be fitted into the rear stinger of a glider so that no key structural components of the hang glider needs altered in any way.... the pigtail of the line will simply clip into such a device....might take me another day to get it all rigged up properly....
I routed the line up and over the shoulder strap to keep all line out of sight, out of mind, and reduce risk of entanglements......keep the feedback coming....I have high hopes for the track we are on right now....
Here is a video showing range of motion:



Here is a short video of ground handling, running, flaring, and so far so good....I do not see anything that can cause any entanglement, loss of control, etc.


an added plus: This line set up offers by far the lowest drag so far... in line with the general airflow.....the sideways motion already proven effective by you, myself, along with video of others going diagonal or grabbing one downtube before impact.....Cant wait to test it...probably tomorrow, i really do need to build a new greenhouse door today. We are suffering high crop loss this year....a family of four racoons ate all our cherries on two trees one night, they also cleaned out all the Kiwis on one of our Kiwi vines the next night.....Dang...I love my cherries and Kiwis...
found a large doe munching down our Blueberries (middle of the day) but used my slingshot to send it on its way...hit that doe three times with a wrist rocket from 45 yards and it vamoosed...but...
If I dont get that greenhouse door fixed the chickens are going to get into the greenhouse and eat all our strawberries......aint gonna let that happen...RS

[Bill Cummings]

Jim,
I think great care should be taken that the anchor point of the right shoulder strap is strong enough to not fail.
The effect of that failed anchor point could be a restraint cord coming in contact with the pilots neck.

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