[Bill Cummings]

RS & Bill,

Although the modification proposed may have some merit I think that the extra weight and complexity would make it impracticable. Having looked at the various devices suggested the simplest would be a line from the pilot harness, chest area, to the centre of the control bar. If it was made so that it took up slack as the pilot moved it should not cause any control restriction or snagging. In the event of a sudden nose in on landing the the line would limit the pilot follow through preventing head contact with the glider nose. An added safety feature of having the line attached to the harness would be if the pilot failed to clip in on the keel he/she would still be clipped to the control bar.

The limit line length only needs to be long enough for the pilot to push fully out when in the flare, I guess about 30 inches? Another safety feature of such a limit line would be for weightless situations or dropping of the top of a bodged loop. The pilot would not fall into the wing which usually collapses the airframe.

ARP,
The take up slack feature makes me wince. Reliability given by seat-belts in vehicles is short of the mark. Sometimes when you want slack you can't get it unless you stop or level the vehicle. (EDIT: What other slack compensation device could be relied on?)
But a bungee cord might take up any drooping slack in a leash cord. (Edit: Rope)
Another worry for me is that if the leash is hooked to the chest might it tip the pilot so that there would be a head hitting the ground?
Your suggestion if figured out might also assist a pilot during a ground loop with a side-ways restraint.
(Edit: We shouldn't forget about the possibility of a water landing and an unfettered escape.)

[reluctantsparrow]

ARP and Bill C........Data received.....processing Data.....Okay.....
The basetube, would, of course, fail if the line was attached to the center of the basetube with no shock absorption, the pilot being flipped head down is a valid concern, etc. etc..
my thought is...how many ways are there to route such a line?

Okay....here goes.....hang a couple small pulleys from the tow loops sewn into most harness shoulder areas or sew a frictionless tube into that area across the pilots chest. Mount two more small pulleys or frictionless tubes near the basetube/queenpost junction area for strength and to keep the line away from our control area, then sew another frictionless tube for the line to slide through OVER the pilots a** area.
this is a continuous loop of line that is free to slide in all directions
This iine has just enough slack to Allow the pilot full range of control with no restrictions or obstructions.
Upon rapid deceleration of the glider this line would limit the foreward swing of the pilots body and would keep the pilots from swinging down into the ground due to an ever tightening pressure pushing down on the pilots a** area.
The down pressure could be predetermined depending on where the line is anchored to slide freely near the queenpost/basetube area. Perhaps a few inches up the queenposts (also called uprights or downtubes)?
The shock absorbtion could come from Whatever the basetube/queenpost pulleys are mounted to such as a bungee running inside the basetube or up inside the queenposts......so that when the pilot has reached the foreward limits of the continuous loop the pulleys in the queenpost/basetube area are pulled upon and the bungee they are attached to stretches out from inside the basetube or queenposts.....
Forming a sort of spiders web that allows total free movement within the needful control range, aligns the pilots body to the correct position in the event of a rapid deceleration, limits the foreward travel in such an event, and also provides elasticity and shock absorbtion.....
god.....I havent really even thought this one all out....just typing away as it comes to me....

[Bill Cummings]

RS, while you were typing I was typing this:
Plan C. Hopes to include ARP's suggestion and once again will include topless hang gliders.
Plan C:
1. What do you think about small PVC nipples, or plastic tubes, about,?, inches long, or maybe two rapid links, one on each of the two rear flying wires that run from each corner of the control bar to the keel.
2. fasten a leash cord to each tube, or rapid link and the other ends of the leash together at the harness back near the main support strap.
3. As the pilot goes past the full, speed-bar, stuffed position the two tubes, or rapid links, slide forward and apart on the rear flying wires.
4. As the tubes separate as they move forward they impede the forward motion of the pilot. This would give some side-ways restraint for ground loops as well.
5. This will reduce weight and complexity as ARP suggested.

[reluctantsparrow]

AH......the rear flying wires
I dont think the tubes should be allowed to slide down the wires. IN regular flight one could slide down while the other does not. Creating an asymetrical situation and possible loss of control.
I also do not think the line needs to be routed up to the keel.

Solid attachment points on the rear flying wires......ONE line running from one solid attachment point on a rear flying wire, through a frictionless tube, Structural loop, or pulley near the harness mains/harness back area and over to the second solid attachment point on the second rear flying wire....with enough slack to provide full range of control movement and to swing into the upright, landing position.
NO lines around the control bar (messy, irritating, and potentially dangerous)
Just ONE line from one flying wire to the other, running freely over the back of the harness......What would this one line accomplish?
1. totally limits the foreward swing of the pilot when the pilot swings past the fully stuffed position
2.Provides a solid resistance in a line fairly parallel with the keel that prevents a pilot from swinging up into the keel
3.a small tendency to pitch the pilots head into the ground that I think would be perfectly countered by the lessoned remaining pendular action of the mains trying to swing the pilot up into the keel.
4. Lots of built in shock absorbiton as the line pulls the two rear flying wires together. i do not think any additional shock absorption would be needed. The act of pulling the two rear flying wires together would suffice in most severe whack scenarios.
5. totally out of sight of the pilot. No messy lines in the control bar area. Absolutly nothing to tangle on if the line could move unrestricted through the structural loop or frictionless tube sewn into the back of a harness.
6. If a pilot can hang on to his basetube when inverted (as I have done), partially prevents the legs of the pilot from falling backward into the sail depending on how much slack is required in the line for regular control..
7. turns the pilots own harness into a five point safety harness as we have discussed previously
8. totally aftermarket device.....NO serious alteration of any key structural hang glider components needed....perhaps a new set of rear flying wires with solid attach points and a dedicated structural loop sewn into the back of a harness....but that is really
The only problem I see so far is it is way too simple....couldnt possibly work....not complicated enough.

[Bill Cummings]

Copper electrical split bolts could be used to make a fixed (yet still adjustable) anchor point on each of the two flying wires.
Would an idler pulley on a bungee cord be needed to keep the slack leash from tangling with pod zippers or catching a foot during launch running?

[Frank Colver]

Copper electrical split bolts could be used to make a fixed (yet still adjustable) anchor point on each of the two flying wires.

Ha, used those many years ago to clamp cables. Will not vouch for safety, however.

FC

[reluctantsparrow]

....doing a mock up of these line ideas to check for range of motion and practicality is just too simple...dont even need the copper connectors to do a mock up....just tie off the line to different locations, hook a small carabiner to the rear of the lower mains, and play around with different lengths of line needed for full range of motion
(mock ups should be done on the ground of course)

[Bill Cummings]

....doing a mock up of these line ideas to check for range of motion and practicality is just too simple...dont even need the copper connectors to do a mock up....just tie off the line to different locations, hook a small carabiner to the rear of the lower mains, and play around with different lengths of line needed for full range of motion
(mock ups should be done on the ground of course)

Would an idler pulley on a bungee cord be needed to keep the slack leash from tangling with pod zippers or catching a foot during launch running?

[reluctantsparrow]

Would an idler pulley on a bungee cord be needed to keep the slack leash from tangling with pod zippers or catching a foot during launch running?

After doing the mock up and the line is long made just enough as to not interfere with control....run with the glider and have someone take video so you can study it.....I dont think a line draping down each side of a harness is going to interfere with zip up.....but a video of the set up would give the feedback needed to complicate the concept if needed.

[reluctantsparrow]

one more note on the material used for the line.
a braided line of nylon (high stretch before failure) as opposed to dacron or other low stretch materials would be my choice.
Used to wash windows on the skyscrapers in Seattle with a variety of rappelling devices and ropes using a bosun chair and the Nylon was awesome fun.
I remember a 22 story building where my window washing partner, mark, who used to ride brahma bulls in the rodeo professionally were hired to only wash the penthouse floor of this 22 story building (continental Plaza).
We got bored with regular rappelling down the remaining 21 stories, taking the elevator back up, moving our ropes over for the next set of penthouse only windows, etc. etc so we started racing each other.....first one to touch the ground wins.....
We wrapped our descent devices so loosely we actually acquired free fall speeds racing each other to the ground....yes...we were both totally nuts...but it was Soooo much fun.....I remember the five gallon bucket of water hanging from my bosun chair started levitating one time I was falling so fast....anyway...
That Nylon line had so much stretch in it that I had to lock off about two stories off the ground and that line would stretch so much it let my body come down within inches of the ground where I would swing upside down and slap the ground before that nylon line contracted and launched me back up into the air......it was a real hoot.
My boss got really pissed and found out though when the heat created by one rapid descent heated up my descent device so badly that I left a 100 foot long black streak of burnt nylon line behind me....oops...busted.
But the stretch of those lines was very impressive and even a short section would add to the shock absorption factor a great deal I think....yes...I am a totally crazy mofo