[reluctantsparrow]

Sure........the tire pump was a budget and convenience decision. An actual shock designed for this specific purpose, once we know exactly what plunge depth and plunge rate is desirable (via actual testing for me since i dont know how to do computer simulations) the device could be designed to certain specifications.
I thought about foam too....foam is lightweight, wont alter the balance of a glider. compressed air devices made to specification would be equally light. Springs of some sort is going to add more weight. Perhaps a combination of air and foam.
I love the v-towing concept. the winches do not have to be synchronized if only one winch is used, dead center,a winch with a double reel holding TWO lines that run out to anchored pulleys on each side of the runway, then back to the pilot.
Two ropes pulling even from one winch?
one more thought about yaw restriction of the bridal on my device. The bridal will be mounted as close to the pilots center of mass as possible, which probably means where the rear mains of a harness meet the body of the harness.
The bridle would not be attached to the rear tip of a prone harness so the slack required for sideways movement with an attachment point somewhere near the pilots butt will not be as much as would be required if the bridle was attached at the rear of the harness....RS

[JoeF]

RS,
I've not yet have time to study all your recent good posts. I will soon.
But I do not want to lose a flash:
... limit line at chest to control frame; lines might route to other parts of frame.
Also: to avoid rebound from air compression or elastic foam: consider sacrificial crunchable rigid foam of a specified density. The crunching eats up energy without rebound.

Soon,
JoeF

[Bob Kuczewski]

RS,

Your innovation and enthusiasm are awesome!!!!!

Be careful with your testing, and keep us posted.

[Bill Cummings]

RS,
I've not yet have time to study all your recent good posts. I will soon.
But I do not want to lose a flash:
... limit line at chest to control frame; lines might route to other parts of frame.
Also: to avoid rebound from air compression or elastic foam: consider sacrificial crunchable rigid foam of a specified density. The crunching eats up energy without rebound.

Soon,
JoeF

Following that idea -- how about bubble wrap rolled up and stuffed up the keel tube ahead of the plunger? (The tube would need a small air bleed hole.)
EDIT
We should keep in mind that many crashes are wing tip hitting first and a sideways cartwheel.

[reluctantsparrow]

yes on bubble wrap and yes on crushable foam.
Creating a larger airhole on my device so the cylinder does not actually hold back any air is a five minute procedure. I could easily enlarge the hole, then insert other materials like crushable foam or bubble wrap to perform identical tests, record on video, and review the results....not today though. I have to build a trellis for our kiwi plants.
I can also close back up the airhole using screws of different sizes to restrict airflow, so all these things can be played with.
I found an excellent zipline crash site on my neighbors property last night but need to ask permission .... I bet he will really be into it though....crashing things into the ground is fun.. (until someone gets hurt)
I think I need to take off the speedbar and replace with a beefed up straight bar before I test. I might also beef up the DTs.....I dont want to destroy the test vehicle until I find the just right settings of line lengths and crushable materials.
But a buddy of mine just called, says he has an old Kiss that the sail is all delaminated and do i want the airframe!!!! so yeah....a second crash test vehicle is on its way to my front door....yeah!

I love the idea of bubble wrap saving lives! That is recycling at it its best! that is using bubble wrap in it best and highest possible usage.....
I think I need a film makers clipboard thingy to start each filming....one can say,...bicycle pump, take one....take two, etc.....then there will be the bubble wrap test, take one, etc.....
I might even try a test loading the keel with Empty Red Bull cans and try to gain some sponsorship?

[Bill Cummings]

You could get by cheaper if you talk your girl friend into doing your make-up for any talking-head scenes. If she wants union scale try negotiating
a non paid, apprentice, talking head, scene, herself. (Tell her this could be her big chance in show business.)
We don't want this production to tank due to lack of funding.
Don't get side - tracked on big wardrobe expenses. Buy her a swimsuit at Saint Vincent de Paul's.
I'm really looking forward to this video.

[Rick Masters]

How about a shotgun shell blank?
The pilot, slamming forward, pulls the shell into the firing pin, the shell explodes, a piston at the rear of the keel pulls the pilot back from certain doom.
I SEEK NO CREDIT FOR THIS IDEA, AS VARIATIONS HAVE BEEN TRIED BEFORE.

[reluctantsparrow]

you guys are hilarious....okay...how do I get one of these little gremlins to work for me?


Okay, the shotgun shell idea has my brain going down a non-constructive avenue.....My brain just turned my rear keel into a totally operative potato gun (an idea from the dark side)

We should keep in mind that many crashes are wing tip hitting first and a sideways cartwheel.

good point...my device requires a reduction of forward motion to activate its trigger, or at least enough reduction of forward to do so even if it mixed up with a little sideways motion...
BTW...speaking of sideways motions....I used sideways motion once to fly myself OUT of a jam. I guess the story qualifies as splat protection technique in case of emergency, so here goes:
Coming in on final on an experimental design, double surface glider (a very fast glider for its day). This happened at a major meet at local Dog Mountain, WA. and there were about a hundred spectators.
I make my final turn perfectly but a huge gust sweeps over the entire LZ and feeds my glider a huge amount of energy and I start climbing out like crazy.....this gust ripped over a bunch of pop-up shelters and tents and got EVERYONES attention....it was really something.....
Anyway,... I am gaining just enough altitude to totally overfly the Lz and over the lip of the Burm that is between the LZ and the lake. The burm is mostly sand and about 60 feet wide at the time.....so whats wrong with that right?

The burm is where we have all our vehicles parked in two long rows for this event. Rvs, trailers, moterhomes, vans, etc. etc. the Burm area is totally packed with vehicles....but there is a driving space left open between all these vehicles....so
I shoot over the burm and crank left to Miss a huge motorhome right in front of me and turn crosswind to fly between the two long rows of about forty vehicles parked about fifty feet apart.....totally doable....but as I am coming around out of my sharp left (with my left wingtip two feet off the ground and gobs of airspeed) I realize there is A huge stump blocking my path to the S.E SIDE OF THIS NARROW LANE.....so I keep the turn going around and about four kids playing in the sand right in front of me on the N.E. side of this lane come into view......so I am doing this high speed left hand turn very close to the ground and as I come around all my options are saying...no way....cant land here.....sorry dude...
It is amazing how fast all this happens.....
that is when I looked straight down and realized I was over sandy ground so I instinctivly just slipped my inside wingtip right into the ground on purpose with just the right inputs of pitch and roll to NOT hammer over but to SPIN in place....putting enough pressure on the inside wingtip to keep it pinned to the ground but keeping the bar pulled in enough to not hammer over.....
I spun that ship in a high speed 360 using my inside wing as the pivot. and it worked pretty good actually. i only took out one downtube.
I would not advise anyone practice this technique but it might be something to tuck into the brain in case you find yourself in a similar scenario.

[Bill Cummings]

Wait! Don't dive into anything too soon. Proof of concept time on one tangent could lead one away from an even better solution. One that hasn't exhausted the brainstorming of the R&D committee. List some more ideas then pick one or morph to a combination of the best two.
Here is another suggestion to pick from or expand on.
We should be able to fly a plan-form that doesn't come to such a sharp point at the nose of the glider.
What if the nose was a shallow arc to allow more room between the nose flying wires?

Blunt nose, wide flying wire attachment points, Fared caster wheel..PNG (22.08 KiB) Viewed 4074 times

Make enough room between the attachment bolts on the underside nose (wide) plate for a fared caster wheel to swivel and clear the nose flying wires. If the nose-in was not straight on but to the side after hooking a wing tip on the ground the nose caster wheel would help prevent the abrupt stop of the gliders nose when it hit the ground.

[reluctantsparrow]

Woke up this morning wondering how stupid can i be?
Okay...I am not stupid and neither are you guys....blind is a better word....its amazing how something can be staring me in the face And I cant see it.....here it is....
The vids idea and keel piston idea is total crapola in its present form.
Take a device to absorb shock such as the keel piston and place it BEHIND the rear flying wire/rear landing WIRE junction.....doh!

this puts the mounting of the device in an area outside of key structural components of the hang glider.
The Stinger is non-essential.....mount it on the stinger...in fact, make the entire stinger the shock absorbtion device.
Run an activation cable a short length towards the nose of the glider, probably inside the keel for 6-8 inches before it dips downward ( running ouT of the keel over a small pully) towards the rear of the pilots harness where it is connected to the rear of the harness or mains.....now we dont need a V-bridal....just one straight bridle will suffice....also....the flying wire/landing wire junction remains untouched preserving the integrity of the glider and to counteract the downward pull of the bridle.....which again, is routed to pull whatever shock absorbing device is conceived in line with the keel....not downward.....
This could be an aftermarket device that bolts on to any hang glider in two minutes....just take off your stinger and install the shock absorbtion system......then remember to hook your leash(bridle) to it before launch.....only one more thing to pre-flight....does not require any modifications to the key structural components of the hang glider.....I like it
I have also invented a second device I am going to share soon that will work hand in hand with this keel Stinger Piston idea....I test flew the second device three days ago and the test was successful.....