For anyone still interesting in this design, please use the attached file. This corrects the placement of the M3 bolt and includes better slip-fit tolerances for the pull-pinBattery Jettison Frame Spacer.stl (513.5 KB)
2 Likes
Instead of a full box, I used a single CF plate. Two very shallow “keys” on the back of the plate eliminate any side to side movement…yet allow the entire battery assembly to fall away. After reading the recent description of the battery fire, I have no desire to fly without this mod. It’s frightening when you multiply the fire by 4.
I’ve been a parachute rigger for 6 years and have built many three rings myself. For sure a 2 ring setup would be better. Or even a ring-less design like what paragliders use when winching. The reason is simplicity. Each additional ring reduces the force needed to keep it closed, three rings are only needed when your pulling g’s in a diving malfunction. Just one wrap around should do , the second is way over kill for 40-60lbs
1 Like
I love the idea to drop them down first, and then cut them away. This could buy us plenty of time to “aim”
1 Like
Yes the weight is not so high but if you have to drop them in a spiral fall gs would be extrem, so i think its a safty plus - but for normal flight you are right, than it is not necessery…
Scenario: you have a silent flight, clean air all ok 500 meters over ground.
Fire starts on your back.
When you keep cool and drop your batteries than all is ok but if you cant drop it before trying to go down you will want to go down fast as possible becouse you dont see whats going on there, so you will have to spiral or b stall, and there you will have a lot of gs.
If you cant stop it or drop it it could be quick desent to hold a fullstall and end it with the reserve 150 meters over ground, you have to land to get away…
thats why i am thinking about a bonpet firestop it weights only 1 kg and maybe stops the fire…
Or keeps it smaller than without
And 3 ring should cut away in any g situation.
Or we land it 7 meters under us…and dont have to drop them total at all.
But i think they could burn thru the webbing and fall by themseve after some time.
All depending how violent the burning is.
1 Like
A 30 pound drop on a 7 foot tether would be quite the jolt!
1 Like
Plus dragging 30 lbs. across the ground and the possibility of it catching on something could result in a really interesting face plant. It might even provide a whole new dimension to “Dirt Diving”. Add in the potential for a grass fire and the offending pilot might even get roasted while trying to pick up his teeth. Coming to YouTube soon…
I have seen gliders with low flying accessories of their outfit at the Coupe Icare during the annual PG costume competition and that made interesting landings at times, such as banners getting caught in tree branches. I tow paragliders for a living and I have seen less experienced tow operators towing at the wrong time and wrong place in the wrong conditions with the tow line snagging in fences, farming equipment or trees , and the end result was always epic.
Found cool video there you see what i mean
Fully loadet milttary skydivers
2 min. 50 sec. You see 2 landings 1 filmed from the air and 2. The filmer himself.
They always drop theyr luggage when under canopy and land forward like paragliders…
Not always found that video:
No idea how he could land that…
Here you see how it works ( at 3 min. 15 sec.) At the end the guy talks about theyr job:
1 Like
Skydivers flare a lot higher and have a much steeper glide. With a tether that long the load would hit the ground long before I ever initiate my flare. My wing is fast and responsive and I’m usually less then 5 feet high when I start my flare.
You are right
I do both skydiving and paragliding but my parachute flys faster and is way more agile than my paraglider.
I always feel like driving a bus when on the same day i fly my paraglider after some skydivelandings.
But the canopy size is less than half of the glider so the wingload is double.
My weight is 190 pound 85kg without gear and my canopy is 120 sqft.
11 m2.
Also the landing in the last video does not look so slow.
It will definitly be challanging to land such a load on a webbing thats for sure.
Btw. It will be an emercencylanding, could use the reserve high up over ground too… than no problems with forwardspeed…
Or drop the reserve in 2 meters height it will open and you can land standing, i did practice that in my paraglidingschool 20 years ago-
not sure how that could work with the motor on the back…
But if it is possible not to drop that high weight and land safe that would be the most responsible way to handle that situation.
2 Likes
Great video!
Sure for the pilot it is the most save and easy to let the bateries go.
I like to fly high in clean air so i will stay over 300 meters over ground most time.
In my case the problem with a webbing load will start at the contact of the load with the ground - or any obstacle…
But as i wrote bevore, we dont let go the bateries for fun so a reservelanding could also be a solution not to be forced to drop a load that heavy without time to “aim”.
But a webbing would burn anyway in short time so the decision to land it or not could be obsolete. But to cut it away total short time after first pull could work eventual with iron nerves.
1 Like
Putting three rings here would be like putting 4 on a skydiver. Even with no mechanical advantage ie. (Pin and loop) they could be jettisoned in a high g scenario. It takes roughly half of a pound on each riser to hold a human with three rings. a 2 g situation which would very extreme would put the same weight on the mechanism as a normal riser has in smooth flight. 4 gs is not possible in my opinion and that’s what it would take to see similar forces as malfunctioned main.
Kite surfers use and awesome mechanism for releasing. My favorite by far though for this is the design made for winching paragliders
Unless it’s made of metal it’s burning
Your numbers fit to that video:
Not much over 3 g here
Also here on a hookturnlanding not much over 2…
Found anorher video of landings.
There you see where the flare starts and what the speed could be about.
2 Likes
Wow 3 g! I had no idea, that’s some serious weight. I thought 2 was pushing it. These wings are incredible compared to skydiving wingsx
