Quantcast

Hi i'm new to the forum but thought i might share my slow deployment technique

The Rocketry Forum

Help Support The Rocketry Forum:

Skydiver120

Member
Joined
Aug 6, 2009
Messages
10
Reaction score
0
I was just curious as to if anyone has tried using a kill-line to slow deployment? I have been playing with this idea for a few weeks and wanted to share it. The idea is that the kill-line is a solid line that attaches from the harness to the center of your parachute. the shroud lines attach to an elastic outer tube with the kill line running down the middle. When the elastic is put under enough pull force to cause it to stretch the edges of the canopy are allowed to drop aft of the center of the canopy allowing huge amounts of air to spill. Since the shroud lines will always be under tension from the elastic tube the canopy will only apply a pre-tuned(tuned by the strength of the elastic) deceleration force at any given velocity(within reason).
Go Go Gadget Flame Suit! :bangbang:
 

DAllen

Well-Known Member
Joined
Jan 18, 2009
Messages
4,821
Reaction score
757
Welcome to the forum!

Heh...A flame suit will not needed here. The mods have things pretty well under control and all of us seem to play nice together most of the time. I am interested in your idea but I am having a difficult time picturing how it works. Do you have a link to a drawing or picture diagramming this?

-Dave
 

Skydiver120

Member
Joined
Aug 6, 2009
Messages
10
Reaction score
0
I drew this pic in ms paint real quick. I hope it helps. It's kind of the construction paper and crayons version LOL.

softdeploy.JPG
 

Skydiver120

Member
Joined
Aug 6, 2009
Messages
10
Reaction score
0
Here is a visual of the canopy after the rocket has slowed
to a safe deployment speed. The bungee will need to be able to withstand
the weight of the rocket without stretching or the canopy will not fully open. So far my diy rocket sled tests have worked like a charm.

opencan.JPG
 

powderburner

Well-Known Member
Joined
Jan 18, 2009
Messages
7,401
Reaction score
4
It's kind of the construction paper and crayons version LOL.
Well in that case, I might be able to figure it out-
Maybe a few more pictures would help?

That is a very interesting deployment system. While we don't usually design for recovery system deploy at high speed (we generally aim for either apogee/low speed or for delayed-but-controlled intermed altitudes at moderate speed), I am sure there are some good applications for this approach.

Welcome to TRF, and we hope you don't really need that flame suit
 

TWRackers

Well-Known Member
Joined
Jan 18, 2009
Messages
2,130
Reaction score
1
Interesting concept, especially since some RocketRage chutes (hard to come by now, but my L3 project has one ^_^ ) have a center line which fans out and attaches at 8 points to the spill hole hem. Curious....
 

Skydiver120

Member
Joined
Aug 6, 2009
Messages
10
Reaction score
0
It would open just as well at apogee or any other situation. The main focus is to open softly even if the ejection delay mulfunctions somehow. My disciption of the deployment sequence was really of the worse case. If an early deployment would occur the opening shock would be greatly reduced. Also this system could take the place of the drouge and the main. If the chute deploys with the kill-line in the kill position the chute will deploy but produce only a specified amount of drag. The kill line could then be relesed by an altimeter at a lower altitude allowing the canopy to fully deploy.
 

Skydiver120

Member
Joined
Aug 6, 2009
Messages
10
Reaction score
0
Interesting concept, especially since some RocketRage chutes (hard to come by now, but my L3 project has one ^_^ ) have a center line which fans out and attaches at 8 points to the spill hole hem. Curious....
My apology if i'm describing something that has already been done. I had never run across anything like it so i though it was a new idea.
 

DAllen

Well-Known Member
Joined
Jan 18, 2009
Messages
4,821
Reaction score
757
Okay...I see the idea now. Sounds really interesting and I don't know of any (other than RocketRage) that have a system like that. This could be a good way to go to prevent or reduce zippers. If you can find a cheap and easy way to make and sell these you could be on to something.

-Dave
 

Skydiver120

Member
Joined
Aug 6, 2009
Messages
10
Reaction score
0
I'll see what i can come up with for a version i wouldn't be ashamed to take pictures of. All of my tests have been done with trash bags string and rubber-bands LOL.
 

TWRackers

Well-Known Member
Joined
Jan 18, 2009
Messages
2,130
Reaction score
1
My apology if i'm describing something that has already been done. I had never run across anything like it so i though it was a new idea.
It still may be a new idea. The RocketRage Quantum chutes (I believe that's what they were called) have the center line but no special mechanism to deploy it any differently from the lines around the periphery of the canopy. I'm thinking a RR chute might be adaptable to an idea like yours. I've wondered on occasion if something could be designed to allow one of these chutes to deploy in two stages, to serve as its own drogue chute.
 

Skydiver120

Member
Joined
Aug 6, 2009
Messages
10
Reaction score
0
A two stage opening with this rig would be as easy as pulling in a length of the kill-line and attaching that to a release of some kind. When the kill-line is released the chute would deploy normally but still take advantage of the soft deploy setup.
 

fox_racing_guy

Well-Known Member
Joined
Jan 18, 2009
Messages
624
Reaction score
0
If you can draw it I can sew it up. You could attach the kill line to a tether system to release at a preset time or altitude.
 

Skydiver120

Member
Joined
Aug 6, 2009
Messages
10
Reaction score
0
I wish i were able to draw more accurate diagrams. What i have in mind is just a standard type nylon chute with the kill line attached to the center of the hemisphere. The the part that makes it work is just a piece of elastic tubing with two loops sewn into one end that the lines are connected to. Both the tubing and non elastic kill line are anchored to the rocket. The kill line is routed down the middle of the tube to keep it centered and free of tangles. LOL i need to learn CAD ......
 

MaxQ

Tripoli 2747
Joined
Jan 18, 2009
Messages
4,415
Reaction score
58
Location
Central Viginia - USA
I wish i were able to draw more accurate diagrams. What i have in mind is just a standard type nylon chute with the kill line attached to the center of the hemisphere. The the part that makes it work is just a piece of elastic tubing with two loops sewn into one end that the lines are connected to. Both the tubing and non elastic kill line are anchored to the rocket. The kill line is routed down the middle of the tube to keep it centered and free of tangles. LOL i need to learn CAD ......
I was reading this wondering if the traditional slider used for years on square canopies (ram air) would work.

BTW: Are you a skydiver ....how many jumps?
 

Skydiver120

Member
Joined
Aug 6, 2009
Messages
10
Reaction score
0
I was reading this wondering if the traditional slider used for years on square canopies (ram air) would work.

BTW: Are you a skydiver ....how many jumps?
I'm sure the traditional slider would work but they are still limited in the speed they can be deployed at and can still slam you if not packed carefully(learned this the hard way!). It's also not very reliable unless you use a D-bag or have some other way of making line stows to ensure line stretch before deployment. I'm not saying my method is better but it governs the force applied vs a slider giving you the opening shock divided in two stages.

I'm a newbe skydiver only 40 jumps.
 

cjl

Well-Known Member
Joined
Jan 18, 2009
Messages
12,549
Reaction score
5
Giant leap sells a slider, so that would work pretty nicely if you're looking for more gentle deployments. One of the best ways though would be a D-bag. Keep in mind that what is considered a gentle opening for rocketry would be a massive shock for skydivers, and some openings in rocketry can approach what would be lethal for skydivers (several of mine have been >30G in some cases, according to my R-DAS).

Chris
USPA A-54917 (52 jumps and counting :D)
 

Latest posts

Top