2 parachutes exiting from the nose cone

[SuperNova-Rocketry]

I wanted to figure out how I could deploy 2 parachutes from my nose cone on a high powered rocket, the first parachute would be a drogue and the second a main parachute (just a regular dual deployment).
I was considering options and have only thought of one: We have a fixed place divider between the parachutes. Both parachutes connected along one shock cord, tie a knot around 3 feet of cord before the main, the knot has to be big enough so that it cannot fit through a small ring on the side which the cord is threaded through. Drogue is ejected with a ejection charge on one side of the divider, it is fed shock cord attached to the main parachute until it reaches the knot. When we want to deploy the main we detonate the pyrotechnic bolts which are holding the ring to the rocket's air frame. This lets the knot pass through the released ring and the main can now freely escape. I'll have to test if the Kevlar shock cord will be strong enough to not break. There are 3 possibilities (im not including failures that can occur with any parachute here) :
1) Successful event
2) Drogue is pulled out but the knot breaks during the pyrotechnic bolt's release, in this scenario the secondary ejection charge then pushes out the main parachute and we lose the drogue but still land safely
3) Drogue is pulled out but after the pyrotechnic bolts release the knot is still stuck, secondary ejection charge pushes out the main parachute with the knot still stuck around the ring, so the main will only be 3 feet above the rocket (the 3 feet is the extra I left between the knot and the main) instead of the usual 6 or 7.

As you can see this is EXTREMELY complex for what could be done much easier with a normal dual deployment method, so I wanted to see if there were any other ideas.

 

[jkovac]

I wanted to figure out how I could deploy 2 parachutes from my nose cone on a high powered rocket, the first parachute would be a drogue and the second a main parachute (just a regular dual deployment).
I was considering options and have only thought of one: We have a fixed place divider between the parachutes. Both parachutes connected along one shock cord, tie a knot around 3 feet of cord before the main, the knot has to be big enough so that it cannot fit through a small ring on the side which the cord is threaded through. Drogue is ejected with a ejection charge on one side of the divider, it is fed shock cord attached to the main parachute until it reaches the knot. When we want to deploy the main we detonate the pyrotechnic bolts which are holding the ring to the rocket's air frame. This lets the knot pass through the released ring and the main can now freely escape. I'll have to test if the Kevlar shock cord will be strong enough to not break. There are 3 possibilities (im not including failures that can occur with any parachute here) :
1) Successful event
2) Drogue is pulled out but the knot breaks during the pyrotechnic bolt's release, in this scenario the secondary ejection charge then pushes out the main parachute and we lose the drogue but still land safely
3) Drogue is pulled out but after the pyrotechnic bolts release the knot is still stuck, secondary ejection charge pushes out the main parachute with the knot still stuck around the ring, so the main will only be 3 feet above the rocket (the 3 feet is the extra I left between the knot and the main) instead of the usual 6 or 7.

As you can see this is EXTREMELY complex for what could be done much easier with a normal dual deployment method, so I wanted to see if there were any other ideas.

It’s a hobby, so you can do anything you want as long as you do it safely and legally, but what you have described seems like a really complicated and difficult approach to doing something that you could do in a much easier way.

As others have commented in some of your other posts, it sounds like you could really benefit from an adult mentor and some exposure to other fliers who you can watch and learn from.

Best of luck to you with your project.

 

[3stoogesrocketry]

I wanted to figure out how I could deploy 2 parachutes from my nose cone on a high powered rocket, the first parachute would be a drogue and the second a main parachute (just a regular dual deployment).
I was considering options and have only thought of one: We have a fixed place divider between the parachutes. Both parachutes connected along one shock cord, tie a knot around 3 feet of cord before the main, the knot has to be big enough so that it cannot fit through a small ring on the side which the cord is threaded through. Drogue is ejected with a ejection charge on one side of the divider, it is fed shock cord attached to the main parachute until it reaches the knot. When we want to deploy the main we detonate the pyrotechnic bolts which are holding the ring to the rocket's air frame. This lets the knot pass through the released ring and the main can now freely escape. I'll have to test if the Kevlar shock cord will be strong enough to not break. There are 3 possibilities (im not including failures that can occur with any parachute here) :
1) Successful event
2) Drogue is pulled out but the knot breaks during the pyrotechnic bolt's release, in this scenario the secondary ejection charge then pushes out the main parachute and we lose the drogue but still land safely
3) Drogue is pulled out but after the pyrotechnic bolts release the knot is still stuck, secondary ejection charge pushes out the main parachute with the knot still stuck around the ring, so the main will only be 3 feet above the rocket (the 3 feet is the extra I left between the knot and the main) instead of the usual 6 or 7.

As you can see this is EXTREMELY complex for what could be done much easier with a normal dual deployment method, so I wanted to see if there were any other ideas.

Both parachutes inside the nose cone? Easily can be done , it's your desicion. You can use a chute cannon. You can use a Pyro release.
You can even use a non Pyro release like a JLCR

 

[jkovac]

Both parachutes inside the nose cone? Easily can be done , it's your desicion. You can use a chute cannon. You can use a Pyro release.
You can even use a non Pyro release like a JLCR

JLCR would definitely be more straightforward than explosive bolts.

 

[3stoogesrocketry]

JLCR would definitely be more straightforward than explosive bolts.

I was think tinder descended type or ammo case style over Kevin's exploding nylon bolts.

 

[David Schwantz]

I like the blowing up of bolts

 

[David Schwantz]

But use a JLCR.

 

[jkovac]

I was think tinder descended type or ammo case style over Kevin's exploding nylon bolts.

Do you have a link or any other info on those bolts?

 

[Titan II]

Do you have a link or any other info on those bolts?

https://www.google.com/search?q=Kev...gzOTUwajBqNKgCALACAA&sourceid=chrome&ie=UTF-8

 

[jkovac]

https://www.google.com/search?q=Kevin's+exploding+nylon+bolts&oq=Kevin's+exploding+nylon+bolts&gs_lcrp=EgZjaHJvbWUyBggAEEUYOTIGCAEQIxgnMgYIAhBFGDvSAQgzOTUwajBqNKgCALACAA&sourceid=chrome&ie=UTF-8

Thank you.

 

[SuperNova-Rocketry]

Both parachutes inside the nose cone? Easily can be done , it's your desicion. You can use a chute cannon. You can use a Pyro release.
You can even use a non Pyro release like a JLCR

Can you clarify by JLCR, just making sure its this one:
https://www.asp-rocketry.com/ecommerce/Jolly-Logic-Chute-Release.cfm?item_id=1155&parent=121

Please correct me if its not that but it seems like its probally that

 

[Titan II]

Can you clarify by JLCR, just making sure its this one:
https://www.asp-rocketry.com/ecommerce/Jolly-Logic-Chute-Release.cfm?item_id=1155&parent=121

Please correct me if its not that but it seems like its probally that

Yes. More info here...
https://jollylogic.com/products/chuterelease/

 

[SuperNova-Rocketry]

It’s a hobby, so you can do anything you want as long as you do it safely and legally, but what you have described seems like a really complicated and difficult approach to doing something that you could do in a much easier way.

As others have commented in some of your other posts, it sounds like you could really benefit from an adult mentor and some exposure to other fliers who you can watch and learn from.

Best of luck to you with your project.

Thank you, we actually do have an adult mentor who owns a private aerospace company and is happy to help, we were so lucky to find him. He regularly helps us improve our rocket designs and make them more reliable and safe

 

[jkovac]

Thank you, we actually do have an adult mentor who owns a private aerospace company and is happy to help, we were so lucky to find him. He regularly helps us improve our rocket designs and make them more reliable and safe

That’s great! Have fun, and if you haven’t already, check out the Jr. L1 program in the UK:

http://www.ukra.org.uk/juniorl1cert

 

[Voyager1]

Can you clarify by JLCR, just making sure its this one:
https://www.asp-rocketry.com/ecommerce/Jolly-Logic-Chute-Release.cfm?item_id=1155&parent=121

Please correct me if its not that but it seems like its probally that

Research HED (head end deployment) techniques and also check out the Tinder “Tender Descender”.
https://www.tinderrocketry.com/rocketry-parachute-tether

 

[SolarYellow]

I would go with a solenoid pulling a pin or an R/C servo unlatching something before an exploding bolt.

There are a LOT of ways to keep a chute bundled until the second deployment. If you're building a big enough rocket to be talking about what you're talking about, there are many, many choices that are easier, safer, and better than what you proposed.