Jolly Logic Chute Placement

Monoxide

Member
Joined
Mar 6, 2019
Messages
10
Reaction score
2
Location
Cedar Rapids, Iowa
I'm adding a JL chute release to a 4" Mad Cow DX3 and I'm wondering about where to attach the chute. My DX3 has an AVbay and forward section for future use, and I'll be using motor ejection. I've checked through the forums and came up with 2 main ideas. I want to start with using a drogue just in case I do have problems with the main, but in the future I'll probably switch to a parachute with a hole to use for stabilization.
1. Single line. 18" drogue attached to forward section, 48" main chute attached 5ft from forward section and 15ft from lower section on a 6" leader.
Pros: Simple, limited chance of line tanglement. Cons: Main needs to pass the upper stage cleanly.
2. Dual line. 20ft between sections. Separate line of 300# kevlar attached to upper section with 5ft to main chute, and another 5ft to drogue.
Pros: Drogue holds main out of way of rest of rocket. Main deploys and when inflated drogue just falls to side. Cons: Increased chance of line tanglement. Complexity.
What do you more experienced folks think?
 

bobbyg23

Well-Known Member
Joined
Apr 15, 2020
Messages
1,232
Reaction score
1,264
Keep it simple. Main 5 ft from upper section. No drogue. Load, launch, repeat.
 

teepot

Well-Known Member
TRF Supporter
Joined
Dec 7, 2019
Messages
3,106
Reaction score
3,121
Location
Pahrump, Nevada
I'm have the same question. I'm going to pack the drogue on top of the main. I was planning on having both attached to the same place, nose cone or payload section as needed. I feel you need a drogue to stabilize the decent. I don't want the chute opening at 500 feet with the rocket moving at terminal velocity. Anybody have any other ideas?
 

crossfire

Well-Known Member
TRF Supporter
Joined
Jan 16, 2011
Messages
5,382
Reaction score
939
It's your rocket but you really don't need a chute to pull out the main chute. The charge and nose cone will do that.
 

Monoxide

Member
Joined
Mar 6, 2019
Messages
10
Reaction score
2
Location
Cedar Rapids, Iowa
I'm have the same question. I'm going to pack the drogue on top of the main. I was planning on having both attached to the same place, nose cone or payload section as needed. I feel you need a drogue to stabilize the decent. I don't want the chute opening at 500 feet with the rocket moving at terminal velocity. Anybody have any other ideas?
My concern with attaching both chutes at the same spot was if the main goes to open and slips between the lines and opens inside the drogue.
 

Nytrunner

Pop lugs, not drugs
TRF Supporter
Joined
Oct 15, 2016
Messages
8,011
Reaction score
3,760
Location
Huntsville AL
Alternate option. Use the chute release to hold the mouth of the main chute closed, with the golded shoot flying ojt behind like a streamer

Our prefect likes to do that and has had great success
 

Scott_650

Well-Known Member
Joined
Sep 16, 2015
Messages
1,685
Reaction score
1,184
Location
Louisville OH
Alternate option. Use the chute release to hold the mouth of the main chute closed, with the golded shoot flying ojt behind like a streamer

Our prefect likes to do that and has had great success
What size chutes does he or she use that technique with? Sounds like a good way to go!
 

o1d_dude

'I battle gravity'
Joined
Jan 18, 2009
Messages
8,379
Reaction score
1,277
Location
A Banana Republic
pic of how I tried it.
Did mine the same way.

A lot of test flights proved that to be the best method for large single break rocket.

A close look shows all of the elements involved including drogue, main, blankets, a chute “slipper”, and JLCR.

Fin can is already on the ground. Electronics bay in fiberglass nose cone has some weight to it. The kit is a Polecat Aerospace Goblin 5.5” (glass wrapped body tube/fin can, four 1/4” plywood fins) and weighs 100 oz all up on the pad with 38mm J motor.
 

Attachments

  • 42046CCF-5228-4124-B13F-7CACBEA4F440.jpeg
    42046CCF-5228-4124-B13F-7CACBEA4F440.jpeg
    37 KB · Views: 50
Last edited:

bobbyg23

Well-Known Member
Joined
Apr 15, 2020
Messages
1,232
Reaction score
1,264
I'm have the same question. I'm going to pack the drogue on top of the main. I was planning on having both attached to the same place, nose cone or payload section as needed. I feel you need a drogue to stabilize the decent. I don't want the chute opening at 500 feet with the rocket moving at terminal velocity. Anybody have any other ideas?
It will not be traveling at terminal velocity. If you have it setup correctly, it will fall very gently and you will have no issues when the jlcr lets go of the chute.
 

Monoxide

Member
Joined
Mar 6, 2019
Messages
10
Reaction score
2
Location
Cedar Rapids, Iowa
pic of how I tried it.
Did mine the same way.

A lot of test flights proved that to be the best method for large single break rocket.

A close look shows all of the elements involved including drogue, main, blankets, a chute “slipper”, and JLCR.

Fin can is already on the ground. Electronics bay in fiberglass nose cone has some weight to it. The kit is a Polecat Aerospace Goblin 5.5” (glass wrapped body tube/fin can, four 1/4” plywood fins) and weighs 100 oz all up on the pad with 38mm J motor.

Thanks for the advice guys, I'll go with that setup.
 
Top