Dual chutes ??

[rsbhunter]

Is using dual chutes problematic? I have a DBRM (who doesn't) or as my grandson calls it, his pirate rocket. The landing area where I launch is a fin eating monster. I have 2 18" skull and crossbones estes chutes, and I was wondering about using a JLCR with both chutes side by side....nightmare, or doable? Thanks for any input....rsbhunter

 

[WizardOfBoz]

In discussing my (still) upcoming L1 certification launch, the Tripoli prefect wrote that they like to have descent velocity less than 25ft per second. OR suggested that my rocket would come down at 27 fps, so I wrote to ask if adding another chute would be useful. He indicated that it would probably tangle. I'm sure that multiple chutes have worked in the past (like, for example on the Apollo spacecraft) but I think that the recommendation would be to bite the bullet and buy a larger chute. At least that was the conclusion I came to from the advice given.
BTW, he indicated that 27 fps shouldn't be too bad. So I'm sticking with my chute size as is.

 

[troj]

Multiple chutes looks neat, but it comes at the price of a greater risk of entanglement. If you're going to do it, I recommend using deployment bags - one for each main, with a single pilot chute that pulls all the bags up and off at once.

You also need to keep in mind that the efficiency of each chute is degraded by being pushed to the side by the other chute. There's some published information out there on it, I don't know the numbers off the top of my head.

-Kevin

 

[Banzai88]

I made up a worksheet that does all the math for parachute clusters. I'll try to find the thread and link it here.

 

[Upsrocketman]

I have used dual chutes on several occasions, the most recent of which was my L3. The only way to use dual chutes and avoid the parachutes tangling with each other is to use a deployment bag. I have seen up to 3 chutes folded together in a deployment bag have a successful deployment. It is a cool sight to see multiple parachutes open up and spread apart. Check out this video on how to pack multiple chutes into one deployment bag.

 

[rsbhunter]

This is kind of a ...if it works....deal. I have 24, 30 and 36" chutes, so it's more of a deal for my grandson, he's 3 going on 4, and loves his pirate rocket. He has the regular Der Red Max that we built together. It's what got me back into rockets!!! If it's a high tangle situation, it's not a " must do"...was just thinking he would be excited to see 2 "pirate" chutes come out....you guys are great, thanks for the advice, links, and experience....rsbhunter

 

[UPscaler]

It helps to put them on a Y-harness and give each parachute a bit of a leader to help prevent tangling.

 

[rsbhunter]

It helps to put them on a Y-harness and give each parachute a bit of a leader to help prevent tangling.

That's how I had planned to do it, give each one about a 18" leader. I have 99% of my chutes on a 250lb snap swivel , so changing them out wouldn't have be much trouble.... I will probably fly it the first time on a single, then try the double set up...rsbhunter

 

[sriegel]

I pack multiples together (spike, stack, fold/roll as one). It is spectacular when it works. However, especially on a cert I would just upsize if you can. And remember that 2x chutes is less than 2x drag as they splay out to the side.

 

[Cameron Tinder]

FWIW, Doing "1 plus 3" (1 drogue and 3 mains) Is highly reliable and very fun to watch, BUT... If you want reliability, you must bag the mains individually and it is best done with a tether and release device.

Shown in the picture below is the lower portion of a 6" V2 that used the original Tender Descender as the tether and release device.



As to the original question about trying to do this with the JLCR, maybe you can figure out how to do this reliably, I can not think of a way that would be anything more than a crap shoot, though it would look cool if it worked!

 

[Banzai88]

I made up a worksheet that does all the math for parachute clusters. I'll try to find the thread and link it here.

Found it. All the math to get the rigging right is in this. POF references in worksheet. The yellow blocks are user inputs: https://www.rocketryforum.com/threads/parachute-cluster-worksheet.168759/

Packing/deployment methods are up to you.

 

[rsbhunter]

Right now, it's a "what if" deal....I'm leaning against trying it. If I had a field with 4" tall grass, I would definitely go for it. But, the field is hard packed clay dirt, and it can tear up an anvil. So, unless I get tired of the rocket, I'll probably go with a 24" to 30" chute with the JLCR....rsbhunter