Deployment bag for 10ft diameter parachute

[leeds]

Hi, we're having a discussion about whether or not a deployment bag is necessary for a 10ft diameter parachute, has anyone launched a rocket with this large a parachute and just packed it in without a bag? A few papers advise against this however our rocket will be 3 inches in diameter and space is becoming an issue.

 

[sharkbait]

Hi, we're having a discussion about whether or not a deployment bag is necessary for a 10ft diameter parachute, has anyone launched a rocket with this large a parachute and just packed it in without a bag? A few papers advise against this however our rocket will be 3 inches in diameter and space is becoming an issue.

I have done 168” without a bag no problems.

Bigger question is what does this 3” bird weigh that would require a 120” chute?

 

[leeds]

I have done 168” without a bag no problems.

Bigger question is what does this 3” bird weigh that would require a 120” chute?

Thank you! Just a couple of questions: did you use a particular folding method and roughly what was your ground hit velocity, seems like most people don't go over 6m/s. We're hoping to reuse some parachutes from a bigger rocket, however, fitting the bag in is proving a problem.

 

[user 30299]

Thank you! Just a couple of questions: did you use a particular folding method and roughly what was your ground hit velocity, seems like most people don't go over 6m/s. We're hoping to reuse some parachutes from a bigger rocket, however, fitting the bag in is proving a problem.

What is the allowable maximum landing velocity per the project or competition guidelines?

And so what chute size do you actually need per your sims?

There is also the question of how much body tube length is available, and what do you have for harnesses.

Are you short on time to get a proper chute, or short on funds to get a proper chute?

 

[rharshberger]

Properly setup a Deployment bag aka D-bag (a different D-bag..) will improve the reliability of paracute deployment and reduce shock loads. A D-bag will prevent the recovery gear from binding inside the airframe, and will order the deployment such that the shroud lines are fully extended before the canopy open, the use of a pilot chute attached to the nosecone to strip off the bag virtually ensures the chute deploys. As long as the nose cone is blown off the pilot chute should deploy causing the chain reaction ending with the main chute properly deployed.

 

[Handeman]

I like 4.5 to 5.5 m/s for ground hit. Depending on materials used, fin configuration, ground hardness, etc. some will go as high 7.5 m/s.

As @sharkbait asked, what is your weight that you need that large of chute, or is it just something available. You could reef the chute also.

 

[sharkbait]

Thank you! Just a couple of questions: did you use a particular folding method and roughly what was your ground hit velocity, seems like most people don't go over 6m/s. We're hoping to reuse some parachutes from a bigger rocket, however, fitting the bag in is proving a problem.

I typically range between 15fps and 25fps depending on the field I’m at.

I fold the gores over parallel i to a triangle then Z fold then wrap the lines then burrito it with a nomex or kevlar blanket

 

[leeds]

Thats great, thank you, we're just looking at options at the moment and hoping to save some money on the parachutes, the ground hit velocity is low with the bigger chute but just wanted to gauge how high some others have gone if we end up looking at smaller paracchutes.

 

[G_T]

You do not want to wrap the lines. That is one of the larger sources of deployment issues. Though, you might mean something other than wrapping the lines around the chute?

Anyone interested in chute packing should check out parachute rigging.

Gerald

 

[sharkbait]

You do not want to wrap the lines. That is one of the larger sources of deployment issues. Though, you might mean something other than wrapping the lines around the chute?

Anyone interested in chute packing should check out parachute rigging.

Gerald

I guess I’m lucky then, literaly over 1000 flights with single chutes ranging from 12” to 19’ with only 2 chute isses, one from a Nose swing that fouled the chute and was the fault of my drogue location and the other was virtually the same thing. It with a booster section and again my fault for poor drogue location. Many double and triple chute recoveries with zero incidents. Not knocking bags or all the other packing techniques that others use with success by no means.

Still have the unanswered question though of why a 10’ in a 3”, what does this thing weigh or is a duration event

 

[3stoogesrocketry]

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Still have the unanswered question though of why a 10’ in a 3”, what does this thing weigh or is a duration event

They do not want to buy a new parachute

 

[sharkbait]

They do not want to buy a new parachute

Still don’t know your weight to properly size a chute, but you can get a 60” chute from Aerocon for $12.00

 

[3stoogesrocketry]

Still don’t know your weight to properly size a chute, but you can get a 60” chute from Aerocon for $12.00

Thank you for the compliment, but my fat butt needs bigger then a 60 inch lol

 

[sharkbait]

Thank you for the compliment, but my fat butt needs bigger then a 60 inch lol

Get two (lol)