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How big a chute can I fit into this space?

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kandsrockets

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How big of a chute can I fit into a 4" x 24" space? I've got a model that weighs 13lb, and need to get as much chute in there as possible.

Would something like this 15 footer:

http://www.omahas.com/product_info.php?products_id=2224

pack into that space?

-Eric
I can pack our KSR-12 in 16" of 4" tubing and it is rate for 13.5-24 lbs at 15-20 fps. I can get our KSR-14 in less than 20" of 4" tubing and it is rated at 18.5-32.7 lbs at 15-20 fps.
 

bobkrech

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How big of a chute can I fit into a 4" x 24" space? I've got a model that weighs 13lb, and need to get as much chute in there as possible.

Would something like this 15 footer:

http://www.omahas.com/product_info.php?products_id=2224

pack into that space?

-Eric
That's a surplus flare parachute and it weighs less than 3 pounds. It should easily fit in that space, however a 15' chute on a 13 pound rocket is going to give a sea level descent rate in the 9 fps range. A 10' flare parachute is more appropriate for this weight rocket and would weigh a mere 10 ounces.

Bob
 

Cygnus

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Thanks for the input. This is a high drag model; an upscale x-wing fighter model I flew at NYPower in 2005. I'm rebuilding the damaged nose section around 4" tubing rather than the original 2.56". Hoping to fly it on a J350 at LDRS this year. I don't expect much altitude, so I'm leaning toward the 15' flare chute.

I've attached an image of model from 2005.

xwing03.jpg
 

ben_ullman

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Thanks for the input. This is a high drag model; an upscale x-wing fighter model I flew at NYPower in 2005. I'm rebuilding the damaged nose section around 4" tubing rather than the original 2.56". Hoping to fly it on a J350 at LDRS this year. I don't expect much altitude, so I'm leaning toward the 15' flare chute.

I've attached an image of model from 2005.
I would go with the 10 foot because remember you do need enough weight to actually OPEN the chute and not make it a streamer. I use a 15 foot flare shoot on a 35lb rocket. I 10 footer is more than enough for this.

Ben
 

Cygnus

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Is there a formula for weight required to open a chute? Is there a way to ensure that a larger chute opens on less-than-optimal weight?

I ask because I already ordered the 15 footer...

-Eric
 

ben_ullman

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Is there a formula for weight required to open a chute? Is there a way to ensure that a larger chute opens on less-than-optimal weight?

I ask because I already ordered the 15 footer...

-Eric
If you are flying this at LDRS I will let you borrow one of my nice sky angle chutes with Dbag that will fit in that space. I have 3 different chutes that would work.

Ben
 

bobkrech

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Thanks for the input. This is a high drag model; an upscale x-wing fighter model I flew at NYPower in 2005. I'm rebuilding the damaged nose section around 4" tubing rather than the original 2.56". Hoping to fly it on a J350 at LDRS this year. I don't expect much altitude, so I'm leaning toward the 15' flare chute.

I've attached an image of model from 2005.
Is there a formula for weight required to open a chute? Is there a way to ensure that a larger chute opens on less-than-optimal weight?

I ask because I already ordered the 15 footer...

-Eric
I expect that you would get 800'-900' out of a 13 pound rocket with a nominal 6" inch cross-section and a draggy cd ranging from 1.8-2.4.

I would also expect that you have an electronic apogee detection system or a 7 second timer on the rocket to deploy the chute at apogee because you don't have much margin for error on deployment of a large chute. With apogee deployment there really shouldn't be an issue of not having time to inflate the chute, however I might consider using a pilot chute to make sure the bigger chute is fully extracted. Once it's extracted, it will open.

Aerocon Systems has a nice pilot chute/deployment bag setup for $20. http://aeroconsystems.com/chutes/p_d_bag.htm Your 15' flare parachute will fit inside this because it's very light weight, however I would really suggest that you look for a 10' flare chute. The pilot chute will pull the deployment bag out and open it up. If the chutes deploy at apogee, they should be fully deployed in a second or two so you won't have much to worry about unless your rocket doesn't go vertical but then you have bigger problems.

Bob
 

rsynoski

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How big of a chute can I fit into a 4" x 24" space? I've got a model that weighs 13lb, and need to get as much chute in there as possible.

Would something like this 15 footer:

http://www.omahas.com/product_info.php?products_id=2224

pack into that space?

-Eric
I've packed a Rocket Rage RRQS50 into that size space. It's rated 50lb@22fps. Actually I have enough room for the RRQS50, deployment bag and a 24" drogue.

Actually it's a good idea to use a deployment bag when stuffing big chutes in small spaces, other wise you will get holes in the chute.
 

cjl

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If you are flying this at LDRS I will let you borrow one of my nice sky angle chutes with Dbag that will fit in that space. I have 3 different chutes that would work.

Ben
While skyangles are nice, they take a LOT of room for their size and drag. If space is an issue, Rocket Rage is a better choice. As said above, up to even the 50lb rated Rocket Rage chute (which is only around an 8 footer or so) would easily fit into that space, and not only that, they open nicely too.
 

Cygnus

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The 15' chute I purchased came with a deployment bag and drogue chute. I found that I could not fit the packed deployment bag into the 4" body tube. So, I removed the deployment bag, and attached the drogue directly to the top of the 15 footer, then s-folded the whole mess into the rocket. It's a tight fit.

I've got the nose set up to recover on a separate 45" chute. I suppose my greatest fear is that the drogue and main will remain stuck in the body tube. Is it adviseable to attach a "break-away" thread between the nose and drogue to help ensure deployment?

One last question: Any advice on the size of ejection charge to use? I'm leaning towards the "blow it out or blow it up" strategy.

-Eric
 

cjl

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If you want, I'll have my Rocket Rage RRQS50 at LDRS - you can borrow it for your flight. It's only around an 8 or 9 footer, but it's rated for 50lbs at 22fps at sea level (so it would come down at more like 10 or 11 feet per second on your model. I guarantee you that I could pack it into that much space with room to spare too. I'll need it on Friday morning for my Deuce, but other than that, you're welcome to borrow it. I'll be in parking spot A141 (which appears to be fairly close to where you're parked), if you're interested.
 
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