Chute Deployment... How Much Time?

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lakeroadster

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I'm gearing up to actually launch some of the rockets in my fleet that I've been building for the last 3 years.

Since I'm a scratch builder... my rockets tend to not fit into the standard "Hey, they all look just like an arrow" style.

My question is in regard to my latest rocket: It weighs 10 ounces. If I fly it on a D12, it's apogee sim's out at 412 feet. It's recovery is via dual 18 inch chutes.

In your experience... is that going to be an issue in regard to the chutes having enough time to deploy and blossom, or would I be wiser to buy a pack of Aerotek E20's so the apogee is at 1,000 feet?​

I could use an Estes E9 or E12.. but I love my rockets to much to do that to them.

Thanks in advance for your thoughts on this.

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Red Columbine Dwg Sheet 9 of 10 Rev 02.jpg
2021-07-23 Open Rocket Simlulation Red Columbine.jpg
 
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mbeels

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I bet you'll be fine. As long as the 'chute doesn't suffer from sticky-plastic-parachute syndrome and stay wadded up all the way to ground. I've done DD in a 24mm rocket and had the chute deploy anywhere between 200 and 400 feet, and it usually pops right open. A quality (preferably non-plastic) parachute packed well will work. Rear eject, with the parachute in contact with the motor tube can melt plastic parachutes.

I've only attempted a few rear eject rockets, with mixed success. I would recommend not wrapping the parachute and shroud lines around the motor tube. Instead do a Z-fold ...... NEVERMIND, just noticed your note 1.0. Great drawings.
 

les

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Use the -3. In case the rocket weathercocks or has higher drag than anticipated and it doesn't go as high as expected
 

lakeroadster

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I bet you'll be fine. As long as the 'chute doesn't suffer from sticky-plastic-parachute syndrome and stay wadded up all the way to ground. I've done DD in a 24mm rocket and had the chute deploy anywhere between 200 and 400 feet, and it usually pops right open. A quality (preferably non-plastic) parachute packed well will work. Rear eject, with the parachute in contact with the motor tube can melt plastic parachutes.

I've only attempted a few rear eject rockets, with mixed success. I would recommend not wrapping the parachute and shroud lines around the motor tube. Instead do a Z-fold ...... NEVERMIND, just noticed your note 1.0. Great drawings.
But... Thinking through your comments... I think I will wrap some crepe paper streamer material around the motor tube before packing the chutes. That should help insulate the chutes from the heat of the motor.

Thanks!
 

lakeroadster

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Use the -3. In case the rocket weathercocks or has higher drag than anticipated and it doesn't go as high as expected
Thanks Les. I thought about that... but since it's a rear eject I don't want the rocket falling through the chutes, so I thought ejecting the laundry after apogee would be preferred.
 
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