Crazy Idea? Using Upper Chute Apogee Deployment to Shake Loose Fin Section & Attached Lower Chute

[jmmome]

"Not a Rocket Scientist" had a successful maiden launch a few weeks ago. But the apogee ejection charge for the fin section, which contained a deployment bag for the 8 foot chute, severely charred the bag and even created a small rip in the bag (chute was not damaged).

Since the fin section, along with the 75mm motor assembly weighs about 20 pounds, and since the upper rocket body has a 10 feet parachute, and since the coupler fit between the fin section and the upper body section is pretty loose, would YOU feel comfortable allowing the sudden "stop" created by the upper chute at apogee to dislodge the fin section, whose chute would still be housed in a deployment bag to allow the lower chute to successfully deploy?

The backup plan would be to set the Stratologger for the lower chute to fire at Apogee +3 or +4 seconds (it took almost 2 minutes to land from an altitude of over 2,300 feet- both rocket sections were attached to each other via Kevlar shock cord), and add another layer of Nomex between the D-bag and the lower ejection charge. I did use a charge calculator, but the 8" dia. body tube & deep cavity at the top of the fin section requires a fair-sized charge.

I did a lot of crazy/unusual things for this build, like a breech-loading upper chute ejection charge system, accessed through the altimeter bay, so this would simply add to the list of unexpected items.

Thanks!!

 

[Seatechnerd83]

What you're referring to is called a pilot chute, they are mostly used in hobby rocketry for DD with a single ejection. But the spaceX and boeing ISS crew capsules use pilot chutes too. If you do use a pilot chute, i highly recommend using redundant drogues, or high speed drogues, as a torn chute when deploying at high speed will ruin a flight. (I saw a guy have his L3 attempt ruined by a pilot chute ripping and not being able to pull out the main.)

 

[rcktnut]

Nice rocket and flight. If the only problem your concerned about is the charring of the deployment bag and possible damage to the chute and everything is working out great otherwise, just add some dog barf before the deployment bag. I know it is dirty but is better than a damaged deployment bag or chute. I add a little on top of all my canisters before inserting the burrito wrapped chutes. No burnt chute protectors or chutes since I started doing that.