u/mrblank5

Hey guys, I'm attempting my L1 Cert this Sunday with my Aerotech HV ARCAS kit with custom electronic payload (https://www.reddit.com/r/rocketry/s/qW2QcWJ9Uw) that adds ~300g to the rocket. I will be flying on an H182R with expected apogee around 2200ft. In talking with the range safety officer, I was informed that I need to use kevlar instead of elastic for my shock cord(elastic comes with the kit). I have purchased 15ft of 1500 kevlar (yes ik it's a bit overkill)

My question is:

How long should I make the shock cord and what can I do to prevent zippering?

With an 11 second ejection delay, the expected deployment velocity is ~20mph(8.67m/s) and with a 10 second delay deployment velocity is 6.5mph(2.83m/s). I assume 10sec delay will be fine as wind will only be ~7mph and I shouldn't have to worry too much about drift coming down. I'll be using a 21" parachute tied 1.5ft from the attachment point to the upper half of the body.

Sorry if this post is a mess, please feel free to ask follow up questions.