14bis
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- May 3, 2018
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Hello everyone.
I'm building a rocket that will have around 10 lb at apogee (~3300 ft, with horizontal velocity of around 33 ft/s)
My problem is: I don't live in the US and I can't seem to find the 1500# shock cord here (chosen from previous experience).(https://www.apogeerockets.com/Build...ar_Cord_1500?zenid=gp72kqr2aq7mq8f2mib89b7214).
What I used to do for single event rockets was to use nylon cord (the same as suspension lines) braid it and cover it with rtv silicone. It works, however it is ugly, demands a lot of time and it's a cheap solution that can cause expensive problems.
So I want to use kevlar, I've used it in the past (in the US), and I found this one (site in Portuguese, but you can see it's image: https://produto.mercadolivre.com.br...amida-40-m-25mm-assist-hook-corda-de-arco-_JM). Specs: 2.5 mm or 3 mm, 1200 lbs.
I calculated my max loading as follow: 10 lb x 20 g = 200 lbs, so I have a good safety margin, but I don't have any experience to how this thin (I think) shock cord would handle the 'shock'.
So if anyone could shed some experience using similar cords or different materials I could use, I'd appreciate it. I read about using nylon straps too, and tubular nylon too. This thread has helped me a bit (https://www.rocketryforum.com/showthread.php?48638-Calculating-Shock-Cord-Size-and-Lengths), but I'd like to try to expand on the material type.
I'll use ejection cannisters and around 3g of 4F BP. Fire is a concern, that's why I'm not sure about using nylon.
Thanks for the help!
I'm building a rocket that will have around 10 lb at apogee (~3300 ft, with horizontal velocity of around 33 ft/s)
My problem is: I don't live in the US and I can't seem to find the 1500# shock cord here (chosen from previous experience).(https://www.apogeerockets.com/Build...ar_Cord_1500?zenid=gp72kqr2aq7mq8f2mib89b7214).
What I used to do for single event rockets was to use nylon cord (the same as suspension lines) braid it and cover it with rtv silicone. It works, however it is ugly, demands a lot of time and it's a cheap solution that can cause expensive problems.
So I want to use kevlar, I've used it in the past (in the US), and I found this one (site in Portuguese, but you can see it's image: https://produto.mercadolivre.com.br...amida-40-m-25mm-assist-hook-corda-de-arco-_JM). Specs: 2.5 mm or 3 mm, 1200 lbs.
I calculated my max loading as follow: 10 lb x 20 g = 200 lbs, so I have a good safety margin, but I don't have any experience to how this thin (I think) shock cord would handle the 'shock'.
So if anyone could shed some experience using similar cords or different materials I could use, I'd appreciate it. I read about using nylon straps too, and tubular nylon too. This thread has helped me a bit (https://www.rocketryforum.com/showthread.php?48638-Calculating-Shock-Cord-Size-and-Lengths), but I'd like to try to expand on the material type.
I'll use ejection cannisters and around 3g of 4F BP. Fire is a concern, that's why I'm not sure about using nylon.
Thanks for the help!