Tripoli Cherryfield May 29, 2022
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- Опубліковано 7 лют 2025
- I traveled up to Cherryfield, Maine to launch my 7.5" LOC Doorknob on a CTI J381 Skidmark for my L2 Certification.
Bonus footage of some other cool rockets.
TRF build thread here:
www.rocketryfo...
Love the view from the rocket’s perspective. 👍
Your hobbies are not strange. Thank you for sharing!
The Doorknob rocks!
Great videography! I look forward to launching with you again soon!
Awesome job. Seems like a lot of complicated electronics for a simple level 2.
Definitely. I wanted to also get practice with redundant dual deploy setups so I went ahead and jumped in head first. This could have been way less complex if your goal is just to get the L2 cert out of the way.
@@pathtouch1where could I find your designs and/shopping list. I am looking to get experience with a similar project before going in on something larger.
Awesome video! You got some great shots, hope to launch with you again sometime!
Paul
Thanks! I have the October launch in my calendar!
Ok thanks mine is up to 17 lb and I'm concerned about the 20fps rate for landing. Also thinking of using a AT425R which is showing about 800 some feet, just chute release no DD for cert. Mine at 64inches shows just at 1.0 for stability so I am thinking of adding 6 inches to get it higher. at 64" not close to the 10:1 body size ratio and the drag C. showing in rks file? Just curious did yo have a sim showing different if your at 64" and 18 lbs more then mine, wonder what your cg was and showing what stability? Thanks, Sterk03
What was the weight of the rocket and what size parachute did you use?
Thanks
It’s about 18lb without propellent. Kinda heavy since i fiberglassed it. Stock 72” LOC chute is fine though, right around 20 feet per second on descent for me.
@@pathtouch1 Mine is 64 inch and 17 lbs but rsk shows right at 1.00 margin stability. I thnk I will add 6inches to move it to about 1.40 and more like the 10:1 body ratio for stability. Do you recall your cg and did you sim it? I would be interested if you did for comparison.
@@Sterk03 look up the base drag hack for open rocket. Without adding that cone, my CP is about 47.8” from the tip, also 64” long. No base drag hack I have 0.6 calibers of stability. Super straight flight. I do have an AV bay so quite a bit of weight forward.
I’ve flown 75mm motors with about the same stability just fine.
@@pathtouch1 Sorry for the delay sometimes life gets in the way. SO yes I have rocksim and LOC has it on their web site. I inquired to a few about running the CD and equation do to the stubby fat rocket I got that no one uses it. I do not show the DC either. So at about 15.8 lbs no motor I show 42.5cg and 51.4 cp with a 1.16 Margin. With the J425R I got 43.7 51.4 and 1.00 Margin... At MDRA you need at least 1.0 margin to launch. I have the weight system in the nose cause people said you will need it but I'm right there. I want a buffer so instead of adding more weight to the nose as weight I do not need, I am increasing the body 6 inches and this spreads out the cp to 56.8 which gives me a 1.94/1.71 margin. I might make it less then 6 inches but at least I know I have above 1.00 and little added weight. I believe it would be fine at 1.00. Ok I appreciate your info and I believe I saw your Doorknob at Pen Yan this past June. Cheers Sterk03