Nice! Hard to tell as I was running the video in a small window.
K455 Flying Case
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Interesting, but I don't understand the point of the "flying case" when you add a regular diameter airframe tube and nose cone to the top of it. OK, you save some weight without a full-length airframe and maybe a minute amount of friction drag. Pressure drag may be same or worse than a normal build due to the transition. However, top speed and/or altitude were seemingly not your goals. Plus, all that work into a disposable rocket...ugh. What's the appeal?
I’m confused with what happened. The charges blew.
loopy
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In this particular case (pardon the pun), he was testing to see if JBWeld was strong enough to survive mach, and also testing some of the other properties (e.g. is it strong enough to handle the heat of being attached directly to the motor as it burns without losing strength).
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Truthfully, my original plan was to use a piece of coupler and trim a nosecone to effectively create a true "minimum diameter" build. However, I decided to hold off for the time being on that concept.
The truth is, basically building a Mach 2 would have only cost a couple hundred feet on the sims. Ultimately, it was just a fun exercise in building a performance rocket and a good opportunity to flex some JB Weld capabilities, too.
There's certainly an element of appealing to the YouTube masses with this build, too. Most rocket folks, myself included, know that JB Weld is more than capable. What was really in question, here, was my ability to build a functioning high-performance rocket.
...I'll be trying again. Lol
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Full disclosure, I did not compress these charges like I do with a lot of mine because I was trying to keep them small and save as much space as possible. My thought is that the altitude combined with the compression only coming from the strength of a nitrile glove (rather than a tight wrap of electrical tape like I usually do) resulted in more of the powder being thrown around than burned.
The next steps in my quest for high-altitude stuff definitely include a priority in a more efficient ejection charge assembly.
I saw a great idea with a lightweight cable cutting pyro that @waltr put on his two stager
It wouldn’t have worked for this build since you plugged the motor charge, but might be worth exploring for your compact builds like this. Basically it was a small brass tube that would cut a zip tie wrapped around the parachute and tied through the brass tube. It was really clever and compact. It would probably be more reliable too than using a taped over well of gun powder.
https://www.rocketryforum.com/threads/chute-release-vs-cable-cutter.164297/post-2096131I guess I should use the search function a little more, but it was like this. It can be generally pretty small (smaller than a JLCR) but also bit more robust (you've had better luck with pyros iirc, so maybe it will serve you better lol).
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waltr
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Yes, I do need to post a thread on my Cable-cutter.
Aeva,
In your avatar photo I an sure that my 2-stage rocket is the one at the far left on the pad. This uses the cable-cutter to deploy the main from an Eggtimer Proton. Functionally, this works like a JLCR except it is pyro activated.
Aeva,
In your avatar photo I an sure that my 2-stage rocket is the one at the far left on the pad. This uses the cable-cutter to deploy the main from an Eggtimer Proton. Functionally, this works like a JLCR except it is pyro activated.
davidb123
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You might want to look into even tighter containment than electrical tape just to be extra sure. Some use charge vials or cardboard tubes with glue/tape, and I’ve been trying out Tony Alcocer’s vinyl charges outlined here. They should work at any altitude, and I’m planning on using them in nearly all my DD flights even if it’s overkill. I bet 1/4” vinyl tubing would work perfect for this type bird. YMMV!
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I had a chat with Tony about his ejection charges at BALLS. I just let it get in my head that 20,000 feet "wasn't that high" and that these charges would suffice.
Live and learn! Rockets this size in the future will likely get the vinyl tube treatment, while bigger high alt stuff is going to get more serious charges.
Stay tuned!
I've flown BP charges in a nitrile finger with 5 wraps of masking tape (extremely compressed) to nearly 28k without issue.
Next year I am planning on sealing my chute bay with o-ringed bulkheads to remove one variable, how much is the vent actually venting? With no vent and the bay sealed, I can accurately calculate the force on the shear pins and replicate that easily on the ground. I then will size my charges relative the number of pins I use. I think its easier to remove a variable in that manner, than it is trying to predict how a charge will work in a low atmosphere environment.
Next year I am planning on sealing my chute bay with o-ringed bulkheads to remove one variable, how much is the vent actually venting? With no vent and the bay sealed, I can accurately calculate the force on the shear pins and replicate that easily on the ground. I then will size my charges relative the number of pins I use. I think its easier to remove a variable in that manner, than it is trying to predict how a charge will work in a low atmosphere environment.
