Iupiter1007
New Member
Hey everyone! I've been getting inspired by the forum for a while now (thanks y'all for your incredible work and talent) as well as the r/rocketry discord server. I've been slowly working on this submin for several months and figured it would be good to share! I have my TRA L1 and L2 certs, and flew an L1000 to 16,000 ft. last October.
My goal for this project was to learn more about really high performance flights and optimization, with a priority of a really solid structural design. Here's the OR:
The fins have a strange cant to the tip chord since I printed it out of Aluminum through JLPCB, and faced similar warping to @Neutronium95's Bare Minimum fincan. It's almost a downscale of his fincan, very similar overall part geometry. I conducted flutter analysis in FinSim and decided on a 0.09" thick biconvex profile:
They have a big tip chord to improve CN_alpha and hopefully reduce movement of Cp as the rocket goes supersonic through M2.5. The other parts are a printed coupler (ditched for reasoned explained below) and a cute printed eyebolt (ditched because it was scary thin, in theory it could support recovery loads but I hated the integration procedure).
New AVbay is a fiberglass sled with 1/8" kevlar cord running through holes. Recovery is via a 15' thin mill chute with a 6" nomex and cable cutter. This is then covered in another 6" nomex. The outer 6 or 9" nomex is a "drogue" deployed when a vinyl tube charge fires. Then main is by cable cutter deployment.
I had considered retaining the main by friction fit like Kip's MESOS and Aeropac, but I'd prefer the cable cutter method, it also uses less kevlar cord. Old diagram pictured below.
TLDR of the old stuff: Be realistic about wiring etc, and actually consider integration procedure, not just if stuff fits together in theory.
______________
OLD DESIGNS:
So you guys have an idea of the analysis paralysis I put on myself and performance brainrot I faced, here is the original OR file from last October:
Soo yeah, lots of changes haha. I switched to a submin since I thought it would be fun. I decided to send it for the J record because it would be a learning experience, boy it was. Here are some of the silly AV bay designs I came up with as the design iterated:
Originally dual redundant with EZmini, Blue Raven, Featherweight, and RDF Beacon (successful config I flew in my L1000).
Then my BR was destroyed in a flight accident (RIP) and I switched to a Fluctus and RDF.
To save space I switched to EZmini and RDF only for a while (NO GPS to 20k plus).
I tried printed this design, a little too optimized and later ditched this whole 3d printed ebay. The goal was to route recovery loads directly through the eye bulkhead and through 4 4-40 screws to the nosecone. Here is how the packing diagram was, inspired by Aeropac's 100k SSDD and Kip's MESOS, but smaller.
For high altitude deployment I've seen that it's important to contain your BP and ensure your ematch is placed so as the BP combusts, it tries to fly out of your vinyl tube/ charge cannon but the ematch is above the BP, ensuring more complete combustion. So, I integrated a charge well in my 3d printed coupler, but I designed it late at night and forgot to make it interface well with the AT fwd closure, so I lathed a coupler to interface between the fwd closure and the printed bit. Here's some progress on it:
I epoxied it in, but added too much and the closure stopped fitting. So that's ditched. Now I'm machining a whole new one.
I made a 7:1 VK nosecone out of 4 layers of soller sleeve (after an unnamed number of attempts, maybe 6 failed mandrels, and a new 3d printer (Bambulabs are cool besides the recalls):
I realized the nosecone didn't give me enough space, so I ditched it an went with a lower fineness nosecone (6:1) and lengthened the straight section from 2" to 6."
My goal for this project was to learn more about really high performance flights and optimization, with a priority of a really solid structural design. Here's the OR:
The fins have a strange cant to the tip chord since I printed it out of Aluminum through JLPCB, and faced similar warping to @Neutronium95's Bare Minimum fincan. It's almost a downscale of his fincan, very similar overall part geometry. I conducted flutter analysis in FinSim and decided on a 0.09" thick biconvex profile:
They have a big tip chord to improve CN_alpha and hopefully reduce movement of Cp as the rocket goes supersonic through M2.5. The other parts are a printed coupler (ditched for reasoned explained below) and a cute printed eyebolt (ditched because it was scary thin, in theory it could support recovery loads but I hated the integration procedure).
New AVbay is a fiberglass sled with 1/8" kevlar cord running through holes. Recovery is via a 15' thin mill chute with a 6" nomex and cable cutter. This is then covered in another 6" nomex. The outer 6 or 9" nomex is a "drogue" deployed when a vinyl tube charge fires. Then main is by cable cutter deployment.
I had considered retaining the main by friction fit like Kip's MESOS and Aeropac, but I'd prefer the cable cutter method, it also uses less kevlar cord. Old diagram pictured below.
TLDR of the old stuff: Be realistic about wiring etc, and actually consider integration procedure, not just if stuff fits together in theory.
______________
OLD DESIGNS:
So you guys have an idea of the analysis paralysis I put on myself and performance brainrot I faced, here is the original OR file from last October:
Soo yeah, lots of changes haha. I switched to a submin since I thought it would be fun. I decided to send it for the J record because it would be a learning experience, boy it was. Here are some of the silly AV bay designs I came up with as the design iterated:
Originally dual redundant with EZmini, Blue Raven, Featherweight, and RDF Beacon (successful config I flew in my L1000).
Then my BR was destroyed in a flight accident (RIP) and I switched to a Fluctus and RDF.
To save space I switched to EZmini and RDF only for a while (NO GPS to 20k plus).
I tried printed this design, a little too optimized and later ditched this whole 3d printed ebay. The goal was to route recovery loads directly through the eye bulkhead and through 4 4-40 screws to the nosecone. Here is how the packing diagram was, inspired by Aeropac's 100k SSDD and Kip's MESOS, but smaller.
For high altitude deployment I've seen that it's important to contain your BP and ensure your ematch is placed so as the BP combusts, it tries to fly out of your vinyl tube/ charge cannon but the ematch is above the BP, ensuring more complete combustion. So, I integrated a charge well in my 3d printed coupler, but I designed it late at night and forgot to make it interface well with the AT fwd closure, so I lathed a coupler to interface between the fwd closure and the printed bit. Here's some progress on it:
I epoxied it in, but added too much and the closure stopped fitting. So that's ditched. Now I'm machining a whole new one.
I made a 7:1 VK nosecone out of 4 layers of soller sleeve (after an unnamed number of attempts, maybe 6 failed mandrels, and a new 3d printer (Bambulabs are cool besides the recalls):
I realized the nosecone didn't give me enough space, so I ditched it an went with a lower fineness nosecone (6:1) and lengthened the straight section from 2" to 6."
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