The Journey to 200k

NateLowrie

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It’s been a bit, but we are back. It's been a busy few years and we are ready to get back to building rockets. My dad and I were talking about what we wanted to do rocket wise in the next few years and we kept coming back to a high altitude rocket attempt. So, we settled on a goal of 200,000 ft.

The Plan

We know that right now we do not have the necessary experience or capabilities for a project of that magnitude without breaking it into achievable chunks. This thread is going to be the journey through this buildout of capability through the actual attempt. Right now we are budgeting for 2 years to complete and go through the needed testing and buildout. So, the flight attempt is tentative to BALLS 2023.

The design for the actual attempt is in a draft state but we do know a few things:
  • We would like to do a 2 stage attempt, most likely an N to an N.
  • We would like to use the nosecone space as part of the recovery. I would like to develop a good HED setup.
  • We want GPS tracking on both the sustainer and the booster. The sustainer is going to end up with a Kate unit as the primary flight computer and tracker.
  • We want cameras onboard: one outward-facing, one downward-facing, and one upward-facing.
  • I would like active stabilization on the launch. It's not necessarily a primary requirement but definitely mitigates some of the risks of an off-nominal launch.
The buildout is also going to require some planning. MDRA and the other local fields have relatively low waivers, and I am going to try to do as much of the buildout on my local fields first but eventually, we will need to go west for a higher waiver field.

Next Steps - September MDRA Launch

The next launch at MDRA is going to focus on:
  • Designing and proving out a HED recovery deployment system.
    • I am designing a system for both 3in and 4in. If possible I would like to pack the parachute system completely inside the
    • Explore CO2 recovery. I have peregrine CO2 modules and want to interface them directly to the bulkhead.
    • Have the outward-facing camera in the av-bay.
    • GPS tracking will be built into all test rockets going forward.
  • Design a camera shroud that can house both forward and rearward-facing cameras.
  • Refining procedures and coordination. The final 200k shot is going to take some coordination for prep and recovery so I would like to start refining roles, procedures, and checklists now. This will seem like a lame step to some, especially for these smaller testing flights, but the name of the game is de-risking the project as much as possible.

Next Steps - December MDRA Launch

The December launch at MDRA is going to focus on:
  • Getting experience with MD airframes and higher altitude tracking. We plan on do a 3in or 4in MD airframe with the HED system from the September launch and kiss the waiver at Higgs.
  • Start the motor design for the program. We have a good formulation characterized. The first step is developing an I and/or J motor with the formulation. We can then start to scale up from there as we prove things out. All motor configurations will be static fired to establish performance for simulations.

Input from you

I always appreciate constructive input and hard questions. The purpose of documenting this journey is to get feedback along the way and hopefully avoid some mistakes.

We are looking for a few more people that would like to be directly involved in the project. If you are near Lebanon, PA and would like to help in person, we do have regular build nights. If you would like to help from afar, we can certainly work something out. PM me with what you were thinking about and we'll work out the details.


For now, we have already made some good progress. I'll be posting some update posts here shortly with status on rocket frames and AV-Bay design. For now, here's a pic of the current state of the AV-Bay in CAD. Design is not done just yet.
AV Bay 7-20.png
 

dhbarr

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It is entirely my personal subjective opinion, but: if one or both of you don't already have a firm background in electrical, electronics, and programming... two years might not be the right timeline for roll-your-own stabilization. Against the background of all the other things you want to get done, I mean.
 

NateLowrie

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Well procedures and check lists are NOT lame when thinking of a 200k goal. The sooner you get them started the less issues you'll have on the big day.

Will be following this thread...

Agreed. My goal is to have a few positions that divvy up duties:
  1. launch coordinator that confirms and double checks every on the list and has a final go/no go authority.
  2. Photography coordinator that coordinates all of the ground photography and video.
  3. Recovery coordinator that coordinates recovery of rocket components including rocket stages, fly away rail guides, and ground modules.
Overkill for a 4in I motor flight to 2k but important to get into the habit.
 

NateLowrie

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It is entirely my personal subjective opinion, but: if one or both of you don't already have a firm background in electrical, electronics, and programming... two years might not be the right timeline for roll-your-own stabilization. Against the background of all the other things you want to get done, I mean.

Appreciate the opinion. My degree is in computer engineering degree and I have many years of electronics/firmware experience, which will definitely be a help here. If I didn’t have the background it wouldn’t have made the list. That said, I have no illusions the software will be easy.

I am hoping to piggyback off of some of the systems currently in development. If it ends up being completely roll your own then you’re right, it will probably get dropped.
 

MClark

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My advice, talk to Jim Jarvis
Read this

 
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NateLowrie

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My advice, talk to Jim Jarvis
Read this


it’s definitely a bookmarked thread of mine, along with Ravenex’s work. I must have read through it several times by now.

Jim is definitely a pioneer for this type of project. I will be reaching out when we get to that point. Right now we were planning on exploring that in Q1 of next year.
 

mikec

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As far as I know, CO2 has a very bad track record for high-altitude deployments, to the point that I would not bother with it. But perhaps I'm wrong.
 

JimJarvis50

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As far as I know, CO2 has a very bad track record for high-altitude deployments, to the point that I would not bother with it. But perhaps I'm wrong.
I'm not aware of a bad track record involving CO2. I'm involved in activities where, if this was the case, I would know about it. I don't personally use CO2 any more, but it is because BP works fine at high altitude if used properly, and I would prefer to avoid the weight/cost/complexity of CO2.

Jim
 

mikec

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I'm not aware of a bad track record involving CO2.
The AeroPac 2012 100K flight report says "the black power in the sustainer's apogee CD3 unit had not burned completely and the CO2 cartridge had not been pierced." Hard to tell, but it doesn't look like any of the Aeropac flights documented in that report got the CD3 to work. And it seems like I've heard of other high-altitude deployment failures associated with the CD3 but I can't readily find that info. Whether that's due to problems specific to the CD3, or user error, or something else I couldn't say, and you would probably know more about than I.

At any rate, it seems like the AeroPac experience is that the CD3 is not a slam-dunk cure-all for high-altitude deployment. Perhaps other systems are better.
 

JimJarvis50

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The AeroPac 2012 100K flight report says "the black power in the sustainer's apogee CD3 unit had not burned completely and the CO2 cartridge had not been pierced." Hard to tell, but it doesn't look like any of the Aeropac flights documented in that report got the CD3 to work. And it seems like I've heard of other high-altitude deployment failures associated with the CD3 but I can't readily find that info. Whether that's due to problems specific to the CD3, or user error, or something else I couldn't say, and you would probably know more about than I.

At any rate, it seems like the AeroPac experience is that the CD3 is not a slam-dunk cure-all for high-altitude deployment. Perhaps other systems are better.
I have recently discussed the use of CO2 with Tom Rouse, and he does make the point that for high altitude flights, the wires to the BP need to be sealed. Perhaps his recommendation is related to known failures when this is not done. When I used the CD3 - probably prior to 10 years ago, I always sealed the wires and I never had a case where the CO2 cartridge was not punctured. I haven't looked at the "instructions" associated with CO2 devices to know if this recommendation is generally known to users. Sounds like it should be.

Jim
 

NateLowrie

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I have recently discussed the use of CO2 with Tom Rouse, and he does make the point that for high altitude flights, the wires to the BP need to be sealed. Perhaps his recommendation is related to known failures when this is not done. When I used the CD3 - probably prior to 10 years ago, I always sealed the wires and I never had a case where the CO2 cartridge was not punctured. I haven't looked at the "instructions" associated with CO2 devices to know if this recommendation is generally known to users. Sounds like it should be.

Jim

I am looking into use the peregrine CO2 system. After reading the aeropac report I did have concern with the CO2 deployment properly actuating. The Peregrine system uses a e-match and small amount of powder to actuate the system. It is fully sealed and has been tested in a vacuum to actuate. I discussed this at length with Cameron Tinder who invented the Peregrine system, who didn’t see any issues.

Other than the Aeropac report I don’t know of anyone else utilizing CO2 for the flight profile we were looking at. If there are other failed attempts, I would love to know about it.

Maybe we use CO2 or maybe we use back powder. I have plenty of experience with basically my equivalent of your shotgun style sealed black powder cartridge if we need to fall back. I also really appreciate the testing article that your did.

Regardless of the system, I want to rig up a vacuum chamber to 1) test reliable actuation and 2) to separation of the rocket in a vacuum. I really want to do as much extensive testing as possible.

Right now, I want to get some experience with the CO2 systems to see how reliably they operate and if it’s an appropriate solution.
 

Scrapmaster87

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Here's an idea: Fully seal the recovery compartment and pressurize to 15 psi for launch. Of course you'll need shear pins able to withstand 30psi, but you'll be able to do a leak down check before launch. You'll need at least 1 o-ring on your nosecone and good sealing surfaces. You might be able to take this further an make your airframe a balloon tank via ultra thin walls (relying on the pressure for the required rigidity).

I'd like to help if I can, I'm semi local being north of Pottstown.
 

NateLowrie

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Lots of progress. Going to break this up into multiple posts.

One of the first things we did was to create cases for the 2 eggfinder units we have. The TRS and eggfinder mini are going to be our base trackers on the test bed rockets we are going to be flying. I've been running these RX units for years by just holding them, so this is a welcome upgrade. Here's the end result.


IMG_1881.jpg

Printer: Ender 3 (highly modified)
Material: PETG

The case fits a 700mah 2S lipo, has a power switch and push-button for the interface, and has mounting holes on the lid for both the RX unit and the GPS receiver option. There is a cover on the bottom by the handle where the lipo charging cable comes out. You just take it off and can charge the lip without needing to undo the case. It was designed by myself from scratch. If people are interested in the files I will post them to Thingiverse.

I am a big fan of heat-set insert nuts for 3D printed parts. A good US source is Adafruit. AS you can see below, the nuts are heated with a soldering iron and set into the 3D printed part. I highly recommend them.

64783366049__B1A2077B-51CD-48BB-A285-946E10C5CFC4 - 01.jpg 64783364783__D7028248-362B-4C12-B80A-F51B6AB08D15 - 01.jpg

Side note: see those black spacers in the pic below. Those are Perler Beads raided from my kids craft room. Turns out those beads make the perfect #4-40 spacer and they are super cheap. They also work for #2 screws if you have the clearance. M3 screws will fit but you need to drill out the bead slightly.

IMG_1875.jpg

Handle connected with heat set inserts. Used flat head screws so I don't put pressure on the lipo battery.

IMG_1731.jpg
Shots of the case. Battery is held in with a clip. There ware a 1/8in of extra space I put it and have some foam inserts compressed to hold it down snug. The wiring is slightly messy but it works.

IMG_1876.jpg IMG_1877.jpg IMG_1878.jpg IMG_1879.jpg IMG_1880.jpg
 

Bat-mite

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Hey, Nate, glad to help in any way I can, but this is definitely not my area of expertise. But if you need a grunt in September, let me know.
 
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