Amateur Rocketry Hack Chat

It absolutely is rocket surgery

Wednesday, November 30, 2022 12:00 pm PST Local time zone:
Hack Chat
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Kip Daugirdas will host the Hack Chat on Wednesday, November 30 at noon Pacific.

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This might be going out on a limb, but it seems like most of us probably fooled around with model rockets when we were younger. Those fantastic Estes kits were great fun to put together, and launching them was always a big neighborhood event, and one of the few that could make even the coolest of the cool kids pay attention to the nerds, if only for a little while. Launch day had it all -- a slight element of danger, the rotten egg stink of spent propellant, a rocket gently floating back to Earth from a dizzying height of 100 meters, and the inevitable tree-climbing party to retrieve a lost rocket.

But while model rocketry is fun, it doesn't scale up very well. If you want to reach the edge of space, you're going to need to make the leap across the border to amateur rocketry. That's where the big kids play, with real engineering needed to produce and control the forces required to reach altitudes of 100 km or more. Kip Daugirdas has made that leap, building rockets capable of almost getting to the Kármán line. It's not easy -- there was plenty of design work, static engine testing, and loads of test flights leading up to it, and surely more to come. Kip will stop by the Hack Chat to help us understand what's needed to press the edge of space, and hopefully share his plans for going all the way.

  • Hack Chat Transcript, Part 2

    Dan Maloney11/30/2022 at 21:12 0 comments

    Dan Maloney12:48 PM
    So what keeps you going then?

    prfesser12:48 PM
    @kjansky1 sugar is cheap but has its own problems. Tripoli allows homemade motors that use sorbitol, dextrose, or erythritol as the fuel. All three (esp sorbitol) have far lower melting points than sugar, and none of them are terribly expensive. Of course, when you're making literally a ton of propellant grains, cost enters into the project.

    Kip Daugirdas12:49 PM
    @Dan Maloney it came to a point where it was sunk cost. I had already invested so much of my time and money into the project that there was no turning back.

    Dan Maloney12:50 PM
    Man, do I know that feeling.

    kjansky112:52 PM
    Well chemically sugar or regular sucrose and dextrose(glucose erythritol) , sorbitol etc. are very similar chemically. I was thinking something with less hydroxyl or OH groups and a higher H bond fraction might provide better energy in the combustion.

    Alex Mi12:52 PM
    it's really, really good achievement, textbook flight... awesome

    Dan Maloney12:53 PM
    So is Black Rocks open to the public for watching launches? Because I live only about a day's drive away...

    Kip Daugirdas12:53 PM
    @Alex Mi thank you. I hope to have a repeat flight on the next go.

    Alex Mi12:54 PM
    lots of work - yeah, that's kinda impossible to beat :) . Would you do this the same way the next time? Judging by your extensive experience, I suspect you knew in advance most of how it's going to look like...

    Kip Daugirdas12:55 PM
    @Dan Maloney yes anyone can go spectate at a Tripoli launch. Most of the launches are held in the summer and fall. Fall being the most popular time because the weather is tolerable.

    prfesser12:55 PM
    @kjansky1 The limitation for such propellants isn't in the fuel so much as it is the oxidizer. Even at optimum, potassium nitrate propellants don't provide much more than half the specific impulse of typical APCP.

    Alex Mi12:55 PM
    but, anyway - 3 years seems like not a whole lot of time for this great results. Grains, machining and video editing... spectacular

    Kip Daugirdas12:57 PM
    @Alex Mi I probably would not change much. The only things I would look at changing would be the protective coatings on the leading edges of the second stage fins. Mach 4+ flight leads to very high stagnation temperatures (on the order of 1300F). To have a composite material survive this environment and not be single-use is a challenge

    anfractuosity12:57 PM
    What's the rocket itself made from btw?

    Kip Daugirdas12:58 PM
    The motor casings are 6061 aluminum. But the airframe structure was mostly fiberglass and carbon fiber composite

    Kip Daugirdas1:00 PM
    So the max temperature capability of the composite structure is ~250-300F. Luckily it is a really poor conductor of heat.

    anfractuosity1:00 PM
    ah cool, and you fold the fibre glass round a mould type thing?

    Alex Ryker1:00 PM
    @Kip Daugirdas For someone with a workable shop (metal lathe, electronics workbench, etc.) and general engineering experience, but not much experience in aerospace specifically, what's the best way to get started with rocketry?

    Kip Daugirdas1:01 PM
    The airframes and nosecone are filament wound. The fins are a complicated multi-step layup. I touch on it in the video that Dan linked to earlier in the chat

    Dan Maloney1:01 PM
    We're about out of time, so I just want to say a huge thanks to Kip for coming on today to talk rockets, and to everyone for the great questions. I really would love to see an IRL launch, seems like so much fun. Here's hoping the next flight makes it to 100 km!

    Dan Maloney1:01 PM
    And I'll post a transcript in case anyone needs links or anything

    Boian Mitov1:02 PM
    Thank you @Kip Daugirdas and @Dan Maloney :-)

    kjansky11:02 PM
    What practical maximum altitude would you expect an amateur rocket to achieve

    Dusan Petrovic1:02 PM
    Thanks Kip and everyone who participated!

    Kip Daugirdas1:02 PM
    @Alex Ryker I would say join Tripoli 100% and find a local club near you. The fact that you have all of those tools puts you a step ahead of...

    Read more »

  • Hack Chat Transcript, Part 1

    Dan Maloney11/30/2022 at 21:11 0 comments

    Dan Maloney10:27 AM
    Hi @Kip Daugirdas! Welcome aboard!

    mark joined  the room.10:52 AM

    bsigler joined  the room.11:24 AM

    Alex Mi joined  the room.11:31 AM

    Alex Mi11:32 AM
    my question :) - how people decide between liquid fuel and solid fuel rockets, especially for big ones?

    Dan Maloney11:41 AM
    Good question -- we'll get started in about 20 minutes, I'm sure there'll be an answer. My guess is it's a tradeoff between complexity and power, with maybe the ability to throttle tossed in too.

    anfractuosity11:49 AM
    Be curious about that too, n2o is stored in liquid form right?

    zombodotcom joined  the room.11:54 AM

    Boian Mitov11:58 AM
    Hello everyone :-)

    Char joined  the room.11:59 AM

    mmorneau joined  the room.12:00 PM

    Dan Maloney12:00 PM
    OK folks, welcome to the penultimate Hack Chat of 2022! I'm Dan, and Dusan and I will be modding today as we welcome Kip Daugirdas to talk about amateur rocketry. I'm quite excited for this one -- love me some rockets!

    Dan Maloney12:00 PM
    Hi Kip -- saw you on before, you still there?

    Kip Daugirdas12:00 PM
    yeah I am here

    Dan Maloney12:01 PM
    Good, good -- welcome! Maybe you can start us off with a little about how you got into rocketry on this scale?

    Dan Maloney12:01 PM


    Dan Maloney12:02 PM
    This is the scale I'm talking about, in case you don't know what Kip has recently accomplished

    Kip Daugirdas12:02 PM
    Sure. I started with high power rocket back in the early 00's (in high school). Went on to study aerospace engineering and then continued to participate in amatuer rocketry as a hobby.

    Kip Daugirdas12:02 PM
    so i have been at it while

    Kip Daugirdas12:02 PM
    a while*

    prfesser joined  the room.12:02 PM

    Begabait joined  the room.12:02 PM

    James Murphy12:03 PM
    What about getting the proper BATF Licenses to manufacture Rocket Fuel? Once you go big you.. go big.

    Alex Mi12:04 PM
    in general, licensing work, all kinds of permissions... that's a lot, and rather orthogonal to technology

    prfesser12:04 PM
    To answer the question about solid vs. liquid propellants (fuel is one propellant, oxidizer is another), solids are simpler. Liquids require plumbing.

    Kip Daugirdas12:04 PM
    to answer the first question regarding liquids versus solids. Solid are far simpler and have a much higher propellant density. This means you can pack more impulse into a smaller package.

    hlew joined  the room.12:04 PM

    Kip Daugirdas12:06 PM
    ammonium perchlorate is not a regulated substance in the U.S. so no permits from the ATF are required to store or make rocket fuel for individual use. However, you do need to be at least Level 2 certified to fly experimental rocket motors at Tripoli rocket launches.

    James Murphy12:06 PM
    Thank you so Tripoli is the authority in this case?

    zombodotcom12:07 PM
    isnt perchlorate incredibly toxic to humans

    James Murphy12:07 PM
    Could you expand on what Tripoli is for those of us newer to this.

    Kip Daugirdas12:07 PM
    Yeah we are essentially self governed. Tripoli worked really hard to get AP off of the ATF explosives list.

    kjansky112:07 PM
    Oxidizer used N2O?

    Alex Mi12:08 PM
    in some rocket communities we've talked about liquids vs. solids. Common opinion was that as soon as solids become large, they become more dangerous - you don't control quality that well, and oxidizer is close to fuel in the charge, so if it starts, it's pretty dangerous. While liquids generally benign before they get in contact. I should admit I like working with peroxide (HTP), and that requires respect - HTP can decompose, but it seems a simpler chemistry, more controllable (just pure peroxide). So to get high impulse, it felt liquids - mechanically harder, but chemically easier - could be safer for amateurs.

    Kip Daugirdas12:08 PM
    Tripoli is a national organization for high power rocketry meaning anything larger than a G-motor. There are local clubs in every state in the US and there are even some international...

    Read more »

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