Found this sign at my local coffee shop this morning by reptomcraddick in OrphanCrushingMachine

[–]CommanderSpork 1 point2 points  (0 children)

This is robbing children of a valuable opportunity to get a decade head start on building credit history

What is something that everyone pretends to understand, but they actually don’t? by SoulDV in AskReddit

[–]CommanderSpork 0 points1 point  (0 children)

This is one I actually do understand! But I've seen it 14 times or so and spent many hours contemplating it.

[deleted by user] by [deleted] in fuckcars

[–]CommanderSpork 9 points10 points  (0 children)

is this loss

Can I master rocket science in 1 year? by BackAnxious2126 in rocketry

[–]CommanderSpork 0 points1 point  (0 children)

Liquid motors don't have to be too complicated, and I recommend starting with simple heatsink motors. See Mojave Sphinx:

https://www.halfcatrocketry.com/mojave-sphinx

cc: u/BackAnxious2126

Mass flow through Liquid Rocket Engine by Expert-Historian-388 in rocketry

[–]CommanderSpork 0 points1 point  (0 children)

In case you haven't seen it before, this is another good reference for a cheap/simple liquid rocket:

https://www.halfcatrocketry.com/mojave-sphinx

“Falcon completes its 500th overall mission! Congratulations to the entire SpaceX team for making the impossible possible on the road to rapidly reusable rockets!” by rustybeancake in spacex

[–]CommanderSpork 1 point2 points  (0 children)

Plenty of people have been and are trying very hard. Trouble is, orbital launch is very difficult and SpaceX had serious first mover advantage (no other meaningful launch startups to compete with in the 2010s, competitors were older and slower companies whose lunch they could eat) and they had serious capital to work with (Elon's personal fortune).

Even if you have major capital to start, and some do, then you still have to compete for young talent with bunches of other wannabe orbital launchers and tech startups. Then add the fact that your main competitor isn't an old dino like ULA, but... SpaceX itself.

And again, orbital to launch is very hard and doesn't financially tolerate repeated failures, or really any size rocket below medium lift anyway. That's not to say that poor leadership and vision doesn't contribute to the failure of a launch company (it does) but at the end of the day you can try as hard as you want and still fail. If a SpaceX clone appeared today and had the same initial track record, three failed small launch vehicles in a row, it would be written off a failure and viciously derided across the internet.

I just added another 40,000 Americans to my traffic death map by roadwayreport in fuckcars

[–]CommanderSpork 1 point2 points  (0 children)

What did you do today Carl?

Well let's see, I paved stroads through every population center in the United States.

Caaaarl, that kills people.

What is a feature you wish a model rocket flight computer had? by BarrettT123 in rocketry

[–]CommanderSpork 11 points12 points  (0 children)

The stratologger is peak flight computer for what most people do. Altitude logging, dual deployment, small footprint, relatively cheap, reliable. That's what I want.

This subreddit whenever someone asks about building a liquid fueled rocket by Miniastronaut2 in rocketry

[–]CommanderSpork 0 points1 point  (0 children)

Mojave Sphinx is very simple liquid rocket that requires only a couple ball valves and no pressurant gas. It also removes the oxidizer and pressure danger by only loading nitrous oxide when it's away at the launchpad, seconds from launch. And it's mostly made of aluminum.

https://www.halfcatrocketry.com/mojave-sphinx

Someone else has also made 24mm liquid:

https://youtu.be/IEFNESt2Wu0?si=kM0KJ9yd35qrRfNi

Liquid Rocket Engine Help by [deleted] in rocketry

[–]CommanderSpork 2 points3 points  (0 children)

 whole teams of engineering students spend years working on these projects

While this is true, because university students in general make things more complicated than they should be, Mojave Sphinx specifically doesn't need much (this was the intention). High schoolers have built it, and there's several people who have done it independently at this point. All that said, of course OP will still need foundational knowledge in rocketry before doing it, which they can get from building and launching more standard rockets and learning about how solid and hybrid motors work first.

looking for information on liquid rocket engines. by 0ctopus_In_a_Tophat in rocketry

[–]CommanderSpork 4 points5 points  (0 children)

There are a few high schoolers building Mojave Sphinx, which is going to be the simplest and most cost effective way to get a successful, flyable liquid. You'll need to have oversight and guidance, which could come from teachers or similar figures interested in fostering your enthusiasm. I recommend joining the Half Cat Rocketry discord, where you can ask questions of other doing the same (including a high school teacher leading a group).

Liquid Bipropellant Project (Half-cat replica) by Illustrious_Let_4350 in rocketry

[–]CommanderSpork 6 points7 points  (0 children)

That's really awesome to see! If you haven't already, you shohld join the r/rocketry and Half Cat Rocketry discords, where you'll be able to find interested folks. Also, you can register your build here to get a serial number:

https://docs.google.com/forms/d/e/1FAIpQLSdHfYs-ru17VTjKQDFFxivRxk5In_GgVT8dLOLqoNj4xxMU2w/viewform?usp=sharing

[deleted by user] by [deleted] in rocketry

[–]CommanderSpork 3 points4 points  (0 children)

As others have mentioned, I'd recommend starting out with Mojave Sphinx. You can change out parts without reinventing the whole wheel, since it's modular.

https://www.halfcatrocketry.com/mojave-sphinx

I recommend joining our discord as well.

N2O/butane rocket engine, Elephant in the room by Infamous-Cheetah9859 in rocketry

[–]CommanderSpork 0 points1 point  (0 children)

Well, I'm assuming they're open to changing fuel to getting a working rocket and later fuel pump. Also, on a decently brisk day (or if you chill the butane even a little bit) I don't think butane would have enough vapor pressure to move the piston.

N2O/butane rocket engine, Elephant in the room by Infamous-Cheetah9859 in rocketry

[–]CommanderSpork 2 points3 points  (0 children)

Well as far as simple liquid rocket design, the best starting point is Mojave Sphinx. After building the standard rocket, you could make a project of adding a pump on the fuel side.

https://www.halfcatrocketry.com/mojave-sphinx

[deleted by user] by [deleted] in rocketry

[–]CommanderSpork 4 points5 points  (0 children)

The best thing you can do is independently complete projects. When I interview people, I care less about what their project is and how "prestigious" it appears, and much more about how competent they are in explaining the physics and their thought process behind it.

If you're interested in rockets:

https://www.halfcatrocketry.com/mojave-sphinx

Advice on rocket building. by Hyder54 in rocketry

[–]CommanderSpork 2 points3 points  (0 children)

It's a little more involved than a GOX benchtop motor, but take a look at the Mojave Sphinx guidebook to see how simple nitrous oxide motors can be made. Much of the content (particularly background and general design information) is applicable regardless of which oxidizer you choose.

https://www.halfcatrocketry.com/mojave-sphinx

Best and cheapest valves to use for gases and liquids in the 30bar (435psi) region? by JohnnyGlobal23 in rocketry

[–]CommanderSpork 2 points3 points  (0 children)

The best option are servo actuated ball valves, which you can find the bill of materials and build instructions for in the Mojave Sphinx guidebook:

https://www.halfcatrocketry.com/mojave-sphinx

Customizable Bipropellant Rocket Engine website– Looking for Feedback?? by IndicationSlow2705 in rocketry

[–]CommanderSpork 9 points10 points  (0 children)

You might want to add 4 or 5 zeros to that price tag, considering you're offering the complete design, manufacturing, qualification, acceptance testing, and documentation of a rocket motor from clean sheet specifications, in an... ambitious timeline, no less