Homemade rocket engine?

>>8228574
I suppose that in most of Europe and us someone will knock you door asking why are you launching missiles

>>8228579
dude dont worry about it

But what I meant was just build the engine, not the entire rocket.

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>>8228574
>>8228579
Just wear a turban OP, and they'll leave you alone because it will be racist to follow it up.

>>8228579
EU has much denser air traffic then US and no fucking deserts where nobody lives. They would not ask why are you launching missiles, they would put you in jail. Maybe at a court they'd do some asking, but I wouln't bet on it...
>>8228574
>working bypropellant engine
what constitutes as working? Providing thrust? Having a usable T/W ratio or ISP? Being able to actually push a rocket somewhere?
Hybrids are reasonably easy even for working rockets. High-school doable, but you'll be using DIY stuff for high pressure. Fuck up and you can loose limbs or die.

Liquid fuel engines can be done, but mostly as working showpieces. Usable engines absolutely require a very well equipped machine shop and knowledge on what the fuck you are doing.
Liquid fuel engines also have a bad habit of exploding when startup or shutdown doesn't work right, and I don't mean just a lame fireball, actual detonations can occur.
Probably not a good idea for a high-school project.
Stick to solids and hybrids, lots of fun can be had.

>>8228574
llegal isssue is most problem

>>8228893
Yeah, regulatory issues are 99+% of the difficulty of flying a large liquid-fueled rocket. Copenhagen Suborbitals has numerous professional engineers volunteering.

However, this only applies to actually flying a liquid-fuelled rocket. In most places, there's little reason you can't build a rocket engine to test on the ground, if you've got a safe place to test it. Particularly as students doing it for educational purposes.

And if you want to launch a small liquid fuelled rocket, this is usually allowed as a form of hobby rocketry.

Get in contact with your local rocketry clubs. Odds are they'll know somebody working in the "experimental" category, who can tell you what you're allowed to do and what hoops you've got to jump through to be allowed to do it.

Note as well that Copenhagen Suborbitals has never managed to launch a rocket above the cruise altitude of airliners.

>>8228885
Working as in, yeah, providing thrust. But I am interested in starting with hybrids as they aren't as prone to hard starts compared to liquid engines. I will look into potential hybrid propellants later.
>>8229082
Thanks for the info dude. I'll try to find a rocketry club around my city when I get the chance.

Now I just need a starting point (e.g know the math, mass flows, etc.)

>>8229082
>Note as well that Copenhagen Suborbitals has never managed to launch a rocket above the cruise altitude of airliners.
uh huh but you still insist regulations are 99% of the problem?

>>8229881
It's not like they're completely free to build whatever they want and try it out whenever they please, and it's not like they're part of a community of hobbyists all free to experiment and share their experience.

They have to explain what they're doing in detail and apply for special permission for each launch. If there's an element of the design that officials don't like, they can't use it.

They're getting permission because they're being so conservative and uncreative. They're failing to make rockets that go to space for the same reasons.

>>8228574
It would probably be illegal, I don't know how a normal high school could afford, let alone obtain the rocket fuel used by most commercial and government space agencies use in their technologies. I don't see a few high schoolers getting hydrazine at the local hardware store.

>>8230154
Hydrazine is mainly used as a monopropellant for spacecraft. Its more stable chemical cousin, UDMH, is used for some launch vehicles with NTO, but this is inferior in performance to combinations such as kerosene with liquid oxygen.

Anyway, hydrazine's a fuel and suitable fuels for rockets aren't hard to come by. Gasoline, diesel, turpentine, acetone, alcohol... all sorts of commonly-available materials are perfectly suitable rocket propellants, with only minor performance and handling differences between them. Kerosene is favored for large orbital rockets for its high density among hydrocarbons, easy handling characteristics, and availability in large quantities due to being used as jet fuel (although slightly different grades are special-ordered from the refineries).

Nitrous oxide is a perfectly suitable rocket oxidizer, and is particularly well-suited to simple pressure-fed designs. Nitrous/rubber hybrid rockets are reasonably popular with hobbyists. Nitrous/propane liquid biprop is also straightforward.

Another relatively accessible rocket oxidizer is hydrogen peroxide, which has the advantage that you can dilute it to reduce the combustion chamber temperature, although this can also be achieved on the fuel side if you choose an alcohol, and of course it reduces performance.

NTO is simple to produce from common off-the-shelf fertilizers and acids, and thus probably the most readily available and affordable to acquire, though somewhat dangerous to work with (and to produce, though if you can't handle that, you have no business working with it), due to its extreme toxicity. One good lungful over an open container is plenty to kill a man. Other than that, it's quite nice, being liquid at room temperature, essentially non-corrosive, incapable of self-detonation, and hypergolic with hydrazine and its derivatives.

Nitrous is probably the most suitable for hobbyists.

>>8228574
Just want to mention.. A rocket is a long, controlled, explosion.

Illegal, yes, definitely, illegal, in Europe, get permission.

"ordinary high schoolers" do not
construct liquid bi-pro rocket engines.
Even the extraordinary high-schoolers
(e.g. Homer Hickam) constructed
solid-prop engines, and those were
rather low-performance.

Fuck off you fucking dumbass underage faggot
No you won't build a fucking liquid fueled rocket with your retarded friend
Stick to water rocketery or kill yourself

As others have said, the kind of heat and pressures you will be working with will be extremely dangerous to anyone - never mind high schoolers. I would strongly advise against building it, unless you could get people who really know what they are doing to check calculations and the standard of what is actually built, etc.

If you are interested, there's a neat little book which might whet your appetite for rocket design called "How to Design, Build and Test Small Liquid-Fuel Rocket engines" by Rocketlab, which you should be able to find for free online. This guides you through some _very_ simplified design considerations, but should be enough for you to begin to appreciate how finicky and dangerous producing a 'useful' motor is. Furthermore it also contains a step by step example for a gasoline/Gaseous Ox motor, really driving home the importance of cooling even for very short burns.

After that, maybe consult "Rocket Propulsion Elements" by Biblarz, which begins to really examine design in a stricter sense.

I'm guessing you're in the US, but if not please check local regulations regarding building solid fuel motors if you go down that route. In the UK, for example, building solid fuel motors yourself would most likely be illegal under various laws, dating back to the 1800's.

Just stay safe, this stuff has the potential to go very wrong.

>>8230532
Thanks man, I found the Rocketlab book awhile back before I made this thread, but I'll read the Biblarz book later.
I also understand that rockets have the potential to explode, so I started researching fuel that doesn't need to be kept at a cold temperature/doesn't need pressure.
As >>8230208 said, I will probably use ethanol-nitrous or paraffin wax-nitrous as my propellants.

>>8230259
O, k, a, y