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Small liquid rocket engine

  1. May 14, 2004 #1
    Me and my friend are planning to build a rocket for our exam project. We're pretty sure going to use some kind of solid fuel, black powder most likley. It's gonna bee great. :biggrin:

    Now, my question is, do anybody know if there is someone who have built and flown a small liquid rocket engine on a amateur basis? I would very much like to know.

  2. jcsd
  3. May 15, 2004 #2


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    Uh... be careful.

    I don't think you've thought it through if you want to use black powder for a class project's rocket fuel. You're not going to be able to control the burn with powder. You're most likely just going to get a bang and a tuft of smoke on the launch pad. I would contact a local amateur rocketry group and find out where you can get an amateur rocket's solid fuel grain for your use. Those are designed to burn properly, and all you really need is to ensure that the casing can withstand the chamber pressure without bursting.

    As for liquids, I'm sure there are some amateurs who have built them. Do keep in mind, that I use the term amateur lightly. Most to all are most likely aerospace engineers who build stuff outside of the office on the weekends. To get a liquid rocket to work you need to work with dangerous fuels under pressure. You need many seperate components, all of which need to work together perfectly. If they don't, you've got a bomb.
    Last edited: May 15, 2004
  4. May 15, 2004 #3
    Well, yeah I know. Anyway the project is just at the idea state and I'we just started reading about it. We're surley going to buy and test a number of prefabricated engines before trying to build one ourselves. We've started making contacts with amateur rocketeers and also planning to make a trip to a rocket launch facility.

    As for the black powder, I found that a blend of sucrose and KNO3 is commonly used in the industry and by experimental rocketeers, and that is most likley what we're going to use too, allthough we haven't done any proper research yet. The project won't start before summer is over anyway. We won't do anything until we're perfectly sure what we're dealing with.

    And don't worry, I won't try to build a liquid fuel rocket engine. I realize I should be very pleased to get anything flying.

    It's just that I'm just curious. Liquids seem so damn complicated, and it would be great to talk to somone who have built one.

    Thanks for replying.
  5. May 15, 2004 #4


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    You are allowed to make the one you want, but please, do not aim at my window!.

    God bless your neighbours.... :rofl:
  6. May 15, 2004 #5
    When I was a chemistry student one of our lecturers had a thermos flask
    with liquid rocket fuel in it! A spark from an overhead projector ignited some ether vapour that had leaked out of the flask and the flask exploded leaving half the class in tears! Liquid Rocket fuel is deadly - stay away from it.
  7. May 16, 2004 #6

    Well put a red light or something in your window so i can see which one is yours and I'll try missing it :biggrin:
    I guess I won't bee that popular in the neighbourhood after this... well at least not among the neighbours older than twelwe years. :smile:


    Ouch that sounds nasty. Did anyone get hurt?
  8. May 16, 2004 #7
    Ouch that sounds nasty. Did anyone get hurt?

    Only psychologically! I ducked under the table I was sitting at.
    The professor's lecture notes were burnt to a cinder and he was lucky he wasn't too!
  9. May 17, 2004 #8
    Oh. I'm glad I haven't had to go through anything like that... allthough I probably will now that I'm going to start building rockets...
  10. May 17, 2004 #9
    First off, don’t try to make your own rocket fuel unless you have some know-how. It’s dangerous and as the handbook of model rocketry states: “A lot of people have been hurt trying to develop a safe rocket fuel.” Or something to that effect. You should read that book before doing anything with model rocketry.

    Anyway, if you DO decide to make your own fuel, unless you have some experience (grade 11 chemistry doesn’t count :smile: ), find a reliable source and recipe for it. Follow all directions exactly.

    As for liquid fuel, this is much trickier to do than solid fuel and requires a lot more tinkering. I’ve heard of concentrated hydrogen peroxide after being passed through a silver ‘screen’ being used as a good fuel, but I’m not sure. Anyone ever read about this?

    Anyway, what class is the project for?
  11. May 17, 2004 #10


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    Yes. pretty low performance, but it's "green".

    Better than a cold gas thruster I guess...
  12. May 18, 2004 #11
    Well, I've had all chemistry I could have in my school, and I got a pretty good grade, allthough it is not the best possible.

    I can't say that I've had any experience with rocket fuels, and any suggestions on what to read would be great... any recommendations?

    Cheers /j.
  13. May 18, 2004 #12
    Hello salamander!
    Here you can order blueprints of liquid rockets or even a whole rocket:
    Take it easy though!

    what will be the goal with your little rocket projet?
    Last edited: May 18, 2004
  14. May 18, 2004 #13
    Wow! For about a year I have been researching( a dreaded word) liquid propelled rockets. I am going to attempt to build one. Basically it is a monopropellent- hydrogen peroxide- with the fuel tank pressurized with n2. Solenoid valves control fuel as it passes through system. There is a pyro ignitor on combust chamber which is fitted with fuel injector-(modified from a car). I have some cad drawings- but their not very clear. Here are some sites I've collected. http://users.cybercity.dk/~dko7904/motor.htm
    But the best stuff is in the books. There are two manuals out there- 1)Design of Liquid Propellant Rocket Engines
    2) Rocket Propulsion Elements
    -Rod Aspera
    Last edited by a moderator: Apr 20, 2017
  15. May 18, 2004 #14
    I think my favourite liquid fuel is water. Well, really compressed air and water. I used to make pretty impressive launches with 2 litre pop bottles and an air compressor. Hours of fun for a fraction of the price of chemical rockets. I’m sure many of you have built these as kids. Have any of you managed to build a multistage water rocket? I’ve seen a few plans and videos of them and they’re pretty neat. Never did make one myself though. Maybe that should be my goal over the summer, try to set an altitude record with a water rocket... hmmm…
  16. May 18, 2004 #15


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    Going by memory from reading done decades ago, the Mercury spacecraft, and maybe Gemini as well, ran the peroxide through a silver wire mesh in the attitude thrusters. The Germans powered a small fighter aircraft rocket (called the Walther, I think), and also they powered the V-2 rocket's turbopump, with peroxide run through a basket of potassium permanganate.

    Concentrated hydrogen peroxide has to be stored and handled carefully. It definitely can explode.
    Last edited: May 19, 2004
  17. May 20, 2004 #16
    I build small rockets, and my advice is not to try your own fuels and motors untill you have worked with pre-fabricated ones.

    And try not to set anything on fire like I have. ;)

  18. May 23, 2004 #17
    Well cheers fellows, lots of stuff to look at, I've been away over the weekend and haven't checked in latley... and I'll look into this as soon as i find time :rofl:


    The purpose of the project is to learn as much as possibly about rockets. We will start of very basic with classic bottle-rockets, moving to model rockets. We also have a ludicrously dangerous idea involving a pressure safe waterfilled steel pipe, a blowtorch, a launch stand, release mechanism and a hell of a safety distance. :biggrin:
    Eventually, we will have learned enough to build a rocket engine, which we will test as well on ground as in flight. We will mainly study nozzle performance.
    Doing this we will:

    A: have a lot of fun.
    B: gain valuable insight in the theoretical and practical aspects of rocket science.

    And possibly:
    C: impress our physics theacher.

    And if none of the above:
    D: descide we'll stay on Terra Firma, saving the world a number of holes in the head.

    perhaps, we will also print t-shirts and sell to "finance" the project.
    Anyone interested?


    THAT IS SO BLOODY COOL! :surprise:
    Good luck and may the Lord have mercy on your extremities :wink:
    Anyway, is your rocket going to fly or will it be sort of like a static demonstration engine?
    I guess it's pretty expensive finding materials and proper parts? How big a engine are you going to build?
    I'd love to see how it turns out, please tell me more.

    About the books, I'm not going to build a liquid (at least not this time) so the I'll leave the first book for now. As for the second, Elements of Rocket Propulsion, I was pretty close buyng that a couple of weeks ago. I descided not to however scince I prefer books with metric units... is there an european edition of this book? If not, is there some other books?

    What the heck, I'll probably buy the book anyway but it would be a lot easier.


    Yea water is nice and harmless. I'we built a primitive bottle launch stand and also boosted a bottle with sodiumcarbonate. It flew. Not as much as wanted it though, I'll work on it this summer. Two stages? I'd love to see that :biggrin:

    Anyway, thanks dudes, you're beeing a great help! Keep posting, please!
  19. May 25, 2004 #18
    for a liquid propelent, back in high school we would had bottle races where we would take a bottle put 3/4 water and food color of your choice and a handful of pieces of dry ice. these bottles had pipe clamps and a loop that a piece of string went throught so it would go strait and not harm anyone. there would be a stopper in a hole in the top with a string in it and you pull out the stopper for an awsome sight. we would do this on the football feild and it would go the distance and slam into the goal post at the other end. this is just a thought on your experiment. i sounds a lot safer than mixing up violent chems. i like all my fingers and arms and nonburned skin.
    later :surprise:
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