Help Designing a Rocket

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Johnnycakes581

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Hello fellow people, I am planning my own rocket design since I have owned one model rocket and built my own off of the model one. My home built one flew the best out of all of them although all of them the parachutes did not deploy. I have been thinking about designing my own liquid fuel rocket so that I can reuse it and not buy the little solid rocket fuel engines by using methyl alcohol as the fuel and Potassium Nitrate, KNO3, as my oxidizer since I found out that you can it is found in high concentrations in stump remover. I few things that I am a little iffy on such as:

  1. [*=1]How do you store and pump the fuel to the reaction chamber? Along with this I was wondering what the fuel ratio would be, I read somewhere that is was 1.2 oxidizer
    [*=1]Is there any more common oxidizers or fuel that work better and are easier to find?
    [*=1]Is there some common dimensions that work great, because I was thinking about 2 inches by 28 inches without nose cone which will be about 4 inches?
    [*=1]Would aluminium be able to contain the reaction of the fuel?
    [*=1]For the exhaust, how wide should it be in proportions to the rest of the rocket?
 
We cannot discuss motor formulas in the open forum. If you are from the US, 18 or older, and L2 certified, you can have access to the research forum, where you can discuss these to your heart's content. I will answer what I can though.

First off, we tend to stay away from liquid fuel motors. They are extremely heavy for their thrust. If you want bigger motors, depending on what country you are from, you can use Aerotech and Cesaroni motors. They have a whole lot more bang for the buck.


The rest of your questions are "it depends". There is no answer we can give without knowing details. Which, you cannot post details in the open forum. :)


Continue to ask questions though, and we will attempt to answer them. If you post a bit more info about yourself (age, experience, general location), we can hook you up with a club where you can get more experience.


Welcome to the forum!!

Matt
 
Hello fellow people, I am planning my own rocket design since I have owned one model rocket and built my own off of the model one. My home built one flew the best out of all of them although all of them the parachutes did not deploy. I have been thinking about designing my own liquid fuel rocket so that I can reuse it and not buy the little solid rocket fuel engines by using methyl alcohol as the fuel and Potassium Nitrate, KNO3, as my oxidizer since I found out that you can it is found in high concentrations in stump remover. I few things that I am a little iffy on such as:

  1. [*=1]How do you store and pump the fuel to the reaction chamber? Along with this I was wondering what the fuel ratio would be, I read somewhere that is was 1.2 oxidizer
    [*=1]Is there any more common oxidizers or fuel that work better and are easier to find?
    [*=1]Is there some common dimensions that work great, because I was thinking about 2 inches by 28 inches without nose cone which will be about 4 inches?
    [*=1]Would aluminium be able to contain the reaction of the fuel?
    [*=1]For the exhaust, how wide should it be in proportions to the rest of the rocket?
First, welcome to TRF, the largest rocketry forum on the web.

Making rocket motors is dangerous, and if your do not understand what you are doing, and how to do it, you will get hurt. From your post it's clear that you don't know what you don't know, and this is the reason why we do not permit discussions on how to make your own rocket motors on the public forum. Please read https://www.rocketryforum.com/showt...eur-Rocket-Motors-belong-in-the-Reseach-Forum

Stick around and learn how to build and launch model rocket using commercial certified rocket motors. Find a local rocket club and find a mentor. Join NAR or TRA (whatever the local club is affiliated with), and after you have build and flown a few model rocket, look into the Junior High Power participation programs. Once you become 18, you will have learned enough so once you get your Level 2 certification, you can make your own motors under TRA Research rocketry. As you are in CA there are additional state requirements.

Bob Krech, TRA Research Forum Administrator
 
Getting your parachutes to deploy would be a good next step..
 
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I have been thinking about designing my own liquid fuel rocket so that I can reuse it

I hate to throw a wet blanket, but the chances of re-using an amateur-designed liquid fuel rocket is pretty much nil. After you blow up a few dozen (along with the rockets they power), you might get to reusability. The motor is the smallest and cheapest part of the rocket. Use something commercial until you really know better.

As an aside, I met one of the NASA propulsion section leads over the summer. He mentioned that he regularly gets requests to help with liquid fuel rocket designs. He always turns them down because he doesn't trust the safety of liquid fuel in amateur hands. If the professionals who do this for a living don't trust it, you shouldn't either.
 
Welcome to the forums, Johnny!


As Blackbrandt and Bob said, I would highly disregard starting from scratch using anything but a certified solid motor rocket. I know from experience that working with chemicals like potassium nitrate or potassium chlorate can be very risky. First of all, using potassium nitrate to create rocket fuel or "rocket candy" is extremely dangerous because you have to melt your ingredients, which poses risk for explosions. If you were going to use or make liquid fuel, it would be highly inefficient and useless since you are working with a small rocket. Not to mention, the fuel would weigh way too much and it would be quite the challenge if it was not possible to fit a liquid motor and all it's components in your rocket. For a rocket your size you wouldn't be using very thick aluminum, and I could guess that it couldn't take the heat a liquid fuel would be giving off. Keep in mind, liquid fuel burns in much higher temperatures and is a lot less controllable than a solid fuel.

If you are new to the hobby, I really suggest starting with a low to mid power rocket. A great rocket I recommend is the Estes Mosquito, then you can learn the basic fundamentals of constructing rockets, and you can get into scratch building rockets, which I assume you enjoy.
 
Find a local rocket club and find a mentor. Join NAR or TRA (whatever the local club is affiliated with), and after you have build and flown a few model rocket, look into the Junior High Power participation programs. Once you become 18, you will have learned enough so once you get your Level 2 certification, you can make your own motors under TRA Research rocketry. As you are in CA there are additional state requirements.

Bob Krech, TRA Research Forum Administrator

As he said, another great idea would be to join a NAR or Tripoli affiliated club.
 
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