Hybrid Rocket Engine Model

I have chosen to remove the contents of this instructable as I no longer consider projects like this to be safe and informative.

Supplies

A real rocket engine requires components that are not easily purchased or manufactured at home. The materials used for this project are not recommended for use in any high-temperature environment.

Step 1:

Please use caution, safety, and common sense when working with rockets. Do not attempt to build your own engine unless you have appropriate training and experience.

Comments

[jplasalle26]

Hi, so I am wondering how you connected the oxygen tank to the tube

[elliott.kim]

If I may ask, how long does this burn for when using the whole oxygen tank?

[pat_pending]

Nice Instructable mate. Agree with the comments about thrust but you mentioned this was a model of a hybrid engine and not something 'flight ready'. If you do want to make a flying rocket, the R-Candy solid fuel that Grant Thompson (A.K.A the king of random) makes works well and is pretty safe using the safety precautions you are taking already. Regarding the 'danger' of what you're doing: at school the teacher would use liquid oxygen and dip a biscuit in it then touch it with a long match/splint. This thing would explode with a wild bang! Guess things weren't dangerous in the 80s. It's a small wonder the human race survived at all :-) . Keep making. Stay safe

[LabRatMatt]

I've flown solid fuel rockets many times before, and I've seen Grant's video on the topic, but I find other forms of propulsion fascinating. Yes, oxygen is dangerous. I cannot legally obtain liquid oxygen though, so I won't be doing anything crazy like that.

"Guess things weren't dangerous in the 80s" is probably the best single sentence I've read in this entire comments section.

[Tecwyn Twmffat]

Obviously safety is an issue here, but what happened with your math grades? Could I use my annual tax return as rocket fuel as an effective tax avoidance scheme?

[LabRatMatt]

Hahaha, the math homework had already been graded, and my grades in math were rather high. My math teacher however, had a tendency to assign a series of long and redundant math problems for homework, giving me a special hatred for the long and redundant problems. I had long joked about hosting a burn party with classmates who shared my views on the assignments, but I decided to destroy the papers with a little more flare instead. 0

I do not endorse any tax avoidance schemes, but that would certainly work as fuel.

[bpark1000]

You need to ignite the engine at the end where you inject the oxygen (could be done with electric igniter inserted all the way in). The "rocket's" success isn't verified unless you measure its thrust-time product.

Be careful, the pipe could explode! You should have secondary containment.

Be careful

[LabRatMatt]

Thanks for the information. It's highly unlikely that it will explode as it cannot build enough pressure to damage the steel, but thanks for the concern. I will re-evaluate that before testing any other types of fuels.

[jdbwizzard]

For a further safety concern you could use a remote rocket launch system to ignite an ematch. I build solid rocket engines and this is how a test fire them so I can be in a safe place while I light them. Good information though.

[LabRatMatt]

I'm thinking of building a much safer ignition system in the future. Using a match wasn't the best idea.

[Tesla_Shock]

Watch Grant Thompson's video on how to make liquid Oxygen and Nitrogen. Combine the two as Oxidant and Combustible, and you get the most efficient rocket that has been (publicly) created to date! If you're feeling a little dumped with liquid Nitrogen, try Alcohol ( 90% or higher is preferable) or Kerosene, like the Germans and Werner Van Braun in WW2. Just be prepared for your contraption to belch black smoke. If you have no idea who Van Braun is, go check him out! You'll be surprised. I'd leave liquid oxygen in the mix, unless you're in the states, because Oxidizers are hare to find. The most popular oxidizer variants to Liquid Oxygen are Hydrogen Peroxide, but for that you need 80% or more and is virtually impossible to find without having a lot of contacts in the chemical industry, or making it yourself, or Potassium Permanganate, which isn't really sold outside of the states (I lived in the states for a looooong time and did this stuff a lot but then I moved to the EU where EVERYTHING IS GOD DAMNED CONTROLLED FOR THE SLIGHTEST POSSIBILITY OF EXPLOSION! AAAARGH!) Anyway, good luck and hit me up if you have any other questions!

[thormj]

Just be really careful with Tesla_Shock's answer... if you mix LOX with some things, it burns really well. If you mix LOX with other things (eg but not limited to, Alchohols), you have an pipe bomb instead of a rocket motor because the flame front is too fast to get out of the nozzle... and it can be unsafe/unstable for -hours-.

Find a Tripoli / NAR club, look up and understand flame fronts and grain designs, and start understanding how a rocket nozzle works and why it is important. Unintended consequences can go from pipe-bombs (why you should use a remote igniter and have a safety shied around the test stand) to 300 feet horizontal launch, lighting a huge fire, and even to more oh-crap-moments.

But a great launch is beautiful to behold. Best of luck and *be safe*!

[LabRatMatt]

I wrote a school paper on Van Braun a while back! I plan on keeping this project a little more simple, as I don't have enough chemistry experience to attempt anything with fancier oxidizers, but I know someone who does. I also live near the east coast of the US, so liquid oxygen is hard to come by. I might eventually get around to some more complex experiments but not until much later. Thanks for the info!

[MichaelAtOz]

I'd suggest a blowback preventer/flashback arrester/whatEvaYaCallIt

https://en.wikipedia.org/w/index.php?title=Flashba...

Particularly if you go to more potent fuels.

[LabRatMatt]

thanks for the link! I will look into that for future tests

[Michal Choma]

nice,

[BudD3]

Experiment.

This is not a "rocket" engine. This is nothing more than a dangerous experiment.

GWR1 said it all. He told it like it is.

[PaulA23]

Research. This is nothing more than someone researching the physics of what makes a rocket work, and is no more dangerous than a "real" model rocket. There isn't any "telling it like it is" because the OP has already REPEATEDLY noted the dangerous nature of the project, as well as the valuable lessons learned. Whatever happened to experimentation and (God forbid) helping, thereby increasing knowledge for all who stumble across the information?

[LabRatMatt]

Yes, this project is dangerous. Fire always is. But this is still a fully functional model of a hybrid rocket engine not unlike those used on suborbital spacecraft (though suborbital spacecraft engines are not usually made from hardware store materials). There appears to be an argument brewing over the safety of this particular project and the nature of dangerous projects on Instructables. I took lots of off-camera precautions and did much research before I even started this project. I knew the risks and how to mitigate them, and I just hoped to share the project and my experiences with this community.

[AlphaOmega1]

Nobody has to make your prototype hybrid rocket engine (which it clearly is). We live in an age (as mentioned above) where nobody wants to take responsibility for their own actions, yet happy to stand around waving their 'holier than thou' flags with no personal cost; yet it gives them (they assume) the moral high-ground. They are usually the ones that never achieve anything. Anyone can point after the event.

I say top marks for your design and planning. You could easily have spent twice as long writing a RA, and yet nobody was hurt despite that! Joining a rocketry club is probably a good idea (although I could just as easily give many reasons for that not being a good idea - you'll be near other people with rockets for one!)

I'm keen on extreme sports, and as a kid blew stuff up with my own explosives (chemistry is fun!), even made my own bullets using casings from a fun fair. Launched Greek fire balls from a home-made Roman catapult, blasted around on motorbikes (of course), taught myself to repel off of railway bridges, on and on! Why am I here in one piece all this time later? I think about and understand the dangers, and don't trust my life to other people.

I have to post a letter in a moment, I don't have a RA, but either way, I could die getting to the post box - such is life.

Live life, be safe and don't be put off.