Oxyhydrogen Water Rocket

[cmwslw] built a soda-bottle water rocket that uses the ignition of oxyhydrogen gas to quickly expel the water, as opposed to the usual compressed air and water mixture. His project contains excellent documentation with photos and it builds on other articles he’s written about generating the flammable HHO gas used to launch his craft into the skies. Every aspect of this project uses items most of us have at home or could score cheaply at most hardware stores.

We love seeing projects that re-purpose everyday materials into something fun. Just be sure to dodge the missile pop bottle as it speeds back to Earth!

37 thoughts on “Oxyhydrogen Water Rocket

  1. HHO is the perfect mixture of gas for ignition/explosion. It is no longer the compound H20 as it has been broken into its gas form, I presume by using electrolysis. At least that’s what I remember from Chem 101

  2. Not sure if HHO is just mixing Hydrogen and Oxygen (because the site is down right now) but be extremely careful. Hydrogen mixed with Oxygen wants to explode and does not need much help getting started.

  3. The gas formula is 2H² + O². Forget about Brown, that guy use to promote idea that violate thermodynamic laws. But the idea of running an engine on that gas only could be nice. Wonder if there’s any conversion that has been done. Hydrogen mechanical engines require a hell of a compression ratio.

  4. I’m doing all I can to try to revive this poor, abused server. I thought it could handle the load but obviously not. And I agree HHO is not the correct since hydrogen and oxygen are both diatomics and their natural state is H2 and O2. Nevertheless, HHO is by far the most common term.

  5. In HS chemistry, we inadvertently did this, by accidentally bumping the collecting tube. (an inverted test-tube, with electrodeds, immersed in water. One electrode was generating oxygen, the other was generating hydrogen, which bubbled up, and collected into two inverted tubes.

    One of the students lifted the hydrogen-gas containing tube, and accidentally lifted the electrode above the surface of the water with the tube. The electrode was a wire coiled around a graphite rod, and it was loose enough that as the rim of the tube bumped it, in the open air, there was a spark. (we assume, after the fact). The spark ignited the air-hydrogen mix, (the oxygen was isolated in a separate tube with the other electrode; and was left behind, fine) – and instead of exploding the tube, it launched it upward, straight out of the student’s hand, at about a 45 degree angle, out of the opening of the vent hood, through the suspended ceiling, (making a neat, round hole), and shattering somewhere above, against the steel roof of the building.

    It was the kind of thing that kept us attentive in class. :)

  6. i nearly incinerated my thumb making this once, using aluminium in a surplus bottle.
    Tried to ignite it with a gas igniter, and expected a small pop. Bad move, resultant flame reached 2 feet and was hot enough to deform the bottle as well as serious burn requiring a week to heal.

    Needless to say be very, VERY careful and assume it will blow up in your face, take precautions associated with high explosives such as full face shield, gauntlets etc.

  7. I experimented with “HHO” systems for about 2 years. I set it to the side because it was a lot of upkeep. Using baking soda as the electrolyte was cheap, but required constant flushing of the system. Throughout the life of my best system, I improved the fuel consumption of my truck by an additional 1.8 mpg for that time of year. No laws of thermodynamics were violated. Gasoline engines are horribly inefficient. The additional 2H2 + O2 simply allows the gasoline to combust more completely, while cutting a few weeks off of the life of the battery.

  8. I can’t remember where I saw the video, but it showed a launch using a 5 gallon filled with hydrogen + oxygen. I think it was able to lift a respectably sized pumpkin up far enough to smash itself when it came down. I think there was also a clip of the 5 gallon container exploding.

  9. Once again this may be a drunken rambling post, but chemistry is my forte and I absolutely ABHOR the the use of “HHO” – The term is NEVER used correctly and most idiots that use it are simply crossing their fingers hoping they can break the laws of thermodynamics. You know, the basic laws of the universe only apply to those who believe in them…

    First, after reading (skimming, actually) aformentioned site, it appears that he’s pressurizing the headspace of the rocket with “HHO” gas instead of the normal compressed air. I’m not about to do the math (or research his setuup for that matter, if you have any knowledge of electrochemistry you’d realize it’s practically irrelevant in this situation)… But, here’s a few numbers for ya – The average 2-liter is rated to 150 psi, 1-liters and 20-ouncers can take a bit more. You can charge to this level a few times before stress cracks are evident. Normally, a water rocket would push 100-120 psi to get maximal loading while staying within the safety margins. Based on his timing, I’d estimate that he isn’t hitting 10% of capacity, likely far lower.

    …Second, IF he was using any respectable amount of “HHO” (which he obviously isn’t, as will follow) the result would be quite a spectacular explosion – These overunity dipshits need to look up the concept of stoichiometry – IE, there is a perfect balance for any reaction that is mathematically derivable – with “HHO” it is 2H2 + O2 -> 2H2O… Flip it around and you have the results of electrolysis, minus conversion and efficiency losses…Just cause it’s impressive doesn’t mean you’re getting anything useful. I’m going to skip a few points, but the basic gist of it is that IT DIDN’T EXPLODE – meaning, that, his perfectly balanced explosive propellant mixture didn’t really do much more than regular air would have. Simple math, providing he did it “right” – 150/14 (14 psi being standard atmospheric pressure) = ~10, which is roughly equivalent to compressing a full volume of “HHO” into 10 percent of its normal volume… Go out and fill a 2-liter with “HHO” and (with all proper safety precautions) ignite it – I can absolutely guarantee you that it won’t take off like a rocket, at least not in one piece…

    This is getting a bit LONG, but a few more points…

    YOU ARE NOT PRODUCINT “HHO” – you are producing a normal, stoichiometric mixture of hydrogen and oxygen. 2H2O (simplified) -> 2H2 +O2. Regardless of whether or not you have an undivided or divided cell, your result will be DIATOMIC hydrogen and DIATOMIC oxygen. There is nothing special about it – The energy obtained from the combustion of a balanced mixture (which is what you get) is the same as what was used to produce it…However, in reality, it ain’t perfect – the conversion loss in your electronics and efficency loss in your electrolysis setup will ALWAYS put you at a net loss – There is some inetersting research coming out (cobalt spinel electrodes, IIRC), but you’ll NEVER hit 100%, let alone anything that would provide worthwhile in terms of energy system conversion.

    …”HHO” DOES exist, just not in the way that the Browns Gas crowd would like to believe. Google the “atomic hydrogen torch” – Atomic hydrogen welding has been known for quite some time, but it has nothing to do with browns gas (and you “true believers” are hopelessly deluded)… In summary, YES, you CAN produce atomic hydrogen, burn it, and get MORE energy than usual from an electrolytic system – HOWEVER, it isn’t magic – The extra energy obtained is pumped in via the high-voltage ionization of the hydrogen stream – In essence, you pump more energy into the system for the net gain of a hotter flame at the output – It IS NOT MAGIC, but to those who do not understand (or simply don’t want to understand) the barebones basic laws of the universe, it appears as such.

    …Finally, to those who wholeheartedly believe in the utility of your brown’s gas generator in your car, a more worthwhile investment would be an odb-2 interface… I have a theory that the only thing you’re doing is tricking your oxygen sensors (likely upstream, as it shouldn’t change anything downstream)… Here’s what I want to see – Has anyone tested their horsepower gain/loss? Has anyone tested said system on an old-ass, non-electronic, carbureted car or brick-shithouse diesel? Admittedly, I haven’t done all that much research into this fad, but knowing the basics of energy in DOES NOT EQUAL OR UNDERRUN energy out basis of literally every system used on the face of the planet, there has got to be SOMETHING else going on here… It ain’t as simple as the free energy crowd is trying to get us to believe, but I don’t have ALL of the answers…I do, however, know enough to call the “HHO” fad absolute bullshit, or, failing that, useful minds that are hopelessly misdirected….

  10. interesting..
    on a side note, does anyone happen to know why a mira moderna would randomly lose power and stall?
    it works fine 99.9% of the time, but the symptoms are like fuel starvation yet it recovers fine if left for 2 mins with engine off.

    i’m thinking ecu here = $$$ but if anyone has any other ideas post here…

  11. Hmm. Lurker has a long and rambling post. I _think_ he’s saying that the overpressure from a hydrogen/oxygen reaction is too brief to harness – the rocket will just explode, or do nothing. Once the heat of reaction dissipates, the Ideal Gas Law says that the pressure should be slightly lower than before.

    I think he underestimates the breaking strength of a coke bottle. Those things can handle better than 500psi before bursting – if you’re lucky, of course. And the heat of reaction shouldn’t dissipate that fast.

    As for the whole brown’s gas in the car thing, anybody who runs a mix of hydrogen and oxygen into their engine deserves the explosion that is likely to follow.

  12. Adding diatomic hydrogen and oxygen to the combustion process of an internal combustion engine will, in fact, increase the efficiency of its operation. It is not magic, and it is not “over unity.”

    Let’s look at it this way: if a cheesy website offered cans of a magic solution that, when placed inside your tires, improved your gas mileage, no one would buy it. But we all know that if you keep your tires properly inflated with air, your gas mileage is improved. It’s not magic. It’s not free energy. By increasing the tire pressure, you simply decrease the contact surface area between the tire and the road, thereby decreasing friction, which allows more energy from the gasoline combustion to be directed toward the desired result – forward motion. Simply minimizing the losses.

    Example 2: Adding a tonneau cover to the bed of a pickup will improve gas mileage. What? You mean that piece of fabric that just sits there is magically adding energy to your truck? Free energy? Nope, just cutting your losses by decreasing drag, meaning that more of the energy produced by fuel combusion in going toward motion.

    Example 3: Adding Peltier devices to your vehicle exhaust/engine compartmnent to improve your alternator and battery life. Free energy? Nope, just taking a small amount of the energy lost as heat and putting it back toward something useful.

    As I stated before, gasoline engines are terribly inefficient, generally in the 20-25% efficiency range. A large part of the reason we need catalytic converters on our vehicles is because of the unburnt fuel spewing out of the engine with the exhaust.

    Oxyhydrogen fuel systems require some energy from the vehicle, and LESS ENERGY IS PRODUCED from its combustion, when viewed as a closed system. However, hydrogen and oxygen that would not ordinarily combust (since a perfect stoichiometric reaction is impossible to attain) is combusted with the fuel/air mixture, allowing the fuel/air mixture to burn MORE COMPLETELY. This results in a lower fuel-to-oxygen ratio entering the catalytic converter, which is why on some vehicles it is necessary to alter the O2 sensors, so that the ECM does not negate the process by calling for more fuel.

    This is why the energy consumption/production of “HHO” systems must take into account the entire vehicle as a whole. To not do this would be the same as analyzing the energy extracted from the vehicle’s battery over the lifetime of the battery, compared to the energy it can contain, without accounting for the energy extracted from gasoline combustion to put energy back in. The system must be viewed as a whole.

  13. In college chemistry class the teacher had a balloon filled with hydrogen which he lit to get our attention. It went up in a ball of flame and made an extended sound.

    He then lit a balloon filled with a mixture of hydrogen and oxygen to teach us the danger of mixing the two. The balloon went off in a flash and sounded like a gun shot.

    Much more force was created with the mixture than if the two were separated. Very dangerous mixture.

  14. @steve eh: That’s a really neat idea! Hairspray is expensive and polluting.
    @lurker: I’m baffled by the fact that you would write such a long criticism with a fundamentally wrong understanding of how my rocket works. You claim that I am pressurizing the rocket with oxyhydrogen and using the pressure to launch it. In reality, the added oxyhydrogen is under normal atmospheric pressure and it’s ignition produces the needed pressure. About the nomenclature of oxyhydrogen: read the note at the freakin’ top of the article! Also, not once in my guide did I claim > 100% efficiency.
    @asheets: Actually there is an excuse: The rocket is a plastic bottle that travels 200ft into the air and falls! Not gonna kill anyone on the way down.
    @Jake: I don’t know where you’re getting the idea that I call it ‘HHO’ since my post clearly does not use the term.

    Wow, sippin’ haterade much? Worse than my ex-girlfriend…

  15. @lurker, you’re mostly right, but I see you aren’t as well versed in automotive technology.

    O2 sensors aren’t very sensitive…adding a little more oxygen at the air intake isn’t going to change them significantly. While I don’t have experience with this sort of thing, I will admit that it is possible, however improbable that an on-board H2/O2 generator will be efficient. Though I have seen injection systems (propane, H2, NO2, even H20) with onboard tanks that really boost combustion efficiency in gas and diesel engines.

    @1000100 1000001 1010110 1000101 you’ve got it wrong too. Tonneau covers on pickups actually worsen the aerodynamics and cause lower gas mileage. Mythbusters even did this one.

    A better example would be a supercharger. I installed a fairly low compression supercharger on my Tacoma and gained both gas mileage and horsepower. It compresses air going into the engine, and of course the work to do that is being done by the engine itself via a belt drive. If you don’t look at any other factors of course physics tells us there is no net energy gain. There’s more going on here but I’m not going to give you a lesson about the modern internal combustion engine. There are plenty of books on the subject.

  16. @Cory Walker — Yea, I suppose that’s why the very first page I ever Googled on building water rockets had 2 pages of rocket building instruction, 2 pages of launcher instruction, and 10 pages of recovery techniques.

    But then again, considering that you are mixing your oxidizer and fuel (and risking spontaneous combustion in your hands), that you care very much about personal or property safety. I’ll stick with water and compressed air, myself, and work on re-usability techniques.

  17. I didn’t think this was talking about free energy. It’s talking about using HHO (which should be listed as H^2 + O^2, since the atoms are bonded to themselves, as diatomic molecules, not each other) it’s just a mix of hydrogen and oxygen, without a reaction, since the temp is too low.

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