[Integza] was reading about a World War II-era rocket plane created near the end of the war by the Germans. The Heinkel He-176 wasn’t very practical, but he was intrigued when he read the rocket was cold and combustionless. He did a little research and found the engine was a monopropellent engine using hydrogen peroxide. This led to some interesting experiments and a 3D printed rocket engine, as you can see in the video below.
Usually, liquid-fueled rocket engines have a fuel and an oxidizer that mix and are either ignited or, in a hypergolic rocket, spontaneously combust on contact. With a monopropellent, the thrust comes from a chemical reaction between the propellant — hydrogen peroxide, in this case, and a catalyst.
There’s a common science demonstration that creates a huge volume of foam using common peroxide and a simple catalyst. For a rocket, though, you need concentrated hydrogen peroxide and certain catalysts. For some reason [Integza] tried different catalysts before settling on what the Germans had used, potassium permanganate. That was much more effective.
Since the reaction isn’t hot, this is a rocket where 3D printing on a consumer-grade printer is practical. In particular, he used a resin printer to create nozzles and a guide to properly mix the peroxide and a liquid catalyst.
For this test, the rocket didn’t go anywhere. Strapped to a fixed mount, [Integza] simply injected the materials with a syringe. The results, though, were impressive and we’d love to see an actual flying rocket or aircraft using this system.
This isn’t the first attempt he’s made at printing a rocket engine, If you want to go the more traditional route, we have some advice there, too.
IIRC, hydrogen peroxide + potassium permanganate were also used by the Germans to power the turbopump of the V2 rocket.
And hydrogen peroxide rocketry has been revived by ARCA SPACE these last years.
My big question is… Why did he mixed the catalyst in liquid form, instead of coating the inner surface? Doing that, the catalyst would be “reusable” and won’t need to add it continuously…
The catalyst needs surface area to be effective?
I thought from the video he would have seen better results with a longer reaction chamber; the slow motion had visible pulsating of the gases which could be a feedback from the injection or more likely the reaction was not completely done as it exited the nozzle
I’m getting an idea. If you could get the PP to “stay” at some place inside the reaction vessel, perhaps coated on the periphery as you said, you could pump a constant stream of peroxide and get all of it to react. While his design appears to use the peroxide tank as the reaction vessel, you could conceivably get away with a much smaller vessel using the pumped peroxide method.
Not that I know anything about these, but aside from being easier I’d take a wild guess it might be a surface-area issue? The peroxide would only react around the periphery of a coated vessel, whereas with liquids you get a reaction throughout the liquid volume as long as it mixes well. I suppose you could have a honeycomb-like structure inside the vessel with all of the surfaces coated in permanganate, but I’ve no idea how practical coating surfaces with permanganate is. And wouldn’t you get gradual consumption of the coating anyway? In this case unless you’ve some way of regenerating the permanganate it isn’t really a catalyst surely?
But the point of a catalyst is that it doesn’t participate in the reaction, only facilitates it. Thus the catalyst, strictly speaking, remains intact. You don’t need to regenerate it.
Sure, but as others have pointed out permanganate isn’t actually a catalyst in this reaction, it gets consumed. So the article isn’t correct on that point.
It can act as a cat even if it’s washed away. The lead in petrol was a catalyst (catalysing conversion of free radicals to back to stable state before being overwhelmed once ignition actually started) and that was washed out of the exhaust too. Yum, lead.
The platinum in my plat car’s catalyst wasn’t supposed to be consumed, but kind of was as that was stolen. Does that stop it being a catalyst as it went missing?
A catalyst just doesn’t take part in the main reaction and is still present in the system/solution afterwards. Still counts if part of the system has been ejected or stolen.
Jet packs tended to use a large surface area of silver which didn’t get washed out the back. Silver plated copper in a well insulated metal converter would work wonders (temperature is not the friend of hydrogen peroxide and causes it to breakdown also).
I want a jet pack!
Potassium permanganate is water-soluble; since H2O is the other product of peroxide decomposition, a water-soluble coating would quickly be worn away. And there’s the problem of getting a water-soluble compound coating to stick to the chamber walls in the first place.
Even catalyst beds made by coating an insoluble catalyst on a ceramic or metal substrate tend to be worn away quickly by the high temperature and corrosive oxidizing environment.
I wouldn’t want to be in the vicinity of the exhaust. KMnO4 is VERY purple—a 1 ppm solution is visibly colored—and the stain from leftover permanganate would be EVERYwhere.
Oh, and the permanganate decomposes fairly quickly to insoluble manganese dioxide, which stain will never come out of whatever it gets on.
I recall that some researchers have used manganese(II) acetate which is a light pink compound, not nearly as messy as permanganate.
Potassium permanganate is not a catalyst… It is a reactant. The resultant MnO2 from the reaction can be used as a catalyst.
https://chemiday.com/en/reaction/3-1-0-356
2MnO4−+3H2O2⟶2MnO2+2H2O+3O2+2OH−
That explains it. Thanks!!!!
I think the choice was for the quick, simple, and reusable option. Just to prove a concept. The liquids would react quickest, and more completely, giving maximum thrust.
The He-176 flew in mid 1939. If that’s “near the end of the war” then we must be thinking about different wars.
Mandela effect! :-P
I don’t know why I thought it was towards the end. I might have been thinking of HE-162 which didn’t enter service until Feb 45 and VE day was in May. Sorry, you are right, the 176 flew in 39 but as far as I know, neither of them (there were two built) ever saw actual service.
Near the end of the Spanish civil war ;-)
Well, it’s near one end of the war…
KMnO4 is pretty water-soluble. The coat would be carried away anyway. Plus, adding some water to the mess isn’t really a bad idea: the reaction is pretty exotermic (despite the “cold” attribute repeated up there). More steam, less temperature, the latter being beneficial to the materials around it.
Let’s not forget the Bell Rocket Jetpack that was shown in the James Bond movie Thunderball was an actual functional piece of hardware.
H2O2 pressurized with Nitrogen and catalyzed with a fine mesh of Silver.
https://en.wikipedia.org/wiki/Bell_Rocket_Belt
+1
Probably one of the few things Bond returned to Q undamaged.
“- Q: Right. Now pay attention, 007. I want you to take great care of this equipment. There are one or two rather special accessories…
– James Bond: Q, have I ever let you down?
– Q: Frequently.”
Rick Brant also developed a Rocket Belt in using H2O2 & Silver.
https://www.amazon.com/Rocket-Jumper-Brant-Science-Adventure-Story/dp/B0007F9FPE
I started down the route of trying to make a simple rocket using silver wire screen, and while it worked, it was dumping a lot of peroxide unreacted (meaning, I probably needed more, finer screen.) I also learned a bunch about concentrating consumer-grade hydrogen peroxide, and about boiling liquid expanding vapor explosions, and ended up deciding it was too exciting. But the silver definitely seemed like a better choice from a safety standpoint than KMnO4.
Yeah, the first thing I thought is why are they not just using silver mesh, nasa has been using that for all their monopropellant engines like what was used on the Lunar Lander Training Vehicle and even on newer stuff for testing landing systems like in this video, which also mentions the thrusters use alternating nickel and silver screens. https://hackaday.com/2021/08/17/wwii-hydrogen-peroxide-rocket-3d-print/?fbclid=IwAR2zLWeVALyUkrMlcd5uAow69mCv46KmiuzHBOhcdf-vwlyhMwN4CYi7yC8
And some long lost internet history. I was looking into this for something rocket related 10 years ago. Can’t remember what.
https://web.archive.org/web/20150103005746/http://www.peroxidepropulsion.com/article/38
Are there 3D printer filaments that contain silver?
I would be extremely careful when working with concentrated hydrogen peroxide – remember a book where Polish members of the anti-Nazi resistance were stealing parts of the crashed V2 rockets (also using concentrated H2O2) often suffered something like (acid) burns when trying to quickly salvage parts of the rockets crashed in remote areas far from planned “landing”. They needed to be quick before the Nazi patrol arrives and then smuggled the parts to the Allied forces.
PS: even the weak medicinal 3% H2O2 is enough to cause problems…
The movie of the resistance capturing a V1 is a great one – called “Battle of the V1” I think – although the true story is probably even better than the movie version.
The stuff the resistance managed to pull off through the war is incredible – and included some truly magnificent hacks and lateral thinking.
This may not be hot, but you are potentially making a bomb. The pressures could easily spike if you inject at too high of a rate and/or make the nozzle too restrictive. Be careful or you’ll shoot your eye out… or lose a hand.
Armadillo Aerospace spent a lot of time investigating various permutations of peroxide rockets in the early 2000s. There’s a reason potassium permanganate is typically referred to as “the purple menace” in the amateur rocketry community…
John D. Clark’s book Ignition! has some excellent commentary on monopropellants and peroxides:
“Your peroxide starts to decompose for some reason or other. This decomposition produces heat, which warms up the rest of the peroxide, which naturally then starts to decompose faster — producing more heat. And so the faster it goes the faster it goes until the whole thing goes up in a magnificent whoosh or bang as the case may be, spreading superheated steam and hot oxygen all over the landscape.
And a disconcerting number of things could start the decomposition in the first place: most of the transition metals (Fe, Cu, Ag, Co, etc.) and their compounds; many organic compounds (a splash of peroxide on a wool suit can turn the wearer into a flaming torch, suitable for decorating Nero’s gardens); ordinary dirt, of ambiguous composition, and universal provenance; OH ions. Name a substance at random, and there’s a 50-50 chance (or better) that it will catalyze peroxide decomposition.” (Ch 5, pg 66)
https://library.sciencemadness.org/library/books/ignition.pdf
Misleading video content: The stubby rocket fighter shown while the audio mentions Heinkel 176 is in fact a Me 163 Komet.
That aircraft was used against allied bomber formations late in the war, IIRC.
Nice ;-) BTW, one of the ways that you can test for thrust is to use a mail or kitchen scale which has a peak weight. These are used to hang something heavy and get an estimate to the max weight. Nice ones have a little lever that indicates the maximum force/weight and can be easily reset. If you get a slide and mount the rocket on a slide you should be able to get a decent estimate of the force produced.
Also, check to see what the necessary ratio for complete reaction — it is likely that you only need to use 1/4 or less of the catalyst.
Fun fact: another chemical with a special Nazi codename was Chlorine Trifluoride, aka N-stoff, reportedly it was so dangerous to work with they ceased all efforts to manufacture anywhere near the amount they had initially planned on. to give an example why, it can cause sand, concrete, asbestos, and even ashes from normal fires to ignite. the only way to store it is with specially treated steel barrels that if there is a scratch or other break on the thin fluoride salt film on the inside of it it will explode and ignite absolutely everything nearby.
https://blogs.sciencemag.org/pipeline/archives/2008/02/26/sand_wont_save_you_this_time
The permanganate is also a fun oxidizer. A classroom demo of permanganate and glycerin used to be something the fun HS Chem teachers did. Keeping it in contact with polymers long-term might make some interesting results. Running on memory , Blue Origin also had some fun earlier on using peroxide/silver reactions, but they seem to have smoothed things out a bit.
Kursk
https://en.wikipedia.org/wiki/Kursk_submarine_disaster