Buiding a more EPIC baking soda rocket

[Spacescifi]

 

So for those of you that have tried it, you know you can make a rocket out of a 2 litre soda bottle with vinegar and baking soda.

My question is, what if you want an even more powerful rocket?

 

No I am not suggesting gasoline, but just household chemicals.

Would adding hydrogen peroxide or rubbing alcohol to rhe mix increase the thrust to weight ratio?

I want a rocket that can go higher than the 20 feet I reach with vinegar and baking soda.

Thank you all you chemisty people in advance.

I plan to really launch these things for fun, so please do not guve a mux of chemicals that might literally blow up in my face and injure me. Thank you.

Edited September 8, 2019 by Spacescifi

[Shpaget]

World altitude record for water + compressed air is 830 m.

No chemicals needed.

[Spacescifi]

7 minutes ago, Shpaget said:

World altitude record for water + compressed air is 830 m.

No chemicals needed.

 

I have a bicycle air pump, but I really am not sure how put compressed air into a 2 litre bottle without reenginering it with pressure valves. 

Unless that is what you're suggesting...

[Shpaget]

You need something that will be able to disconnect to release the pressure when needed (push of a button or when certain pressure is reached) and launch the rocket, but yeah, in principle, that's what you want.

Edited September 8, 2019 by Shpaget

[cubinator]

Maybe you could keep the chemical the same, but produce a better pressure vessel and nozzle. My guess is that baking soda+vinegar will give a higher Isp than plain compressed air and water. If you did it in something like a scuba tank, with a nozzle on the end, you might be able to get much higher altitude.

Hydrogen peroxide makes a great oxidizer, but not only would you be dealing with an actual liquid rocket, at the concentrations needed it tends to explode on its own. Not recommended.

A typical water rocket might benefit from household peroxide, though, as it is heavier than water and would therefore give you more reaction mass.

[Spacescifi]

30 minutes ago, Shpaget said:

You need something that will be able to disconnect to release the pressure when needed (push of a button or when certain pressure is reached) and launch the rocket, but yeah, in principle, that's what you want.

 

Thanks. Currently I use a wine cork on for the cap, put on just so that the pressure builds for it to blast off. I use baking soda wrapped tightly inside a paper towel  to delay immediate reaction so I can quickly place the cork on the cap hole.

I was thinking though... what if I prick the bottle with a needle, insert a basket ball air needle, and start pressurizing the bottle with the wine cork fitted on tight.

As I build more and more pressure either the bottle will explode or launch. The baking soda would have plenty of time to react here too.

Good or potentially injurous idea?

33 minutes ago, cubinator said:

Maybe you could keep the chemical the same, but produce a better pressure vessel and nozzle. My guess is that baking soda+vinegar will give a higher Isp than plain compressed air and water. If you did it in something like a scuba tank, with a nozzle on the end, you might be able to get much higher altitude.

Hydrogen peroxide makes a great oxidizer, but not only would you be dealing with an actual liquid rocket, at the concentrations needed it tends to explode on its own. Not recommended.

A typical water rocket might benefit from household peroxide, though, as it is heavier than water and would therefore give you more reaction mass.

 

Same question to you.

[Elthy]

Both pure water rockets and soda+vinegar rockets work by pressing water (vinegar is mostly water) out the nozzle at high speeds. The difference is that a water rocket has its pressure supplied form the outside by a pump while the soda rocket creates it with a chemical reaction.

You can improve both by increasing the pressure inside the rocket, here your limit is the valve and the bottle. The valve of the soda rocket is supposed to fail, you "just" have to make sure it happens later, so thats an easy way to optimise it. If the bottle becomes your weak point (i hope your are wearing safety glasses even at bigger distances) you can try reinforcing it, e.g. by wrapping firbe reinfroced tape around it.

 

Edit: There is a limit on how much pressure a soda+vinegar reaction can create, im not sure if its low enough to be reached by household stuff. You will notice it if the rocket cant press the plug out anymore.

Edited September 8, 2019 by Elthy

[cubinator]

1 hour ago, Spacescifi said:

Same question to you.

You'd want to know the pressure ratings of your tank and any valves you use, and do some math with the gas laws and stoichiometry to figure out how much pressure to expect from your ingredients and whether the tank can handle it.

If you're around any pressure vessel that might explode, you should definitely stay far back, wear safety eyewear, and preferably have some kind of physical barrier to stand behind. Even an exploding soda bottle can create dangerous shrapnel. If you go for higher pressure, you might want to find a way to begin pressurization remotely, so that you don't have to be holding the tank at all.

[Spacescifi]

3 minutes ago, cubinator said:

You'd want to know the pressure ratings of your tank and any valves you use, and do some math with the gas laws and stoichiometry to figure out how much pressure to expect from your ingredients and whether the tank can handle it.

If you're around any pressure vessel that might explode, you should definitely stay far back, wear safety eyewear, and preferably have some kind of physical barrier to stand behind. Even an exploding soda bottle can create dangerous shrapnel. If you go for higher pressure, you might want to find a way to begin pressurization remotely, so that you don't have to be holding the tank at all.

 

Wow. Looks like we are getting serious here.

Well... humans DO like stuff to go boom!

I certainly do, although I would be happier with a high ascent.

[cubinator]

5 minutes ago, Spacescifi said:

Wow. Looks like we are getting serious here.

Well... humans DO like stuff to go boom!

I certainly do, although I would be happier with a high ascent.

Indeed. And if you want a high ascent, you need to know whether the cork or the bottle will pop first. More energy for ascent means more pressure needed in the tank (at least for this kind of propulsion) and that means greater danger. You should know what to expect so that all that energy goes into something fun and not something painful.

[tater]

We have a ton of crappy disposable water bottles. They have really weak screw caps---they hold water until you first unscrew the cap, but the cap never goes back on as definitely again...

Drink some water, add duct tape fins, and a weight on the bottom. Stick a piece of dry ice in, screw cap on quickly, and put in a bush or something with the bottom up.

Oh, and run. (sometimes they fly, if the cap actually works... RUD).

Edited September 9, 2019 by tater

[cubinator]

If you want to go high and fast, you might want to look into actual solid rockets as well. They are much more predictable to launch and pretty safe to handle. There are a number of sources online for parts you can buy to make your own rocket, and simulate it in OpenRocket or RasAero to try to get the best performance.

[Meecrob]

I tried a few water rockets before I got into proper model rockets. I found a truck tire valve stem that fits standard bottles perfectly with the persuasion of the claw end of a hammer. Also, use 500mL pop bottles with a basic nosecone. Water bottle walls are thinner, and 2 litre pop bottles have horrible drag (or whatever the technical term for the ratio of wetted area vs weight is - imagine throwing a balloon). We aimed for distance, since we couldn't measure altitude reliably well, and could get them to go around 100-150 feet from the "launchpad". Play around with the amount of water you add. Around 50/50 water/air by volume is a good starting point.

[Guest]

It is possible to make a rocket with ethyl alcohol vapors and air. Optimizing that could probably get you decent performance, though with gaseous propellants you'll always have relatively poor endurance.

Considering that ethanol and LOX rockets have gone into space (though not to orbit, not without solid upper stages at least), vodka is actually a pretty good fuel.  The French also had some success with good old turpentine. The problem is oxidizer, atmospheric oxygen isn't very effective, and most other choices are rather nasty chemicals. Household peroxide is very dilute. 

[kerbiloid]

3 hours ago, Dragon01 said:

It is possible to make a rocket with ethyl alcohol vapors and air.

The bottle rocketeer confirms.

Spoiler

 

A pulse engine,

Edited September 9, 2019 by kerbiloid

[Nuke]

you can get a little more umph if you use cleaning vinegar, it usually has a little bit higher concentration. maybe also try reducing your vinnegar to get a higher concentration. if i didnt think spraying acid everywhere was a bad idea, id recommend getting some muriatic from home depot, not that i would recommend that kind of thing. peroxide works as a monopropellant if you can find high concentration peroxide and use a catalyst (platinum works, just find some plated platinum jewelry scrap).

Edited September 10, 2019 by Nuke