Flour Rockets

We take a look at how flour rockets work. Flour rockets are just like water rockets except the water is replaced with dry flour.

[@Nighthawkinlight]

Fantastic video, and excellent analysis of the powder behaviour. I so badly would like to convert that into a combustion rocket, but I suppose that's against the air rocketer's code of conduct.

[@AirCommandRockets]

Thanks NightHawkInLight. :) I know it is very tempting isn't it?, but it is just too dangerous. Love your channel!

[@jgreep]

The cloud of flour should be explosive. Have you thought of trying to ignite it?

[@AirCommandRockets]

It is never a good idea to ignite anything coming from a water rocket. It doesn't matter if it is flour, coffee creamer or a flamable liquid. They are all dangerous when ignited.

[@cmdrterrorfirma4244]

to get any thrust from an ignited flour cloud it would probably need a nozzle cone after the exit point of the rocket. Unless it was purely for the visual.

[@michaelwni]

Air Command Rockets I have confidence you can manage the danger ... I’ve seen you launch rockets powered with flammable propellant

[@RobertSzasz]

Flour coming out the back of the rocket would probably be about as safe as any material you could light. It shouldn't be able to burn inside the rocket, and would just make a big, short lived, fireball on launch. A flare a handful of feet from the launch platform would probably do the job as safely as possible. There wouldn't be anything burning going down range, and any hazard would be limited to a couple yards around the launch pad. Edit: you would need to be careful of the radiant heat weakening the rocket I guess

[@jmar1371]

@@RobertSzasz The resulting explosion could kill you. Aerated flour deflagrates when ignited.

[@dazzifoxking1560]

My day is always a great one when you upload a video! I love your channel!

[@simontillson482]

What a brilliantly observed and well explained experiment. We need more of this!

[@joshguevara796]

Another awesome rocket video!

[@TomDillon13]

Loving these videos!

[@Allan_aka_RocKITEman]

I love the _floury language_ you use when narrating this video. 😝😝😝

[@vaterchenfrost7481]

I'm always enjoying your videos. Thank you for sharing with us. By watching launches of flour filled rockets I've got the impression that they are a better aplied as a bosster, or a first stage of multistaged water rockets then ones filled with water. That with the relation of performance (peak altitude) to weight in mind. I'm aware that I can be mistaken, and it's just a diameter of the nosile, that is not optimized for flour runs, that fools me. Any way thank you. It's always a pleasure.

[@lilyrooney]

You know how flour is flammable if you ploom it into a cloud and then light it? it would be cool to get some fiery footage. That'd make it feel just like an actual chemical rocket launch, even if the propulsion doesn't come from the fire

[@SidneyAlves]

Awesome! The flour looks like smoke from space rockets.

[@clomb1234]

Excellent video.

[@DWPhotog]

Love it George. Nice video.

[@AirCommandRockets]

Cheers Derek :)

[@TheXcluzif78]

I love how the exaust flour looks like real powdered rocket engine.

[@AmIonArock]

Cool, You are almost ready to do your own contrails

[@RhyssRocketProject]

Great experiment

[@AirCommandRockets]

Cheers Rhys :)

[@RaketfuedrocketsDeutschland]

Very nice experiment! It looks quite fantastic but it's fore sure a lot of mess to clean up. Another thing you could try is a convergent-divergent nozzle now that you have expanding fuel. ;) Keep it up! Julian from Raketfued

[@AirCommandRockets]

Thanks Julian. Yes you want to clean it off the equipment before it gets wet otherwise it turns to glue and then it is a lot harder to get off. It was fairly easy to clean with the air from the scuba tank. :) We just disconnected the air line and blew all the flour away. We had exactly the same thought about using a CD nozzle with a powder since like you said you have an expanding gas. It may be interesting to also try different gases like helium that should hopefully give the particles higher velocity. The powders can also be used to explore reactive masses with a lower density than is possible with liquids. I wonder how microballoons would go?

[@69RocketBones]

I enjoy your videos George.

[@AirCommandRockets]

Thanks Darren :) We have fun making them.

[@GrandadIsAnOldMan]

Fascinating

[@MarinusMakesStuff]

We used to make these with liquid mercury, worked a treat! ;)

[@ali-a-agames7292]

So nice 👍

[@SterremanWillie]

As always, great video, very interesting and very educational! Nice and messy indeed! I assume you did, but just keep the possibility of a powder explosion in mind! Perhaps ensure the rocket is electrically grounded (not sure if it will work with plastic), but anyway, try to prevent charge build-up, which may lead to a static arc, setting off a dust explosion!

[@AirCommandRockets]

Thank you Willie. Yes, we are aware of the potential for the powder catching fire, though I think the odds are very low. This is why everyone is well back and there is nothing really combustible around it. We considered using baking soda but the problem is that is not very healthy for the grass.

[@WATERROCKETSCLUB]

Wow, Looks awesome! Excellent emitation rocket launch! But do not set fire, as many commentators advise. It may be too dangerous!

[@bogrick1947]

Ok... this looks like fun... So for the next experiment, if you put 2nd stage as a water stage, and then a 3rd as a pyro stage, do you end up with a bread rocket.... Long time no talk by the way, you may remember me from Ireland as TOR Water Rockets a long time ago when you fist started. And WOW have you come on a long way way since I first met you George. Keep up the good work

[@AirCommandRockets]

Wow, Richard! It sure has been a long time. Glad to hear from you. :) It was one of the things we talked about at the launch site, one rocket with flour, then one with milk, then sugar, another with eggs, and the final one just filled with candles. All you would then need is a pyro rocket to cook the cake and light the candles. :) How are things going at your end?

[@michaelwni]

Flour is very flammable when aerated... I’d like to see a secondary chamber/ nozzle that ignites the flour for additional thrust.

[@robertherndon4351]

That tends to explode rather than burn. The pressure surge might ignite/detonate the primary chamber...

[@michaelwni]

Robert Herndon flour is inert unless it is well aerated ... meaning you can put a lighter to a pile of flour and it will only scorch a little

[@robertherndon4351]

@@michaelwni But by the same token (exploding when well aerated), it would likely make it hard to maintain an ongoing flame in a secondary chamber. (And the compressed air means it doesn't have to be quite so well aerated, since it contains ~10 times more air than in the flour sack.)

[@michaelwni]

@@robertherndon4351 when you light the spray from a can of hairspray it doesn't explode the can... but even if the flour rocket did explode.... then that'd be cool, too

[@robertherndon4351]

@@michaelwni There's no air in the can... the propellant is usually propane or something similar. In the rocket, you have both fuel (flour) and oxidizer (air), making it a possibility, though flammability is likely to be problematic/erratic.

[@vaterchenfrost7481]

I can imagine, that flour rockets can utilize a higher weight-to-pressure ratio than water rockets. It is an interesting thought-experiment: to compare flour to water rockets with the same max pressure and maxed up weights of the flour and water respectively to its highest efficiency.

[@AirCommandRockets]

This is an experiment we would like to do. I agree it would be interesting to see what the optimal amount is.

[@jeremy000]

Very nice George. Could be fun using coloured powder in layers maybe?. or would it be over too quickly to bother? (Holi or Throwing powder)

[@AirCommandRockets]

Hi Jeremy , I think that's a great idea! I will have to look into that. :)

[@BNETT21]

I really would like to see a test between 33% full using flour and 66%. I think it might do better due to the way it acts as a more dense air. Also a much finner powder may do better. Like the hydrophobic powders.

[@AirCommandRockets]

Definitely a worthwhile test to see what the optimum fill volume is for a fine powder. We've found that definitely the finer the powder is the better.

[@parrotraiser6541]

Sand might work as a reaction medium, too.

[@AirCommandRockets]

It's certainly possible, though you want a very fine sand. We found that the smaller the particle size the better. If the gaps between the particles are too large then the air tends to escape through those gaps before it has time to push the particles out.

[@patrickfle9172]

@@AirCommandRockets you get sandblasting sand in many varieties

[@mrdewilliams]

How does the weight of the flour compare to the weight of water? Since some of the air is held within the flour, I am wondering where that puts the optimum ratio or flour to air.

[@spacefinn8968]

One of my favorite videos so far. Keep it up! But i have one question: Where is the optimal point between nozzle size (diameter) and pressure? Is it better to have a 9mm nozzle or a full bore 2 cm nozzle with, lets say 10 bar of pressure? Finn

[@AirCommandRockets]

That's a great question, and depends on other factors as well and what you are trying to achieve. Generally a larger nozzle will give you a little bit more performance, over a small nozzle, but not by much. A large nozzle will give you lots of acceleration and higher speed, but because drag is proportional to the square of the velocity, you also generate more drag than with a smaller nozzle which works against you when trying to gain altitude. A large nozzle is able to lift a heavier payload. The faster acceleration also puts more stress on other components on the rocket so you have to make sure they are well attached. The size of the nozzle also depends on the type of launcher you use, not all nozzle sizes can be launched from all launchers. Rockets with larger nozzles are harder to film/photograph than ones with smaller nozzles. Larger nozzles can accommodate larger launch tubes. For optimum size, run the rocket through a simulator and see what the difference is.

[@spacefinn8968]

@@AirCommandRockets Thanks for your comprehensive answer, i appreciate it. I think i'll run a simualation or try to experiment with the nozzle size...

[@istvanfrank9201]

Flour are lighter as the same amount of wather so you can put more in and that drive longer the rocket. Or thats not the case ?! Greeting from Hungary Sopron 😃You are awesome!

[@venian646]

This is an interesting video that got me thinking. If matter in the pressure chamber falls out uniformly, what if you could get the air to release uniformly? My simple understanding is that the reason why water rockets are efficient is because they take some time to release all their working mass. This got me thinking about how a empty water bottle will deform if you suck on it or expand if you blow in it. Would a piston like what is seen in a syringe offer more efficiency compared to a traditional air rocket?

[@AirCommandRockets]

Not sure I quite understand how the piston would work? In a syringe the force is produced by the user, in a water rocket the force is produced internally.

[@brianhill1048]

Hi, this is a very interesting demonstration. During the slomo of the upturned flour ¨rocket¨ we can observe the flour infused by high pressured air going up and partly out the nozzle along with the invisible air towards lower pressure. It certainly looks like this is a one way outflow. I miss seeing the reaction part claimed to how rockets work. Should not particles visibly push down on the bottom of the ¨rocket¨ as visible reaction force?

[@billymonday8388]

now do a liquid mercury one

[@pterodox123]

Have you made sure you have the right amount of air to the right amount of flour? Does it run out of air before flour or flour before air? If you still have pressure left over after expulsion of the flour wouldn't it be thr most efficient use of the bottles capacity if you add more flour media until you run out of air and flour at the same time?

[@AirCommandRockets]

No, on these flights we didn't have an optimal amount of flour. It is not just a matter of one running out before the other. You have to take into account the weight of the flour as well and the effeciency of it being accelerated out of the nozzle. We will do some follow on flights where we will determine the optimum amount of flour.

[@pterodox123]

@@AirCommandRockets that'll be epic.

[@welshpete12]

I just had a BIG THUNK , what about using self - raising flour , would it go further ? :-))

[@HuntingTarg]

Self-rising flour is infused with yeast culture or just baking powder; it has a shorter shelf life but the 'just add water (& eggs, depending)' feature. But that is all WAY too slow to add to a water-style rocket's Isp. I don't know if this falls under the umbrella of 'water rockets' (PROBABLY NOT!); if you rig a rocket with a metal throat and nozzle, you can pass industrial hydrogen peroxide by gravity over a ring of Manganese dioxide suspended in the throat - and STAND THE ○●□■ CLEAR. (No, seriously, I mean 100 feet clear. In a dirt clearing. And paint your rocket bright neon colors so you can find it easily and quickly.) [NOTE: _Concentrated Hydrogen Peroxide IS _*_hazardous material_* and is used as RCS rocket fuel aboard the Soyuz modules. _DO NOT_ acquire or handle without proper instruction and safety precautions.]

[@LiamHood]

So if there's air between the flour particles that helps push it out, is it possible then to use a higher volume of flour than would be feasible with the same volume of water?

[@AirCommandRockets]

Good question. We do plan on doing some more tests to see how the volume of flour affects performance.

[@robertsteinbeiss8478]

Do you have any comparison to the reached height for the same rocket with flour vs. water?

[@AirCommandRockets]

We don't have that data yet, but we do want to do some comparison flights to see what the differences are. I still think water will be more effective though but I don't know by how much. .

[@k8zhd]

My guess is that the height would be proportional to the mass of the flour vs. water, assuming the same volume and pressure of air. Of course there are LOTS of variables in play. Looks like a fun set of experiments coming up! @@AirCommandRockets

[@PatGilliland]

It would be interesting to compare equivalent masses of water and flour. I am guessing the flour would give less thrust but over a longer time.

[@AirCommandRockets]

Agreed. We do plan on doing some comparison flights to evaluate performance. We will compare to the optimal amount of water and also try different amounts of flour to see how it compares. Unfortunately there aren't any simulators available where we could run powder based simulations.

[@pixelpatter01]

Try mixing some colored chalk powder with the flour or instead of the flour. The chalk powder is used in construction to give color to string lines. Red and Blue are the common colors.

[@AirCommandRockets]

Someone else recommended using the coloured Holi throwing powder. I think that would work quite well. We will have to give this a go.

[@easylife7619]

It explains what happens when you sneeze facing up in the sky

[@masi416]

If the compressed air is between the particles, does this mean you can fill more of the bottle? Have you done a test series with different amounts of flour to test the maximum performance?

[@AirCommandRockets]

Good question. We do plan on doing some more tests to see how the volume of flour affects performance.

[@JBaker452]

I am curious as to how a parachute release is accomplished without an ejection charge.

[@AirCommandRockets]

Here is a tutorial on how we build our parachute deployment systems. www.aircommandrockets.com/construction_7.htm

[@chriswatson2407]

Why add flour? What contribution to thrust does the flour make compared to just using air?

[@AirCommandRockets]

The flour provides a reactive mass the same way water does in a water rocket. If you fly a water rocket on just air you end up flying to only about 1/2 to 2/3 of the altitude you can achieve with water. We are going to do a few more comparison flights to see what the overall performance difference is. kzbin.info/www/bejne/eqOzpWB3oNl8g9U

[@monu.r.c456]

Sir what effects seen...if we take sand or cement in place of flour or water

[@AirCommandRockets]

Only one way to know is to try it. I think the finer cement would work better than the coarser sand.

[@DeliciousDeBlair]

Have you tried other finely divided materials such as powdered sugar or powdered salt, or baking soda?

[@AirCommandRockets]

We considered using baking soda but that isn't that great for the grass at the launch site. Salt would probably have the same issues. Perhaps something like fine clay powder may work?

[@DeliciousDeBlair]

@@AirCommandRockets I can definitely see fine clay working, I work doing excavator work and can drum up TONS of super fine clay every day without effort! Its so light it blows in the slightest breeze, and it moves like a fluid, so jamming up is likely not a problem. If it were necessary, I could dig up a whole bunch of high purity clay and dry it out, ball mill it in my cement mixer [with a cloth over the top to keep it from all blowing away!] and ship it to you, but even with a flat rate box, you might be money ahead to find some kind of inert clay like untreated/unscented kitty litter and grind it up locally. One thing I am sure you know already, just like with toxic combustion emissions, be sure people are not standing down wind of dry propellants! Gypsum board would work, its pretty inert... I was just thinking how my uncle has a huge pile of it out behind his barn my brother and I are considering pulverizing for the sake of adding necessary calcium to the depleted soil on my uncle's farm. Its easy to get free from construction sites as waste and powderizes quite easily with something simple like a power sander, just be sure to wear respiratory protection.

[@Mongo63a]

It would be interesting to see the performance difference if you used a heavier powder like aluminum or iron/steel.

[@AirCommandRockets]

I agree, it would be nice to know what performance differences there are with different powders. From past experiments we know that the smaller the particle size the better. Heavier powders may not necessarily result in higher altitudes. Although you produce higher thrust you also must lift the heavier powder that is still in the rocket.

[@RobertSzasz]

Or micron sized tungsten?

[@AirCommandRockets]

Perhaps dry clay particles. I think these go down to 0.002mm.

[@AirCommandRockets]

Interesting. I was wondering what kind of powders exist that would be more free flowing.

[@RobertSzasz]

@@AirCommandRockets any powder designed for compressed powder sintering should be about as free flowing as possible.

[@Starlite123]

Strange i shot 2L bottles filled with 1/2 Chalk and 100 psi and nothing but air came out bottles didn't even fall over. We did something wrong?

[@cmdrterrorfirma4244]

So... if the flight results are pretty much similar to water filled, and the flow of the flour is nearly the same as water... what is the advantage of using flower other than maybe it is visibly more interesting? Seems like more cost and more mess for the same results. Or is this purely for the sake of the experiment?

[@AirCommandRockets]

This is a good question. In terms of cost, one launch was around $0.60 worth of flour so not prohibitive in terms of cost per launch. A powder may however, allow you to use a convergent-divergent nozzle that doesn't work for liquids. Powders also can allow you to explore less dense reactive masses compared to liquids.

[@gopalkumawat1212]

Sir how to make this rocket

[@ctakiute]

Does the amount of flour change the height of the rocket? Please do a experience with different amounts of flour.

[@AirCommandRockets]

Good question. We do want to do some comparison flights with water and air only.

[@robertherndon4351]

It looks like this might work slightly better than water, in that the flour/air mixture can and does expand as it goes through the nozzle. It also looks like the expansion of the air in the mixture may make it work better with a higher fraction of flour-to-air than works well with water-to-air.

Oh great experiment! Are you getting better performance from the dry flour? I think the smallest a fordable particle powder you can get is laser printer toner. But maybe it's too dangerous as it's composed of very tiny particles. Thanks for sharing!

[@AirCommandRockets]

Thanks Francisco, We don't know what the performance is like compared to water yet. We do want to do some comparison flights to find out. I still think water will perform better, but we just don't know. One thing I think may be worth investigating is using convergent-divergent nozzles, as you are getting an expanding gas on the way out, it just has heavier particles in it.

[@TentoesMe]

There was a pretty good poof of air when the flour ran out. Perhaps a little more flower would work.

[@AirCommandRockets]

We do intend to try different flour amounts to see how that affects performance. Adding more flour also adds more weight so that may work against the overall performance.

[@P61guy61]

Flour is fairly light. Theoretically, would a heavier powder create more thrust at the same PSI and volume of air / powder ratio. For example, lead powder vs flour. Or water vs flour. And yes it is obvious one wouldn’t use lead because of the pollution and poisonous nature of PB.

[@AirCommandRockets]

That depends, a heavier powder may not necessarily lead to greater altitude. Although you create more thrust, you are also having to lift the heavier powder that is still in the rocket. Here is an experiment we did where we compared liquid densities and their effect on altitude gained. kzbin.info/www/bejne/fKaWo3yfhd6SZ5o

[@santa0350]

you can try to make a sugar rocket?

[@AirCommandRockets]

Unfortunately no, it is illegal in Australia to make your own solid motors.

[@santa0350]

@@AirCommandRockets ok 😫

[@deandeann1541]

I think, maybe, they meant sugar in place of flour, rather than sugar and kno3. Confectioner's sugar might work!

[@AirCommandRockets]

@Dean, ahhh ... in that case we have done that before :) kzbin.info/www/bejne/aYKyd2eqpqeIn9U

[@robertherndon4351]

That would also make for an easy test of granule size: does confectioners (powdered) sugar work better than granular (baking) sugar?

[@The141335]

Original idea! Try to use pigment grade titanium dioxide (or Fe2O3 pigment) instead the flour.

[@AirCommandRockets]

This is not an original idea. Flour rockets have been flown for many years they are just not common. How fine is the titanium dioxide?

[@The141335]

@@AirCommandRockets About 14- 15 mkm (for pigment). For glass industry and metallurgy more coarse.

[@scottyates9723]

Should of tried self raising flour

[@redfive9559]

Can a bottle be pressurized at 120psi??

[@AirCommandRockets]

Yes. The ones that are designed for carbonated drinks. They will blow up at around 180psi.

[@redfive9559]

Thanks a lot

[@redfive9559]

Another question please:at 120psi a solenoid valve can work for lift off

[@AirCommandRockets]

You just need a solenoid valve that can handle those pressures.

[@michaelwni]

Imagine how cool it would be if you ignited the flour during a night launch ... I think that would be the most favorited video for GK of all times! Especially if it was was with the huge booster rocket 🚀 🤯

[@user-li5be1bn8p]

If add some fire ....

[@pierrec1590]

I am not sure I get it at all. Flour density is about half that of water. Your acceleration comes from the equation F=ma. I would bet baking soda (density 2.2g/cm3, $1.46/Kg) would be much better than flour(density 0.6g/cm3 $1,62/kg) or even water(density 1g/cm3) for equal initial pressure.

[@AirCommandRockets]

Higher density doesn't necessarily lead to higher altitude for the rocket. Although with higher density you will create greater thrust, you are also having to lift a greater mass of the higher density material that is still in the rocket. Here is a comparison of the performance of different density liquids: kzbin.info/www/bejne/fKaWo3yfhd6SZ5o

[@ReevansElectro]

Flour can be ignited when dispersed and it would be exciting to have an ignition source.