A Massive Three Grain Rocket Motor - Arduino Static Thrust Test Stand - Elementalmaker

Testing the massive THREE GRAIN rocket motor on the Arduino based load cell test stand to get thrust data.
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Parts I used:
Arduino Uno R3: amzn.to/2QhskRv
50Kg Load cell: amzn.to/2DVYHxo
HX711 Board: amzn.to/2lg2r5L
LCD Keypad Shield: amzn.to/2E9q6fN
5V Relay: amzn.to/2SEgqhn
In addition you will also need some jumper wires, and a 10+ foot USB 2.0 Cable - A-Male to B-Male to log the data to your laptop.
Link to PDF by Nick Cinquino and Len Johsnon: archive.org/details/ArduinoMo...
Video Building the Static Thrust Test Stand: • Arduino Rocket Motor T...
The above are amazon affiliate links which earn the channel a small commission and help me to produce the videos.
Special thanks to Luke Foley and his team for providing the rocket motor!

[@ElementalMaker]

Help me continue making science videos www.patreon.com/ElementalMaker

[@brucebaxter6923]

homogeneous or eutectic?

[@powegger2]

i dub thee rocket shitz

[@psychosk8er]

Three grain motor just three ingredients, wheat, barley, and oats. When combined these three grains make a powerful propellant that can also be used to make a healthy loaf of bread. 😂

[@CanineDefenseTechnologies]

I wanted to build a propulsion test stand and didn't know where to start untill I saw your early videos which have me a kickstart of Ideas! Then I check back and wow wee those are some HUGE motors!

[@Orbis92]

"a little bit of schmutz" I always get a big smile on my face when I hear German words in English video :) I didn't not take a look at your arduino code, but if you are using the analogRead instead of some low level ADC readout you might get some timing jitter with your measurements (hence the unsmooth graph). Its possible to run the ADC at a fixed frequency and read the ADCs value with an internal interrupt. This would let you calculate the measurement time more precisely than storing and relying on the millis() for example I would love to take a look at your code right now, but first I have to get through my exam period starting next week :| But I'm no rocket engineer and could be complete wrong, your measurments might be totally correct and the unsmoothness of your data is just the graphite nozzle breaking apart.... :)

[@earlturner6023]

o/

[@darkxxhimxxlight]

I'm guessing casting a grain to fit the cannon would be a bad/wonderful idea....?

[@IchMagandMeGusta]

Where has this channel been all of my KZbin life? Subscribed.

[@ElementalMaker]

Thanks for your sub Logan!

[@x9x9x9x9x9]

Hell yeah! Love these motor tests.

[@tissuepaper9962]

Just mix stump remover and "log" remover.

[@guythat779]

Log remover?

[@tissuepaper9962]

@@guythat779 Sorbitol has a reputation for giving people horrible diarrhea when they eat too much of it.

[@guythat779]

@@tissuepaper9962 I know but... so you call poop logs aight gotcha

[@thatguynameddan2136]

That was pretty cool. Another thing to tack on my long list of projects.

[@bearbaler1456]

"The second best wrist work-out my hands had for a week,... maybe a day." 🤣🤣🤣 Think I just broke a rib.

[@TomokosEnterprize]

It is always a fun visit fella. Love how it went.

[@illumiNOTme326]

Just added that link as my homepage for Amazon. Hope it helps bud keep up the great work.

[@ElementalMaker]

Truly appreciate your support!

[@m3sca1]

Bloody hell that burned up quick! Was expecting slower, good job.

[@leod7454]

Sorbitol is an alcohol. Maybe that pronunciation clue will help.

[@Nuovoswiss]

Loving these DIY rocketry videos. One minor point, seems something went awry with the specific impulse calculation. However, you scaled the impulse (20600 gFs) by 100 instead of the mass of propellant, which was 225 g according to the spreadsheet, and 300 g according to your batch calculations. So the Isp should be around 90 seconds.

[@ElementalMaker]

Ah crap I screwed that one up then 😕

[@micahrandall1344]

just did the calculation... it is 93.433424 seconds

[@buggsy5]

Yep, the Isp is very poor, not much better than you get from compressed black powder. But you have a good start on the basics. It is about time to transition to an AN, aluminum, rubber grain - ratio about 70:15:15. One major advantage is no melting of the uncast fuel - since the rubber fuel is the binder. That nozzle orifice is far too large for your 3 grain motor - but MIGHT be OK for a 5 grain. Does the casing have overpressure protection, so the nozzle end blows, rather than the casing turning into shrapnel? This is often accomplished by a relief cut around the inside of the casing, right in front of where the nozzle closure threading ends.

[@firstnamelastname.7749]

Isp should be around 110-130 for knsb

[@wrinkyscarnagecrew]

Time for a 4 grain and a bigger load cell love your videos Man

[@JR-kk6ce]

Great, great video! Thanks to Luke Foley for kicking it all up a notch. I will use your Amazon link. Last time I was fidgeting with rockets I was using Ammonium perchlorate and epoxy using the readily available NASA rocket booster formula. Using the epoxy formula makes the engines impervious to humidity and you can store them for years without any degradation. They also have a longer burn time. Thanks again for bringing rocketry back into focus.

[@ElementalMaker]

Glad you enjoyed and I truly appreciate your support. I just got a gallon of R45 resin and isonate curative yesterday, along with 6 pounds of 200 micron AP, so get ready for some composite tests here!

[@TwZlr.]

I like the humor as much as the rest.

[@TrojanHorse1959]

Great video & your humor is second to none, thank you! You cheer me up and make me laugh, I need that these days, thank you! P.S. Can you make your link work with Amazon Smile?

[@ElementalMaker]

Thanks for the kind words Robert! And yes great idea for amazon smile. Here is a link that works with amazon smile: tinyurl.com/yyx2xymv I truly appreciate your support.

[@HealthThroughNutrition]

It shows in your results shown on the computer what happened with the back of the nozzle and from the video it did look like a propellant blockage which caused the the sudden increase and then decrease in thrust. I'd love to see what that puppy could do with a smaller nozzle. Great video

[@iamhe981]

Great video, I have been waiting a long time to see you do this as you promised. It would of been good to see a comparison test without the Iron Oxide. I hope we dont have to wait another 6 months for more video's.

[@A_Casual_NPC]

I absolutely don't care what you do in your videos, I just come here to listen to that buttery smooth voice

[@ElementalMaker]

I do eat alot of butter 👍LOL

[@burntorangeak]

At some point; Would you be willing to run potassium based oxygen-sorbitol mix in a blender or coffee grinder for long enough to become exothermic? Your channel seems like a good place for such an experiment.

[@ElementalMaker]

Very cool idea! I just might have to try that!

[@mustafayasiraydin]

Great work keep them coming!

[@deathqueef69]

U know I have been waiting for this, thanks

[@SDesigns2023]

YuuuS!! Thanks for your vids! Always sick!

[@TheRocketeer]

I think the nozzle damage was caused by impact from the hard schmutz particles that were observed at the head end of the motor and collected on the nozzle. The pressure spike is usually caused by a void or crack in the fuel but in this case the hard particles exiting the nozzle may have played a role in it. I like to use poster board or file folders as my liner with two wraps to prevent damage to the case. Not enough thermal barrier may cause the case to blister or damage it. Great video and keep up the good work!

[@Spacedog49]

I agree with you, the nozzle damage resembles particle impingement impacts. Large particles passing through the throat area would reduce the exit area, increase chamber pressure, and produce thrust spikes.

[@rawfpv1207]

just curious but, how would changing the bottom inner diameter to same size as nozzle and the top inner diameter larger like a cone.

[@cyclo360]

Mate, love your vids, interesting and entertaining. With that voice, you should do commercial voice overs lol. atb from Adelaide South Australia.

[@ElementalMaker]

Thanks a bunch! Glad your enjoying the videos!

[@jordangipson1125]

That’s a hell of a rocket! That as an initial with maybe 2 slower burning rockets of equal or lesser value might a pretty decent candle make!

[@richardsolomon8076]

Wow wicked fast, nice job

[@seymourpro6097]

There is a lot of science in the differences between the grains. Grain by the nozzle can have a larger bore and maybe a finned interior surface, the grain near the closed end can have a smaller bore. Remember that the grain by the nozzle must pass three grains worth of hot gas without being abraded by hot gasses, then any abraded material hammers the nozzle.

[@MrKclo42112]

a trick I learned is to put a dab of Karo corn syrup in the mix it premelts a bit and the melting starts way sooner and the heat evaporatesthe water in it so it doesnt effect the burn rate

[@joshuabarosin779]

A 206s Isp for a sugar rocket is insane. A small tweak to your code for the arduino can allow you to launch it from your laptop where you collect your data. Basically you would be replacing the button with a code word, and using the serial monitor from the arduino to light your candle

[@JoshStLouis314]

Wrist workout leads to brief thrust, ending with crusty gunk. You know what content your audience likes.

[@ewouk61]

would you compare a center burning core vs an end burning core?

[@truckingjourneys]

I look forward to these videos everyday

[@timg.413]

I'd highly recommend using a thicker liner of sorts to help insulate the motor casing from the heat of the motor. Smaller motors you might get away with it but as you get bigger you'll start having failures of the motor casing and it would be a shame for such a nice casing to end up in pieces.

[@jamesmorton7881]

Know any tricks for a long burn time at medium thrust?

[@m3sca1]

Have you thought about putting a little grease in the nozzle to give it a little more oxidative resistance?

[@mwilson14]

Awesome man. I wanted to watch your video on Patreon when it came out, but I've been pretty busy processing the remaining rock etching waste solution containing the thallium salts. It's the most scary crap I've had to deal with to date.

[@ElementalMaker]

Yeah man that's some scary stuff! Stay safe

[@williamlivingstone4326]

Spectacular beginning 😂

[@mute8s]

Since black powder has such a fast burn rate (enough to classify it as an explosive) I wonder if that's what caused the blowout of the nozzle. If you feel your ignitor needs help maybe try using just a bit of some type of smokeless powder. Something like a pistol powder which burns faster. I would maybe try something like universal or unique. But that's just because that happens to be what I have on hand. What are your thoughts on this?

[@OrbitalRose_01]

next time you do one of these, can you measure the mass of the paper before you load it as well as the leftover mass to calculate combustion efficiency? Also are you going to publish the thrust curve data like you did with other tests?

[@HomeGrownPyrotechnics]

i suspect that what got spat out of the nozzle was probably the paper liner that was on one of the fuel grains. it would probably be a good idea to use a much thicker carboard, maybe like a cereal box. did the motor come with instructions for what liner to use?

[@buggsy5]

I have never seen a liner get spat out the nozzle, even when lubricated with Vasoline. The liner is plenty thick for his current propellant, but may need to be thicker for AP chemistry. I think Firefox, or one of the rocketry supply specialists, has some standard diameter liners that are specifically designed for composite propellants. Hopefully the casing is the standard 29 mm.

[@UpTriTie]

Nice video lots of time and care .

[@ejohn1164]

Crazy awesome video. Just throwing this out there... But have you thought about looking in to recording the chamber pressure of the motors? I have no idea how high the chamber pressure will be. But there are tons of repetitively cheap pressure transducers on ebay. I will even tackle modifying the code to output the extra data. If you think it is worth it let me know and we can go from there. Again... Crazy awesome video. Keep it up.

[@oussamalasfer4860]

Its thrust like sugar engine did you try to make sugar engine before?

[@backyardalchemy1223]

LOVE YOU TROLL FACE !!!!!! AS ALWAYS THE ULTIMATE BEST

[@stephenfowler4115]

You could try using wax paper to wrap your spindle to prevent sticking

[@lutheruchiha1163]

Great work! I would like to know 3 things: is it possible to get the same moulding tubes that you use (I am unable to make my own)? - How can I make the same 3-grain motor as yours? -How can I make nitrocellulose for my igniters? Thank you

[@shadowbanned-9577]

It expands... more wraps of paper to account for expansion...?

[@joelblevins]

Would love to see foley defense offering those casting casings to consumers willing to buy them.

[@buggsy5]

Put a thin film of Vasoline inside the casing before assembling. The grains will go in more easily and it will make the casing easier to repair. The nozzle damage looks like normal erosion due to the supersonic gas flow.

[@ujjwalraj7419]

How can we increase the burn time..... Plzz help

[@flihx2218]

I have to ask since i couldn't find the answer to this question: Why make 3 Grains instead of one big grain? Whats the advantage?

[@paulscottpadgett1996]

Much Respect 💪

[@acc4481]

Laxatives inside a long hard tube that spews legendary "potassium based oxygen"? Wow you're a force to be reckoned with, kind sire. :O

[@huppscustom]

Love that rocket tooling! The inconsistent data spike shows when the erosion happened at the nozzle. Pretty cool. You are correct the damage was from by product of the fuel. Debris moving that fast can do some damage in short work. When you move up to a cast Ap fuel using epoxy the burn is very smooth and powerful. Also very clean. Thanks for the video. Always entertaining! Go to firefox.com they have everything you need. Then go to pyrochemsource.com to get the AP.

[@ElementalMaker]

Funny timing... I just was contacted by a fan who had bought a huge lot of chemicals at an estate sale. Included were 6lbs of AP and a gallon of R45-M along with a quart of isonate curative. Luck had it he wanted to donate these to me and was within driving distance.... So composite motors will be coming soon!

[@huppscustom]

@@ElementalMaker O man that is great! You will really love these. I have formulas if you need any. I can help you out with anything you might be missing.

[@buggsy5]

@@ElementalMaker If you can find it, get your aluminum in multiple particle sizes. The major difficulty in making AP propellants is getting the approximately 15% aluminum into the mixture. Also, depending on the binder, you may want to get a vacuum pump and make a vacuum chamber to de-gas the propellant as it cures.

[@pj7362]

I wonder what the PSI is from the nozzle of the motor. Amazing the determination of nature, the elements if you will. How would you figure that ? Time to make my brain hurt.

[@jmar1371]

The primary job of the casting tube is to inhibit the outer surface of the grain. Observations... To prevent cracking a grain, you should pull the coring rods while the grains are still slightly warm.The "hiccup" in your thrust curve is due to a small internal crease in a grain created by your packing technique, and your nozzle(s) will benefit from the use of graphite inserts. And you might want to back off on the RIO a taste. 2% is a LOT of catalyst, even in candy.

[@Perceivedshift]

Can you slow the burn rate? A long burn rate with about 2k-3k grams of thrust average would be nice.

[@RichardCranium321]

As if the subject wasn't enough to get me onto gov't watch lists, the innuendos will no doubt place me on a very different kind of "watch" list

[@robrocksea]

Already on file, with a few notes going back to when I was a Kid. The last interview Pi$$ed Me Off so much! I asked if they knew how to read or if they bothered to run a file check 1st. They can't tell the difference between my Grandfather, my Father and Myself. The Only one I had any respect for being professional used too be the Secret Service.

[@jonassalk1387]

Occasionally I get a Similar thrust factor from 3 bean mix in a can. I find that Grains generally make my performance sluggish.

[@euclidallglorytotheloglady5500]

I haven't worked with it yet, but how do you think compressing a puck of satanite and machining a nozzle out of it would work? Don't know if a harder binder could be added??

[@ElementalMaker]

Very interesting idea! I need to get a proper hydraulic press for it to work though I'd think

[@euclidallglorytotheloglady5500]

A bottle jack and some pipe to cram it in. Again I haven't worked with it yet so I have no clue how hard it gets. Being in a upstairs apartment, I'm already pushing my luck with the lathe, anvil and animalistic sounds coming from here at odd hours.

[@designworksdw1949]

I wonder how fast you can fill one of those huge balloons if you stuck it over the end of one of these things

[@kensiyaka2081]

try a nother 3 grain motor, but make the final grain a slow burner with perchlorate, middle stage a normal sorbitol, then first ignitor a FeO mixt. this should give you a quick off the pad launch, then a normal burn then a slower continuous burn to reach maximum height as it loses fuel mass. somehow need to find a progressive burn instead of all firing at the same time. maybe a "degradable firewall" between the grains?something that lets the first grain burn 90 % before letting the second grain ignite and subsequent to the third..

[@noahhastings6145]

I believe your thrust was actually higher than what you measured. Your test stand showed some considerable deformation under load, meaning energy was lost and the normal force on your load cell was diminished. Because the normal force was diminished, your load cell did not deform as much as it should have, resulting in a loss in measured load/thrust.

[@SuperDd40]

I beleive that we are gonna have to watch this one twice also. ;)

[@kwayy9787]

forbidden caramel

[@Draakdarkmaster6]

thats a hell of a rocket my man, i'm kind of wondering what would happen if you used a tungsten nozzle instead of graphite, would its weight be an issue? it would undoubtedly be very expensive unfortunately but i cant see it being damaged by any of these tests.

[@sandmanbub]

Nice set up. I think you might find that by applying a thin coating of petroleum jelly to your motor mold's core spindle, the grain/propellent will be much easier to remove. The petroleum jelly won't contaminate and affect the burn rate.

[@ElementalMaker]

Thank you John. I do need to give petroleum jelly a try next go round!

[@drmarine1771]

lol crack me up. Love watching your videos.

[@shanek6582]

When you’re done you can make a form 1 from that casing.

[@benjaminbrown3939]

That is an Excellent Specific impulse, almost on par with NASA's Space Shuttle Solid Boosters.

[@firstnamelastname.7749]

No, he calculated it wrong, somewhere in the comments someone calculated the isp to be around 80, well below the over 200 for shuttle srbs. Sugar propellent should be around 110, so his isp is actually pretty low.

[@bunnykiller]

I was thinking it was a strong H or a low power I at the thrust you mentioned for a second or so....

[@ATINKERER]

Two things: First off, if you used one hollow grain at the nozzle followed by two solid grains you'd get a longer burn using your current propellant. Secondly, if you added some smokeless powder to the mix, by kneading it in to the propellant after the KNO3 and Sorbitol have been melted and are starting to cool, you'll get a lot more power. This high energy hybrid propellant would allow you to use 3 solid grains for a pure back-burn setup. However, one long grain would be better for back-burn. You should leave out the Iron Oxide in this hybrid mix.

[@rverm1000]

I want to try a softball bat as a motor. With a aluminum drinking canister cut in half as a nozzle for the motor. It would be welded on of course

[@wrinkyscarnagecrew]

If I could only KNOw what your secret ingredient is LOL

[@tissuepaper9962]

potassium nitrate? never heard of her.

[@rektangel333]

@@tissuepaper9962 he probably meant KNO3

[@tarstarkusz]

and when you're not making model rockets, you can make pancakes for the wife.

[@theterribleanimator1793]

In that hotplate, wifes gonna think she got the flu.

[@tarstarkusz]

Sorry if it's a stupid question, but why does the nozzle have to be graphite? Is there a reason why you couldn't just machine a new end cap with a nozzle built in made from the steel?

[@ElementalMaker]

Steel would probably hold up pretty well also, but graphite is one of the gold standards as its quite chemically inert and can handle super high temperature without melting (as metals can).

[@tarstarkusz]

But you _could_ use it if you really wanted to? I presume that such a brittle material would have to be redone periodically? Do you have a video of you making that nozzle? Thanks. Love your channel.

[@wrinkyscarnagecrew]

Wow I can't believe that didn't fail they machined that thing really good

[@buggsy5]

Bah, at that low pressure, there is no failure risk.

[@matg919]

Do the grains expand when out of the mould due to the humidity?

[@ElementalMaker]

The composition is quite hygroscopic so they will rapidly absorb water out of the air to the point of becoming a syrupy liquid mess. Keeping them in a desiccant bag keep the humidity down so they dont absorb water.

[@impatientpatient8270]

adding an additional 10 parts of sulfur to the red iron oxide spiked mixture makes it even better but be careful to not set it of when cooking it sulfur has a low autoignition temperature i always take of the pan a sprinkle a miniscule amount of sulfur on the heater and see if it's hot enough to ignite it so i don't set my whole batch on fire that would SUCK

[@orkblutt]

Hello, First I love your videos. Very instructive and fun ! I'm playing for years with rocketery using aluminium tube to make motors (still using KNO3+Sugar for propelant). The one your testing is amazing. I would love to get in touch with Luke Foley to buy some. Do you think it's possible ? Kindest regard

[@whitesmotoadv]

Where can I find the mold and the rocket casing?

[@ElementalMaker]

They are from Foley Defense. You can email them for the rocket motor parts price list.

[@Shashank0208]

@@ElementalMaker where can I find them on Instagram or do they have a website?!

[@tomothanrahan4467]

Is it sad Ik kno3 is potassium nitrate by heart at the point

[@pedrocaro6076]

I have been re-watching your vids and I just started into my own little project. would Fe3O4 or black iron oxide work just as red iron oxide???

[@ElementalMaker]

I do believe black iron oxide will work as a catalyst.

[@buggsy5]

@@ElementalMaker That is correct, either works fine. When fine tuning the mixture, a small adjustment in the amount of oxide is necessary.

[@mattparker9726]

why are you using graphite instead of something else like copper maybe?

[@ElementalMaker]

For the nozzle? Copper would melt very quickly, steel might for for a bit before melting. Graphite is about the only thing that can withstand those kind of temperatures.

[@franktedder1236]

Why was the burn time with 3 grains so much shorter?

[@ElementalMaker]

Likely because of the higher chamber pressures it creates a positive feedback loop causing it to burn faster.

[@truetech4158]

On a side note, did the griddle heat up and cause the green cutting mat to not want to remain flat anymore like heat did to mine? Guess it sure helped having a air spacer between the mat and the heat involved. Careful with that people or you will become disgruntled accordingly!

[@ElementalMaker]

No mine didn't warp at all from the heat

[@jhyland87]

Also, in regards to using your goo.gl Amazon link, people need to be sure to highlight the link, then copy that. If they right click on it and copy the address, they actually copy the KZbin redirection link that sends them to that; or if they have some browser settings that confirm foreign redirects then they would see that alert every single time. I suppose that might still work, but if KZbin changes anything it could impact that (but I suppose I could be wrong)

[@shanek6582]

Can you make a mock LAW rocket with shoulder fired tube or is that illegal? No charge, just the rocket.

[@ElementalMaker]

I would love to but I think KZbin would immediately strike my channel

[@shanek6582]

keith moore, that would be cool, I’d love to see elementmaker do that, get an old LAW tube to launch his model rockets through.

[@ozzymandius666]

Graphite can be compromised by oxidation. I've seen propane torches burn a hole in graphite crucibles. I wonder if one can nitrate sugar (or sorbitol) with fuming nitric acid?

[@ElementalMaker]

That's definitely a possible cause as well that I neglected to mention 👍 I found a couple old articles that tested the nitration of sucrose and they stated that it had little value as an energetic as it is extremely sensitive and prone to spontaneous decomposition.

[@ozzymandius666]

@@ElementalMaker Bummer. I guess that would have been literally too easy.

[@ElementalMaker]

Luckily there are tons of other easily available options for nitrations.

[@ozzymandius666]

@@ElementalMaker Like toluene and urea?

[@PotatoesAssistant]

What would happen If you dissolved both the sorbitol and potassium into water and mixed them so they’re combined kn a molecular level

[@benjaminmiller3620]

I think the solubility in water is too low. And they would tend to crystallize out separately which defeats the purpose. This trick DOES work on blackpowder though, because it allows the nitrate to recrystallize _inside_ micropores in the carbon. But that's because the carbon doesn't dissolve.

[@trulyinfamous]

I'll never get tired of that deep science voice. Also, could you call these rockets "Sub-orbital sorbitol?"

[@slngblde]

That rocket blast reminded me of the sugar free (sorbitol) haribo gummy bear reviews on amazon

[@ElementalMaker]

I've tried them and I can tell you it's identical 😂

[@edgeeffect]

At 5:41 that propellant look as though it'd be quite nice to eat! Years ago, I used to play with Estes model rockets.... this looks like it'd be much better but I'm pretty sure it's illegal here in England.

[@ElementalMaker]

I just looked into it and unfortunately it does look to be illegal in the UK. That's a real bummer as it's quite safe and educational. Looks like the only experimental rocket motors you can make over there are hybrid or liquid fueled. Quite crazy.

[@aldenhauser9555]

Amazon link saved!

[@ElementalMaker]

Thank you so much! 👍

[@darkfur18]

Get a custom tungsten carbide nozzle made... Almost the same melting point, and much harder