Testing The Biggest Rocket Motor I've Ever Built on Arduino Stand - ElementalMaker
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- čas přidán 23. 07. 2024
- Testing the massive single grain motor on the Arduino based load cell stand to get thrust characteristics.
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Link to Data set: goo.gl/5PLrd5
Parts I used:
Arduino Uno R3: amzn.to/2QhskRv
10Kg Load cell & HX711 Board (You can probably find better): amzn.to/2PohhAN
50Kg Load cell: amzn.to/2DVYHxo
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...
The above are amazon affiliate links which earn the channel a small commission and help me to produce the videos. - Věda a technologie
For a moment I thought I was watching the AvE channel. Sound just like him.
You may consider using one of those squishy ear protection devices to plug the nozzle... This will hold the e-match in place and secure any loose black powder, when in normal launch configuration orientation.
Damn that's genius!
Beautifully done, my friend. Can't wait till the next test! Keep plugging along!
I really wish more people knew about your channel
You and me both! LOL
@@ElementalMaker question why did the propellant go so fast
I found him exclusively because some other CZcamsr copied his video and he called such CZcamsr out on the comments. So I'd say the algorithm isn't helping a lot...
That's just the nature of this particular propellant. Its very fast burning stuff!
Maybe you should try 3lb black powder!
Hey,
I just wanted to let you know that you inspired me to start making videos. Your videos are great btw, and this rocketry series is awesome!
The LASQAD (loose and sloppy, quick and dirty) method for finding the area under the curve, insert the image of your graph into a Fusion360 CAD canvas, scale the dimensions and select the find area command.
Awesome job! Can't wait for the next one...
Great to see my cheery friend again.What can I say,"Bigger is Better" eh. Woohoo bud. Bring on the 6.3 my friend !
I'm commenting because yt promotes content that gets comments and I want your channel to succeed! I'm in school studying engineering right now and it helps so much to see these concepts in action.
I truly appreciate you commenting! I hope you are enjoying the content, and continued good luck at school!
Glad I found you. Great info on this channel.
That was a really cool video.
Can't wait to see more testing.
Super cool.
:D
Great video and rocket motor testing!
I'll admit that I know next to nothing about what you are doing, but I'm learning a little bit more with every video, thanks!
That casing/nozzle setup is absolutely farking awesome. The test rig you built is super cool too. Great vid, that was super interesting. Loved it.
Thanks Thor!
Hears, "TODAY!..." Expects, "A Treat Especial!"
Is this a doppleganger or twin?
I’ve been waiting for this video!! I’m happy now! 😊
Hope you enjoyed!
ElementalMaker Very much so! Can’t wait to see the results with the smaller nozzle! Hey, along with different nozzle sizes, have you given any thought to trying different shapes? I could be wrong, but I think a flat taper is supposed to work pretty well.
The simplest way to integrate over a dataset in excel, I think, would be to sum up all your data points, and then multiply by the length of the timestep.
Edit: Doing that with the data you linked between the marked start and end points gives me ~50.1 Newton-seconds of impulse, so the motor would be a class F, and your specific impulse is 68 seconds (an exhaust velocity of 668 m/s).
I've just done the same (worked out average thrust from data points, although changed start and end points you labelled)
So can back up Zuthal's Maths
Total Impulse = 51.61 Ns
Isp = 70.23 Sec
Eff Exhaust Vel = 688m/s
A smaller nozzle diameter/high chamber pressure should yield higher exhaust velocity and efficiency
Awesome setup
Wow...Congratulations ! Excellent video, well explained. Especially the terms most your viewers probably are familiar with but I wasn't. Thanks for sharing the experience, loved it...Peace
Thanks Grant! Glad you enjoyed!
I keep hearing this classic rock song in my head. MOTOR GRAIN!!!
Thanks Bud
Nice test
Great video! Awsome!
nice motor , nozzle and great cooking :) .. looking forward to 6.3 mill .. awesome ..
Great video! I love rockets.
Haven't seen you in a while. Glad you're good
Hey congrats on your first burn with that grain! I've been experimenting with KNSU cold packing rocket motors and they are a lot of fun!
It’s so cool to see this crap actually work after so long of working on it great job man hopefully you can get something in the air soon
Thanks! Hope so!
I love these videos!!!!!!!!!!!
I'd be interested to see the effects of fine Al powder addition on performance, though I'm not sure how safe it would be during the "cooking" step.
It seems like a lot of people are just calculating the total impulse, which I agree is around 50 N-s. This isn't the full story however, specific impulse or Isp is better way to gauge the performance of a rocket.
Isp = I/(m*g0), I being the total impulse, m being the propellant mass, and g0 being the local acceleration of gravity. propellant mass is 75 g (0.075 kg), g0 is 9.8 m/s^2, and I is 50 N-s
50/(0.075*9.8) = 68 s. Pretty good Isp for a sugar motor.
Typical estes motors can range from 50-80 s. The space shuttle SRBs were around 250s.
A cool program to check out, ProPep 3 uses thermochemical calculations to give you the optimum Isp for a particular propellant mixture. It also spits out other parameters that can help calculate the ideal nozzle expansion ratio. There are hundreds of chemicals to choose from it really helps when designing hobby motors.
www.rimworld.com/loggerusb/propep3/intro.html
how'D you get the Impulse/I
@@princemiro7241 Total impulse is area under the Impulse curve
Andrew Mitchell you just need to multiply each data point by delta t and add them up. This will give you a good approximation.
been wee-aitin for it! BLOW me away. side note, if you add an ad at the end ill "watch it"
Truly appreciate it Bob!
core shape makes a difference, a lot of the solid boosters are 8 prong star shaped
A bp acetone slurry in the core ensures that everything gets lit instantaneously. The powder doesn’t do near as good of a job!
brilliant
Cool beans thanks for that information see i did learn something today,my kids will be surprised....lol i can hear it now taught an old dog something new. Thanks again love your videos !
Glad you enjoyed Jeff!
Milk of Magnesia is pretty good, cheap anti-seize. Good power!
The guys at Morty Thikol did the SRB motors and stack for the Shuttle. Interesting how fast the motor peaks.
Nice video
Awesome!
This was a very cool video! Can’t wait to see some more tests! Could you maybe test out all the motors and nozzles in one shot? Load up all the casings you have?
I will probably end up doing a compilation video of the various motor tests once I do enough testing combinations. It would be an insane amount of work to mix and test several propellant combos and motor combos for one video. I might do a simplified version though comparing a few types of propellant in the same motor casing with the same nozzle.
Hello, how do you read the pressure force as you did and make a table accordingly as shown to you in the 10; 00 minute
Excellent video and beautiful test!! Just a recommendation, for best results during the measurement, you could put the test device in a rigid surface, because I suspect that the grass absorbs part of the rocket engine energy 8:32 and consequently you will measure less thrust (or a different curve). It would be curious to see if there is any difference. Your channel is awesome! Regards.
Thank you! Yeah I was hoping the 2x4 base would help prevent that, but it did visibly push into the ground a bit. Im sure my data is a bit low due to that. I plan to make some kind of more rigid base in the future.
I've done some calculations in R and seems like the area under that curve is 5107.915 g-s with absolute error < 0.55. The error (which is really small) is due to the adaptive quadrature method used for evaluating the area. It could be a little bit higher because of the Hermite spline interpolation done on the data, but still I don't think that could be problematic at all! The area is calculated on the raw data given, I don't know if there was some scaling to do beforehand
So the result comes out to be roughly 50 N-s
That is most certainly not the Isp.
Yeah I calculated 5096 g*s, in Excel. I just did rough area calc by taking difference in time data points * thrust data point and then summing them all up. riemann sum.
Yes the error is small. I think you're overlooking something. Don't you?
@@PaulHollandWheels Being the data without any error, the only error is in the evaluation of the area under the points which is given directly by the function in R! The resulting plot is very well-behaved so I would expect the error on the area to be small
@@Wompylulz I was just giving you a hard time . I'm in awe of people like you I really have no idea and it's right or wrong I don't even know for sure what the equation is I know it pretty cool to be able to do that though😉
Are these casting molds available to buy and if so, where?
Really nice video as always👍 keep up the good work
Will you ever build rockets that fly?
Thank you! I definitely will get something in the air soon!
~5107g g-s, so about 50 N-s. Happy to send you a spreadsheet.
I got a hair lower using excel but not far off. If rounded up what I get comes to 5kg so yeah not bad for a sugar motor with too big a nozzle. He's into midpower with an F motor.
I have to disagree with this value. Just by "eye-balling" a close up of your chart...ie: length of burn ≈ 1.15 s and the MEP (mean effective pressure) appears to be ≈ 2500 g so the product of these two would be the Impulse (area under curve) ≈ 3000 gram-sec or about 30 N-s. The MEP can be judged fairly accurately by eye, if you imagine a horizontal line that would split the rocket engine's graph in half area-wise. I estimated this line to be at 2500 g.
you should add a really small amount of copper oxide (or copper dust) and get a green jet.
Copper oxide works great for color in AP based motors, but on nitrate-sugar based motors there is just smoke :(. It does increase the burn rate a bit though! I will be using copper oxide in some future videos on AP motors.
@@ElementalMaker As you probably know, it is because the particular 'ammonium-based solid oxygen' you are referring to has Cl in it and can therefore act as a chlorine donor.
@@ElementalMaker also hybrid motors are pretty cool *wink wink*
@@hiddencow3272 hybrid motors are on the way 👍
Have you ever replaced the water in your hho generator? By the way I built a HHO generator using your design but with 10 cups.
I've replaced it a couple times so far. And awesome! Hope its working a treat for you!
There always that side of me that wants to see a failure but not so much on this awesome setup.
I second that.
I can't say I disagree! Although I would hate to see my thrust stand and electronics go up in smoke... Still though LOL
Fuk the pair of ye, I wanna see an explosion🙌😂
Wait I noticed something we watch the same videos!🙂
wrong x9
Very pretty.
Area under curve would be total impulse(just a sum of all the data points divided by the number of samples per second). To get specific impulse you then have to divide by weight of the propellant burned during that period.
Makes me wonder if a suppressor body (no baffles, or baffles removed) could be used as a high capacity engine case and nozzle.
The suppressor case doesn't have a nozzle, just a hole, so it would basically be a cylindrical pipe section...
Where can I get the whole mold kit and a 1, 2, and 3 grain test case please?
Hello! Great video :) The proportions of sorbitol and potassium based oxygen which you used on the mixture are molar or massic?
Do you have a video where you fly the motor? Would like to see that.
Taking 1.2875s of data, the total impulse was 49.89N-sec, for an average thrust of 38.75N. You could call it an F39. Thanks for sharing the data!
How can you order those k.f.a. stainless rocket fuel pod molds and the nozzles and those perfect aluminum tubes with threaded ends from Foley Defense
They are pretty damn awesome! Im not sure if the regularly sell them, but definitely try giving Foley Defense a call!
THE MAN!!!!!!!!!!!!!! +1
Hey alright! Awesome. Still haven't used my rocket motor Dynometer. To cold here.
Keep up the good work. Love the vid's. Approximate power of motor = (RMS of Peak) x time. As it was a pretty smooth "bell curve."
The area under the curve, using a trapezoidal riemann sum, is 5108. This is calculated by summing A[n] = Δt*(x[n]+x[n+1])/2 for n = 1...N-1 (Δt is the time step size, so 1/80s).
That's a spicy-a marshmallow!
I'm a big fan of your channel! How do you calculate the diameter of the core rod for optimum thrust without blowing up the grain/engine? What percentage of the OD on the engine grain is the diameter of the core hole in the engine?? 25%?? Thanks
I see Sorbitol was used but what did you use as the oxidizer KNO3, KCLO3, or KCLO4?
KNO3. KCLO3 is far too reactive to be used in rocket motors. KClO4 is one I haven't really tried for motors since I have NH4CLO4 available
Is there any chance you will make these parts for sale at some point? (talking about the metal casing and nozzle etc.) I would love to have something like this.
These were sent in by a viewer who is big into rocketry and has a machine shop. Sadly these are out of my league to make with my dinky little lathe. You can reach out to Luke at Foley Defense and see if they are selling these
after watching some of your vids the term lubing your shaft definitely has more than one meaning!! Birchwood Casey choke tube lube might be better for the threads, seeing how it's made for shotgun choke tubes. they tend to take high pressure and heat in extended firing sessions at the range, i've had pretty good experience with it! do you think the slight overheat may have sped up the burn rate any? i expected a bit longer burn for it being that sized motor.
"A double entendre!", he ejaculated.
What happens to the excess motor propellant, can it be used again or does it need reheating? I have never played around with rockets so I have no idea.
I expected the motor to burn fast, but not that fast.
The left over propellant from casting can be stored with desiccant until needed. From there you can just reheat on the skillet and cast another grain.
any word on a price for that wonderful mold and motor casing kit? I suspect its well beyond what I can afford but you never know :-)
I already 3d print my rockets. I wonder if I could 3d print a propellant grain? mix the powders into a filament? I doubt it would work but would be neat if it did !
I have no idea if they are even willing to sell the motor kits, but you can try reaching out to luke foley and seeing.
In the US, HPR casings are available from various manufacturers. There should be some manufacturers or resellers in Europe as well.
Why not heat the side of the chamber so that it melts and settles easily ? And also can u do a video on different oxiders? Like I used patassium permanganate instead of potassium nitrate to make gun powder(kinda worked) research the different types of oxiders
Hey what would make a hotter burning thermite to melt through half or quarter inch steel, and LOVE THE VID!!!
More thermite LOL
in the future it would be interesting to know more data on the motors, like the mass before and after the burn so we can know the percentage of propellant burnt.
Awesome video man! Anyone ever said you sound like Negan from TWD? Because you do. (Not a bad thing)
I've heard it quite a few times! LOL
Have you ever used a octo-star core rather than that smooth cylinder?
How much did overcooking the propellant effect it's burn and thrust?
Overall very nice.
I haven't yet but plan to in the future. That core geometry gives an incredible thrust curve. The overcooking likely decreased performance very mildly, since it was just barely caramelized. I will have to repeat the test with a fresh grain to quantify any difference.
What's the material you use as the motor case???
You should have a cover over the Arduino and a warming box for the laptop so it stays live for you.
Also what about using flash paper instead of black powder? I would think that might be a little bit cleaner.
WooHoo! So, what is the limiting factor for the size of the grain? Could you make one twice as long for twice the burn duration, as opposed to two stages of the same length?
Is the limiting factor nozzle erosion?
This is the only channel I find myself referring to repeatedly to. Like school texts.
My test stand is complete and I just graphed an old Estes A8-3.
I drilled holes in the pvc and hold the motor in with those squishy ear plugs. 3 of them hold it through the ejection charge.
I added an igniter continuity LED and a 1.8" Display (invisible in full sunlight) Might need a piezo buzzer....
Long comment to bump CZcams Algos.
Thanks for the great comment 👍. What kind of thrust did you get from the A8-3?
@@ElementalMaker 968g peak. Wish I could post pictures... Just posted the graph on twitter: _Mycroftxxx
@@_mycroftxxxadamselene922 wow pretty impressive thrust!
@@ElementalMaker I was surprised. I bought these about 10 years ago. Thought they would be trash. (But I live in the Phoenix, AZ area) Even the igniters still work! with 9ish volts.
@@_mycroftxxxadamselene922 black powder doesn't go bad as long as it's kept dry! Graph looked beautiful. Great data 👍
can you tell us how you record all that data and what are you using with arduino to make all this ?
he did a video on that like a couple weeks ago, check the channel, its somewhere recent
I use paraffin wax for my spindles. And you can put 2 to 3% of powdered graphit in your grog or bentonite clay. I use a bentonite powder, clay litter, and graphite in a mix for my nozzle and bulkhead. That's a good idea tho
If you want to integrate that you just need to multiply each data point by delta t and add them up.
Nice experiment and great maker build. Have you considered trying Matlab or Freemat for analyzing your data? I think there might be something there you could use.
Ill have to take a look at them! I cringe hearing Matlab after my college experiences with it LOL but that was some time ago.
You should get ahold of some MACOR!
It's a machineable ceramic. Could be just the ticket to avoid eroding graphite nozzles. Should handle higher pressures as well for lower nozzle dias.
how did you build your tester? that would make a good video
Check my other videos and you'll find it 👍
Just out of curiosity, where is it you're getting the casings, nozzles, and casting hardware? A lot of what I found online is just single use stuff rather than metal
Search on High Power Rocketry.
Have you tried extruding instead of casting?
Someone propably asked already, but I can't find an answer anywhere... Where to find this cooking plate you're using?
It's just a cheap electric skillet I got from Walmart. I'm sure you could find them anywhere. Just be sure you have a good infrared thermometer, because you can't trust the temperature indicator on the skillet adjustment.
To get your total impulse a quick way would be to take the average of all your thrust data points and multiply it by the duration of the burn. Might have to convert thrust data to a proper force unit of Newtons though.
For the area under the curve, just sum all the data from START to END, and multiply the result by the timestep Δt (time between two consecutive measurements).
A = ~5098 [grams-force seconds] = ~50.01 Newton seconds
That's because you're building the area from little rectangles.
Every rectangle has height=value in grams-force and width = Δt.
=> Area of the rectangle is Ar = height * width = value * Δt
So we just sum all the areas:
Total Area A = ∑i (Ar_i) = ∑i (value_i * Δt)
But since Δt is the same across all rectangles we can simplify that to:
A = Δt * ∑i (value_i)
Wow I didn't think how simply I could have calculated it! Thanks for shining some light into a dim section of my brain 👍💡
@@ElementalMaker
Yeah, that's why I like discrete math stuff xD
I've also made a spreadsheet with graphs and other cool numbers.
Maybe it could save you a little time, so you may want to check it out: goo.gl/n1HqdH
Thank you for the good content!
@@ElementalMaker Use rectangles where the curve goes through the center top of the rectangle. This approximates better because it takes the somewhat triangular section of the segments into consideration.
You can use different width rectangles - as long as you also use the appropriate time for each segment. It is even possible to use horizontal segments, or a combination of the two.
have you tried to do multiple different ones like one of the fast burn (with the iron oxides) and the last one is a normal so that it has a lot of thrust and then it goes into the normal for long burn and yada yada and then have the burst charge to make a awesome rocket. should do a video of making a rocket and letting it fly
Would be interesting to see you try and maximize the burn time instead of thrust. Good video.
IIRC you can add corn starch to lengthen the burn
Why not use a icing bag or large syringe to fill it or even better pile it in upside dow without rod init then push rod through it with it flush to the table it will compact better.
It is not NASA who cast the motor segments for the shuttle boosters. It was Morton Thiokol (later ATK, then Orbital ATK, now Northrop Grumman Innovation Systems). I know this because I interned there.
Yep NASA doesn't cast rocket motors. There were a few other's out there who cast rockets and tried to get the contract for those boosters... like Thiokol's old competitor Hercules (who was later bought by Thiokol/ATK)
@@stoneworld7556 Yep, Hercules cast the motors for the Titan III, and Titan IV rockets back in the day. That plant had over 6000 employees working and they were in full production. In fact, that is where I was, I just know so much about rocketry that I knew who really made the shuttle boosters.
Sum up all your data points and multiply by the time interval between samples, yes?
your loving that lube lol
I think you want "total impulse" which is the integral of force and time (area under your curve.) Each row in your SS is a "slice" of time - say 0.001 seconds. So, each row needs to be converted to Newtons (x 0.00981N/g) then multiplied by the time slice (0.001S) and then you SUM() that up.
Ok I made the sorbitol rocket propellant and it did not have liftoff. I don’t think it burned fast enough. Should I add some red iron oxide?
Way too many potential variables to know what the issue was. You would need to give me all the details of your motor.
@@ElementalMaker well i made it out of pvc 1/2". i think the problem might be that it wasnt cored well. my coring thingy broke off so it only went half way in. thats what im thinking
@@ElementalMaker also my nozzle wasnt very good. it was just bentonite clay and it blew out instantly.
Weigh the cut out curve and weight a square inch of the same paper and you can compute the area
oh i see you got inspired by the yellow thing from the last video
That I sure did! Nearly there! LOL
How do you calculate the proper nozzle diameter for a given motor?
There are actually some rocket motor calculators online that can provide all the parameters of motor.
@@ElementalMaker Thanks! Rusty, last time I DIYed this sort of thing was 1976 or so. A while ago and pre-Web :)
If something blew up, the nozzle was too small - so make the next nozzle with a bit larger throat.
If it was successful, it may too large, so make the next nozzle smaller.
If you haven't yet, you could change to a more powerful graphing software. For midrange stuff and making very pretty plots, I recommend Kaleidagraph