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PSHHH PSHHHHHH, PSHHH! (That says “Great work, Tom!” in RCS)
Google translate won't help me write a reply
Tom Stanton lol
I follow you both. It was really cool to see Joe on your channel! Keep up the great work and content guys!!
Or "HOW DARE YOU SIR!"
You low key look like Elon. 😂
So cool! The idea to convert the throttle values from a standard flight computer was really clever.
Thanks Grady!
I was surprised a simple, naive threshold worked so well!
Yes, exceptionally clever considering nobody else anywhere, ever thought to do the same thing. An original comment for an original idea.
@@alphaforce6998 This feels alot like sarcasm
@@calebsherman886 I think we can build a test rig to help determine that conclusively.
Is it a bird? Is it a plane? Is it a flying submarine? No, it’s just one of tom’s creative inventions
It is a drone. (Or if you mean that man there? He is Superman.).
2 words: pressure regulator. Tune the system for (pulling numbers from thin air), say, 40 psi. Install a pressure regulator and set it to the aforementioned 40 psi. Fill the bottles to the max pressure your compressor can output: 116 psi, IIRC. The regulator should regulate the 116 psi down to 40, giving you constant, predictable & repeatable thrust until the bottles drain to below 40 themselves. Problem might be finding a pressure regulator with a low enough mass to not overload the drone.
Frederick Evans 72 words actually
@@Trxps-_- lol
yup. completely right dude
So much this, pressure regulators are required for any gas system. Micro pressure regulators do exist and the lightest one seemed to be from landefeld. Their R M5 series is lower than 50 grams and rated up to 8 barg(2L PET bottles seem to hold up-to 150psi which is around 10barg, he tests the flights with 100psi) but additional setup will certainly be higher than 50g.
The mass is the problem here. He would probably get less flight time then he would gain from them.
This guys playing kerbal space program in real life Edit: if you edit a comment you lose your heart.
*JEB NOOOOOOOOOO* **Boom**
What's a "space program"? Some new computer simulation?
Oh hey Ryan M, it's me Ryan M
Needs moar boosterz.
@@alphaforce6998 its fun try it kerbal space program
"Let's just admire how little thrust this system actually produces." Love it.
If it was in space though a little thrust is all it needs, it could actually go quite fast.
I recall that years ago there was a small group (I've forgotten the name, unfortunately) in B.C. or Washington state that was sending soft drink water rockets over 1000 feet. They modified the bottles by wrapping carbon fibre around them using epoxy. These bottles were pressurized to as much as 2000 psi. Part of the success at reaching such heights was that they used dilute water/dish soap along with air for propulsion. They just poured it into the pressure vessel bottles before charging. As I recall, the most difficult problem was coming up with a reliable and safe way of setting them off. Another observation for this project is that you don't need a separate bottle for each nozzle, in fact it may be counterproductive to do so. Interconnecting the bottles would provide a more consistent pressure at each nozzle. Or add more bottles. Or make a custom bottle that utilizes all the dead space currently existing between the separate bottles.
This guy looks like a hybrid of Elon musk and Mcauley Culkin
Lol
Nailed it
My exact thoughts
Steve Buscemi haha
And he runs like Dr. Evil
You need to have a converging nozzle. Diverging nozzles like the rocket nozzle are for supersonic flow!
This. Thrust comes from acceleration of the fluid. Even better, use the air supply to drive an air multiplying housing instead of using it directly. For those who haven't heard of air multipliers they are industrial devices with no moving parts, powered by compressed air and used to move air for ventilation. The Dyson fan uses this concept.
That entire part of the video was so frustrating to watch!
You can see at 6:22 he uses a converging nozzle. He probably changed the design after being told but didnt explain it in the video.
He does have supersonic flow. Going from 6 bar to 1 bar will give you supersonic flow at the nozzle throat.
He can't have supersonic flow at all, no matter what the gas pressure is. The reason rockets have supersonic is the fuel is burned, producing the shockwave, which is funneled through nozzle.
Whoever wrote the subtitles deserves a medal.
"Yes I'm typing this by hand"
@@Faldrian when does this come up? did not see it-.-
@@RCP-1136 19:50
@@RCP-1136 Look for the flight test part. :)
The pure joy on your face @ 12:14 when it's working is absolutely heart warming. I love seeing this level of human emotion. Especially during moments of triumph. Keep at it brother! You're awesome!
15:35 I love that sci-fi sounds this drone emits during liftoff attempts.
You need a converging nozzle cause you have a subsonic air flow passing through it. The higher the pressure in the tank the narrower has to be the nozzle and the more thrust you'll get out of it. This is true until you hit mach 1 in the nozzle narrower section, at that point you'll have to start increasing the nozzle section in order to further accelerate the air flow.
6:18 he did end up using a converging nozzle
@@Zaros262 but he didn't use the expanding nozzle after the converging section
@@junovzla It likely doesn't reach Mach 1 anyway, so it would actually be bad to have a diverging section.
i love how he called one of his rockets "Thrusty McThrustface" :D I'm guessing this is a community effort? :D
yes, muh macmuhface
There is a submarine named boaty mcboatface
muh1h1 mc blank face , comes from the idea that when u insult someone you call them a FUCKFACE! the mc comes from .. mc lovin. so. mc *insert word* face
The creators of a polar research ship invited a public vote to name it. A prank name, Boaty McBoatface, suggested by a radio dj, went viral, and won. But the owners rejected it in favour of 4th place vote, RSS Sir David Attenborough. They did, however, give the name to a small, unmanned research submarine. It's a well known story here in the UK, hence the jokey Thrusty McThrustface
@@hgwells1899 i know the story. I've also heard about a city who introduced a new machine to throw salt and gravel on icy roads and asked the public for names. The winning entry was something like "itsy gritsy teeny wheeny yellow anti slip machiney" :D
When he flicked that self level switch on the controller it made me smile from ear to ear. That was really very cool to see working for the first time. This whole thing is amazing.
Love how encouraging your dad (I'm assuming that's your dad) is in so many of your videos... He has every reason to be incredibly proud.
Can we be best friends
Elon living a second Life as a de-aged clone. Man is rich enough
Most underrated comment on this video! He sure does look like ELON and also trying to do basically the same thing ELON is conducting, which is to say, bringing back and landing a rocket on its own!
i am convinced this is actually the truth. @elon musk. what did we win?
I cannot deny that .. looks suspious
This guy isn't an evil supervillain however
Except Elon isn't an engineer and hasn't really done anything worthy in terms of engineering.
It would be great if you attached an LED at each corner connected to each valve. That way you could slow down the video and watch the valves operating 🤔😜
Wow awesome idea For slow motion tuning like a black box for your eyes to see what's taking place or needs to.. u guys are amazing
@@cenabitednbfpv587 Exactly!
The joy of getting a project behave as expected is unparallel. Great work, this will help engineering students who are studying control systems and have no idea where it's going to be applied.
0:32 "Let's talk to someone that knows more than I do" *Elon musk enters chat* 🤣
Yep, that guy is looking like Elon Musk and does simmilar things.
0:42 i literally JUMPED from my couch when i see joe im huge fan of his rockets
De Laval nozzle. A narrowing of the flow increases speed of the flow and thus thrust (that's how subsonic jet nozzles look like). The widening is only needed if your flow reaches the speed of sound at the throat (supersonic jets and rockets). Wikipedia has a good overview.
It should be able to go sonic when the pressure is roughly twice atmospheric.
Thanks for chiming in with what you read on wikipedia. Clearly all it takes for anyone to become an expert on any topic is a cursory scan of wikipedia, and off you go to a comments section to dispense qualified advice.
@@alphaforce6998 Wikipedia is not always wrong, or even wrong half the time, and he never admitted to being an expert. Anyways this not even anything complicated, it's like if the guy was asking what 2+2 is, and this guy replied 4, you don't need to be a mathematician to be able to learn that or even find it out yourself.
@@dapz Well, that's the thing - nobody was asking anything... And he would have first consulted wikipedia's entries about the number 2, addition, and basic arithmetic.
@@alphaforce6998 What seems to be the problem? Looks like the only thing wrong here is your attitude.
Can we all take a second to appreciate the fact that tom typed all the subtitles in this video by hand
Excellent! From here in the States, Bravo! It sure is green where you are! Thanks for sharing and the very best of luck.
There is a simple way to have a compressed fluid that doesn't change pressure as it is vented: use a liquid that boils below room temperature. Propane should work (though the pressure gets sketchy-high for 2 liters on warm days). If flammable propellants aren't your thing, then "canned air" should also work. Using boiling liquid has the added benefit of being able to carry much more propellant in your tanks.
dry ice would definitely similarly very high pressure, a pressure release valve might help mitigate that
maybe chemical gas generator? CaC2+H2O or something like that?
Well spotted! Propane has a density of 493kg/cm3, while compressed air has just 1.2 kg/cm3, that's why using compressed air you need an unbelievable amount of pressure to stabilize anything (rockets/drones/etc., etc.). Please check the propane gas thrusters created 5 years ago by Amazingdiyprojects. He created this system for his steam model rocket motor. If BPS will use propane, booya, we are going to see some serious fireworks. :-)
oh goodness, i just realized what would happen using propane with a solid rocket propulsion mechanism
Did someone actually suggest venting propane for thrust instead of igniting it? We must be at a genius convention here... Maybe you can just power the drone by getting an extension cord and plugging it into itself for abundant free electricity.
for a better control system: pulse the valve on and off at (relatively) high speed and you essentially have throttle control. instead of a simple gate you could have more like a minumum and from there to maximum it scales the pulses.
Not sure if solenoid valves are that fast
I don't think the valves can move that quickly
Pulse width modulation? If the valves can react fast enough that would work.
@@arnavjain7564 to expand on why I said relatively, there is an absolute minimum time to open the valve and another time till closed, which will result in a limit to the maximum cycle frequency. I understand this reality. It certainly won't maintain RC PWM freqs, but something alike PWM done in Hz frequencies is what I have in mind. I'd keep the gate on the input, but make it trigger lower. if the input > gate, then the thruster should start a cyclical pulse who's duration is proportional to the magnitude of the input (up to 100% duty cycle for a 'full throttle' command). Many smaller pulses should use the same amount of air as a few big pulses, so I don't think we'd see a huge drop in efficiency or anything. These are test bench questions to answer. In full size rockets utilizing RCS's in space, they don't deal with any of this because they're not inherently unstable balancing broomsticks quite like a wingless thruster in an atmosphere is. The RCS activity looks like a few 'pings', followed by silence as the ship rotates for a minute, then a ping or 2 more to stop that rotation. our implementation would need to differ in this regard to account for wholly different stability circumstances. I also implore Tom to revisit the nozzle. the bell of a rocket nozzle is useless without first accelerating the gasses supersonically with a throat restriction. The bell was also simply too big, in my estimation. The bell of an Estes rocket motor is smaller, and that motor produces hundreds of times the thrust. just saying, possibly a lot more efficiency could be squeezed out by looking back at the de Laval design principles. It is also 3D printed with FDM, meaning the inside is ribbed with a repeating half circle pattern. this will mess up your boundary layer flow which means turbulence which means loss in efficiency and thrust. Tom, if you come up with another nozzle design I can print it with an MSLA machine, threads and all, polish the interior surfaces with a lathe and ship them to you. Otherwise I'd look into acetone vapor polishing the nozzles printed in ABS. I also have the setups for doing this if you need.
@@chrismofer yea a couple hertz like say 5Hz should be possible i think
I love how you get enjoyment out of the "failed" attempts.
Love it...happy nerd. One suggestion...fill it with smokey air. Then you can see the thrusters actuate. Still great...keep it up.
Smoke! Great idea
smoke and a red led together...
Guy owns a rocket called "Thrusty McThrustforce." ㅋㅋㅋ
*face
No dip, Have you ever seen his channel!! "In thrust we trust"
my first and only thought was air flow being drawn down around the bottles causing un-even disturbance with the thrust, was this looked at with your testing. ...cheers Tom. i'm enjoying this
Love all your videos! Something about the sound of air control surfaces that dazzels my mind.
He also does look like jr version of Elon musk lol just saying XD
He looks like some sort of Neanderthal
thought that aswell lmao
his friend looks like baby of Mask and Zuckerberg 😊
I know, right? I realized that myself after a few minutes of looking at him, then it clicked
He might be a elon clone who knows
Now what I want to see is using flammable gas, and igniting the gas when fireing the thrusters.... THAT would be awesome....
I would like to see heavier fuel, to perhaps set stuff on fire.
why not hypergolics??
@@kadmow Hypergolic fuels are, to say the very least, quite toxic.
@@astrofox2409:yep, I realise.. but... think of the Coolfactor with a hydrazine and di-nitrogen tetroxide mix. Lol. (It was a joke "obviously")
5:43 2 years late to the game here, but it makes sense that the straight through nozzle worked best. Rocket nozzles only work well because the fluid reaches >= mach 1 at the throat, so the expansion of the fluid afterwards increases the speed. In subsonic fluid flow, fluid expansion causes it to slow down, and the bell nozzle expands fastest, losing the most velocity in the escaping fluid. If you wanted the escaping air to go even faster, invert the bell nozzle so that it tapers down to the throat.
Tom, this is fantastic. You are an inspiration in ingenuity and perseverance.
Not gonna lie, legit had me for a solid second thinking Elon Musk was the skype call... (watches video more...) Close enough...
Same
for a second I was really surprised
He does kinda look like a young Elon.
Same
Same.. looks very much like a young Elon Musk..
You should put diy ice in the bottles it will make that cool smoke affect while also giving you TONS of pressure
Co2 pressures will burst those bottles
@@ipodhty not with a pressure regulator....i think you could have sort of a manifold who let some reactions occurs at a selected low pressure threshold...., by timing the chemical reactions.dry ice with air might be touchy to control in time since it active with oxygen. im no chemist but neutralizing some acid in little timed quantities might be a pretty neat iea .you make the reactions take place one at the time in a 4 thicker bottle that feed the 3 others and have a pressure regulator...Still you will have weight that's reduce in flight to program in the arduino.
That was an excellent project. You had good results far faster than with the reaction wheel controlled drone.
A good attempt is never a failure. It is merely one more step to the goal. Keep it up, I want to see it fly.
Great stuff Tom. expanding nozzles need a gas with energy to do the expanding , compressed air has little additional (heat) energy.
@Rick Lokers IF it comes at high pressure, which is not the case here
Yeah, also for any nozzle you want speed for pressure which is why the constricting worked best, though it could probably be optimized a bit further. The exceptions for the energy rule is entropic explosives and low speed deflagration combustion, in essence the actual rule is that the bell nozzle and aerospikes wants supersonic flow of propellant, which in essence mean combustion products.
Wouldn't it work better if he reduced the flow BEFORE the expansion nozzle? So if he used a 2mm supply line that fed into a nozzle that first reduced to 1.5mm THEN expanded to 4mm wouldn't that work better? I'm not sure what the most efficient numbers are but you get the idea, right?
@@leveckfamily8841 Not if the flow isn't supersonic, if it is super sonic there are other reasons to avoid it sometimes like structural integrity, but in general then it's a good idea, in those cases you need a different type of restriction though.
@@leveckfamily8841 the best would probably be a diverging nozzle with a small throat like the one he settled on (≈2mm) and that expands to 4mm or 5mm. Also it would probably be a good idea to sand it smooth to decrease drag/turbulence
You could probably gain some efficiency by also ducting the nozzles. Venturi effect etc.
The venturi effect may increase the velocity of the gasses, but it doesn't change the mass, therefore doesn't change thrust. The nozzles actually increased the surface area which increased drag which reduced thrust.
Andrew Krause you trade pressure for mass flow. Just what you want. The ducts around the nozzle would work somewhat like the duct around the prop.
@@andrewakrause p=m*v F=dp/dt
@@andrewakrause Yes but the trust equation is a function of mass, flow, and velocity. Thus it would increase.
Try it, let us know.
I have no use of the information on this channel in anything I do. At all! But I just jump up and down of joy every time I see a video popping up from Tom Stanton and his fight against gravity!!! :D
The drone gas thrusters are awesome! The sound tho, it's very satisfying! Its like a spacewalk when people carry thrusters to control their direction. Exactly sounds like that.
Add a pressure sensor to the tanks, create a lookup table for each pressure level that adds or removes bias from your valve timing values.
The exact pressure is not critical, so maybe the weight and complication of a pressure sensor can be avoided. If you started with variables for pressure and volume, then you could calculate how much gas comes out of a nozzel during its on period. Updating a remaining-volume variable would enable you to predict the remaining pressure which feeds into the calculation for the next nozzle release. In this way you could compute the pressure to use when compensating for loss of thrust. The arduino board that is converting a gradient signal to on/off might be able to manage this between thrusts.
Are either of you guys control systems engineers?
@Jonny B i asked bcause i had a PLC question
pid values*
less gas more time.time must be scaled !!!!
I absolutely love seeing two KZheadrs I watch independently collaborating
If the valves can open and close fast enough you could use Pulse Width Modulation instead of a plain threshold. I imagine it'd just give a bit finer control when under the threshold for plain on/off (but above another threshold defined by how quickly the valves can pulse).
The moment you put it direct to the gas too nice!!
NASA's flying bedstead DIY style. Just needed a pilot to eject prior to the crash. :-)
You actually want a convergent nozzle; you're not supersonic.
Yep, he's also using only expanding part of "rocket nozzle". And straight nozzle is not that bad, subsonic flow converges and accelerates in straight pipes because of boundary layers (of course it's more noticable in longer tubes :) )
A CD nozzle requires a heated gas or fluid since it uses it's expansion to accelerate it. However if he heats the gas the container weakens and may melt if heated sufficiently, since the gas is less dense you need a larger container, this grows perpetually and you end up with a big tank that's supposed to fly that but support itself, if he heats the gas outside the tank sufficiently he needs a large heater. It works for rockets because rockets use combustion engines where the combustion occurs outside the tank and because it's combustion at all it's extremely hot.
I think he should consider Venturi Effect in the design of the thrusters. I think something like a Dyson "bladeless fan" air-multiplier would move a lot more air in the intended direction (and increase the moment on the vehicle for the same cost).
That exists, and I believe is called an ejector nozzle(?).
@@perfumedmanatee6235 - yes, thanks for the reminder. I know I've seen this before somewhere...
So we all going to ignore the fact that Elon has sent a clone of himself back in time.
See my post above!....lol
Nice work Tom. Redirect the perseverance. Enjoy the development stages.
I love your work, and this is another awesome example, but I wanted to also praise you for something that most people probably don't even notice: putting on safety glasses. Always gotta have the right PPE!
And he took them off when the pop bottles were at 100psi...
Best part of vid was to see you giggling and enjoying every little step to the final success !!👍💪!! Nice to observe pure dedication !
Spectacular levels of intelligence and determination and ingenious between these two minds 👏
I think for a prototype you done a great job fantastic job for a young man
No ways, you never cease to impress me Tom!
I don't know if the bottles are connected to each other, but if they aren't it's probably a good idea to do so. This way you don't have differences in pressure per nozzle. I know it might be obvious but it's just something I thouht of. It's really cool to se a drone being controlled this way, you just keep being amazing!
Yeah if it is windy and the drone is trying to tip the one bottle gets used way more
At around 17:45 I believe what is happening is ~simple inertia buildup~ defeating the ~air thruster's~ ability to manage any control over the inertia created by the swaying "back and forth",, which with each additional sway motion, the air thruster(s) aren't a match enough to maintain any stability! The solution in simple terms is, how do you increase ~air thruster response~ to the increase in simple inertia created by inertia and gravity!?! Increase the psi in the air bottles??? But air pressure availability is finite! Unless you maybe try ~vectoring the lift air~ somehow,, or,, maybe add a sort of ~Kites Tail~ directly under ~dead center~ of the fan motors and maybe the kites tail will give a natural control over the wavering side to side motion???!!! Love your work!!! Cheers! Sonny.
Congrats! I'm sure that this must have been one of the more satisfying projects for you to work on. It was one of the more satisfying to watch. Good on ya dude! PS... Joe actually LOOKS like a young Elon!
Such an enjoyable vid ! Your explanations are on point ! Thanks ! 👍🏻👍🏻
I remember my professor saying something along the lines of "that's the method of tuning the PID controller, but to be honest, you'll probably end using trial and error"- I guess aerospace buisness holds better standards than some backwoods uni:] That drone flew quite well for "eyeballed" values! I saw some drone projects using 3 motors instead of 4 and I was wondering why it isnt't a standard configuration- you managed to clear this up with one sentence about propellers induced yaw change:D
It isn't even about holding higher standards - it is absolutely normal to make informed guesses with control systems. It's just that cost of making mistake with rockets is incredibly high. Properly and precisely calculating right control parameters is incredibly complicated and time consuming, for even simplest of cases.
It's sad that he already had the test bench setup to measure minimum thrust at minimum opening time for the valves. It would have been easy to setup a reference table in the Arduino, and given better control at near-zero pitch/roll
For some of these drones, you may want to consider designing the arms at a slightly upward angle. This is commonly used to improve a drone’s stability and, even though it’s mostly only for propeller drones, may help your case a bit.
Thanks Tom, It was really nice to hear the birds tweeting away in the background in the garden
Seriously impressed! Engineering was a completely different kettle of fish in my day. The first cnc machine I worked on had a computer the size of your kitchen fridge.
Cool project! I really like how you use test stands instead of simulations.
You should try a nozzle which gets narrower up to a certain point and then wider again. When tuned correctly the speed of sound is reached at the "waist" of the nozzle and the gas accelerates before the waist and after the waist. Which leads to maximum momentum of the gas. I think this technology is also used in rocket propulsion
I think you are right, but the nozzle would have to be super narrow and he would need to calculate the width. I think it's a good idea but it's to complicated to be worth it.
this is a de leval(?) nozzle. tom was on the right track with the bell nozzle, but it's far far too big and only going to decrease his thrust.
*See.....the straight nozzle has the most thrust. The converging nozzle is a straight nozzle...you're just increasing pressure before using a straight nozzle.* Very nice video so far. Back to the build.
Great closed-caption subtitles!
This is great! I think you could put the same bottles, valves, and micro-controller on an air bearing (like an air hockey table) and maneuver like a satellite in 2D.
Looks like you need in-line pressure sensors and variable solenoid valves instead of binary. Great job man! Really impressive.
He can do the pressure part in software. The computer knows how long it was firing, and he can separately figure out pressure vs time. Then it would of course need to be started at a specific pressure. But it saves the weight. Maybe I just see everything as a software problem because I'm a software developer.
@@TheJohnreeves In this video he already tried adjusting the PID values to vary the release time and didn't work as well as my suggestion would. He needs a hardware-based gradient valve solution that would change based on the relative pressure after it's released more and more.
@@umbra1016 The problem is that flow and pressure are linked when using a fixed nozzle. A pressure transducer linked to the throttle gate value should help though.
The problem that the drone will not lift off directly from the ground seems to be caused by the air that is escaping underneath the curved downside of the bottles. Similar to the wing of a plane this causes a drag, but in this setting the drag is pointed towards the earth in the opposite direction of the thrust generated by the propellers lowering the overall lift of the vehicle. Great video, love your channel. Stay healthy! Many greetings from Germany.
Sweet project, me likey. 👍 I think one of the reasons your ducted fan wasn't performing as well as you'd have liked was because the blade and duct surfaces weren't smooth enough perhaps? I think if sanded and sprayed with resin, to be as smooth as glass, 🤩 it would let air flow through the system with less turbulence.
Really awesome concept Tom! To fix the stability issues at different pressures you could incorporate a small gas pressure transducer and use the value to adjust the threshold tuning on the fly.
put dry ice in one of the bottles should keep the pressure much higher and more constant
would the super cold temperature not affect the pressure capability of the plastic?
Great work Tom. First class video mate.👍👍👍.
0:32 I was expecting a "Hullo, Scott Manley here"
Maybe it’s childish, but the funniest part of these is hearing Tom giggle when things work.
Adam Jackson - I find myself always giggling right along with Tom - his projects are Brilliant!
Ken Romero, no, I agree, just funny watching the smile break and transform into a giggle.
What if you made a gas thruster controller blimp? Then you get cool noises lol
Idea: Entirely mechanical RC car? With a series of universal joins between axles, up to a handheld controller? If that makes any sense...
This project is so cool. Great job!
Your first nozzles (divergent )were based on supersonic flow, i don't think the exit velocity is supersonic, you might need to try convergent nozzle.
He looks like Elon too 🤷🏼♂️
Talk and act like him too. If he sounded like him... then wow.
"Hey they got discount Musk!"
he has his manerism which i think is lame..ok i see that he admires elon musk but..fuck off mate have your own personality
@@chemgreec this comment is so uselessly mean the fuck
I KNOW, the way he moves too it's kind of insane!
Excellent! We need more scientists like you!!! Should use pulse width modulation for thrust vectoring.
Try putting smoke in the compressed air (at the input of the compressor), just to visualize how the stabilizing works :) The high motor speed is probably due to the second propeller not being very efficient in the fast airflow of the first one. For the compensation of the pressure drop, try a counter to monitor the valve time, and decrease the PID gate threshold when the counter increases.
Those bell nozzles sucked because they only work for supersonic flow, where Bernoulli's principles are essentially reversed. What you don't see in those nozzles is further upstream, where the transonic region occurs at what's called the throat. Further upstream of that is actually a converging portion, which follows the rules of subsonic flow in order accelerate the flow up to the throat. That upstream portion is what you were essentially looking for, so it makes sense you went with a teensy hole!
Love your content Tom! Really cool project. I am so pleased you actually got it to work, it looks really difficult
So cool! The idea to convert the throttle values from a standard flight computer was really clever
for added stability, you can fuss around with some fancy software and make the computer understand the torque difference between the positioning of the 3 arms and give it the capability to spin on the yaw access or understand the pressure difference by using other hardware, but id recommend using a 4 arm drone just for the sake of simplicity.
Hi Tom. Congrats on the success. =) Modern turbo charged cars comes with a solenoid valve called Boost Control Solenoid (BCS). The job of this BCS is to gradually taper in/out the boost pressure from the turbo to the throttle body. Most of valves use PWM at a frequency at about 16 Hz. The frequency choosen is based on how fast the BCS can open/close. i.e. how much mass the plunger has. You can run these valves almost at any air throughput from 0% to 100%. You could try using this method to improve the performance of your drone. Great work as always! PS. The BCS valve is very similar to the ones you use. So you should be good to go without upgrading your valves.
A really high performance turbo might run at around 30PSI of boost. Joe is running 60-100PSI or more for his thrusters. Care must be taken with choosing a valve for a thruster, because they tend to fail if you use more than their rated pressure. The failure modes can be leaks, failing to open, failure to close, or destruction of the valve itself.
@@USWaterRockets they run civics at 60psi
I agree with you,but I see another one say p =mv. F =pt. So its just like the fuel injector.fuel flow decide by the pulse wide . I think it's a easier way to control the force. Bad English . :-p
@@-_-5352 Yes agreed. I was thinking F=mass of air/time But there could be a problem with the amount of time and deadtime of the valve. Your English is just fine. =)
@@USWaterRockets Yes agreed. Keep the valve he has. It's made of metal. Many car BCS are made with plastic bodies and prone to crack and leak over time. On my project car I switched from a PWM valve to a ball and spring type manual one. It holds shut until desired boost is achieved. The boost comes on hard and datalogs show no leaks. Tom should keep the metal ones he has. But if he tries the PWM method he can add a hard cut of airflow once the desired angle is achieved. That minimizes the over compensation. You could even taper by ramping the PWM width and/or time at the end.
15:56 - Ladies and Gentlemen, may I present: The Venturi effect, courtesy of the large curved surfaces of the bottles.
I'd say it's a coanda induced ground effect as the Venturi effect is mainly used to describe air pressure's relation to velocity inside a tube or pipe
@@benfillman4049 accelerated air underneath the bottles, making a low pressure, sucking the drone to the ground. venturi effect
@@benfillman4049 dumbass read what you said again
The Venturi effect is the reduction in fluid pressure that results when a fluid flows through a constricted section (or choke) of a pipe. Coanda effect is the phenomena in which a jet flow attaches itself to a nearby surface and remains attached even when the surface curves away from the initial jet direction. You Decide.
@@MrDaewen Phenomena is plural. "is the phenomena" is nonsense. You decide. No, wait. No discussion.
Well done! (If you ever upgrade your compressor you could consider wrapping carbon fibre tow or single layer sheet around the bottles to strengthen...)
The bell nozzle, correctly called a de lavel nozzle (hope I’ve got the spelling right!) only works if it contains a constriction between the bell shaped bit and the feed pipe
13:38 GEEKGASM looool love your vids man one of the best youtubers ever....
Love the message in Joe's mirror: "Subscribe to Tom!"
Tom u'r amazingly a genius - mechanical, electrical, aerodynamic and chemical expert at same time 👍
Nice work Tom. How about a pressure regulator on the valves? Small, light en always the same pressure till the main pressure drops below the regulator. Find out what pressure is needed to control the drone and go to the minimum to extend flight time. Also try to get more compressed air stored to maximize it.
These videos are so satisfying to watch , so congrats! For being my fave channel
You could use a regulator set to around 50 psi before the valves, and then experiment with different nozzle shapes at that pressure to find the most efficient one
Add: pressure sencor to read back pressure to arduino, two to three nozzles per arm at diff distances. In high pressure deliver pressure to inner nozzles and as pressure drops let compressed air channel to outer nozzles.
Nice project. If the air jets are rigidly fixed then I think more predictable forces would result .