This is in a Different Class Than a Raptor Engine!

[@TechIngredients]

Hey guys, we just posted on X trying to reach out to Elon and Gwynne. If you can help us out by sharing our post with them, we'd really appreciate it! Thanks to everyone for watching the video!

[@studentofcoin8483]

Ah, don't do this Elon thing... you're better than this and don't need to be associated with this drug addicted pretengineer.

[@mastermachineman1462]

Hi would it work in a vacuum with out the atmosphere holding the gas in? And also can it be used as a breaching device if you put the muzzle against a door?

[@eychene]

Will increase your radius by 1mm 🙏

[@rdbchase]

It would be much easier to interpret the graphs if they all had the same scales and were set side by side.

[@rdbchase]

Why Musk? What makes you think that he or SpaceX want to/can move into pulse detonation engine research? They've been being researched -- is your test rig unique, does it produce greater specific impulse, is it more durable?

[@KORKEL-]

oh my god i would kill for a 3 hour episode on rotating detonation engines

[@MrBroberds]

We'd be deaf by the end of it but it'd be totally worth it.

[@atrumluminarium]

SAME

[@jtjames79]

I'm planning on feeding all the research to an AI. And then just have it 3D printed for me in China. I honestly don't care if they copy me, actually that's untrue. I really really hope they do. It would force competition. I want consumer jetpacks.

[@eriklondon2946]

Well hopefully you wont need to kill someone to get it.

[@agr18181]

Brap brap brap brap brap!!!

[@eriklondon2946]

Never before have "propane and propane accessories" looked so good.

[@anotherguy9402]

I don't think you can buy that at Strickland

[@benjaminrogers9848]

Hank would be proud

[@countvonthizzle9623]

Dale has one in his garage.....

[@steveg6199]

@@benjaminrogers9848 - You beat me to it. LOL

[@fALSE.fLAGGOT]

​@@countvonthizzle9623Rusty Shackleford has one Dale don't know nothing about anything.

[@ProlificInvention]

I remember asking years ago for you to do a video on Pulse Detonation Engines, you responded you would in the future: and here we are. Just frickin awesome is all I have to say.

[@CaedmonOS]

Welcome to the future. It's a little shit here.

[@piccalillipit9211]

If you don't ask - you don't get...!!! You asked - you got.

[@Michael-ro5dp]

I built a pulse detonation similar to yours about 8 years ago- mine was about a meter long of heavy wall 4130 steel with a about 2” ID and several “obstructions” of steel circles spaced about 4-5 inches to create the turbulence to initiate detonation. I too received “complaints” from my neighbors for the noise- I used straight air and propane fed into the engine through a rotary valve ignited by a standard spark plug as the valve closed. With a piece of copy paper positioned about 1” from the nozzle, and completely unsupported except by a clothespin, I was punching clean 2” holes in the paper at each detonation. This confirmed the high velocity of the exit pulse- I will support you as needed. Regards, Mike

[@TechIngredients]

Great! God's speed.

[@homermorisson9135]

Glad to see you back in teaching mode, these are the best versions of any of your topics I ever found on YT. =)

[@berniestep]

The clearest scientific explanations on youtube - always superb. thank you

[@High-Overlord-Pugula]

his neighbors have to absolutely love him

[@TechIngredients]

You can see it in their eyes!

[@HanSolo__]

​@@TechIngredients There is no way you guys have ANY neighbours (still)! 😆 The love must be immense.

[@DyingCr0w]

Bet no one in a 10 mile radius has cats for pets.

[@aguy3896]

Man I would love to be this guy's neighbor. Sounds like WW3 outside? "Kids! Grab your ear pro and go learn about whatever Mr Ingredients next door is up to today!"

[@Kev2Bee]

The backyard BBQs must be a BLAST.

[@rohesilmnelohe]

I hope the local law enforcement is aware they have mad scientists operating in their AO. That sounded like an autocannon.

[@The_RC_Guru]

They do. They’ve met them too 😅. And i believe called ahead of a test of something particularly loud before.

[@steffenjespersen247]

yea that does sound like an autocannon.

[@haydenf1353]

A fellow diver o7

[@shanesmith6815]

how long before it gets weaponized?

[@Mallchad]

@@shanesmith6815 Already is... Its essentially a sonic weapon... There are more portable versions of this though, and more effecient ones.

[@spookydonkey2195]

I just realized that my neighbors with the professional PA sound system have been asking me to build one of these for years. Thanks!

[@jacobposs1925]

I love that guy! :) Most youtubers just make weird ideas happen, but he explains in great detail why those ideas work. He'll never dissapear out of my subscription list.

[@drhxa]

Love this series. If you succeed in building a rotating det engine, you'll be king. I don't expect it's possible to do without major funding, but rooting for you guys! Keep going, huge inspiration

[@TechIngredients]

We appreciate your support! It's a daunting task to say the least, but we're up for the challenge.

[@TinusTegenlicht]

​@@TechIngredientsCan't wait for tue next video!

[@youareliedtobythemedia]

Building one isn't that hard. Building one that works reliably and for long durations is.

[@liamwinter4512]

Yall are living my dream. I yern for a shop of your caliber eventually. Until than ill just live vicariously through youtube

[@r.b.ratieta6111]

I think it's fair to say the majority of us who dream of having such labs and shops but lack the funds to create them live vicariously on KZbin. 😅😅

[@NoxiousPluK]

@@r.b.ratieta6111 absolutely :)

[@meanman6992]

Same…. I would like to have something like a 6,000 sq/ft shop and a very large budget to spend on equipment, from lab equipment to a CNC mill and lathe, MIG and TIG welder etc. I work in fabrication in a sheet metal shop so it’s in ways so close yet so far away. 😕

[@BackYardScience2000]

​@@r.b.ratieta6111yeah, even someone like me who has a lab and tons of space is a bit jealous of the funds that they have to be able to do such things. I'm working my way up to it, though. Maybe one day...

[@TechIngredients]

It needs to be a long-term plan. The skills and acquired knowledge guide the equipment and facilities choices. The resulting projects expand your knowledge further and so on. The budget expands with funding from commercial work or KZbin profits, and so on.

[@allineedis1mike81]

I've read a few articles about Rotating Detonation Engines being tested in the last few years. Somebody is trying to build an air breathing RDE for hypersonic propulsion. I think one of the breakthroughs that have been made is in the propellant injectection because the timing has to be so precise. The last one I read about was using a Tesla Valve wrapped around the bottom of the combustion chamber in a circle. No moving parts and the Detonation wave actually pulls in the mixture from the Tesla Valve if I remember correctly. Sorry I cant give you a source but I'm sure you could find the article I read. It may have been in Wired but not sure. Thanks for the great videos all these years. Even when you guys didnt have a lot of followers you kept at it. Which i'd imagine takes some effort. YT should really be promoting you guys with the top tier of science educators. A lot of people just dont get science these days, they dont understand how it works and it leaves people vulnerable to all kinds of disinformation. You dont have to be a genius to understand the fundamentals of science and why it is the singular method we have for determining what is real. People need that and you are doing the world a service. Thanks again!

[@DuelPorpoise]

Terran space academy on youtube has videos on the subject of rotating detonation engines with sources.

[@BienestarMutuo]

Yes a tesla valve is a good addition.

[@nicholasmanson8615]

​@@DuelPorpoise yeah that guy is smort

[@GiesbertNijhuis]

In your calculations, don't forget the air inside the tube, its mass, inertia. Even the mass of the air just outside the tube is giving resistance against acceleration, once every pulse. In a vacuum there is no air-propellant mass to help ya. Great experiments, love it!

[@wingracer1614]

Atmospheric air pressure doesn't help, it hurts. This thing (just like rockets) would make more thrust and a higher specific impulse in the vacuum of space than in atmo. Thrust comes from the acceleration of the reaction mass in the engine (in this case, the exhaust gasses created by the detonation). Atmospheric air pressure restricts and reduces that acceleration.

[@GiesbertNijhuis]

@@wingracer1614 Not so. What you say is true for a constant flow, but we are talking about pulses here. An example to make my point clear: when we place a metal bal in the tube, then fire it, you will get a enormous propulsion kick. Just like a gun. Because the mass to-be-accelerated is much higher.

[@Exorcistt94]

@@GiesbertNijhuis Everything is an pulse we are just talking about frequency of that event. In simple words screens, bulbs etc are not constant event it's just an very fast pulse. In vacuum you shouldn't have problems with air pullback and pressure variations.

[@larsieo]

I’d just like to second your first comment. Would be nice to see if the vacuum performance of this engine holds up.

[@Johnny-fw9xj]

This is easily one of the most informative and yet concice demonstrations I've seen on KZbin. I could listen to this man talking about physics for hours as he's keeping me invested because I can actually understand what he's saying, and therefore I'm learning a lot. Thank you for the video.

[@TechIngredients]

Thanks! That...is why we actually do these videos.

[@aerbon]

rotating detonation engine when? edit: i didn't expect you to actually be already working on it

[@thorwaldjohanson2526]

If they manage to make a rotating detonation engine, I will her VERY impressed. It's currently the holy grail in aircraft propulsion. Getting it stable is very hard.

[@carlericvonkleistiii2188]

He's hard at work at the factory at Peenemünde!

[@TTTzzzz]

Top notch! A vert clear explanation of a subject that is not easily explained.

[@HorochovPL]

Imagine going to complain and finding two madlads You're a fan of

[@manitoba-op4jx]

i'd be happy.

[@jimurrata6785]

DADlads....

[@dman8951]

When I first learned of rotating detonation engines I thought they were out of reach for anyone without a lab. I’m excited to see what you can do!

[@MaximumBan]

Explaining a topic as complex as a supersonic flame front expansion using only words and two hands is a form of art. Chapeau!

[@marcuskrushansky6557]

NICE. YOU GUYS HIT A MILLION SUBS!!

[@BackYardScience2000]

They deserve millions more.

[@TechIngredients]

Thanks!

[@karolniedbao5420]

24:20 What you can do to achieve better oxygen to propane ratio is to use 5 inlets for oxygen and one for propane, then you can use the same pressure on both regulators and therefore you dont have to worry about non linear flow resistance in the tubes.

[@TechIngredients]

Good point. It might be simpler to create tables for each gas vs. the delivery tube IDs. That would keep the design simpler and lighter weight.

[@markawbolton]

@@TechIngredients Was going to say the same thing. Easier just to calibrate the flow rates and keep the parts count down.

[@Spencergolde]

​@@carlericvonkleistiii2188What are you even talking about? Is this the first amateur rocketry/jet engine/engineering video you've ever seen?

[@pompeymonkey3271]

Funny that you slipped and nearly said "laser". Right from the start I kept thinking of the mechanical laser analogue. "All" (lol) you have to do is get it resonating with a constant fuel flow and you'll have smooth flying. ;) Thanks for sharing your mad and educational hobbies. I really enjoy watching your exploits. :)

[@raycar1165]

1 Million!! Congrats! Much Love

[@feger481]

I find your sustained continuity of your train of thought, even out shines the subject matter you were discussing. Obviously you're doing it all in one take nothing clipped together, very impressive.

[@TechIngredients]

Thank you!

[@MrAndrew990]

Please make a video about a rotary detonation engine. Love your content.

[@elitearbor]

Pulse detonation engines are on my relatively short list of devices I personally just won't mess with. I have to imagine than many otherwise handy people who love to tinker are the same, and there's precious little data publicly available. Thanks to you, there's an awful lot more data available now. Thank you for advancing our collective knowledge as a species, yet again. 🙂

[@atvheads]

They are just loud, not dangerous. No compression to talk about.

[@TechIngredients]

They are dangerous. The shockwave can crack the fittings. Just because there is no compression between pulses, the shockwave is a compression wave.

[@notsam498]

Yeah, I think anyone thinking about it needs to hold them selves to the kind of standards we use in a lab. You need multiple layers of safety to handle something that explodes safely. You need, PPE, protective enclosure probably multiple and a contingency plan (that plan must include injuries). Playing fast and loose with things that go boom will result in a life changing event. Oh and don't forget you need calculations and verification procedures to avoid catastrophic failures.

[@WildArmsResearchAndDevelopment]

We have a couple rocket projects under way, first a hypervelocity rocket using traditional composite propellant, the second rocket is based on a 1980s patent that uses raw & loose smokesless powder as rocket fuel that does not blow out the nozzle. We have some samples being printed in inconel to test soon that you may be interested in seeing

[@BackYardScience2000]

That's a great channel you have there! I hit the sub button as soon as I saw the rocket launchers and rocket engines. 😃

[@deadcarbonboy]

The harmonic of you running your hand along the exhaust pipe at 15:54 is fantastic, a great sound

[@gydo1942]

Congrats on 1 Million subs and awesome video as always! This channel is such a gem! Rotating detonation would be incredibly cool to see too.

[@tripledprojects]

Dephlegmators to deflagrators... this channel does it all

[@slamdvw]

"Sir, you can't have a silencer, they're illegal..." "I know, this isn't a silencer, it's a loudener!"

[@mandowarrior123]

"Sir, you can't have a silencer, they're illegal..." "WHAT???"

[@joelkilborn7621]

NASA demonstrated a rotating detonation engine which is just a continuous version and highly efficient as well.

[@hahahano2796]

RDEs are less efficient can PDEs and CDEs (SDEs) due to the rotating wave within the volume. They also suck due to cooling and cell size considerations so they have to be really, really, really big to use desirable fuels/oxidizers.

[@error.418]

He mentions RDEs in the video

[@karliszauers1]

​@@hahahano2796 Btw for people thinking detonation engines being better than regular rocket engines just because they have a greater efficiency - they aren't any better Detonation engines have extremely high dry mass and low exhaust flow The downtime between pulses means it's not firing for a long time. Rotation detonation engines technicality don't have a downtime but most of the combustion chamber isn't used - the detonation occurs only in a small part of the combustion compartment The place where detonation engines could be useful is for pressure fed/ non pressurized rockets as they could achieve a greater combustion chamber pressure without having to resort to a fuel pump

[@DonaldJacobbb]

@@karliszauers1 Calm down. Things can be improved.

[@karliszauers1]

@@DonaldJacobbb I'm not mad or anything... Detonation engines are known for a long time just like pulsed jets Their flow rate is too small for standard rocketry you won't be improving that by much, physics stands in the way Funny how they mentioned raptor engines as being the most advanced ones. Well raptors have a far lower propellant efficiency (ISP) than most hydrogen engines by design because they're using methane. And raptor 2 has a lower ISP than raptor 1 to get a better flow rate. Just showing how ISP isn't everything Where the raptor absolutely shines is the thrust per area and SpaceX got this by severely sacrificing ISP, adding extra film cooling etc.

[@mmmmm49513]

My PhD advisor was a graduate students that worked on AFRL’s Long EZ pulse denotation plane. To my knowledge it’s still the only manned plane that’s flown with a detonation engine. I think he specified the efficiency metric for a pulse detonation driven turbine. It’s cool stuff. I took his class on detonation propulsion so I’m familiar with most of the concepts involved. He’s always wanted to build a better pulse detonation engine. The place that make the most sense to me is at small scales as a combustor, since the magic thing with detonation is the “pressure gain” in “pressure gain combustion” :is its not additive its multiplicative. So if a tradition small engine compressor pressurizes the air coming into the engine to 5 atmospheres and it then goes through a 3:1 pressure gain it effectively becomes an engine operating at a 15:1 pressure ratio. Of course that’s in the ideal case. But that significantly improves the performance of the engine especially since a detonation improves the bad efficiency of small combustors. There’s some cool ideas of building a continuous pulse detonation engine/combustor where a series of tubes (think like dozens of small tubes instead of the one big one in this video) is used to maintain a continuous traveling detonation wave. I think it’s been built already if I remember correctly. Ultimately though all the research money in this field is currently invested in rotating detonation engines and rotating detonation rocket engines. My professor has talked to a lot of the normal funding sources and that’s what they all want to look at these days… RDEs are cool too, but I think we are far away from RDEs being practical since they are just so complicated to fine tune and only give a few percent increase in efficiency at the large scale. Rotating detonation rocket engines (RDRE) are farther along and I can see those being used practically sometime in the next decade or two if the major kinks are worked out.

[@D.K81]

It's always a good day when I see a new video from you guys. I always learn something while being fascinated the entire time too. Thank you!

[@Implicacean]

@Tech Ingredients On the off chance this hasn't reached you. Some research came out recently that Galanstan alloy + ceramic aluminum nitride makes an amazing TIM. The paper is called "Mechanochemistry-mediated colloidal liquid metals for electronic device cooling at kilowatt levels"

[@TechIngredients]

I'll look for it. Thanks!

[@thehuggz-i9k]

Researchers sure know how to name papers to attract the crowds! 😂

[@djbs65]

If one were to make a rotary valve around the combustion chamber, you could control the fuel input timing by speed and nearly eliminate backflow of the fuel gasses. It would require electronic control and timing, but you could greatly reduce time in-between pulses increasing thrust.

[@amarissimus29]

This is what happens when you comment prematurely. Unless you are suggesting that rotation requires moving parts.

[@djbs65]

@amarissimus29 Yes of course. That's indeed what a rotary valve is, a moving part.

[@royb.1441]

The spring getting eaten alive during detonation is a great example of why you should not ignore your car engine pinging (detonation). Or any regular ICE.

[@grfn3135]

I love this channel! Thank you so much for creating all this amazing content and sharing it with the world!

[@kiweekeith]

Thanks Yet Again for a Super Interesting Vidclip .... As a Retired 'Engineer', Toolmaker, CNC Machinist etc I sure do Enjoy and Appreciate All the Input, Thought and Expertise needed to produce just a Single vidclip .... Very Best to ALL, so too Best wishes for the 'Festive Season' .... Cheers from ChCh, NZ

[@ZoonCrypticon]

@27:30 It sounds like artillery sound in a war zone.

[@OtherWorldExplorers]

It sounds like a 40 mm Bofors 😅

[@2canines]

And resembling one.

[@Jake9066]

@@2canines Beat me to it by a significant margin, "It LOOKS like a 40 mm Bofors"

[@dennissorensen8765]

😂👍

[@lohikarhu734]

And looks like it could send a projectile quite effectively...

[@slateslavens]

My first thought was Orliken, but yes, 1000%

[@kellyschlumberger1030]

Intuitively, i think the cone nozzle at the end is pulling a greater vacuum, as the nozzle is evacuated by the high velocity blast over a larger area. This might allow a cleaner tube / engine for each injection.

[@jason1440]

Glad you guys are still going after it. Really enjoy these.

[@DavidKonyndyk]

Really stoked to see you do rotating det. That may even be something you should move off the stand and into practical application as a demonstrator. Slap it on that boat I see back there.

[@BluesyMarco]

Finally found a(nother) guy who uses the Metric system while talking science. Thanks for that.

[@willusher3297]

who doesn't use the metric system when talking science?

[@pdrg]

Since imperial units are defined in metric (eg the official standard for an inch is 25.4mm) then not using metric is just adding extra scaling factors to calculate out!

[@jakospence]

Chemistry KZbin is confused by this statement

[@jwm6314]

Superior minds can use both for the appropriate use. I SCUBA dive in metric for the gas law calculations. I fly airplanes using imperial. I build furniture in imperial. I work on both domestic and foreign cars and equipment that I own taht use both. What's asinine is when a car has both imperial and metric parts. THAT is unforgivable in any language, region, or application.

[@BluesyMarco]

​@@willusher3297, @Vatsyayana87 : Examples ? here are some : Neil de Grasse Tyson -- still talking in miles, degrees Farenheit, etc ... Tom Stanton -- This car travels farther than you push it using - AWG instead of mm2 Mark Rober -- Integrating both systems, but frequently using imperial Destin Sandlin -- Smarter Every Day, primarily uses imperial Derek Muller -- Veritasium, often includes imperial measurements MythBusters -- Although no longer airing the reruns (mostly) reference imperial Dianna Cowern -- Physics Girl, tends to use imperial, but also provides conversions James Orgill -- The Action Lab, often imperial units, sometimes metric William Osman -- Mostly if not always imperial units MinutePhysics -- often metric for scientific accuracy but includes imperial NileRed -- uses a mix of both but often includes imperial Luckily subject to changes, but damn, after +/-200 years ??? I'll give you another example but I'm not sure if you'll like it: The Euro came into effect around +/- 2000 It took a while, but they managed to get (almost) all Europeans to use the same unit. Of course there are still a few old farts and recalcitrant folks who use Pesetas, Francs or German Marks. These are people who have wanted to work counterclockwise for 20 years. So they DEMAND all other Europeans to convert everything into their outdated units. The Imperial system has been replaced and/or adopted for about two centuries, EVEN in the US... but they are still a few hundred million people who want to turn back the clock. So it's not just the fact that one has to convert thirty-six different units and an illogical fraction system into the much simpler decimal system, but the fact that approximately 500 million people are demanding that the rest of the world adapt to their "calculations" ... So, again, thanks for using metric ... I did NOT complain, I just thanked the authors of this clip and I'll do it again, every time somebody shows some goodwill !!! Keep up the good work, and whatever science project you're working on, it's always a PLEASURE to watch you guys

[@SteveEh]

I came to comment on your homemade scaffold planks, simple, cheap, look strong! Good job

[@TechIngredients]

Thanks! I built much of the "barn" we use in some of our videos using this setup.

[@ignilc]

​@@TechIngredients what scaffold are you talking about? The blue one in the background?

[@MauroTamm]

You need a long pole with a large flag, "Loud experiment in progress."

[@TechIngredients]

Ha!

[@apostolakisl]

@@TechIngredients Was it my imagination, or did I hear the sound echoing back off the terrain for several seconds after you shut down? If indeed, that sound must have been easily heard for miles.

[@hamjudo]

​@@apostolakislI heard the thunder, too.

[@gcewing]

Maybe an air raid siren?

[@wobblysauce]

To be placed in the paper 4 weeks from now.

[@Tylerthomasmiller84]

This always has been and will forever be the best channel on KZbin. Thank you guys.

[@BenKistner]

This is the kind of research we've needed for years! Fantastic!!

[@Sailor376also]

DTD Great for throwing pumpkins. Oxygen/propane. 5 pound pie pumpkin a half mile. Your igniter is in the wrong position. The way to truly detonate is the flame front becomes the compressor to over compress the fuel air mixture an cause a detonation. Move the spark plug forward to ignite the mixture at a midpoint in the tube. Each charge of fuel air will then ignite, deflagrate until sufficient pressures are achieved, and detonate. The next charge flows into your engine and deflagrates when it reaches the igniter, and repeats the pressure to detonation sequence. I buried the butt end of the 300 pound cannon 2or 3 feet into the ground to absorb the substantial recoil.

[@jhonbus]

OK, I happily watched all the introduction and the explanatory part, thinking "OK, loud engine, got it." I was a little confused when you mentioned the guy coming across the road because he was so concerned. Then I got to 26:00 and understood why 😂 This thing sounds like someone's shooting an autocannon! The poor guy must have thought his business was being invaded by a platoon of infantry fighting vehicles!

[@Partimepeasant]

The funnel is a manifold @ discharge not all of the fuel is burning until an increase of a lean mixture furthers the discharge. And the funnel is a shock wave preceptor to the discharge. Six years jet engine testing in the Air Force.

[@TechIngredients]

A shockwave preceptor?

[@book67891]

Do you mean the exiting shockwave bounces off the funnel and adds impulse or what I think is more likely which is unburned gasses in the volume encompassed by the funnel ignite and bounce off the funnel and add impulse.

[@Partimepeasant]

@@book67891 Add a doughnut manifold @ venturi with a burner pressure probe to release the secondary fuel flow.

[@Partimepeasant]

Show it in slow motion and thermal you can see it.

[@Partimepeasant]

@@TechIngredients Pushing out raw fuel into a low pressure zone / the fire / ignition hits this zone with the optimum fuel air mixture.

[@Alexander-nw6xs]

I am impressed by the complete openness of all your detailed findings, which could encourage others with means to continue and advance this type of engine development.

[@TechIngredients]

I'm glad to hear that. Hopefully, if that happens, we'll hear about it.

[@AlbertRobinson-v3y]

Wonderful video and as always..simple explanations of complex subjects which is amazing.. Thank you !!

[@meanman6992]

Valveless pulse jets have had my attention for a while.

[@chriscampbell7245]

they have the attention of anyone in a mile radius

[@Nuovoswiss]

About the specific impulse numbers, you aren't accounting for the mass of air that back-fills the tube after each detonation. Like a pulsejet-engine, there is a vacuum caused by the inertia of the exhaust gasses, which draws ambient air in. Even in theory propa-LOx can't exceed 250s, so this wouldn't be a great option outside the atmosphere. You should also consider a pre-mixer, or a head design like liquid rocket propellant injectors. The differences in density and temperature between propane and oxygen from the feed lines would limit gas mixture, and also make it difficult to determine flow rates (and rate variances) as a run went on. This might explain why there were conflagrating gasses escaping before the detonation exited the tube.

[@rayjay848]

Also need to consider the additional mass of dampeners.

[@dirtypure2023]

There is definitely a rocket science-y explanation for their unusually high I-Sp result and yours makes sense.

[@Pystro]

I didn't quite understand what you meant when you said "accounting for the mass of air that back-fills the tube after each detonation". The air that flows backwards into the tube goes in the wrong direction and should _reduce_ thrust. But then I realized that it also has to come back out - and it does so violently. So the engine is probably expelling under 50% exhaust gases and over 50% ambient air.

[@wazza33racer]

@@Pystro reflected pulse wave.....the air rushing in violently, will hit the ignition end of the tube and then reflect back out towards the nozzle end. IF the next detonation is timed correctly, then it can coincide in direction and time of the reflected pulse wave to the nozzle end and assist thrust. This is used routinely be engineers designing internal combustion engine, air intake tracts and plenums to provide a kind of free supercharging.

[@alandoak5146]

@@wazza33racer Or is the engine becoming partially air-breathing, which affects the mass of oxygen in the ISP equation? Or both?

[@fabracht]

Your care with words is truly inspirational.

[@TechIngredients]

Thanks!

[@johnashcroft8355]

The best explanation I have heard of a pulse detonation engine. Bravo!

[@royb.1441]

You guys did a great job capturing the audio of such a high DB event. Enough so that I could and did turn the volume up on my headphones because the quality was good enough to justify some hearing loss 😂.....that was AWESOME sounding.

[@inthefreytoo]

When I reached 65 and, because of my love of rock music and things that go "BANG", I lost most all of my high frequency hearing. I got tinnitus and pondered the high cost of hearing aids. Science hasn't quite figured out how to give us back our hearing once it is lost. Take my advice, please go easy on your ears mate! 🦻

[@ABoringTool]

I think i can fit 3 of these in a miata

[@BackYardScience2000]

4 if you strap one to the roof, you know, for that extra boost.

[@Turkeythigh420]

Do it!

[@hamjudo]

​@@BackYardScience2000The thrust must always be directed through the center of mass or the Miata will cartwheel. If the rocket engines are mounted parallel to each other and the thrust isn't synchronized and well balanced, then bad things will happen. For safety reasons, each engine should point through the center of mass. The space shuttle liquid engines weren't parallel with the solid rockets. This means that the rocket engines have to be behind the center of mass. Also, my wife's Miata is a convertible, roof mounting wouldn't be an option.

[@kennethporst1738]

HAHA TRY IT I triple Dog DARE YOU.

[@chrisbleurgh7425]

​@@hamjudoNot many MX5s arent convertible, sorry just gotta say.

[@xploration1437]

I just deflagrated my pants.

[@meanman6992]

My favorite word I can’t barely say or recall half the time for a vigorous combustion.

[@gadiantonx8474]

dint tell the truth?

[@xploration1437]

🐈💨@@gadiantonx8474 what?

[@nwekuy]

come to think of it, do flagrance, and deflagration have the same root? guess so (edit: error thought of different word, fragrance)

[@dogcarman]

“Liar, liar, pants deflagrated” just does not have the same je ne sais quoi.

[@mikeycurtis7861]

😮 ❤ My neighbor, right across the street from me, has been trying to get me to quit working for my best friend and start working at SpaceX.. I am showing him this video as soon as I see his truck in the driveway!!

[@dean5263]

As you explained the operation characteristics, it reminded me of a prototype pre-ignition injector for a diesel engine I came across years ago, there it followed the same ideals as your project up to an extent. I was not surprised at a larger record of energy produce with the exhaust nozzle on, I truly believe that without it on that the energy merely pierced to atmosphere more efficiently and therefore resulted in less perceivable thrust. This was an enjoyable video, you guys are A no hype, all fact type of people.

[@ZoeyR86]

Why not use an accelerometer on a known weight sliding plate. The total force can be calculated from the acceleration of the plate

[@TechIngredients]

That's a good option.

[@ZoeyR86]

Some new accelerometers can read in the millions of times per second. This will get you very accurate data. A simple esp32 can handle all that hardware the valves, even a few temp probes as for as for mixture a simple piezoelectric sensor on the back of the chamber can pickup the speed of combustion based on the shock wave and adjust to produce the fastest pulse. As for the fuel I this the degrading power is simple the liquid to gas exchange rate of the propane, causing fuel pressure to drop as it runs I'd suggest a tank heater. This pressure drop is amplified by the restrictions in the lines. This video gave me some ideas including adding wave reflection to compress the combustion chamber during ignition I think fine-tuned you can use the back wave for compression ignition at a tuned frequency. Also given this is hypersonic the nozzle would fail using the expansion method of the von b method it would be better to treat it like a compressed sound wave and follow the methods used in horns. It's only hypersonic at 1 atmosphere inside that tube it's under maybe 50-100bar near the exit given the expansion ratio of the fuel used The speed of sound in a carbon/water rich under that kind of pressure is crazy high. If you want a good damper for the plate ridged attach a 2gal bucket to the moving plate and add 1gal of water. Another option is a dead weight on a slide against a spring the pulse compression of the spring. This is a physical RC filter lol

[@HL65536]

The theoretical limit for hydrocarbon fueled rocket engines is below 500s. That means your results are impossible to achieve (at least in a vacuum). The specific impulse is atmosphere and atmospheric speed dependent. Turbofan engines achieve far higher specific impulses, but only in an atmosphere (even if the atmosphere does not contain any fuel/oxidizer). I suspect that your engine is dropping significantly in specific impulse when in a vacuum or at least in much lower pressure. Air remaining in the tube or nozzle could be acting as additional reaction mass, being expelled in addition to the combustion products.

[@kellyschlumberger1030]

I suspect the cone nozzle on the end is utilizing the blasts to create a vacuum, clearing the tube before next blast.

[@TechIngredients]

HL, You're basing that limit on steady state conflagration. You can actually generate the real thermodynamic limit pretty easily. Take a 1 gm, stochiometric mix of propane and oxygen, look up the thermal energy content. Enter that energy into the kenetic energy equation of E=1/2 (1gm)V^2. Solve for V, and you'll find it's close to Mach 20! Calculate the acceleration, and the limit is 680!

[@DuelPorpoise]

was about to say that limit you stated is for conflagration, but some youtuber beat me to it.

[@zygmuntzarzecki]

@@kellyschlumberger1030 yes, like in 2t stroke engines

[@klz5218]

​@@TechIngredients One potential source of such a high max Isp estimate for a HC fuel is not accounting for vibration and rotation modes in the combustion products. They "absorb" a significant fraction of the energy released.

[@sc0or]

The afterburner couldn't work because ALL momentum was created inside the chamber. Once it accelerated a portion of gas and fuel (as a result of explosion) a momentum was created, and it does not matter what happens with the gas after that. Otherwise it would look like a fan on a boat blowing to a sail.

[@silience4095]

The fun part is: a fan blowing on a sail does work.

[@sc0or]

@@silience4095 With a keel it might work, but we have no any substance to use to convert a momentum

[@SHAGG13]

​@@silience4095 Only if the sail is tacking or angled from the fan ..😂😮

[@silience4095]

@@SHAGG13 Even if you're blowing perpendicular to the sail, it deflects some air backwards which, from conservation of momentum, does produce some forward thrust. Though this depends greartly on the sail and fan arrangement. It helps if the sail is allowed to curve a lot, and the air can "ride" this curve. It is not very efficient, you'd be better off just pointing the fan the other way, but it does work. Some airplane thrust reversers work this way, by just sticking an obstacle behind the jet engine exhaust, though it's shaped better than a sail for deflecting the air backwards.

[@ScrewTSW]

1:04 "We are not obnoxious enough! Hans, bring out ze loudener!" XD

[@darwinboor1300]

Thanks. Reminds me of the shock tubes we used to do blast wave testing. The detinations were contained behind a rupturable membrane at the sealed inlet end of the tube. When the membrane ruptured, a hypersonic shock wave in air was created that traveled down the rest of the tube and over our experimnts. Obviously, the membrane had to be replaced between shots. Our smallest tube was 9 inches in diameter. With the bigger tubes (multiple feet in diameter) and a local temperature inversion, we occasionally had complaints and rattled glasses 10s of miles away in the general direction of the blasts.

[@TechIngredients]

That must have been really interesting. Just another day at work...

[@StabbyMcStabwood]

Finally, I can be the rocket man like the movie from the 90s

[@ButterBallTheOpossum]

Why didn't you ever upload the body armour video you mentioned in a previous video?

[@DJChesley]

I second this notion.

[@FireStormOOO_]

Very cool, though I think your specific impulse calculations are off - theoretical performance for oxygen-propane (e.g. 100% of the energy in the fuel converted to useful thrust) is only in the 300s AFAIK. If I had to hazard a guess, I'd wonder if you're sucking air into the tube between pulses, and then getting the benefit of that extra reaction mass on the next pulse. Again very interesting if true, but wouldn't happen in vacuum. Next step in any case is test it in a vacuum chamber. For reference, theoretical perfomance on methane-oxygen doesn't break 400s either, and hydrogen-oxygen is well short of 500s.

[@TechIngredients]

I think your analysis is wrong. It is within the typical range of conventional conflagration based engines. However, try the analysis based on a stochiometric ratio of propane and oxygen and the thermal energy released by one gm of the mixture. Now, enter that energy into the formula for kenetic energy, i.e., E=1/2 (mass =1 gm.)V^2. Solve for velocity. I got a specific impulse of 680.

[@Gladaed]

@@TechIngredients I get 236. The chemical energy is about 50 MJ/kg -> the mixture has m/mol propane (44)/ m/mol mixture (204) energy resulting in 10.8 MJ/kg. Converting this to kinetic energy gives 2300m/s of velocity. Divided by g (9.81 m/s) this results in 236. This is quick napkin math. Your video showed sparks. This may have affected your measurement. I also did not check for non-complete combustion possibly resulting in higher ISPs.

[@klz5218]

@@TechIngredients Said thermal energy distributes not only into kinetic energy of motion, but also of rotation and vibration of the combustion products.

[@spaceminions]

@@TechIngredients First, at stoich I calculate that about 0.2 grams of propane per gram of mix means a release of 10kJ, so sqrt(20kJ/gram) is 4472 m/s. Divided by 9.81 that's 456. But second, when you don't assume complete combustion and you look at the mass of resultants for the sake of velocity at a given temperature, it throws the numbers around even more than stuff like the energy trapped in making water a gas. Third, hydrogen/oxygen is 530 to 520 by that calculation depending on fuel mix iirc, while the real world result landed around 450 to 470 iirc. I think that monster lithium fluorine hydrogen tripropellant got 542 test and idk the theory.

[@FireStormOOO_]

Those are the often cited limits for normal rocket engines you'll find widely published; they're taking into account additional losses beyond 100% conversion to KE. I'm not sure they apply to a detonation engine and/or to all heat engines. As far as the calculation just based on 100% chemical energy to KE: Wikipedia has propane's enthalpy of combustion at 2.22MJ/mol, or 10.8MJ/kg resulting in 475s specific impulse. 1mol C3H8 + 5mol O2 -> 3 CO2 + 4 H2O, 204g/mol. I was in the same ballpark as you the first time I ran this (609s) b/c I left off half the oxygen and had the mass of reactants at 124g/mol. The 50MJ/kg number I see floating around is without the oxygen. You could also have gotten ~680s if you accidentally left the 2 out of the sqrt.

[@christopherkey2069]

I like how you explain everything in your videos.. it's very educational and entertaining.. thank you..

[@johndoughcrypto9688]

Your videos are incredible. I like the topics you cover, the depth of explanations too. Never stop never stopping

[@PhunkBustA]

29:22 did someone shoot back? 😅

[@delphicdescant]

Here for the discussion of "low tolerance" meaning "high precision."

[@hamjudo]

I try to use _loose_ and _fine,_ rather than _high_ and _low_ whenever I'm in teacher mode.

[@xploration1437]

You don’t need to get ahold of Elon. Get ahold of Gwynne Shotwell.

[@TechIngredients]

We plan to reach out to both. If any viewers have other suggestions, we'll follow up on that, too. The numbers are VERY impressive and will likely generate some evaluation if the right people become aware of this.

[@xploration1437]

@ Tim Dodd, Everyday Astronaut, could probably help.

[@xploration1437]

@@TechIngredients I met this gentleman, Ron, down at Starbase this past spring. He knows some people at SpaceX. kzbin.info/www/bejne/e4anoqKfnaykpbMsi=gAL4LHRxZSFpzEzs

[@xploration1437]

@@TechIngredients I met a gentleman named Ron down at Starbase last spring. He knows people at SpaceX. I bought a Starship heat shield tile from him too! kzbin.info/www/bejne/e4anoqKfnaykpbMsi=gAL4LHRxZSFpzEzs

[@xploration1437]

@@TechIngredients I met a gentleman named Ron down at Starbase last spring. He knows people at SpaceX. I bought a Starship heat shield tile from him too! kzbin.info/www/bejne/e4anoqKfnaykpbMsi=gAL4LHRxZSFpzEzs

[@violadagamba7555]

Doctor, I absolutely worship you. Your videos are on a whole different plane of existence. You are super literate, incredibly articulate, and you delve very deeply into very interesting topics. Fascinating!

[@TechIngredients]

Wow, thanks!

[@davidsteinhour5562]

Amazing results! Love the channel, thanks for the education!

[@TechIngredients]

You're welcome!

[@svenhoff2653]

Damn that thing sounds like a German WW2 Flak 38 Anti Aircraft Gun 😂 No wonder your neighbours were checking out what the fu. . . is going on outside. Regarding the Rotating Detonation Engine: Integza made a very interesting video about it. He went to Germany and visited a research facility that works on these engines. (watch?v=fRMMSyCcTDI)

[@slateslavens]

thanks for the link. He does fun videos!

[@jsjs6751]

What are the odds of SpaceX not already knowing about this engine? I mean, they are rocket scientists, and it has been known since 1940 or longer.. and the Wikipedia article seems to have been added in 2006... 😊

[@BackYardScience2000]

SpaceX seems to have a 1 track mind, Elons mind. See Everyday Astronauts first guided tour with Elon at Star Base as an example with the cold gas engines. A simple discussion with an outside mind lead to changes in how they do things. Who knows if they've already thought of this and ruled it out as an option, but unless one makes the effort to see if they have, we'll never know if they have or not, and why not send that email to be sure? It's always worth checking to be sure, just in case and it doesn't hurt a bit to check.

[@TechIngredients]

I agree with BackYard. It can't hurt, and it might actually help. And, who really wants to spend two full years getting to Mars?🤔

[@thehuggz-i9k]

I think the main issue with RDEs is that they're just not as well researched as traditional rocket engines. For their Raptor, instead of pioneering a lot of new research on something that would be a huge gamble on a 120 meter rocket ship, SpaceX chose to build off of an already well researched and understood technology and take it to the next level. That, in and of itself, was already a pretty big gamble, but it was a safer gamble than choosing a technology that's so far unproven at scale. The other issue is that, when you're building a project like a space rocket, you kind of have to know what engine you're putting on the thing FIRST so you know how the rocket needs to be designed. At this point SpaceX is so heavily invested in Raptor, and Raptor is performing so well it doesn't make sense to change. It's not that researchers and the heads of space agencies don't see the benefits of these engines. I think it's clear to everyone what the promises are, but it's not clear when those promises will be deliverable on a scale that get over 5,000t off the ground. You could argue that maybe RDEs could be used only on Ship and leave Booster sporting Raptors. But then you have 2 different types of engines that need to be researched, improved and maintained. Simplification is the key to cheap production, and 2 different engines is not more simple. Not saying don't talk to SpaceX. By all means, have at it. Maybe it can make a difference somehow. I just suspect they already know.

[@Imaboss8ball]

Space mainly uses well established tech. Their main innovation is landing rockets.

[@TechIngredients]

A detonation engine would not be an option for lift off. Even a rotating design limits the maximum average thrust. Where it is most attractive is as a simpler, more efficient, final stage once in orbit. Then, it's all about propellant efficiency because the engine can fire for hours to days.

[@scottsammons1666]

This is the first video of yours ivs seen and i am 100% fascinated with all of this . I need more !

[@TechIngredients]

Welcome on board!

[@chrismurrayguitar]

Even after all the warnings, I was impressed by the sound. That was really fun. You can even hear how long it continues to bounce back at you.

[@thezeus6831]

I'd be excited to see a rotating detonation homebrew, always love the videos, very informative.

[@audas]

We loved the speaker tech - things we can use are amazing.

[@barry7608]

Stunning, I'm amazed. All the best from Australia.

[@TechIngredients]

Thanks!

[@Zpicismrad]

this is hands down one of the most interesting channels on KZbin. I really appreciate the variety of your projects. I'm sorry I don't know your name, but you would be a great teacher, I bet a good half of the kids in your classes would want to become scientists.

[@valerigeorgiev5615]

Бравооо! Гениалните технически решения винаги са прости! Тази техника се прилага в оръдията против градушки! Там в началото използват ацетилен! Успех в ротационния пропулсор!

[@Reptex_cs]

That thing is stupid loud. Imagine that on the Starship.. Your way of explaining how things work is supreme, I fully enjoy and understand all of it every single time. Thanks for sharing.

[@oscaranderson1822]

The numbers sound very impressive... Outstanding good luck with your research.

[@DavidAndruczyk]

Very cool! I love your thoroughness in explaining it all.

[@Hogslice]

Crazy that the bell increases the output so much. Well done and congrats on 1 mil!

[@TechIngredients]

Agreed and thanks!

[@DanielinLaTuna]

I’m never going to build one of these, but it’s fun watching what happens when someone (Eric and Alex) do!

[@raoul4859]

Extremely good video! Love to see the rotary detonation too! 🫡

[@JorisBohnson-jl4bg]

Love this video (and the channel)! Thank you for the effort of making them!

[@andreaskampe9143]

I am an electronic engineer. Your channel is amazing. Educational and interesting, 5 stars.

[@McLovinMods]

If you are really making an RDE, you're a madman and I love it!

[@benmcreynolds8581]

I can't even imagine how loud that would be in person! Because it comes thru the video like it's really loud & i know it's gotta be impossible to convey the actual sound intensity as well as any sort of possible vibration effect coming off of that powerful beast. Love the work that y'all do & the content that y'all make 💪🏻

[@TechIngredients]

Thanks! Take another look at the segment where we ran the engine with the nozzle. You can actually see the leaves bouncing off the ground with each pulse.

[@vancave3539]

Very informative and stimulating.. Thank you for your work I enjoy the content you present. Happy Thanksgiving