I actually wouldn't mind you going over china's anti ship weapon along with their strength and weakness of them

Nicely done. Thanks. Former USAF officer here. Trade offs. The issue is one of materials science. Rotational detonation engines (RDE) provide much greater pressures and thrust but you have to have the alloys strong enough to take the high temperatures and pressures without failing. Those types of alloys increase cost and very likely weight. Have served in the Tactical Air Command, I am fighter biased, but RDE technology may be better suited to 1) missiles that make one trip to their target; and 2) naval vessels that have less concern about weight of the propulsion systems. Air superiority depends on mission readiness, availability, and turnaround time. The more sophisticated the jet, the longer and more complex the maintenance. That increases turnaround time even if you have the tech, parts, and highly educated human capital to sustain such intense maintenance. That is difficult in a secure environment far from threats, but much harder closer to combat. As noted, these jets would be ungodly expensive as would be parts and maintenance. That leads to fewer jets and fewer training hours for the pilots-availability and readiness issues. I am not saying this is not a potentially revolutionary technology, nor am I saying that we should not deploy it where it is better suited. What I am saying is that we have to think about full lifecycle technical trade offs, costs, logistics, maintenance, availability, and readiness to best achieve our strategic and tactical objectives.

I used to know quite a few DARPA people (not all were engineers) and there is a common saying they have. 'About 50% of the things that are said to be impossible really are'.

The proper, simple, explanation for why detonation engines might be worthwhile to pursue, is this: All thermodynamic engines get their energy from fuel being burned with oxygen. That's the start, and it's the same for all engines. There is not 'more' energy available for some engines than others. It's only the chemical energy in the fuel, a fixed amount. Same for all. What is not same for all, is how much of that energy, the engine is able to convert into work. This is why we have the concept of thermodynamic efficiency. (With rocket engines and jet engines we also have propulsive efficiency, but forget about that, because this does not concern that.) Now it happens that all thermodynamic engines extract their work from the ' *_Expansion_* ' phase of their working gas, which typically - and particularly in this case -, is the same as the combustion gases. The greater the expansion, the more work = useful energy, is extracted. Now we come to the first point: You can have more expansion if you first *_compress more_* . This is why we have Diesel engines. It's why the most advanced jet engines have pushed to 80:1. It's why SpaceX is pushing for +300 bar in their Raptor rocket engine. But, here's a crux: As the fuel burns, the combustion gas expands (in *jet* *engines* and *rockets* , in piston engines you of course get the combustion *_before_* expansion), because the expansion moves faster than the burn reaction. So you don't get to suck all energy from the max, theoretical, possible expansion. What if you could have the reaction (fuel burn) take place before the gas expands? This should result in better fuel efficiency. And it will be achieved if the reaction (fuel burn) is faster than the gas' expansion. And that is what we call *_detonation_* . The full burn first, then the expansion, instead of expansion during the burn.

I'm not going to lie. It's a good time to be an aerospace student. Things are getting shaken up in a really cool way.

You may not be a scientist but you explain pulse detonation and the difference between a internal combustion engine and this process better than most science articles I've read about it. I'm a science and technology geek and your information is always spot on and accurate something I applaud you for. You take the time to get the details right. Your humility leads to higher accuracy.

Alex, thanks for the excellence of your English, a rarity on KZfaq these days. Needless to say, your content is superb.

Great video, Alex. I've been saving it for a few weeks, but it was worth the wait!

Another outstanding and informative video. Thanks for all your hard work putting these together. 👍

Absolutely love technical advancement videos like this! Super, super interesting! 🤙

I worked with Dr. Fred Schauer on the worlds first self-aspirating PDE in the early 2000's, which is later developed to what you see at 7 minutes. You can basically eliminate the pumping losses of a compressor section, and get MUCH higher exhaust velocities. We built it out of a cylinder head on a shoestring budget. I thought this tech never panned out, but this concept is great! The donwside...this thing sounded like a jackhammer, but as loud as artillery. An RDE might also make a decent tip jet on a helicopter or prop.

I read of a future scenario where the f35/22 control 10s of drones in a forward position while they are in the rear. Couple that with drone refueling and the navy and fighters will be somewhere over the horizon in a battle. Great analysis!

This is the coolest military news channel. I love all the videos.

It's actually really interesting how the energy is extracted makes a big difference. We have detonation in diesel engines but it's been a struggle to get it to work in gas. I don't know if the entire charge detonates in diesel engines even. It might be interesting if it could be made cheap enough eventually to offer an option for vehicles. It could make the transition to lower carbon power sources easier. Cool video. I would like to hear the one about China as well. Yours is the only one of these style channels that I feel gives quality information and isn't tacky. Keep up the good work.

I got excited when I saw the notification (for which I had been waiting) and what the topic was. Awesome video. At least 3 times I went to click the thumbs up and forgot I already had.

Thanks for digging in to this!

Great video! I have never seen anything about this technology. Awesome!

Great video, as always, Alex! Have you thought about doing a video devoted to the LRASM system? The more I learn about them, the more sci-fi-is-now they seem to be. Pack 'hunting' anti-chinese ship weapons. Their programming behavior is very, very interesting and I think would make a great video!

Reminds me of those ships in Battle Los Angeles when the engines kept turning on and off it was like little explosions couple times a second. Pretty cool stuff

Nicely done video. Excellent explanation and pace. Thanks!

As always informative and well explained!

Your excellent channel definitely gets a score of five Ian's out of five for weaponry youtube channels. (Five little pictures of Ian McCollum giving a thumbs up) Subbed and chit.

Very good overview of RDE technology. I learnt quite a lot from it, thank you.

Super interesting topic. Looking forward to much more info on this new tech.

Heard about it 5 years ago. From what I remember they had huge problem with two of those rotating shockwaves (there always has to be at least 2) bumping into each other causing whole thing to be unusable

Alex I love your videos. I appreciate all the time and work you put into your videos. Keep up the great work buddy...

love to see more about these engines!!

Outstanding video - as usual Sir.. Thank you!

How loud are these engines compared to conventional jets today? Doesn't seem like you'd have a lot of means to do baffling. Not a big deal for missiles or even planes if they're going Mach 5. But for ships, does the engine stay above the water? Or is it detonating in the ocean? Water carries sound very far and fast - and if there's a stronger pressure wave (ie: louder), you could both increase detection range and probably kill or disorient a lot of fish and whales and other marine life (already a problem today). I haven't looked into it, but just curious.

I thought that “afterburners” went out with turbo jets.Turbofans, if so equipped, have “augmenters”, instead of afterburners.This is an important distinction because in addition to what goes through the combustor, augmentation uses clean unburned air bypassed AROUND the combustion chamber. This cools the combustion chamber allowing it to operate at higher pressure ratios AND provides fresh air to the augmenter. All modern fighters use augmented turbofans these days.

Hi Alex, You should look into the Sunflower Program. It was the development and testing of the first prototype heat seeker. Obviously, it was a highly classified program. If I remember correctly, it ran in the late forties and into the fifties. I think Sunflower was the name of the program but that might have been the name of the device. Anyway, it was mounted in the top of a B25 (I think) and it tracked the sun as they flew around South West United States. I believe at one point the plane crashed and there was a scramble to find it covertly. I'd love to hear the whole story. Thanks for all the excellent videos.

Its awesome how fast this engine is progressing. Its now 2023 and i just seen the video of a long time Test fire of this engine and it looks awesome.

Definitely do a video on China’s anti-ship weaponry and their “1,000 mile radius”. People make them sound invincible, and I’d love to see your breakdown of their strengths and weaknesses.

The two variables in these things are pressure and volume, similar to voltage and current (or amperage) in electricity. I'm curious if the flux density of the detonations, or of the space between them is a factor in their size.

Rotation Detonation Engine Engines are so cool!!! 👍

Hey great vid ! Just to add in more technical detail the reason detonation creates more thrust from the same amount of fuel or 'specific thrust' is due to the increase in thermodynamic efficiency as seen in comparing a Fickett-Jacobs and Brayton cycle P-v digram. This is due to detonation wave moving at sonic velocities creating a shock and pressurising the reactants without the need for a piston/compressor blades. this is why its so called 'pressure gain combustion' although when looking at the cycle as a whole no thermodynic laws are being broken as the name suggests. Also i think some italian guys have already flown one on a model rocket as well as mbda looking into this concept recently, i alos know of a paper detailing the incoperation and running in of a RDE combustor in a gas turbine. Can source if intrested.

I had this idea years ago also and its perfect for long range stealth aircraft because of the reduced heat signature of the thrust.. and commercial airliners with vertical takeoff and landing..

Hey, could you do a video or series on the current and near future state of anti air weapons? Which MANPADS do exist, what will replace the Stinger? What is the state of lasers? Which longer range options for ships and on land do exist? What do fighters have to shoot down other planes? What is currently in service or in development, either by government contract or from manufacturers? This would work well as a mini series either by range/type of defense or country of use.

Yes would enjoy a video on the range of missiles from China anti ship stuff. Thanks for the content and keeping us lay people in the loop of qhats going on behind the scenes. We spend a lot of money so it's nice to see where some of it is going

Wow this rotation combustion technology sounds very promising the future, well presented, even I could understand this concept.

I'm curious to see if the RDE concept is what would power a potential hypersonic fighter, which I believe you discussed in another video or perhaps on your website. The use of RDE in manned fighters and drones would indeed go beyond next gen.

Love the presentation, I understand how this would work in missiles and aircraft, but I'm not how this would work in ships. I understand that the engine produces thrust, I'm not sure how it would produce torque however.

Frreeman Dyson used a simular idea or technology to use a Nuclear Powerplant to power infrared waves on to a metal tungsten rod that reacted to infrared waves to create a non 02 detonation and create a detonation pulse that would in theory provide a infrared magetic pulse engine. He worked for General Atomics at the time and this was supposed to be used for the Orion Space Craft slated to go to Mars. I do not know if we ever went. I can only dream we did as an explorer. This is like sailing a ship to a new far distant land.

DARPA is amazing. Please keep it up!

Thanks for a particularly interesting video. I guess the strategic advances yielded by such an engine development would be relatively short-lived, but that is the nature of all bleeding edge technology in weapons design isn't it?

Def would like to see how to penetrate the 1000 mile bubble zone. Thanks, Alex :)

Great video. This tech is closer to working its good to get a better idea of just how it works.

Hi Alex this Franck S.im a big fan.your description of rotation detonation is flawless so my question is : Don't you think that other countries might listen to your perfe description of the project and start working on it too?

I think these engines were tried by Heinkel Hirth at the same time as von Ohain Jet engine was being developed in the 1930s. They were referred to as 'constant volume' jet engines instead of the 'constant pressure' types we know. A compressor filled several combustion chambers in turn using poppet valves. Sparking plugs ignited the mixture and the exhaust propelled the aircraft. They operate at much higher pressure and temperature ratios. Mentioned in Anthony Kays "German Jet engines and gas turbines"

I am very excited to see what the space exploration industry can do with this technology. I'm thinking space-based telescopes, that are stationed in an array, around the outer limits of Pluto's orbit. Think about the group of land-based telescopes that were responsible for the image that we got of black hole M87, and then make a telescope array, the size of Pluto's orbit.

Wow, good job, Sandboxx!

Thanks again for your videos

How long does it typically take DARPA to develop & refine a concept to where it's out in the field for the military & is operationally available?

Think about it, this tech has its roots all the way back in the 1930's with the German V-1 Buzz Bomb.

Another outstanding video, my friend! Greatly enjoyed your breakdown of this new combustion concept. I see a very crude and oversimplified illustration within the Wankel rotary engine. Again, thank you for another enjoyable video. Have a fantastic week, my friend. 🇺🇸🦅🇺🇸🦅🇺🇸🦅🇺🇸🦅🇺🇸

Awesome! Thanks Mr. Sandboxx! I have heard talk about RDEs since maybe the 2005 timeframe, AIAA conferences I think. "Detonation" sounded good, "rotating", OK, but the efficiency didn't make the headlines for me. You have pointed to the key characteristics, efficiency and smaller size (alluded to?). Now I need to find the equations, go Internet!

Rotation Detonation Engines work on basic thermodynamics: the higher the starting burn, the more efficient the engine ought to be. What stops the highest temperatures: materials. Diesels have to use inter-coolers after the turbo-boost just to save the engine. From a purely thermodynamic point of view, the ideal engine wouldn't have one. (Highest efficiency would degrade unit specific output -- less HP.) RDE hopes to fuse the episodic burn seen in ICE engines -- where the burn temperature is quite high compared to the containment metals -- with the flow through seen in open Brayton cycle engines. ( gas turbines ) If RDE geometry can be solved, the Big Change would first show up in the use of MUCH cheaper metals for turbines. RDE tech would not change the nature of after-burners. They'd still be fuel pigs. For ultra-speed applications, we've already hit the wall in terms of materials. RDE -- it is hoped -- would allow super exotic performance when exotic materials were employed. It'd be like a rocket motor that does not need regenerative cooling. (The latter chills expansion gases that you really wish to keep super hot.) Such wasted thrust is most evident in the classic NASA footage of the Saturn V at lift off. A skirt of un-burnt propellant shoots down -- hiding the flame -- until about 2 meters below the nozzles. Then the gas bursts blindingly white hot. Of course, the whole idea of using naval air against Red China is a joke. As seen in 1945, carriers sail close only to deliver the coup de grace. Red China will be defeated by radio announcement. Once the USN broadcasts that merchants sailing to Red China are suicidal -- no-one will do so. There will be no repetition of the Battle of the Atlantic. (1939-1945) Red China's war industries will collapse faster than Putin's.

Is there a question about the theory of decentralizing existing platforms and is whether it is possible to create a decentralized ground-based AEGIS system for the US ARMY and another air transported for the USAF? Thank you for your time and work.

For the curious, Scott Manley has a video on RDE. Sandbox: how about do one on what is known about pulse detonation engines?

This would be huge for the future of tanks as well

Great work as usual... definitely interested in seeing more on China's growing capability to strong-arm its neighbors and what can be done to help those neighbors maintain their sovereignty and counter it.

I think the airline industry would benefit from this technology by save a lot of money on fuel consumption thus lowering the cost of passenger tickets.

I studied pulse-jet engines in PreFlight School at Pensacola in 1961. Their example was the German "Buzz-Bomb" of WW2.

Great video, Alex. Is there any similarity between pulse jet engines and the German V-1 'buzz bombs' from WWII ??

imagine it reaching the private sector as well, electric cars with little generators operating on the principle. the fuel savings per watt and lack of costs related to maintenance and upkeep of combustion engines.... as well as being used by commercial companies who charge customers for electricity... the savings are far more impressive... reducing costs and such... i wonder what the emissions are like for them, i would assume much better and you would never need a catalytic converter ever again.

I can't remember a single modern airborne missile, arming planes in aircraft carriers, that uses liquid fuel. It's probably a solid fuel RDE, that's a whole different thing.

Excellent content, thank you.

We used to call RDE "ultra compression" and knew that it was much more efficient than a traditional design, but it isn't exactly zero maintenance. Parts wear out so quickly that it makes for a disposable engine core with all of the stress fractured components.

Due to a fuel shortage Germany is considering coal fired missiles.

Little history on Pulse Detonation devices. Throughout the 80s, 90s, there were unique contrails seen in the skies. Which made perfect flight paths from Area 51, Nellis AFB, Edwards AFB and Lockheeds old facility in California. The contrails and Sonic booms measured and seen, are only possible when using pulse detonation as a propulsion.

0:00 - 3:41… So far this reminds me of the story of Kenichi Yamamoto and the Shijyu Shichi Shi inspired journey into the success of Mazda R7 that carried the torch of the story of Felix Wankel, a visionary born out of Lahr with nothing but a vision to develop an engine like none other at the time of conception … Wonder if this will follow a similar comparable/analogous/etc journey, taking the lessons learned, to formulate future successes of DARPA’s game changing tech ❤️🤍💙🇺🇸💯NATO/QUAD/ASEAN/partners/alliances/ friends/etc

I was sorta' kinda' able to follow along. Good job!

Deflagration made a lot of noise, so detonations means it will do a lot more noise. I don't think it will find many applications on ships and low altitude flights, and I believe it is better to use for a short period due to its instability.

China gonna copy this too

Hi Alex.. Could you take a deep dive and make a video about the current and future US military's anti ship missiles? From the LRASM and NSM to PrSM and the Offensive anti surface capability, Increment 2.

Very exciting new technology wow!

It would be great if you would compare China vs. The United States of America’s industrial and manufacturing capacity. Any war between us and China is going to come down to who can build more ships, tanks, planes, landing craft, etc. Shiny new weapons are nice but unless we have the steel, aluminum, IC chips, and factories to build them they are useless. Germany had lots of cool weapons programs during the Second World War but we just produced far more then they could ever dream of. China will come at us with tens of millions of troops across every island in the pacific. We had better be able to build more aircraft carriers and other ships than they can or we are toast.

Great Coverage as Always Alex!

Scott Manley has a video on how rotational detonations engines work, if you're interested.

Anyone else see DARPA and get excited?

Thank you again for your video, , my friend. I recently read an article which, if memory serves, dealt with Toyota and its pursuit and development of a rotational detonation engine which could find application in the company’s automotive industry. Thank you again and have a great week. 🇺🇸🦅🇺🇸🦅🇺🇸🦅🇺🇸🦅🇺🇸

Excellent and intriguing.. thank you. A video on DRONES & SUBMARINES..??

There are these 2 things to extend an airplane's range we've been using for years - drop tanks and air-to-air refueling.

Could you go over the two top helicopter's. The V280 and the definese for the army. Plus get to the problem with the V22 with it's engine problems. I believe you always great updates. Keep up the great work. Go airpower and B21.

Alex, you should do a video about nuclear propulsion for the Navy, since its the only gamechanging propulsion to outfit most larger Navy vessels with nuclear so its not vulnerable to oil reserves etc.

Great video. Excellent narration.

Your videos are the best. Period.

Love your work

Awesome video!

That’s pretty mind blowing

How small can this type of engine be produced and how efficient can they be? I would love to see if this engine can be used as a compact turbine generator using alternative fuels.

How about a comparison on the potential pro/cons between these and variable bypass engines upgrades?

How do you actually start an RDE? Is it like a ramjet or a scramjet that requires another method to get the vehicle to speed or can it start from standing?

Yes, I want to know about the areal denial issue!!!

You seemed to have missed the boat on the improvements described and bought into just reporting what was in the papers. If there is more power from the rotating detention engines, they can go farther or faster or any combination of these. The Navy’s ship description probably assumed the same size engines - otherwise a smaller engining, equal power and all benefits in range could be done, or same range, greater power/speed. Same thing for missiles, jets and everything. Redesign can put all the benefit in any area - the split would be based on some arbitrary constraint. If a F-35 engine could be made smaller, perhaps more space/weight for weapons. One of us missed something, as this fundamental change in power plants can be used for whichever benefit is desired. Missiles are a good initial role, as the pressure/temperature profile may be significantly different and missiles don’t have the need for as long lived operation. Thanks for an interesting video.

Great job

I supported DARPA high technology programs from 2001 to 2015. There are basically two types (there may be more) of programs: classified and unclassified but both have the same goal to produce new high technologies for the military and in some cases for civilian use as well like NASA. In the 14 years I supported various both classified and unclassified programs, I'm not aware that any of them produced useable technologies for the military. In my opinion, there are several main reasons. First, DARPA openly declares that it is not interested in solving current military requirements but rather to solve problems the military hasn't even identified. That was interesting since the military budgets aren't interested in anything that doesn't meet it's current and future requirements. Second, perhaps more importantly, DARPA doesn't engage the procurement offices in the military to follow the new technologies it's developing for which the military has no current or future requirement so even if DARPA hits the proverbially paydirt for a new technology that might be a game changer (and I supported a couple of them), procurement offices are wedded to the FYDP or Five Year Defense Procurement and so DARPA would have to produce something that was so futuristic and game changing that procurement managers would have to eliminate technologies in the FYDP that have already been approved, but about which they have no idea what DARP is talking about. But here is the real problem. Because US Universities know have enough talent that can get a security clearance, DARPA makes the technology development unclassified to allow foreign PhD's to participate. All of these egg heads' future depend on publishing technical papers and so they descript in detail the world what new technologies we are trying to develop for our military in white papers and in technical journals. This means that the rest of the world not only has insights as to what kinds of new technologies we are trying to develop for our military, but they have all of the technical data, formulas, and descriptions about them as well. In my opinion, Bad Dog; No Bone!!!!. Just my opinion but I think DARPA should be more like the Lockheed Skunk Works where new technologies are developed and tested in secret. But like I said, apparently the US doesn't have enough PhD's who can get a classified clearance and so the world gets to know exactly the kinds of technologies we are working on for our military. As for me, I continuously held a Secret or Top Secret or Top Secret / SCI from 1968 to 2015. Somehow has a Marine officer from 1968-1989 and as a civilian I had no problems holding some of the highest security clearances. But somehow, we don't have enough PhD's in the US who can get a security clearance and we have many foreigners on the DARPA technology development teams getting insights to all of the new technology developments. Some of them had difficulty speaking English. Go figure. Not only that but DARPA hires technology program managers who have no f*cking idea how the military operates because they are just egg heads only interested in their future academic careers and so the new technology they propose to DARPA is base more on their personal interests than on future military capabilities. I'm not kidding. I supported a DARPA program manager who thought a "kill chain" was a communication concept for US forces instead of how to best defeat the enemy's ability to target and destroy our military. Consequently, in all of the DARPA programs I supported, and some that as 21 year Marine infantry officer veteran I felt would have been real game changers, were all turned down by the military because they had no idea what the heck we were talking about. Secondly, there are the DARPA major classified programs where the military shows up with a convoy of semi-trailers with money to address a current or future capability the military needs that DARPA said they weren't interested in, but follow the money. The Air Force comes to DARPA and says it needs a hypersonic missile. That is a current requirement of the Air Force which DARPA publicly said it wasn't interested in supporting current military requirements. But then there are all those semi-trailers of money and so DARPA makes it a highly classified program and because the military is funding most of it, DARPA is happy to address current and future capabilities of the Air Force. Ditto, the Navy and Army. Since the Marine Corps is part of the Department of the Navy, in the 14 years of support, I was never aware of a dedicated Marine Corps technology program. My point is this. DARBA gets about a 6 billion dollar budget a year, not counting black programs in the budgets that are off the books. In classified programs funded mostly by the military and NASA, DARPS is happy to support whatever the military wants. But in programs the military isn't funding, DARPS gives a rat's flying potato what the military wants. DARPA doesn't even solicit what the military requirements are because in my opinion DARPA doesn't care what the military needs unless the military is dumping large sums of money into DARPA to get what they want. There is no doubt that DARPA has access to major talent that can get security clearances, but only for high priority technology that the military wants now or in the future. The rest of DARPA in my opinion is a huge waste of money to unclassified programs with foreigners who produce technical papers about technologies that DARPA is interested in. To be honest, in my opinion, most of DARPA's unclassified programs would be worthless to any military because the program managers have no idea what might be beneficial to our military. However, I did support a few that in my opinion would have had the potential to be game changers, but procurement managers had not idea what the potential of the technology might be and so they never made into the FYDP budget. So here is my point. In my opinion DARPA is a waste of 6 billion dollars except for the classified program that the military is sharing the costs. How can I support DARPA programs for most of 14 years and the military didn't care about one of them????? The DARPA 6 billion dollar budget could be used more effectively by giving it to the military to do their own research. Not a single Director of DARPA has had any military experience nor has any DARPA deputy director had any military experience. In 14 years not a single program manager had any military experience. That would be like me as a former infantry officer trying to tell PhD's who have never cooked how to how to make a 5 star Mechlin meal. Can you spell Cluster F*ck? In my opinion that is what the taxpayers are getting. My apologies for the long post. I feel very emotional about what I've said. The waste in our government is mind bobbling beyond anything you can possibly imagine. There is no one in our government who can monitor a billion dollar budget. And a Congress Trillion dollar budge is impossible to manage. So when the Pentagon says the can't account for a 6 billion dollar discrepancy and says it will give that 6 billion to Ukraine, should that not pause and ask yourself, If the Pentagon has no idea how they lost 6 billion dollars, then how do they know it can all go to Ukraine? Think about that. We are F*cked as a country unless our government is transparent, accountable, honest, and stops just lying to us every freaking day.

Excellent analysis

Pulse detonation, in conjunction with an aerospike nozzle would enable maximum efficiency at all altitudes, as well. Niiiice!

Reminds me of the Project Orion Spacecraft nuclear pulse engine design from way back when that was never built. Yet.