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The pace of early aircraft development is still one of the most unbelievable human achievements. To go from the the Kittyhawk to jet planes in under 40 years was insane.
world wars will do that to technology. Nothing boosts technology advancement quite like humans doing their level best to figure out better and more efficient ways of killing each other
I think the two World Wars that would sadly occur in the first half of the 20th century definitely acted as a catalyst to powered flight, specifically the developments made around the time of World War II, as necessity is the mother of invention. Particularly the contributions of Sir Frank Whittle, and his efforts to create the first jet engine as a major innovation in the history of aviation. Receiving a patent for his design for the turbojet engine in 1930 and then founding Power Jets LTD in 1936 to further develop his ideas. Leading to the first successful jet engines being tested in 1937 and, although disputed, still one of the first jet powered aircraft, utilizing Whittle’s Jet engine in the Gloster E.28 & E.29, with them first taking to the skies in 1941. Obviously, Germany’s efforts cannot be ignored, with the Heinkel HE 178, designed by Ernst Heinkel. With his prototype jet aircraft first flying in August on 1939. The U.S. can certainly not be ignored in terms of contributions to the field of jet powered aviation, with the Bell P-59 twin jet engine powered aircraft that took its maiden flight on October 1st 1942. Although impressive, all three of these aircraft didn’t really see much, if any action during World War II but, what followed would set off the biggest change in commercial aviation in the history of jet powered flight with the advent of massive Jet powered passenger planes, like the British built De-Havilland Comet taking its maiden flight in 1952 and the American built Boeing 707, first taking flight in 1954 and entering into commercial passenger use in 1958 with PAN-AM. De-Havilland obviously then suffered issues with the Comet, due to its design leading to the forming of stress crack in the fuselage after cycles of pressurization and depressurization, causing it to break up mid flight on multiple occasions. This then caused the British to loose their lead to Boeing, McDonnell Douglas, Lockheed etc. However, the joint venture between BAC and Aérospatiale to design and build the magnificent Concorde. Quite possibly, one of the most advanced, safest and definitely, the fastest and most beautiful (imo) commercial aircraft ever build but, despite these accolades, it was technically a financial failure. Due to legislation restricting supersonic flight over land and its one crash that was as a result of a freak accident causing a fuel leek in the left wing fuel tank when a huge piece of a blown 747 tire from the plane taking off before it, being left of the runway, was then thrown up, hitting the left wing with sufficient force to rupture the left wing fuel tank causing it to burst the plastic welds. Fuel leaked out of the left wing and into the hot jet exhaust of the two left engines, igniting it and causing a fire that consumed the plane until it finally crashed only shortly after takeoff. That combined with increased fuel prices due to the then recent breakout of war in the Middle East, was the death knell in that magnificent aircraft’s illustrious history. Now we have the duopoly of Boeing and Airbus and innovation has seemingly stagnated and as an American, it pains me to see the serious decline of the once great Boeing Company. I hope that serious innovation will soon return to the field of passenger jet aircraft design and production.
As an aerospace engineer who specialized in propulsion, this video is very nice. Very comprehensive way to explain in layman's terms an extemely complicated topic. A quick detail on turbofans, they are substantially quieter than a regular turbojets due to the air bypass, which is nother advantage and quite a massive on at that. Approved!
I can back up that sentiment. I was an engineer working on the original design of the PW100 turboprop (think ATR 72 and/or the De Havilland Dash 8) back in the early 1980s, and then on the iconic PT6 series. Your summary, while heavily simplified, was spot on. Though I had to grit my teeth in the early stages when you showed a turtofan while talking about a turbojet.
Turbofans are more fuel efficient; but is there a trade-off with speed? Seems like a larger frontal disc on the engine would mean higher drag for the airframe. As I recall this was a drawback of the WWII air-cooled radial engines; it made the frontal face of the fuselage less slim.
@@Eric-gu2rs Not really. You are right, for the old radial piston engines, the cross section of the engine facing the airflow represented a lot of drag and created turbulent airflow. But remember, in a turbo fan those big blades, which make up most of the cross section facing the airflow, are rotating such that they pull in the air and push it down the bypass. So there is essentially minimal drag and it does not create any turbulent airflow problems. The limiting problem with respect to speed for turbofans engines is that those large fan blades would probably not withstand the shock of breaking the sound barrier. That is why the Concord had turbo jet engines, rather than turbofan engines.
This video provided about 75% of the information on turbine engines that we covered in my Aircraft Systems class way back in 1999, and did it in a lot less time. Lots of excellent information here, particularly for folks who aren't aviation/aerospace professionals. Well done, Simon.
I've got a topic for you: the Internet! Everybody uses it but very few people knows _how_ it works: how the "network of networks" work and what it does really mean, the various services (e-mail, the Web, FTP), what's really a VPN.... It's a vast subject, but it should also be possible to reduce it to layman's terms without wandering too much or go too deep into the intricate technicalities - just like you did in this video.
Excellent video but you neglected to mention the key technologies that makes modern jet engines so efficient. Thermodynamics requires the engine be run at higher temperatures to improve efficiency and the blades in the turbine section bear the brunt of these high temperatures. In some of these engines the blades actually run at temperatures ABOVE the melting point of the metal they are made from. The two key technologies that allow for this are are cooling channels within the blades to air cool them so they don't melt. The other key technology is single-crystal turbine blades. In short, typical alloys begin to deform under heat and stress and turbine blades are under a lot of heat and stress (from spinning so fast) so they want to elongate, or "creep" to use the metallurgy term. To get around this problem the blades where heat treated to directionally re-crystalize the grain structure which worked for a while until they wanted to run the engines even hotter. To solve that problem they figured out a way to make the turbine blades as a single crystal with no grains, hence no grain boundaries and therefore no creep. This is a key technology that is highly guarded trade-secret and only a few companies in the world know how to do this. Materials Science to the rescue!
Metals always fail on grain boundaries, where impurities can exist, and that is where corrosion happens... not sure if lack of grain boundaries stops creep at high temps though.
holy crap wtf how do they make a single crystal blade that big?? I knew single crystal Sillicon was a thing in the semiconductor industry but didn't know it was possible for a metal, that's crazy!
My oldest brother worked on the lasers for over 20 years at P&WA that were used to make these single crystal blades. I worked there assembling the engines for a few years.
I work in aviation and I absolutely love this video. We're actually having a CFM56-3 engine being built and we're expecting delivery within the next couple weeks.
Too simple for a whole video. A basic form of a steam engine was made all the way back in 30 BC. There is not a whole lot you can do with steam, only two things really. A turbine or a piston
@@hi-fidude6670 lots of implementations though, even just in turbines. Nuclear power and conventional power steam cycles, multi stage drive turbines, different types of turbine blades, condensers, steam plant chemistry, single stage turbines, electronic vs mechanical governors, naval vs civilian... I think that could easily fill a half hour, and that's without adding in piston engines.
@@hi-fidude6670 You really have no clue how much engineering is involved in making a steam engine when you actually start pushing for proper performance, do you? There's an insane amount of variations in both boiler and motor units. Sure, a child can make a trivial, small engine that does no useful work aside from looking funny, but outside of the basics that has nothing to do with proper engines.
@@Kriss_L yup. Spent a number of years in that world. Hot Rock, make steam, make shaft go roundy roundy, make ship go. Steam is just a medium, a connection between power sources and mechanical action, but it's one of the best for doing it at large scale.
Awesome how you successfully "expanded" on the basic concept of "suck - squeeze - bang - blow" for a basic jet engine. Love Megaprojects content, look forward to more of "How it (really) Works", cheers Simon & team!
This is more like what I thought Megaprojects would be like when it started. I do like the historical perspective you usually provide, but I also enjoy engineering/science focused videos.
Small correction, at 4:12 you say the 'gas wants to diffuse'. This is the wrong term. The hot gas wants to expand, not quite the same thing. Diffusion is the net movement from a region of higher concentration to a region of lower concentration, nothing to do with temperature. Keep up the good work!
I give a hat to this guy for being entertaining but he isnt the most reliable if you want knowledge. 90% of the time he sounds like hes getting info out of his ass
Great overview! I'll add that high bypass turbofans actually get the majority of their thrust from the big fan in front, very little of it is from exhaust gasses.
I want to give this video a mega thumbs up. I've been waiting on this one. I was hoping it was maybe like 4 hours, but I'll settle for 20 minutes! Thanks again for bringing this to us.
0:40 - Chapter 1 - The basic principles 1:10 - Mid roll ads 2:25 - Back to the video 9:35 - Chapter 2 - Turbojets & turbofans 14:30 - Chapter 3 - Turboprops & turboshafts 17:40 - Chapter 4 - The ones with no or few moving parts
21:00 The X-43 refers to the entire hypersonic test vehicle, not just the engine. It was an integrated system where the airframe itself functioned as part of the scramjet engine.
I think the two World Wars that would sadly occur in the first half of the 20th century definitely acted as a catalyst to powered flight, specifically the developments made around the time of World War II, as necessity is the mother of invention. Particularly the contributions of Sir Frank Whittle, and his efforts to create the first jet engine as a major innovation in the history of aviation. Receiving a patent for his design for the turbojet engine in 1930 and then founding Power Jets LTD in 1936 to further develop his ideas. Leading to the first successful jet engines being tested in 1937 and, although disputed, still one of the first jet powered aircraft, utilizing Whittle’s Jet engine in the Gloster E.28 & E.29, with them first taking to the skies in 1941. Obviously, Germany’s efforts cannot be ignored, with the Heinkel HE 178, designed by Ernst Heinkel. With his prototype jet aircraft first flying in August on 1939. The U.S. can certainly not be ignored in terms of contributions to the field of jet powered aviation, with the Bell P-59 twin jet engine powered aircraft that took its maiden flight on October 1st 1942. Although impressive, all three of these aircraft didn’t really see much, if any action during World War II but, what followed would set off the biggest change in commercial aviation in the history of jet powered flight with the advent of massive Jet powered passenger planes, like the British built De-Havilland Comet taking its maiden flight in 1952 and the American built Boeing 707, first taking flight in 1954 and entering into commercial passenger use in 1958 with PAN-AM. De-Havilland obviously then suffered issues with the Comet, due to its design leading to the forming of stress crack in the fuselage after cycles of pressurization and depressurization, causing it to break up mid flight on multiple occasions. This then caused the British to loose their lead to Boeing, McDonnell Douglas, Lockheed etc. However, the joint venture between BAC and Aérospatiale to design and build the magnificent Concorde. Quite possibly, one of the most advanced, safest and definitely, the fastest and most beautiful (imo) commercial aircraft ever build but, despite these accolades, it was technically a financial failure. Due to legislation restricting supersonic flight over land and its one crash that was as a result of a freak accident causing a fuel leek in the left wing fuel tank when a huge piece of a blown 747 tire from the plane taking off before it, being left of the runway, was then thrown up, hitting the left wing with sufficient force to rupture the left wing fuel tank causing it to burst the plastic welds. Fuel leaked out of the left wing and into the hot jet exhaust of the two left engines, igniting it and causing a fire that consumed the plane until it finally crashed only shortly after takeoff. That combined with increased fuel prices due to the then recent breakout of war in the Middle East, was the death knell in that magnificent aircraft’s illustrious history. Now we have the duopoly of Boeing and Airbus and innovation has seemingly stagnated and as an American, it pains me to see the serious decline of the once great Boeing Company. I hope that serious innovation will soon return to the field of passenger jet aircraft design and production.
I was going to say this as well. Suck. Bang. Blow. Which seems simplistic, and it is, but so are gas turbines. The details are tricky, but the concept is stupid simple.
@@cruisinguy6024 Suck--->Squeeze--->Bang--->BLOW (you forgot that one). 4-stroke. 2-stroke engines just combine suck/squeeze and bang/blow. There is no 3-stroke engine.
@@jeromethiel4323 Who invented the 3-stroke engine, and when was it? As a mechanic for nearly 40 years, and a jet engine enthusiast, I can confirm there is no such thing as a 3-stroke. Suck--->SQUEEZE (you forgot that one)--->Bang--->Blow 4-stroke. 2-stroke engines just combine suck/squeeze and bang/blow.
One of your clips is the T-9 test cell at Dyess AFB running an f101-ge102 B-1 engine. My old test cell. I now work for RR as an SME for the BA engines, specifically Pearl 700, 15, and now 10X. As mentioned, you were a little off on diffusion, but pretty good video... Think of the diffuser as the exit of the compressor, thats where we need the HIGHEST pressure, so we avoid a surge. Surge is bad. Overall, good job. Gas Turbine Engines are VERY complex devices, so to get decent info across in 15-20 minutes is excellent.
My brother in law works on jet engines and he loves it, he's sent me some videos over the years of how complicated they are and testing etc, mental stuff.
I don’t know how many million miles I’ve flown in over 50 years, averaging a quarter million miles for at least half of them and I continue to marvel at two aspects: 1. How these many tons of metal (and now carbon fibre), people, fuel and cargo stay up there, and 2. Why these engines don’t melt down or compressor blades fracture? I know the physics of lift and thrust but still think it’s magic…and a helluva leap in technological expertise: so many parts that could fail but don’t to an amazing level of reliability and how airframes can withstand the stress of severe turbulence I’ve experienced more times than I’d like to recall! Thanks for this deep look at a true engineering accomplishment that most people overlook when they reflect on what marvels planes like the B747 or A380 “jumbos”.
12:45 Bypass air is unfortunately not "free" thrust. The Fan part of Turbo Fans draw their power from the exhaust gases of the jet's turbine. This necessarily reduces the exhaust velocity of the engine. It does make the engine more efficient, though, since jet engines are most fuel-efficient the closer their exhaust velocity is to the aircraft's airspeed; they move a greater volume of air at a lower average velocity, producing more thrust for less fuel.
Great piece. Disappointed the Whittle jet engine wasn't discussed in detail although the axial engine "won" in the end, it's not like Whittle was a flash in the pan. Maybe another piece comparing the two.
Whittle did axial-flow and centrifugal. There were *five* turbojet engines in the UK under R&D in WW2: *Centrifugal,* by Whittle (Rover); *Centrifugal,* by Frank Halford (DeHaviland); *Axial-flow,* by Metro-Vick; *Axial-flow* by Griffiths (Rolls Royce); *Axial flow compressor, with reverse flow combustion chambers.* The ASX by Armstrong Siddeley; The Metropolitan Vickers designs were test flown in 1942 producing more thrust than anything Germany produced with a longer service life. The axial-flow were more expensive compared to the centrifugal designs with still development problems to solve, so being funded by the government they were never selected for any aircraft with cost being one of the rejection points. Metropolitan Vickers produced the first successful turbofan engines rated double anything Germany ever produced during the war. Also the turboprop engine found largescale use post war because of its excellent fuel consumption.
Megaprojects usually has reasons for the thing being done or made, with failures and successes, plus budgets and maybe notable figures - i feel like this series would be difficult to really implement that without a longer format video, but its worthwhile either way
Nice video! One topic to break down, the difference between an Afterburner and an Augmentor. This would further separate the differences between the turbojet and the low ratio, fully ducted, turbofan. Thanks for the video.
I really like these dives into technology. Today I found out😂. Seriously though this could be a good addition to the channel. How about a dive in to electric vehicles?
If you threw a turbojet onto one of those styrofoam airplane models with the plastic propellers you get at the dentist office, you'd essentially have a turbo fan
Next to the gas turbine, another little thing that would have been worthy of note is the supercruise as you mentioned F22, Typhoon and Concorde. In particular for the concorde because only uses the afterburner at take off and transsonic region. Then it continues accelerating until cruise speed, without the afterburners.
My husband and i love this kind of series. I feel like steam engines would be a really interesting one because of the time and scale of impact on the modern world...might be longer than 22 mins though lol
Afterburners are frequently referred to as 'reheat'. TheHarrier DID use thrust vectoring during the Falklands war to shoot down several Argentinian aircraft!! Turboshaft engines are also being used to power smaller US Navy vessels.
One major design aspect that is a little beyond the scope of this video is nozzle design (and engine geometry in general). This is especially true if the air transitions between subsonic and supersonic anywhere in the engine, because unexpected shockwaves could cause damage or disruption, and because subsonic and supersonic gas flows behave very differently when it comes to compression and expansion. Also, another odd place to find a turboshaft engine: a tank! Specifically the M1 Abrams
There are a couple of important points about the operation of all turbine engines (whether turbojet, turboprop, turbofan or turboshaft) which are the most common misunderstandings many people have about how these engines work. This is often a result of people who do understand how piston engines (whether petrol or diesel) work, but then try to apply this to turbine engines. Which is understandable, since both are internal combustion engines, and both use the same "induction, compression, combustion, exhaust" sequence - but accomplish this in rather different ways. The biggest single difference is that piston engines do this literally as a sequence (piston strokes doing each part, one after the other, in the order quoted above), a turbine does all of them continuously and simultaneously - in the same order but starting at the front of the engine and finishing at the back. (1). In a piston engine, the majority of the oxygen in the air drawn into the cylinders is consumed during combustion, with very little oxygen remaining in the exhaust. However, turbine engines draw in far more air than is necessary for combustion alone. By this I am talking about the air which goes through the engine core and therefore through the compressor (not the bypass ratio which only applies to turbofan engines), so this is the same for any of the turbine engine varieties mentioned above. The vast majority of the compressed air is not used for combustion, and is used mostly to mix with and cool down the high temperature combustion products, though some is also routed into the cooling channels inside the turbine blades. This is also why afterburners can be fitted to the engine downstream of the turbine stage - because the exhaust still has enough oxygen content to support further combustion of fuel. If all the oxygen was consumed in the core combustion section, an afterburner on a turbojet would not be possible. (2).In a piston engine, the pressure inside the cylinder increases a great deal when the fuel-air mixture is ignited, and it is this large pressure increase acting upon the piston which generates the power. However, in a turbine engine the highest pressure is just downstream of the compressor known as the compressor discharge pressure. The combustion of fuel does not increase the pressure at all. What does increase is the volume and the velocity of the gases, since the combustion products from the burning fuel are all gases, and of course the combustion adds a great deal of energy. This is also true for rocket engines, in which the highest pressures are just downstream of the fuel pumps: This pressure is what forces the fuel and oxidiser through the injectors at the top of the combustion chamber. A common error is the assumption that the pressure increases in the combustion chamber of a rocket engine - but if this was the case, then the higher pressure would prevent the propellants from flowing through the injectors and into the combustion chamber. What actually happens is similar to the combustion chamber of a turbine engine - the volume and velocity of gases both increase enormously, and are then accelerated even further when the hot combustion products flow through the nozzle. The difference being that the temperature can be much higher, since there is no turbine downstream of the combustion chamber in a rocket engine.
Our lecturer explained the compressor turbine relationship as trying to pick yourself up by you shoelaces, but actually succeeding. Obviously, adding fuel is the tric, but you get what I mean.
I was quite surprised they day I figured out that a Turbofan engine was basically just a giant air compressor and that the whole point of the central combustion chamber is to spin the fan to draw in bypass air. It was blitheringly simple!
What makes jets so complicated and expensive is metallurgy, weight savings, and fuel control. The blades on the compressor are such a major component, where it used to be the turbine blades in the hot section for obvious reasons, all whilst giving longevity and safety and a lower rate of fuel burn. Something a jet engine will probably never be good at as they love to consume a lot of fuel.
High-bypass engines produce their bypass thrust from what's called a convergent-divergent bypass duct. The fan blows air into the narrowing part of the bypass duct where it compresses through the narrowing space and this bypass air expands and accelerates through the divergent part of the nozzle and that's how they produce jet thrust. Low-bypass engines have a linear bypass duct which means the bypass flow isn't processed and allows the fan to directly produce thrust almost like a propeller, most people think it's the other way around, lol
Pretty good, especially appreciate the small but important distinction between airflow and gas flow once the air is mixed with fuel, sure that would have been picked up on my fitters oral exam if I got that wrong! No mention of centrifugal compressors (just showing axial flow which I guess is fair enough), or turbo fan bypass air also cooling the exhaust gas and reducing noise from the core making them better choices for passenger aircraft, but overall you achieved in 20 minutes what took a total of 6 months for my mechanics course to fully explain (though they only had OHP’s to work with!).
Rather than "normal" turbojet vs turbofan, one might identify them as pure jet vs turbofan. The distinguishing feature of the pure jet is that all of the air entering the engine passes through the compressor, combustion chamber, and turbine(s) and thrust is derived from the energy remaining in the gas after exiting the turbine section. The distinguishing feature of the turbofan, by contrast is that the turbine section is designed to extract more energy from the exhaust, converting it into the mechanical energy needed to drive the fan, reducing the thrust contributed by combustion gases exiting the turbine section. In a high-bypass turbofan, the goal is to extract as much energy as possible from the exhaust gas so that almost all of the engine's thrust comes from the fan's interaction with the bypass air. FWIW: a jet engine compresses air for a few reasons... the increased pressure improves combustion, so fuel burns more completely, but just as importantly, when the gas temperature is raised by combustion, it wants to expand; the higher the pressure at which this occurs, the more work this equates to.
Wings are interesting with many types and profiles. Some for slow and some for very fast. Some stick out straight, some sweep back, few sweep forward and one X plane with one side swept forward with other side swept back.
This should have been an "Everything you need to know video." I'm still yet to watch but I'm sad this isn't an hour long video diving deep into the history and advancements of the jet engine. Let's see where it takes us. So i have watched the video. Smells like theres going to be follow ups going into details of the different types of engines. A megaproject would be to document the history of the first Jet engines and how it was a secret race during ww2 between the axis and allies powers.
This is a good video but should include the difference between one-spool and two-spool engines and the battle for efficiency between composite blades (GE/CFMI), three-spool engines (Rolls Royce), and Geared Turbofan (Pratt and Whitney). Also, the difference between an afterburner, which goes on a turbojet versus an augmentor which goes on a turbofan.
I would love to see a deep dive into how torpedo's work. On the surface they seem rather simple but if I am not mistaken they are actually quite complex. At least modern ones are I would imagine.
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The pace of early aircraft development is still one of the most unbelievable human achievements. To go from the the Kittyhawk to jet planes in under 40 years was insane.
First heavier than air flight to landing on the moon in 65 years is the most insane leap in my opinion
world wars will do that to technology. Nothing boosts technology advancement quite like humans doing their level best to figure out better and more efficient ways of killing each other
I think the two World Wars that would sadly occur in the first half of the 20th century definitely acted as a catalyst to powered flight, specifically the developments made around the time of World War II, as necessity is the mother of invention. Particularly the contributions of Sir Frank Whittle, and his efforts to create the first jet engine as a major innovation in the history of aviation. Receiving a patent for his design for the turbojet engine in 1930 and then founding Power Jets LTD in 1936 to further develop his ideas. Leading to the first successful jet engines being tested in 1937 and, although disputed, still one of the first jet powered aircraft, utilizing Whittle’s Jet engine in the Gloster E.28 & E.29, with them first taking to the skies in 1941. Obviously, Germany’s efforts cannot be ignored, with the Heinkel HE 178, designed by Ernst Heinkel. With his prototype jet aircraft first flying in August on 1939. The U.S. can certainly not be ignored in terms of contributions to the field of jet powered aviation, with the Bell P-59 twin jet engine powered aircraft that took its maiden flight on October 1st 1942. Although impressive, all three of these aircraft didn’t really see much, if any action during World War II but, what followed would set off the biggest change in commercial aviation in the history of jet powered flight with the advent of massive Jet powered passenger planes, like the British built De-Havilland Comet taking its maiden flight in 1952 and the American built Boeing 707, first taking flight in 1954 and entering into commercial passenger use in 1958 with PAN-AM. De-Havilland obviously then suffered issues with the Comet, due to its design leading to the forming of stress crack in the fuselage after cycles of pressurization and depressurization, causing it to break up mid flight on multiple occasions. This then caused the British to loose their lead to Boeing, McDonnell Douglas, Lockheed etc. However, the joint venture between BAC and Aérospatiale to design and build the magnificent Concorde. Quite possibly, one of the most advanced, safest and definitely, the fastest and most beautiful (imo) commercial aircraft ever build but, despite these accolades, it was technically a financial failure. Due to legislation restricting supersonic flight over land and its one crash that was as a result of a freak accident causing a fuel leek in the left wing fuel tank when a huge piece of a blown 747 tire from the plane taking off before it, being left of the runway, was then thrown up, hitting the left wing with sufficient force to rupture the left wing fuel tank causing it to burst the plastic welds. Fuel leaked out of the left wing and into the hot jet exhaust of the two left engines, igniting it and causing a fire that consumed the plane until it finally crashed only shortly after takeoff. That combined with increased fuel prices due to the then recent breakout of war in the Middle East, was the death knell in that magnificent aircraft’s illustrious history. Now we have the duopoly of Boeing and Airbus and innovation has seemingly stagnated and as an American, it pains me to see the serious decline of the once great Boeing Company. I hope that serious innovation will soon return to the field of passenger jet aircraft design and production.
Then to the moon not long after that. Just insane rate of advancement.
Or Kitthawk to moon landing in what was it, 66 years?
As an aerospace engineer who specialized in propulsion, this video is very nice. Very comprehensive way to explain in layman's terms an extemely complicated topic. A quick detail on turbofans, they are substantially quieter than a regular turbojets due to the air bypass, which is nother advantage and quite a massive on at that. Approved!
I can back up that sentiment. I was an engineer working on the original design of the PW100 turboprop (think ATR 72 and/or the De Havilland Dash 8) back in the early 1980s, and then on the iconic PT6 series. Your summary, while heavily simplified, was spot on. Though I had to grit my teeth in the early stages when you showed a turtofan while talking about a turbojet.
Turbofans are more fuel efficient; but is there a trade-off with speed? Seems like a larger frontal disc on the engine would mean higher drag for the airframe. As I recall this was a drawback of the WWII air-cooled radial engines; it made the frontal face of the fuselage less slim.
@@Eric-gu2rs Not really. You are right, for the old radial piston engines, the cross section of the engine facing the airflow represented a lot of drag and created turbulent airflow. But remember, in a turbo fan those big blades, which make up most of the cross section facing the airflow, are rotating such that they pull in the air and push it down the bypass. So there is essentially minimal drag and it does not create any turbulent airflow problems. The limiting problem with respect to speed for turbofans engines is that those large fan blades would probably not withstand the shock of breaking the sound barrier. That is why the Concord had turbo jet engines, rather than turbofan engines.
@@Eric-gu2rs Turbofans are slower, yes, but there is no need for more speed in commercial aviation.
Can’t stop poopin
This video provided about 75% of the information on turbine engines that we covered in my Aircraft Systems class way back in 1999, and did it in a lot less time. Lots of excellent information here, particularly for folks who aren't aviation/aerospace professionals. Well done, Simon.
I've got a topic for you: the Internet! Everybody uses it but very few people knows _how_ it works: how the "network of networks" work and what it does really mean, the various services (e-mail, the Web, FTP), what's really a VPN.... It's a vast subject, but it should also be possible to reduce it to layman's terms without wandering too much or go too deep into the intricate technicalities - just like you did in this video.
they could make an entire series about just how the internet works
@@mastershooter64 it is fascinating. you could make a whole video series on TCP/IP alone.
Excellent video but you neglected to mention the key technologies that makes modern jet engines so efficient. Thermodynamics requires the engine be run at higher temperatures to improve efficiency and the blades in the turbine section bear the brunt of these high temperatures. In some of these engines the blades actually run at temperatures ABOVE the melting point of the metal they are made from. The two key technologies that allow for this are are cooling channels within the blades to air cool them so they don't melt. The other key technology is single-crystal turbine blades. In short, typical alloys begin to deform under heat and stress and turbine blades are under a lot of heat and stress (from spinning so fast) so they want to elongate, or "creep" to use the metallurgy term. To get around this problem the blades where heat treated to directionally re-crystalize the grain structure which worked for a while until they wanted to run the engines even hotter. To solve that problem they figured out a way to make the turbine blades as a single crystal with no grains, hence no grain boundaries and therefore no creep. This is a key technology that is highly guarded trade-secret and only a few companies in the world know how to do this. Materials Science to the rescue!
Metals always fail on grain boundaries, where impurities can exist, and that is where corrosion happens... not sure if lack of grain boundaries stops creep at high temps though.
holy crap wtf how do they make a single crystal blade that big?? I knew single crystal Sillicon was a thing in the semiconductor industry but didn't know it was possible for a metal, that's crazy!
@@mastershooter64 It's very hard to do, that's why only 3 or 4 companies can do it.
My oldest brother worked on the lasers for over 20 years at P&WA that were used to make these single crystal blades. I worked there assembling the engines for a few years.
My booty burnin
More, please! There are other channels that cover similar topics, in similar easy-to-understand ways, but I appreciate your guys' take!
I work in aviation and I absolutely love this video. We're actually having a CFM56-3 engine being built and we're expecting delivery within the next couple weeks.
Steam power technology would be pretty cool in a video. Locomotives, steam turbines, air ejectors.
Amazing what you can do with a bit of boiled water.
Too simple for a whole video. A basic form of a steam engine was made all the way back in 30 BC. There is not a whole lot you can do with steam, only two things really. A turbine or a piston
@@hi-fidude6670 lots of implementations though, even just in turbines. Nuclear power and conventional power steam cycles, multi stage drive turbines, different types of turbine blades, condensers, steam plant chemistry, single stage turbines, electronic vs mechanical governors, naval vs civilian...
I think that could easily fill a half hour, and that's without adding in piston engines.
@@hi-fidude6670 You really have no clue how much engineering is involved in making a steam engine when you actually start pushing for proper performance, do you? There's an insane amount of variations in both boiler and motor units. Sure, a child can make a trivial, small engine that does no useful work aside from looking funny, but outside of the basics that has nothing to do with proper engines.
Keep in mind also that nuclear power, which is just a fancy way of heating (usually) water with a magical rock, is also steam power.
@@Kriss_L yup. Spent a number of years in that world. Hot Rock, make steam, make shaft go roundy roundy, make ship go.
Steam is just a medium, a connection between power sources and mechanical action, but it's one of the best for doing it at large scale.
Awesome how you successfully "expanded" on the basic concept of "suck - squeeze - bang - blow" for a basic jet engine.
Love Megaprojects content, look forward to more of "How it (really) Works", cheers Simon & team!
This UA-cam channel, along with Biographics and Into The Shadows seriously deserve more subscriptions... absolutely outstanding content
Definitely a great format! Would love more of this
This is more like what I thought Megaprojects would be like when it started. I do like the historical perspective you usually provide, but I also enjoy engineering/science focused videos.
Love the new content, let’s hear about lasers and the future applications of them
Small correction, at 4:12 you say the 'gas wants to diffuse'. This is the wrong term. The hot gas wants to expand, not quite the same thing. Diffusion is the net movement from a region of higher concentration to a region of lower concentration, nothing to do with temperature. Keep up the good work!
I give a hat to this guy for being entertaining but he isnt the most reliable if you want knowledge. 90% of the time he sounds like hes getting info out of his ass
Great video, it could have been a proper 90min deep dive epic and we would all enjoy it!
As an aspiring A&P with my powerplant written test in a week. This is a nice refresher
Good luck!
Good luck!
Great overview! I'll add that high bypass turbofans actually get the majority of their thrust from the big fan in front, very little of it is from exhaust gasses.
I want to give this video a mega thumbs up. I've been waiting on this one. I was hoping it was maybe like 4 hours, but I'll settle for 20 minutes! Thanks again for bringing this to us.
Definitely like this new video idea Simon and Co! Would love a video on the inner workings of a standard/typical vehicle engine
Hats off to all those highly-knowledgeable people who explain things to those of us outside the Knowledgeable group.
This was great Simon! More of this style video please.
0:40 - Chapter 1 - The basic principles
1:10 - Mid roll ads
2:25 - Back to the video
9:35 - Chapter 2 - Turbojets & turbofans
14:30 - Chapter 3 - Turboprops & turboshafts
17:40 - Chapter 4 - The ones with no or few moving parts
21:00 The X-43 refers to the entire hypersonic test vehicle, not just the engine. It was an integrated system where the airframe itself functioned as part of the scramjet engine.
The name Frank Whittle comes to mind!
Oh and Rolls Royce! 👌
I think the two World Wars that would sadly occur in the first half of the 20th century definitely acted as a catalyst to powered flight, specifically the developments made around the time of World War II, as necessity is the mother of invention. Particularly the contributions of Sir Frank Whittle, and his efforts to create the first jet engine as a major innovation in the history of aviation. Receiving a patent for his design for the turbojet engine in 1930 and then founding Power Jets LTD in 1936 to further develop his ideas. Leading to the first successful jet engines being tested in 1937 and, although disputed, still one of the first jet powered aircraft, utilizing Whittle’s Jet engine in the Gloster E.28 & E.29, with them first taking to the skies in 1941. Obviously, Germany’s efforts cannot be ignored, with the Heinkel HE 178, designed by Ernst Heinkel. With his prototype jet aircraft first flying in August on 1939. The U.S. can certainly not be ignored in terms of contributions to the field of jet powered aviation, with the Bell P-59 twin jet engine powered aircraft that took its maiden flight on October 1st 1942. Although impressive, all three of these aircraft didn’t really see much, if any action during World War II but, what followed would set off the biggest change in commercial aviation in the history of jet powered flight with the advent of massive Jet powered passenger planes, like the British built De-Havilland Comet taking its maiden flight in 1952 and the American built Boeing 707, first taking flight in 1954 and entering into commercial passenger use in 1958 with PAN-AM. De-Havilland obviously then suffered issues with the Comet, due to its design leading to the forming of stress crack in the fuselage after cycles of pressurization and depressurization, causing it to break up mid flight on multiple occasions. This then caused the British to loose their lead to Boeing, McDonnell Douglas, Lockheed etc. However, the joint venture between BAC and Aérospatiale to design and build the magnificent Concorde. Quite possibly, one of the most advanced, safest and definitely, the fastest and most beautiful (imo) commercial aircraft ever build but, despite these accolades, it was technically a financial failure. Due to legislation restricting supersonic flight over land and its one crash that was as a result of a freak accident causing a fuel leek in the left wing fuel tank when a huge piece of a blown 747 tire from the plane taking off before it, being left of the runway, was then thrown up, hitting the left wing with sufficient force to rupture the left wing fuel tank causing it to burst the plastic welds. Fuel leaked out of the left wing and into the hot jet exhaust of the two left engines, igniting it and causing a fire that consumed the plane until it finally crashed only shortly after takeoff. That combined with increased fuel prices due to the then recent breakout of war in the Middle East, was the death knell in that magnificent aircraft’s illustrious history. Now we have the duopoly of Boeing and Airbus and innovation has seemingly stagnated and as an American, it pains me to see the serious decline of the once great Boeing Company. I hope that serious innovation will soon return to the field of passenger jet aircraft design and production.
Jet engines can be broken down to 3 basic components: a sucker, a burner, and a blower. Great video!
As opposed to an internal combustion engine which is suck, squeeze, bang.
I was going to say this as well. Suck. Bang. Blow. Which seems simplistic, and it is, but so are gas turbines. The details are tricky, but the concept is stupid simple.
Suck--->SQUEEZE (you forgot that one)--->Bang--->Blow 4-stroke. 2-stroke engines just combine suck/squeeze and bang/blow. There is no 3-stroke engine.
@@cruisinguy6024 Suck--->Squeeze--->Bang--->BLOW (you forgot that one). 4-stroke. 2-stroke engines just combine suck/squeeze and bang/blow. There is no 3-stroke engine.
@@jeromethiel4323 Who invented the 3-stroke engine, and when was it? As a mechanic for nearly 40 years, and a jet engine enthusiast, I can confirm there is no such thing as a 3-stroke. Suck--->SQUEEZE (you forgot that one)--->Bang--->Blow 4-stroke. 2-stroke engines just combine suck/squeeze and bang/blow.
One of your clips is the T-9 test cell at Dyess AFB running an f101-ge102 B-1 engine. My old test cell. I now work for RR as an SME for the BA engines, specifically Pearl 700, 15, and now 10X. As mentioned, you were a little off on diffusion, but pretty good video... Think of the diffuser as the exit of the compressor, thats where we need the HIGHEST pressure, so we avoid a surge. Surge is bad. Overall, good job. Gas Turbine Engines are VERY complex devices, so to get decent info across in 15-20 minutes is excellent.
Nice video Simon, more of this type of material please!
Thanks! That was great :)
Yes, I would like to see occasional videos of this type. Thanks to this video I feel that I now know the basics of jet engines.
Thank you for creating this video. It cleared up a lot of debates made in the comments of your other videos on jet engines
A video all about the engines on the sr-71 would be awesome. They are truly a marvel of jet engineering and a wonder to behold for sure
They were what, combined cycle ramjets (or afterburning turbojets, but I think the afterburner worked like a ramjet)
My brother in law works on jet engines and he loves it, he's sent me some videos over the years of how complicated they are and testing etc, mental stuff.
I don’t know how many million miles I’ve flown in over 50 years, averaging a quarter million miles for at least half of them and I continue to marvel at two aspects: 1. How these many tons of metal (and now carbon fibre), people, fuel and cargo stay up there, and 2. Why these engines don’t melt down or compressor blades fracture?
I know the physics of lift and thrust but still think it’s magic…and a helluva leap in technological expertise: so many parts that could fail but don’t to an amazing level of reliability and how airframes can withstand the stress of severe turbulence I’ve experienced more times than I’d like to recall!
Thanks for this deep look at a true engineering accomplishment that most people overlook when they reflect on what marvels planes like the B747 or A380 “jumbos”.
12:45 Bypass air is unfortunately not "free" thrust. The Fan part of Turbo Fans draw their power from the exhaust gases of the jet's turbine. This necessarily reduces the exhaust velocity of the engine. It does make the engine more efficient, though, since jet engines are most fuel-efficient the closer their exhaust velocity is to the aircraft's airspeed; they move a greater volume of air at a lower average velocity, producing more thrust for less fuel.
Great video -- like Tim Hunkin of "The Secret Life of Machines" you cut it in half to explain how things work. Keep more coming!
I share these types of videos to my friends so they can finally understand my fascination with these sorts of things
I’ve watched a few other jet turbine explanation videos but this by far was the best and easiest to understand. Thank you!
I think good candidate for this "series" would be stealth technologies. Air and maybe underwater, too. Very nice video, thanks .
Really enjoyed this,look forward to many more
Great piece. Disappointed the Whittle jet engine wasn't discussed in detail although the axial engine "won" in the end, it's not like Whittle was a flash in the pan. Maybe another piece comparing the two.
Whittle did axial-flow and centrifugal. There were *five* turbojet engines in the UK under R&D in WW2:
*Centrifugal,* by Whittle (Rover);
*Centrifugal,* by Frank Halford (DeHaviland);
*Axial-flow,* by Metro-Vick;
*Axial-flow* by Griffiths (Rolls Royce);
*Axial flow compressor, with reverse flow combustion chambers.* The ASX by Armstrong Siddeley;
The Metropolitan Vickers designs were test flown in 1942 producing more thrust than anything Germany produced with a longer service life. The axial-flow were more expensive compared to the centrifugal designs with still development problems to solve, so being funded by the government they were never selected for any aircraft with cost being one of the rejection points. Metropolitan Vickers produced the first successful turbofan engines rated double anything Germany ever produced during the war. Also the turboprop engine found largescale use post war because of its excellent fuel consumption.
Isn't it fun that even though it's a turbine, and not a bunch of cylinders, it still operates to the rule of "suck, squeeze, bang, blow"?
Megaprojects usually has reasons for the thing being done or made, with failures and successes, plus budgets and maybe notable figures - i feel like this series would be difficult to really implement that without a longer format video, but its worthwhile either way
Nice video!
One topic to break down, the difference between an Afterburner and an Augmentor. This would further separate the differences between the turbojet and the low ratio, fully ducted, turbofan.
Thanks for the video.
A great video.👍👍.
Totally something I wanted to know about. Thanks!
Im here for the breakdowns on how thing tik, Id love for this to be a recurring thing on this channel :)
Great video. Very clearly explained. Nice.
You guys should’ve featured the M-1 Abrams Tank in the TurboShaft portion of the video. Tank powered by a jet engine is kinda awesome.
Thanks, liked the new format!
I like the new format - and would also like some more of this type :) A mix between "Our own Devices" and "Real Engineering" :)
It is crazy that you upload this around the time I begin studying to be an aerospace engineer you cheeky bugga
17:27 holyy crap bro!! That is the coolest Bike ever!!
Avid listener to your channels, I love the idea of these ‘How this Works’. I’d also love to hear some cold read versions!
fantastic video and format! It's always fun and interesting to learn how technology work on a basic level. Hoping for more of this type of content!
Really like this idea for videos.
I love this style of video. Learning about how complex things work in a simple way is the bessst
As an avid AVgeek, I didn’t really learn much - BUT as an avid follower of your channels, I enjoyed the video nonetheless. Good job!
Do a video in this style on the colossal marine diesel engines found in the biggest container ships!
I really like these dives into technology. Today I found out😂. Seriously though this could be a good addition to the channel. How about a dive in to electric vehicles?
Well done thank you!
If you threw a turbojet onto one of those styrofoam airplane models with the plastic propellers you get at the dentist office, you'd essentially have a turbo fan
Next to the gas turbine, another little thing that would have been worthy of note is the supercruise as you mentioned F22, Typhoon and Concorde. In particular for the concorde because only uses the afterburner at take off and transsonic region. Then it continues accelerating until cruise speed, without the afterburners.
My husband and i love this kind of series. I feel like steam engines would be a really interesting one because of the time and scale of impact on the modern world...might be longer than 22 mins though lol
A&P working for an airline here... good job.
Yeah, more like this please.
We want more of this kind of video
I hope for many videos in this series!
Another video idea is ultra mega examples of the simple machines we learned about in middle school/secondary school
Well lets jet on then shall we?
Yes more like this please
great video. looking forward to this as a series :)
Afterburners are frequently referred to as 'reheat'.
TheHarrier DID use thrust vectoring during the Falklands war to shoot down several Argentinian aircraft!!
Turboshaft engines are also being used to power smaller US Navy vessels.
One thing to mention is that, in a turbofan engine, the thrust generated by the fan reaches 80% of the total thrust generated by the engine.
Great video 🎉
Warped Perception put a transparent housing on a small jet engine. Definitely worth a watch.
That was well done.
One major design aspect that is a little beyond the scope of this video is nozzle design (and engine geometry in general). This is especially true if the air transitions between subsonic and supersonic anywhere in the engine, because unexpected shockwaves could cause damage or disruption, and because subsonic and supersonic gas flows behave very differently when it comes to compression and expansion.
Also, another odd place to find a turboshaft engine: a tank! Specifically the M1 Abrams
If you do a series about jet engines, please mention the coming generation of open fan jet engines - like the CFM RISE
There are a couple of important points about the operation of all turbine engines (whether turbojet, turboprop, turbofan or turboshaft) which are the most common misunderstandings many people have about how these engines work. This is often a result of people who do understand how piston engines (whether petrol or diesel) work, but then try to apply this to turbine engines. Which is understandable, since both are internal combustion engines, and both use the same "induction, compression, combustion, exhaust" sequence - but accomplish this in rather different ways. The biggest single difference is that piston engines do this literally as a sequence (piston strokes doing each part, one after the other, in the order quoted above), a turbine does all of them continuously and simultaneously - in the same order but starting at the front of the engine and finishing at the back.
(1). In a piston engine, the majority of the oxygen in the air drawn into the cylinders is consumed during combustion, with very little oxygen remaining in the exhaust. However, turbine engines draw in far more air than is necessary for combustion alone. By this I am talking about the air which goes through the engine core and therefore through the compressor (not the bypass ratio which only applies to turbofan engines), so this is the same for any of the turbine engine varieties mentioned above. The vast majority of the compressed air is not used for combustion, and is used mostly to mix with and cool down the high temperature combustion products, though some is also routed into the cooling channels inside the turbine blades.
This is also why afterburners can be fitted to the engine downstream of the turbine stage - because the exhaust still has enough oxygen content to support further combustion of fuel. If all the oxygen was consumed in the core combustion section, an afterburner on a turbojet would not be possible.
(2).In a piston engine, the pressure inside the cylinder increases a great deal when the fuel-air mixture is ignited, and it is this large pressure increase acting upon the piston which generates the power. However, in a turbine engine the highest pressure is just downstream of the compressor known as the compressor discharge pressure. The combustion of fuel does not increase the pressure at all. What does increase is the volume and the velocity of the gases, since the combustion products from the burning fuel are all gases, and of course the combustion adds a great deal of energy.
This is also true for rocket engines, in which the highest pressures are just downstream of the fuel pumps: This pressure is what forces the fuel and oxidiser through the injectors at the top of the combustion chamber. A common error is the assumption that the pressure increases in the combustion chamber of a rocket engine - but if this was the case, then the higher pressure would prevent the propellants from flowing through the injectors and into the combustion chamber. What actually happens is similar to the combustion chamber of a turbine engine - the volume and velocity of gases both increase enormously, and are then accelerated even further when the hot combustion products flow through the nozzle. The difference being that the temperature can be much higher, since there is no turbine downstream of the combustion chamber in a rocket engine.
Our lecturer explained the compressor turbine relationship as trying to pick yourself up by you shoelaces, but actually succeeding. Obviously, adding fuel is the tric, but you get what I mean.
Thanks, Coop!
I was quite surprised they day I figured out that a Turbofan engine was basically just a giant air compressor and that the whole point of the central combustion chamber is to spin the fan to draw in bypass air. It was blitheringly simple!
What makes jets so complicated and expensive is metallurgy, weight savings, and fuel control. The blades on the compressor are such a major component, where it used to be the turbine blades in the hot section for obvious reasons, all whilst giving longevity and safety and a lower rate of fuel burn. Something a jet engine will probably never be good at as they love to consume a lot of fuel.
Well done Simon! I actually understood all that! Please keep up the excellent work!
High-bypass engines produce their bypass thrust from what's called a convergent-divergent bypass duct. The fan blows air into the narrowing part of the bypass duct where it compresses through the narrowing space and this bypass air expands and accelerates through the divergent part of the nozzle and that's how they produce jet thrust. Low-bypass engines have a linear bypass duct which means the bypass flow isn't processed and allows the fan to directly produce thrust almost like a propeller, most people think it's the other way around, lol
I now need a collaboration with Simon and Kurzgesagt with the writer putting in ‘in a nutshell’ in the script.
Pretty good, especially appreciate the small but important distinction between airflow and gas flow once the air is mixed with fuel, sure that would have been picked up on my fitters oral exam if I got that wrong! No mention of centrifugal compressors (just showing axial flow which I guess is fair enough), or turbo fan bypass air also cooling the exhaust gas and reducing noise from the core making them better choices for passenger aircraft, but overall you achieved in 20 minutes what took a total of 6 months for my mechanics course to fully explain (though they only had OHP’s to work with!).
Still nothing cooler than a DC-3, turbo props i do believe is the best with all these small town airports popping up.
That was a great explanation
Great Video! I'm always looking forward to more!
I really liked this one. I think it's a great idea. Maybe do one about the Internet next? ^_^
Rather than "normal" turbojet vs turbofan, one might identify them as pure jet vs turbofan. The distinguishing feature of the pure jet is that all of the air entering the engine passes through the compressor, combustion chamber, and turbine(s) and thrust is derived from the energy remaining in the gas after exiting the turbine section. The distinguishing feature of the turbofan, by contrast is that the turbine section is designed to extract more energy from the exhaust, converting it into the mechanical energy needed to drive the fan, reducing the thrust contributed by combustion gases exiting the turbine section. In a high-bypass turbofan, the goal is to extract as much energy as possible from the exhaust gas so that almost all of the engine's thrust comes from the fan's interaction with the bypass air.
FWIW: a jet engine compresses air for a few reasons... the increased pressure improves combustion, so fuel burns more completely, but just as importantly, when the gas temperature is raised by combustion, it wants to expand; the higher the pressure at which this occurs, the more work this equates to.
Wings are interesting with many types and profiles. Some for slow and some for very fast. Some stick out straight, some sweep back, few sweep forward and one X plane with one side swept forward with other side swept back.
This should have been an "Everything you need to know video."
I'm still yet to watch but I'm sad this isn't an hour long video diving deep into the history and advancements of the jet engine. Let's see where it takes us.
So i have watched the video. Smells like theres going to be follow ups going into details of the different types of engines. A megaproject would be to document the history of the first Jet engines and how it was a secret race during ww2 between the axis and allies powers.
You should do one of those videos on turbine engines. They are really generally misunderstood.
Good one!
This is a good video but should include the difference between one-spool and two-spool engines and the battle for efficiency between composite blades (GE/CFMI), three-spool engines (Rolls Royce), and Geared Turbofan (Pratt and Whitney). Also, the difference between an afterburner, which goes on a turbojet versus an augmentor which goes on a turbofan.
I would love to see a deep dive into how torpedo's work. On the surface they seem rather simple but if I am not mistaken they are actually quite complex. At least modern ones are I would imagine.