The amount of work and research gone into designing every aspect of a jet engine just blows my mind. This is not just a piece of machinery, it's a work of art.
I am a retired RF design Engineer and will never work on a jet engine but I love the videos and the time and detail you put into them. I just cant get enough I am sure you love your work and its easy to see that you are very good at what you do. Thanks for all the effort and time it is greatly appreciated. please keep the videos coming.
@xxJohn1977xx We are using Mobil Jet II synthetic turbine engine oil. These engines are dry sump. Each bearing has it's own sump that is emptied by its own scavenge section of the main oil pump. That pump has three sections: one pressure element and two scavenge. There is also a separate scavenge pump for the gearbox. The oil supply in out tests is that silver box you see under the engine. Most installations have a large remote reservoir holding a hundred gallons or so.
"I don't know" (how they work)" The 1st step to "here's how they work". I could work alongside you sir, and am sure we'd get along fine. Thanks for the great videos, you make it look easy. Scott
@pjvenda I've just been doing some reading on combustor design, and as always, it's a bit more complicated than I present in this quick, easy video. Although there is no control for fuel-air ratio in a jet engine, the ratio in the combustion zone does change on its own. Because of the interaction between fuel spray patterns at differing fuel pressures, and air density at different compressor discharge pressures, the air-fuel ratio changes from lean at start to rich at full power.
Wow! I never really knew how pilots control the power of the engine and I couldn't find any information about it until now! Very nicely and clear explained. Love it!
You are a gifted person. Amazed the way you explain everything in great detail. It is a great service to the engineering students and amateur aviation enthusiasts.
@Morkvonork Many of the engines we work on are fuelled with natural gas, and those ones we test with propane. This engine runs on jet fuel, so it will be tested with Jet A.
Your videos are amazing, i got to learn and see the actual combustion chamber components in your video for free which i did not get to see so clearly in a 3 year degree course in my university, respect top man
Best explanation of the operational principles of a modern jet engine. I always thought the fans were electrically driven - but the fans are actually impelled by the combustion of fuel as it is expelled from the rear of the combustion chamber-forcing air into the chamber through the turbine fans as it is being compressed through volumetric reduction. Incredible technology-very counter intuitive.
@mwroush Once the fire is lit, it stays lit. For safety, during takeoff, airliners keep the ignition sparking just in the one-in-a-million chance the flame might be lost. Otherwise, when you see a jet flying overhead, the ignitors are turned off. If you watch my test videos, the ignitors are turned off before the start cart is shut down. They are only used for a few seconds to start combustion in the engine.
Agent,I suspect you really enjoy making these good videos and you enjoy educating others There are many excellent technicians out there,but not many of them have the ability to to explain these concepts in an informative and entertaining manner.
Yes you are right despite of the complexity of design and manufactiring still even Rolls-Royce never made such a detailed video like you do God bless you...
@AgentJayZ I get positively giddy whenever you post a new video!, absolutely fantastic informative and interesting. Really makes me want to work with this.
Thanks for this video. I knew how jet engines worked, but never knew how they were regulated. Very informative! Oh by the way, my dad's family is from Canada; Chatham/Kent, so that's another plus.
This engine has a large electric starter. Some larger engines use air-turbine starters, because an electric motor large enough to start them would weigh several hundred pounds. Modern turbofans are going back to electric starting because they have a smaller "core" to spin up for starting, and because electric motors are getting much more powerful for their weight.
@rschulemann The radial drive shaft is ised to supply power to the gearbox to drive the accessories. The difference in industrial engines is that there are less accessories driven. This engine produces about 10 thousand Hp.. in the form of hot, high velocity gases exiting the engine... to be sent through a separate power turbine, which then turns a shaft.
Wow, I didn't expect an answer that fast. Thanks, I'll look that up. P.S. I've enjoyed the videos you've done that I've discovered recently. Thanks for taking the time to do them. It helps a lot of us enthusiasts understand what's going on under the hood, er uh cowling. ;)
You have an education superpower. Thanks very much for the learning and the inspiration. Wondered if you had thought about endoscope cameras - cheap now and provide stunning internal views of tight spaces...
I'd love to see a video on the fuel control system. It looks mindbogglingly complex. (Also, another boggler is how much of this technology was done with slide rules. )
When you talk about high pressure air, mention percentage of oxygen and Boyle’s law of partial pressures. Same principle applies to deep sea divers. Good video. I learned sumtin’
@ProjectWolfDragon This is all true, except the last bit. The only engines I know of that use some sort of heat-transfer evaporation feature for vaporizing fuel as it is fed to the combustor are the Tubomeca helicopter engines, and the Orenda Iroquois. All other large engines spray the fuel directly into the burning zone. Some of the most modern airliner engines incorporate "pre-mixing" zones for air and fuel, but even the manufacturers don't call them evaporators or vaporizers.
@elcuervo1984 Occasionally we experience icing of the inlet during our testing. I've only seen ice build up on the leading edges of the struts in the front frame. This happens at just above freezing when the humidity is high. On days like that when we are having a test, we place one person where they can watch for ice in the inlet, and if they see it, we stop the test. The reason is the engines we work on are not equipped with anti-icing capability.
Do any turbojet/turbofan engines use a fully annular combustor section or are they all segmented like this one? Man Im so grateful for this channel! It teaches me so much about how these things work that we didnt get in academics.
If you go to my channel page, and type combustor liner into the search box, you will find a series of vids I've made about combustor liners and cases. If you look at them, you will see the evolution from old style single can combustors like these in the 1940s and 1950s, through cannular designs in the 1950s, through to the modern full annular design, which almost all engines use today.
@krbruner The flame travels to all the other combustors essentially instantly. If there was any banging or roughness in starting, these engines would have an ignitor for every fuel nozzle.
Him pulling that fuel nozzle out of the engine reminded me of when I replace the fuel pump on my van. Couldn't believe all the stuff fastened to one mounting plate.
I found it interesting that the natural gas fuel nozzles look almost identical to Halon fire suppression system nozzles. That surprised me as the density of the gases involved are so very different. That's from my engineering back ground in fire suppression and detection systems. Interestingly there's lots of useful cross over science for me in what you're teaching. I find it fascinating and thank you for your excellent efforts explaining all of the nuances. I am much richer for it. Plus quite frankly you make it fun too. I work for the same university that the creator of the famous Lockheed Skunk Works did his ground breaking wind tunnel research in just before WWII. It's still there, I've been in it. We have a whole section of one of our campuses dedicated to aeronautics and an aviation museum with cutaways of turbojet engines (we even have a GE J-79). I didn't understand them until I heard your explanations, now they make perfect sense, especially the combustor sections. The light went on over my head when you explained the design philosophy of applying cooling air. Your insistence on precise language is absolutely spot on. Brilliant! :D Thanks again, Ted N. from Ann Arbor, MI, USA
Wow you're amazing, thank you so much! I'm going to download this whole channel for study offline, and start to think about aircraft restoration as a possible future hobby! I've always been fascinated by jets, but I had no clue where to start, and there seems to be a lot of elitist gate keeping around this area of technology! Well you open gates by making these and you are very much appreciated for it! A random video of a test fire led me to these videos of yours, for once the RU-vid algorithm has given me something useful! Thank you again, much appreciated! I hope your company does well, you deserve the best!
I guess if you want to download my videos for repeated watching that's OK... but please don't copy and share them. That denies me the tiny amount of revenue that helps me get by... Thanks for understanding!
@@AgentJayZ I would never do something like that, I only share when asked to by the author, I meant in case they are taken down or my unreliable internet stops working, or god forbid, start again after Corona or similar event, with whatever is available, that's why I got a bit excited, you make it understandable and real to me for the first time. For the theory I have books and my math degree. For the practical I will have this. For my grammar, I'm sorry, lol. Thanks for replying, Rachel
Fuel injectors have nozzles but it is only one part of the whole injector. It also has a coil, a seat, a body, and a valve. The nozzle, as also on the turbine engine.
Hello and thanks again AgentJayZ. I too learn a lot from your videos. It sounded like you said that only some of the combustors have ignitors and that the hot gasses communicate via the interconnectors so do the ignitors need to run constantly or once the fire is burning in the combustors, they stay lit as long as there is fuel? A cool view you gave us of that nozzel being fitted into position.
