What Makes a Turbine Turn ? 

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I mean this as sincerely and respectfully as possible; I have a profound respect and appreciate for your method of explaining the little things. "I'm not going to give you a one click link to buy, if you can't buy a book by it's name you wouldn't be able to read it anyway." Excellently put. It's why I miss the aviation maintenance field, it was full of extremely intelligent people with no nonsense attitudes. If you don't know something that you should reasonably know they're not going to spoon feed you but they'll go to great lengths to explain anything you want to know to better understand how something works. Once. (Which is perhaps the way it should be) your work and methodology is exceptional and I don't believe I've ever said it but I'm grateful for all the time you've taken out of your life to lay the stuff out barney style! Keep up the great work, eh!

I am not a jet engine technician but was curious about jet engines and how they work so I clicked on your channel. I have to say that the information and technical details you provide have increased my understanding tremendously for a lay person. Thank you sir.

Now THAT is an answer!!! You wanna know? You really wanna know?? We'll sit tight and hang on because you're about have knowledge coming your way! Way to go AgentJZ. I love these long, detailed and yet simple and easy to understand explanations. BTW, I agree about the older manuals.

Gas turbines make me think of a perpetual motion machine, when combustion happens it doesn't blow out both ends of the combustor, it only goes out the back because the compressor pushes it out the back, but the compressor only spins because the combustion being forced out the back spins the turbine, you have the energy of the fuel and at start up the engine is spun getting the air moving, it all seems like a very fine balance.

It's ironic that in the engineering world, the older manuals, produced without sophisticated text and graphics publishing software, put so much effort into explaining the details of the product, not just how to use it.

JayZ, what an educational video. I shared this with the whole aviation community in America today which was shared several times over from my FaceBook site for new A&P mechanics in training. A big pat on the back for sharing your knowledge with all of us.

Thanks AgentJayZ. Excellent presentation. There is no such thing as an unimportant question, in the quest for knowledge. I appreciate your quest to explain things to people that ask questions they can't truly understand. Back in the 50's when I was being trained on Jet Engines, my instructor substituted the word impact for impulse, just to make it more understandable. It made more sense.

I know nothing about any of this stuff.. not my profession... But watching your passion made me want to continue to watch. I agree wanting to understand what you're going to be working on and how they work vs. "robotic" instructions. Adds more interest in your career and more likely to be happier with the work you do.

Your passion for what you do is contagious. Keep it up! Awesome videos.

One of my first flight instructors asked me how airplanes actually fly, I scrambled to find an answer because I wasn't really sure and I was just starting with the theoretical knowledge. After multiple tries, I gave up and he pulled out some money from his wallet and set it on the table. Nuff' said haha. AgentJayZ reminded me of that legendary moment at the beginning of the video. Thank you Agent Jay!

'if you can't look up a book by it's name you probably can't read it anyway' - legendary

The 1950's G.E. stm. turbine manual is one of the best! and explains impulse and reaction forces very well and easy for a layman like me to understand!, they illustrate impulse forces with a tea cup!

Have often wondered what is going on inside these engines that makes them work as they do. Not an engineer. Not a mechanic. Flew puddle jumpers for a few years in the 90s. Thanks for the insight. Absolutely fascinating, with a great presentation. You are correct. I learned something today.

I am , by no means, a specialist on Turbine. I am just someone with a physics degree. I think the reason for the name "impulse" might have something to do with the physics's definition of the concept impulse. In short: impulse in physics is defined as the instantaneous change in momentum: Delta P(P stand s for momentum). The source of thrust to push on the turbine is produced by creating a difference in momentum. Let me explain: Newton third law says momentum must be conserved. Meanwhile, the speed of gas leaving the turbine is faster than its speed entering the turbine, therefore gaining momentum in one direction(momentum is a vector). However, momentum is conserved, that means the the turbine must 'lose' the same amount of momentum( it is equivalent to gaining momentum in the opposite direction )to ensure momentum conservation. therefore, the turbine accelerates in the opposite direction of the gas leaving the turbine. Again, I could be completely wrong here about why it is called "impulse turbine", and my explanation for newton's third law here is merely superficial. Edit: more detailed look at the equations: www.sciencedirect.com/topics/engineering/impulse-turbine

Thank you for taking the time to produce these videos! They're great, very interesting and educational.

Thank you Agent JayZ . for this in-depth explanation. I am going through A&P school now. I will be showing this to other classmates when we get back to Jet engine section again.

i have always liked how you dig right in. from this side of the camera it seems a conversation,,must be strange on your side,,talking to a lens. thanks for all the time you invest!

The easiest example to explain the reaction turbine is the plane's wings. The same working principle of the lift caused by a plane's wing due to velocity and pressure variation.

Why have I just gone onto Amazon and bought a book on Aircraft Powerplants? Ah well, no knowledge is ever wasted. 😊 Thank you for interesting me in a new subject due to all the videos of yours which I have found by chance.

Hey JayZ, been watching you for years. I became an aircraft tech and you made going through the books muuuch easier. Really surprised to see that this topic was never covered before! Anyway, I just wanted to add (and confirm whether my memory serves well...) IIRC the proportion of reaction/impulse of a turbine depends on the application, i.e. a turboshaft turbine would be more impulsive (or less reactive) than a jet turbine, since you want to maximize torque and can allow for less gas velocity exiting the turbine. And vice versa. To be honest I wasn't sure anymore and would have to go through my neato notes with the vectors and all, but since you showed the air starter turbine being purely impulsive I'm a little more confident with my memory. But this is JETcity, so sorry if it's irrelevant! Thanks, again great stuff!

Hi @AgentJayZ - I have discovered your videos just recently and they're awesome! I have learned a lot from them - and that's from an Aeronautical Engineer and a 20+ years turbine engine user (pilot). One thing that I couldn't get my head around since my Uni days - how do centripetal turbines work? How do they differ from the axial ones?

An instructor of mine flew the VC10 for EAA. They went bust, and he retrained on the 707. When he returned he told me the 707 flew, due to the engines being not balanced, this caused the wings to flap, and THAT is what created the thrust..

Really well presented. Based on your accent, I suspected you were 🇨🇦Canadian🇨🇦. Then you mentioned curling and removed all doubt. Thanks for making this video.

Very true about the older service manuals! I've got a old manual of my Boeing 502-6 that goes through the theory of operation. Great videos man!!! Cheers.

What an eloquent and informative explanation of Newton’s laws, Aerodynamics and Jet Turbine Design to say In layman’s; “fast air pushes the windmill on the back of the jet engine and keeps the other windmills spinning” gotta love it though, lots of brilliant insight into the thought that goes into every detail of it all. Thanks mate.

We did learn something from this. Very good basic stuff. Enjoyed this. If you keep making this I will keep watching

Thank you for all the information you providing to us.

Really helpful, i'm currently doing ATPL theory and these do come up in the AGK/Powerplant module, this has really helped my understanding. thanks!

"The pressure and speed of the gases passing through the impulse turbine remains essentialy the same, the only change begin in the direction of flow. The turbine absorbs the energy required to change the direction of the high-speed gases". In my opinion, while the pressure does not change significantly, the speed decreases.

I thought this one would be boring and basic. I was wrong. Y'all need to hit up the patreon link: cheap. worth it.

Curling forces...I love it. 40 years in aerospace and I've never encountered curling forces in a turbojet engine.

Thanks a lot for this informative video , you make things easy to understand, great channel.

Thanks for the early birthday present!

love your passion, i retire next month....gosh where were you as a teacher back in 1977/1982....power plant operator i am , steam plant and now a ge lm6000 operator ,8 units.....but time to retire.....

Impulse turbines extract the most power per turbine stage, theoretically up to twice the power of the very common 50% reaction turbine. Therefore ideally they could be used in jets, and could cut the turbine's length and weight by a big factor. The reason that they are not used in jets is that there are severe issues with leading edge heating in these turbines. In effect they can't be cooled around the leading edge, which is also where heating is maximal. They are very commonly used in water and steam turbines where heat is not a problem. It is also common in cold air starter turbines (cold being the operative word), like the one shown here, where this design can result in the lightest possible starter turbine. On the other hand, a reaction-impulse turbine can be cooled, due to the comparatively "fat" leading edge, so it is suitable for gas turbines. A 50% reaction turbine also offers the least frictional loses.

So, in the theoretical limit a pure reaction turbine would rely on aerodynamic lift only while a pure impulse turbine would rely on the deflection of mass?

Great session. Almost easier to visualize when you think of water hose spinning a disc. The proper angle gives higher rotation. Or toy pinwheel you find the right angle to blow on it to spin it faster

Great video, thanks a lot. Best regards from Brazil!!!

Like watching your video. I worked the assembly floor in Middletown Ct on JT8s and J59s back in the late 70s. Before that I was an avionics Tech on P3s. I went with communications. Someone once told me that being an auto mechanic was more lucrative that an A&P with all the FAA crap.

thank you for this great channel

It's all the same but it is all different. :) This is so true in a wide variaty of fields. The fundamental principles stay always the same and only the details are changing. I also like the older books more. First you need a solid fondation, then you can start to build on it and become a specialist. Great video as always!

I am getting a good understanding of this technology and love it Always have Thanks again for teaching us And for your time

3:05 Finally got an answer to that, which I actually also asked about some time ago but didn't got an satisfactory answer to. So up to 90% of the energy can be extracted, actually in the neighborhood to what I thought it had to be, good stuff.

I love these videos!

Dear AgentJayZ, You told me to send my question here rather than Facebook. I am a self taught but very capable automobile and pickup truck mechanic. I know all the basic and some intermediate garage skills. Where would I need to start to build up my knowledge foundation if I wanted to build my own jet boat? What are the most critical things I would need to know to not die from a critical failure? If I may add this, where would someone in the USA get a hold of a New Zealand style race boat? I cannot thank you enough for your time and for posting these videos!

“If you can’t look up a book and find it by it’s name, you probably won’t be able to read it.” Never heard any truer words. Great video and content like always.

just like my old mentor said to me when i still work as a automotive helper mechanic. all engine are the same and have the same priciples on how it works. its just the technology and application that is diffrent. from an automotives perspective

amazing information, thank you sir

Thank you for this.

Great video

Please do a video explaining the progress the newer engines have made and perhaps what the next generation might look like.

That was enlightening

Agent JayZ,thanks for the wonderful explanation,what is more of the driving force for that extra oomphh on the turbines,pressure or temperature?

In goes air, magic happens, then fire comes out, makes it easier for my brain 😂😂😂😂

Hi JayZ, ex RAF propulsion tech here. In your experience, are there any turbines that use pure reaction, ie, straight NGVs?

Can you show high pressure and low pressure turbines and why they use the combination?

Sir, Thankyou for the information. Please upload a similar video for compressor. What is surging in compressor and what could be its impact?

Thank you!

Sheer force of pilot will makes the turbine spin.

It's not supposed to be fun? See, this is why I prefer a person that does something passionately vs as a job. For instance the countless parts changers in any mechanical industry, that only change parts, but cannot troubleshoot or design a simple tool to get the job done. There is a huge diffrence when you can visualize in your minds eye how and why something is done, instead of just doing it for the sake of getting it done. As soon as you start doing something without a pssion for it, that certain perfectionist spirit seldom follows.

Why are the turbine blades jagged on the outer edge? Is that from scraping or are they made like that on purpose?

old school wind turbines do also use curved blades, and at lower altitudes near trees and buildings, they are still far more efficient than modern 3-bladed wind turbines.

21:33 so there are a jet engines inside of a jet engine :D

U making great videos, great work ! This knowledge have big supplement in particles accelerators . Also try to apply it to Tesla turbine ... We using synthesis , not only analysis ))) Thank U ! best regards from Ukraine !

I have not seen a high bypass engine on any of your videos. Do you work on them and will we see one in a future video?

Thank you

Impulse part of the turbine harness the kinetic energy of the gas stream while the reaction part harness the thermal energy (by allowing it to expand with the heat it carries reducing pressure, accelerate the gas further to regain the kinetic energy lost in the current impulse stage and pass it onto the next impulse stage). Am I correct?

sir AGENT JAYZ, can you make videos about small Gas turbine engine starter specs.?

Many thanks for not going into high & low pressure like they do with lift of a wing. Once someone explained to me that the reason a wing creates lift is simply because more atoms are hitting the bottom of the wing than the top, it made it more real than talking in terms of pressure.

So, what you’re saying is… The combustor makes the magic fairies, and the turbine slows them down thus producing energy purely from the deceleration of magic fairies

Hi Jay; I appreciate your videos a lot. You have mentioned a number of different books, both in this video and others. As a "layman" I want to buy one to share with my kids. Ideally has good pics, older is great also. Do you have any specific recommendations? Thank you.

To get a precise measuring of the impulse turbine, you could stick the blades into some epoxy putty and let that cure (harden). Measure the indents in the negative now :-)

Which part of the turbine blades produces more thrust ? the root or the tip ? and why the tip airfoil has a greater angle than the root ?

Im assuming the front and rear bearing housings stop the shaft from coming too far forward or too far rear. You mentioned before that there is about a 1/4” play because of thermal expansion/contraction with the shaft. Is this why the space is so large between the blades and stators? Closer is better for “transmission” of power i think you said before.

Help me think through this one....why does it take so long for a jet engine to stop spinning after you stop fuel delivery (turn engine off). If the compressor section of say the LM1500 takes 30,000 hp to turn then once you turn it off wouldn’t it come to an abrupt stop?

17:40 Should be measuring perpendicular to flow direction. Any radial array of the same number of objects will just be the circumference of the circle / n parts. Easier to measure using the back side of the calipers too.

So I have a question. Watching a video here on the Boeing 707 plane I noticed how long and narrow the engines are compared to the newer ones. I think I understand why the RR engines are so short because they have 3 rotating shafts. Maybe it is due to different turbine blade technology?

Your videos are amazing! I have a question. I have a 1979 solar turbine generator and it was doing hot starts and also running hot. At 710 degrees f the high exhaust temp light comes on and it actually got to 800 degrees and then shut itself down. The intake had a lot of oil and dirt buildup around it which was restricting airflow and causing some of the issues. I cleaned it out and pressure washed the inlet out while it was running and I think it helped. Have you ever done a turbine wash on a running engine? It’s a 750 kw generator and the turbine probably is capable of 1200 to 1500 horsepower Also wondering how likely it is that the fuel control or fuel injectors are failing. I was thinking it could be something like that but after I saw how filthy the intake was I’m hoping that the dirt buildup is the main issue. It’s a backup generator on a dairy and has oil dripping a bit out of the front housing near the intake

The video is great but I couldn't hold my laugh at 4:10.

Great video like Great explanation but already know basic physics

Hi,l,m still alive and still have dyslexa,could you please do one on hellicopter roter jet enghines, thanck you.

I had always thought that a gas traveling over a wing crates lift because the gas must travel a longer distance from front to rear if it goes over the top (the distances is greater) than under the bottom. If the gases arrive at the rear of the wing at the same time then the gas traveling over the top had to ‘speed up’, reducing the pressure and creating a higher pressure area at the bottom of the wing, creating lift. Since the blades are essentially wings the same principle would apply, pushing the blade in the direction of the longest surface (the top edge). Is that a bad way to think about the lift process?

Ty rocker dr

What's your another RU-vid channel? Something pattren page.... I don't get. Can u help me with that?

Question from Jacksonville Florida. Can a jet engine run away like a Diesel engine if a failure in the fuel system was to dump excessive amounts of fuel into the engine, or is the speed limited to its design? If you have covered this before, I guess I missed it. Love your videos.

Hello AgentJayZ, speaking of older books the 1950's and seeing the turbine engines you usually work on, while reading I noticed that two of the most common and widely used turboprops of the day are both turboprops designed in the '50's (these being the Pratt & Whitney Canada PT6, and the Honeywell TPE331). It made me wonder, is it really such a technological feat thus such a hassle ($$$$) to research and develop new turbine engines so much so that a 1950 design is considered as good as new?

Is possible to use a milk tine to make jet engine

Is there a opposing torque on the stators? Something measurable in your dyno cell?

Great video. Just a simple and silly question , how is these engines different from GE FA, HA or Siemens SGT series engines. I work on Gas Turbines utilised in Power Plants.

What is the starter turbine made of? Steel or something lighter?

Agente jay

Morning! I read an accident report recently which used the term "core lock" and it's part in a double engine failure. I've never heard of this before. Have you ever seen this phenomenon?

What is the book called?

What causes the high pitch whine on a turbine ?

So the reaction is version is more like a pelton water wheel and the impulse reaction version has more to do with the turbine blades utilizing the aerodynamic principles for lift adding to the commutation of the turbine...

A book in my collection { Gas Turbine Theory - 7th Edition By H.I.H. Saravanamuttoo,‎ G.F.C. Rogers) good basics

Do you steam turbines work the same way?

What makes a turbine turn? The same thing that makes congress, (or parliament) go. Hot air!

I think turbine blades can be compared with an airplane's wings: they have concave aerofoil with big curve and i suppose except deflecting of the gas flow (plane's wing deflects it too), there is difference in pressure on the concave and convex side of the aerofoil, hence lift force. Summary, i suppose in both a plane's wing and a turbine's blade, there are 2 principles of crteating force: deflecting the flow and difference in pressure because of shape. And may be I mistake), but in the first book there was a phrase that pressure and velocity of the gas flow don't change after impulse turbine, where was the energy for turbine wheel rotation taken off in this case?