I recently completed my honours project on CFD of a gas turbine, and I learned so much from your previous videos explaining how the different parts operate and also from the books that you have suggested in the past. So just wanted to say thank you and keep up the amazing videos.
This is one of the best Series i ever watched on RUclips. I highly recommend to become a Patreon and watch it from the beginning. It will also bring clarification to a lot of questions asked in the Forum. Good Job Agent JayZ
Love the hand painted pointer! It fits you perfectly. Oh, and the beautifully restored and better than new perfectly running engine is pretty nice too.
Nice, flaming start 👍 great work, I bet it must be a huge satisfaction seeing an engine run, knowing that you've spent countless hours to fix / put everything together
@@AgentJayZ In his 80s, He loves tech, so do I. He went into semiconductor research and production systems after the AF. I was a Navy avionics tech, but into all aspects of operational readiness. He has told me how much he admired the Sabre, for it's excellent performance for it's time.
Cool!! All my buddies,when we were kids building models,always gave me crap about trying to find a Sabre Dog!!! I thought I was the only one who thought that was the best looking model!
Yes!! Beautiful engine. Can you show us what the inside of a hydromechanical fuel control looks like? All I've studied are diagrams and I can't understand how something so complex can function reliably enough to put on a plane. Thank you :)
Below temp, higher thrust, and low vibration. What is the main cause for that? Is it just more modern components like modern and better bearings? Or better balancing? Or all of the above? That's pretty neat.
Stock parts, careful assembly, and "boutique" balancing procedure, as our manager calls it. The thrust is always great with the Orendas, because I think the factory was very conservative in their ratings.
You must have done a damn good job to get the thrust above spec and both the temp and vibration below spec. I was under the impression it was near impossible to get all 3.
totally engrossed in those engines ,.. Wanted to work on jets when I joined up , but they decided I should dangle from a parachute and walk everywhere..
@@AgentJayZ ENA (Ecole Nationale De aerotechnique) school who helped Mikey Mcbryan with his dc3 restoration, The school aquired a jet plane I think they were/are going to save. Cheers
Why would you abbreviate that? Is that a household word? Even in the aviation community? Jeez. I offered those people two engines for the CF-100. They never got back. I think they realized the project is more than they could handle and lost interest in ever getting it flying.
Sabre is one of my favorite airplanes thank you. Can I have a general question for any Jet engine. When a turbine ingests moisture in the form of a cloud or rain is there any thrust advantage from the expansion of the water from liquid into vapor? When I was a kid in Colorado we used to use vapor injection in our old gasoline motors to get a little bit of performance at high altitude above 6000 feet. Just curious thank you
Cloud or rain, no matter how heavy, will have no effect at all on any turbojet. Injecting a lot more into the combustor, will lower the temp and produce steam, so even more fuel can be sprayed in. Result, more power.
always great to see a fine piece of engineering restored and put back into service! Any idea how big the stock of these engines is, and whether the owners of F-86s might have to consider fitting other engines?
If you blow up a balloon and release it, is it the high velocity air coming out the hole pushing against the air that makes it move, or is it the pressure difference inside the balloon?
Neither. Once the balloon is filled with air, it tries to contract due to the nature of the rubber. But is resisted by the air traped inside, which is under a slight amount of additional pressure than the atmosphere on the outside of the balloon. This contained pressure creates no thrust because the balloon is sealed. When the balloon is released, the pressure-differential between the inside of the balloon and the outside atmosphere causes the air to eject out the neck of the balloon. The balloon continues to compress the remaining air, causing a continuation of the air moving from inside the balloon out the neck of the balloon. The acceleration of the air from inside the balloon is what caused the thrust, as air has mass, and every action creates and equal and opposite reaction. That is, every time a mass is accelerated, it resists, or pushes back. It has nothing to do with the escaping air "pushing against" the air that is outside the balloon. Because it will work in outer space where there is no atmosphere at all. The air mass inside the balloon escapes at a velocity, which means it accelerated, it has mass, and it accelerated, therefore it creates an equal and opposite reaction. Rockets generate more thrust in outer space than they do at sea level because there is no air resistance in space. The air resistance around the rocket at takeoff actually robs it of some thrust. Watch a video of the spaceX Falcon 9, as it reaches outer-space the rocket plume gets wider and wider in the thin air.
@@Triple_J.1 Thanks Justin that was an amazing answer I appreciate it! I thought about the space scenario as well.. since we have a smart guy on the line, I wanted to ask you about this.. for years I have watched the depiction of lift on an airfoil as a stationary wing with streamlines of air passing over. I dont think this in any way an accurate rep of what is actually happening. The stationary air molecules get moved by a wing blasting through them, moved up, object in motion wants to stay in motion creating a vacuum.. idk thanks again!
@@Triple_J.1 I’m renowned for giving long-winded answers, but yours is even longer than I would have given, and I’m going to contradict your “neither”. This is an example that I have used recently in my STEM presentations to primary schools here in the UK - and the answer is BOTH, because you can’t have one without the other. However, while the air is being expelled from the neck of the balloon, it is NOT producing any resultant force on the balloon. This is a basic misunderstanding in the minds of so many people. The potential energy stored in the membrane tension in the balloon envelope is converted into kinetic energy in the expulsion of the air through the neck, resulting in a classic demonstration of Newton’s Third Law. The air is propelled in one direction, the balloon in the other. That answer might satisfy a physicist, but it doesn’t satisfy an engineer like me. So what about Newton’s First and Second Laws? There must be an unbalanced physical force acting on the balloon somewhere to cause it to be accelerated from rest in a direction opposite to the air being expelled. So what and where is that force applied? The answer is simple: it is the internal pressure (which is greater than atmospheric pressure) acting on the projected area of the balloon neck on the interior of balloon envelope opposite the neck - and nothing else! However, this cannot happen unless and until air is expelled through the neck of the balloon, where there is obviously no pressure being exerted on the balloon envelope.
@@paramtrx9558 Please see my contradiction of Justin J’s “neither” - and you have hit upon an issue I’ve raised in another STEM presentation that I’m giving next week. We see videos of wind tunnels with flow visualisation smoke trails around aerofoils, aircraft, cars, etc. However, they are stationary, while the air is moving and has kinetic energy, which means that it wants to continue on its way, induced by a fan somewhere downstream. That is not what actually happens in the real world, where the air is stationary until the aircraft or the car arrives. In this case, it is the aircraft or car that possesses kinetic energy, some of which is transferred to the air transiently, with some of the air being dragged along in the slipstream - the “hole in the air” to which motor racing commentators so often refer. If you want to see a graphic demonstration of what an aircraft actually does to the air, look for photos taken of aircraft flying just above the cloud tops (I’ve included a couple in my presentation). You will see that the aircraft produces a deep ‘trough’ in the cloud tops, with a distinct downward ‘curl’ at the sides, as a result of the wingtip vortices. It’s a classic demonstration of Newton’s Third Law: the wings are producing a downward force on the air, the result of which is an upward force on the wings ie, ‘lift’. Of course, there is the matter of where the force is actually applied on the wing (and how). The greater proportion of the lift force is applied to the upper surface of the wing, as a result of a reduction in pressure. The increase in pressure on the underside of the wing is a relatively smaller proportion of the total lift force. If you want an explanation (none of that ‘equal transit time’ nonsense), check out Professor Holger Babinsky of the University of Cambridge.
Hey mate , love all your videos, I’ve learnt so much . Love the way you explain everything. Its easy to understand, Can I ask ,what does a turbine stater/nozzle do ? I understand the gas pathways through the turbine itself and how it changes the direction and speed of the gases to make a or multiple turbines turn but can you tell me what do the staters do in regards to how the gases are changed and how does it impact the flow of gases to the turbine behind it ? Thanks in advance from Australia
Part of the stators function is the way they guide the gases to flow into the turbine blades at an angle that makes the energy transfer happen most effectively. The other part of the stators function is how they form a narrowing passage between each other, so the gases flowing through them accelerate before they encounter the turbine. Luckily, the angle at which each individual stator vane needs to be set in order to direct the gases at the right angle, and also create a narrowing pathway between them, seem to coincide nicely, when combined with the design of the thicknesses, shapes and curvatures designed into the individual nozzle guide vanes. There are some excellent diagrams out there. The search bar is your friend!
The turbine stators, commonly referred to as nozzle guide vanes (NGVs), are what the three words suggest. They are nozzles: they convert the pressure of the hot gas into velocity in a converging passage. They are guides: they guide the accelerated hot gas in a circumferential direction. They are vanes, obviously: the term vane is conventionally used for a stationary aerofoil, and the term blade is used for a rotating aerofoil. Having been turned, or 'whirled', in a circumferential direction, the accelerated hot gas then encounters the turbine blades, which also have converging passages. The turbine blades turn the hot gases in the opposite circumferential direction, extracting power in the process, with a further reduction in pressure. The amount of power a turbine stage extracts is measured by the change in the whirl velocity, ΔVw. As AgentJayZ has told you, there are excellent diagrams out there: you need to get your head around velocity triangles. PS At the design point of the turbine(s), the angle of the hot gas exiting the NGV row, and entering the row of rotor blades, matches the inlet angle of the blades, and the outlet angle of the blades ensures that the angle of the gas entering the following NGV row matches the inlet angle of the vanes, and so on. Now get your head round velocity triangles!
I have a question: how thrust is measured? It is a sensor on the engine, outside the engine, or a estimation based on engine parameters like revs and fuel flow?
Thanks for the video agent JZ. I just bet it was very nerve-wracking. Old stuff is less perfect in it's understanding. Jury rigging is a big part of making this prime time. I am not sure what it's thrust was but you can bet it was not very much maybe double on afterburner and still less than 10,000lbs. No way could this engine pull the Sabre straight up. You can imagine an f-15 breaking the speed of sound straight up well that ain't this but still a beautiful engine.
No. Helicopter exhaust outlets are divergent, specifically to eliminate any residual thrust from the engine exhaust... which would be an annoyance to the pilot. If the pilot wants thrust, he/she will ask for it, by using the controls. The cyclic, I think. I'm sure a few helicopter pilots will let us know...
And with the same ancestry as the J65 (the Armstrong Siddeley Sapphire), all marks of the Armstrong Siddeley/Bristol Siddeley/Rolls-Royce Viper had total loss lubrication for their centre and rear roller bearings.
You have to remember: it's a combat jet engine, designed to survive all the abuse a young hot dog pilot can dish out, and then some. It wants to run, and it is very hard to wreck!
In a simple turbojet like this one, about 2/3 of the energy produced by the combustion of the fuel is "harvested" from the exhaust gas stream by the turbine to supply the power to turn the compressor. So very roughly 20 thousand Hp to drive the compressor, and 10 thousand left to squirt out the back and provide thrust.
Yes, as AgentJayZ has said, the power is "harvested" to drive the compressor - but it is not "lost". As I have explained numerous times before, it is 'recycled' in the compression/expansion processes.
@@grahamj9101 And I would think that the higher RPM , the more usable thrust from the combustion through the blades exits into the convergent pipe faster , making more thrust , but lower RPM holds up the thrust working the turbine . So like JayZ said in a video , The Engine performs best at full throttle
@@christinadaly7743 The engine "performs best" at full throttle because that is at (or near) its design point. At part-throttle the engine is operating off-design, and both the compressor(s) and turbine(s) are operating inefficiently, in terms of their aerodynamics. The engine is also operating inefficiently as a heat engine, in terms of its thermodynamics, with both the maximum cycle pressure and temperature reduced. PS As I've explained to someone else, at the design point of the turbine(s), the angle of the hot gas exiting the NGV row, and entering the row of rotor blades, matches the inlet angle of the blades, and the outlet angle of the blades ensures that the angle of the gas entering the following NGV row matches the inlet angle of the vanes, and so on. The same applies at the design point of the compressors: the air angles and the blade angles are matched. Off design they are not, and the angles are mismatched in both the compressor(s) and turbine(s). Consequently, they are operating inefficiently, with increased losses.
@You are correct But Of course it's not a perpetual motion machine. The work done in the turbine, as a result of the expansion of the hot gas through it, becomes work done on the air in the compression process - with inevitable losses, as a result of inefficiencies, in both the turbine and the compressor. Nevertheless, what is compressed in the compressor is expanded in the turbine: that is what I mean by 'recycling'.
JJ Abrams star trek seen plenty, is on now film 4 in which AgentJayZ said in the Engineering room is a LM1500 compressor stage, I normally pick these things up I cannot watch it again, or I could miss it, have seen before since aware, but missed it! I wonder if any fans of our Jet Tech, could help me with when or time, might help me, TX I would love to see this and appreciate the help ? love the might gas-turbine .
Hey, I saw a fella take an automotive turbocharger and run it with compressed air, with the idea to then do steam later on. He had this interesting idea, after passing the steam through the turbine the plan was to cool it right after the turbine with the air coming out of the compressor end. Initially I thought it seems dense cause you're just throwing away all that heat, but cooling the steam at the outlet of the turbine would lower the pressure there even more thus giving it to my understanding something equivalent of a vacuum effect potentially gaining you efficiency. Does this compute? if not, could you please enlighten me on why not?
It seems an idea inspired by closed cycle steam turbines, which do condense all the steam, and return it to the source of heat, to boil into steam again to power the turbine. However, trying to explain what another person thinks they want to do with an old turbocharger is not really possible...
@@AgentJayZ I suppose I asked it poorly. What I meant to ask is, would cooling the steam after it exits the turbine increase the efficiency (or power output maybe?) of the turbine? To clarify, not strictly cooling for recycling but drastically dropping its temperature just at the outlet of the turbine. Which I assume would drop the pressure at the outlet creating a sort of pulling effect for the steam still inside the turbine. Effectively creating more work by dissipating heat? I'm just trying to understand whether that would be a thing that can work & gain efficiency or is there something in the workings of a turbine that is overlooked and would make this pointless or impossible to do? I was binging through your videos and I stumbled upon something seemingly similar, unless maybe I misunderstood something and am wrong. The video is.. "Working on a Turbojet: 12" @ about 28min mark
If the steam exit from the turbine is designed properly, the exhaust pressure would be very close to ambient. So cooling the exhaust would do nothing but cause a pool of water to drip on the floor.
The cooling of the exhaust of the turbine shown in my video you mentioned is more for safety reasons. It has no effect on the power made by the turbine. Also note: it is very difficult to compare combustion turbines with steam turbines. Apples to pineapples...
Passing air (or steam) through the turbine of a turbocharger, assuming there is a load on it from the impeller, will result in a temperature drop across the turbine. I recall, as a student, doing a lab test on a small air turbine, using compressed air from a large air reservoir. At full load, there was ice forming on the turbine exhaust ducting.
Those are combustors. That's the way it was done in the 1940s. Later on, the annular combustor was found to be more efficient, so that's the way it's done now.
Proper combustion is one of the trickiest parts in jet engine design. Flame outs were one of the most dangerous things that regularly happened to early jet engines. Many of these designs had interconnected burn chambers so that a flame out in one cell was quickly reignited by the neigbor. You can see this connection in the picture of your link: The side port of the burn chamber tube. It happens to be easier and more resilient if arranged in multiple smaller units, before the whole tech was mastered sufficiently. So this is what early designs used... for the price of some efficiency. Fuel has to burn very fast, as the air only spends fractions of a millisecond in the burn chambers, before it enters the turbine section. BUT fuel does not burn fast enough, if it's not in a proper mix ratio with air. Unfortunately the result of perfect air/fuel-combustion is WAY too hot even for modern materials. So you have to shield this overheated gas flow from everything inside the engine by making sure all parts are wrapped by cooler gas flows with the hot gas streaming in between the cooler gas and mixing before entering the turbine stage. It was a permanent ride of the blade between the engine blowing itself out and melting its own guts... ^^
@@AgentJayZLater on? Metrovick's first jet engine had an annular chamber in 1941, which eventually led to Armstrong Siddeley's Sapphire having an annular vaporiser chamber in the late 1940's (years ahead of anything in the States) - and to an obvious technology transfer to the Iroquois.
Within a couple of days of seeing this vid, I happened to come across an airplane-disaster vid about a case where a combustor can that had been repaired, blew its head into the wing, puncturing the fuel tank. So that was a striking coincidence for me to experience, that right after learning what one was, I got to see a doco about one failing catastrophically.
The Avon Sabre was never exported, and is not popular with collectors and owner/pilots. Some said it was heavy and unreliable. I've never seen an operational example.
@@AgentJayZ you will soon Jay, there’s a restored one near me I’m visiting in a couple weeks at my local RAAF Base museum known as Fighterworld in NSW Australia (Williamtown is the city), I’ll take some photos and send them your way.
The Canadian version with the British base centrifugal engine was much more powerful then the axial flow engine used in the American sabres. The engine shown is the centrifugal engine, you can tell by the thrust bottles
The Canadair Silver Star had a R-R Nene engine, but AgentJayZ probably knows a lot more about this than me. The Nene was a centrifugal engine, which was reverse-engineered by the Soviet Union as the Klimov VK-1, and used in the MiG-15. It was uprated, relative to the Nene, and produced about the same thrust as the J47 in the F-86 Sabre, but was a lot lighter.
PS If the F-86 had been designed for a centrifugal engine, it would have looked fatter, because of the larger diameter of the engine, relative to the J47. In other words, it would have looked more like a MiG-15.
![BLACK BAG - Official Trailer [HD] - Only in Theaters March 14](http://i.ytimg.com/vi/Du0Xp8WX_7I/mqdefault.jpg)
I recently completed my honours project on CFD of a gas turbine, and I learned so much from your previous videos explaining how the different parts operate and also from the books that you have suggested in the past. So just wanted to say thank you and keep up the amazing videos.
Excellent!
This is one of the best Series i ever watched on RUclips. I highly recommend to become a Patreon and watch it from the beginning. It will also bring clarification to a lot of questions asked in the Forum.
Good Job Agent JayZ
I can't imagine how nerve racking it must be to start up a 60 year old jet engine, great work !!!!
Congratulations on all of your hard work.
Congratulations on another Orenda 14 brought back to life. Beautifully done.
Love the hand painted pointer! It fits you perfectly. Oh, and the beautifully restored and better than new perfectly running engine is pretty nice too.
Nice engine! And the pointer is a brilliant addition, please keep using it.
Very well done. Thanks for taking the time to share it with us..👍💪
Nice, flaming start 👍
great work, I bet it must be a huge satisfaction seeing an engine run, knowing that you've spent countless hours to fix / put everything together
Great news. Big congrats to all involved with this very cool project. Would love to see a vid of the engine in action on the Sabre.
Wonderful to see it come to perfection!! Great Job, nice work. The only new Orenda 14 in quite a while, eh? Love it, thanks.
To create elevates the soul and feels good.
Thanks for bringing us along.
Congratulations, what a sense of accomplishment this must bring! Great job!
Wow, My dad talks glowingly about working on Sabres in Morocco during his USAF deployment in the '60s.
I really like that noun turned into a verb turned into an adjective. It's made of familiar parts, but still has an exotic style.
@@AgentJayZ In his 80s, He loves tech, so do I. He went into semiconductor research and production systems after the AF. I was a Navy avionics tech, but into all aspects of operational readiness. He has told me how much he admired the Sabre, for it's excellent performance for it's time.
(glowingly: filled with admiration.)
And thank you Agent JayZ for showing us this wonderful Engine. The F-86 is a true classic. I think the F-86D is the best looking version.
Cool!! All my buddies,when we were kids building models,always gave me crap about trying to find a Sabre Dog!!! I thought I was the only one who thought that was the best looking model!
Well done. My favorite part is seeing that look of relief/satisfaction/happiness.
Amazing run
Very cool video. Thanks for showing us your passion.
Nicely done.
Congratulations on successful start.
Finally get to hear a jet engine run after months.
Finally........
It's alive!
Yes!! Beautiful engine. Can you show us what the inside of a hydromechanical fuel control looks like? All I've studied are diagrams and I can't understand how something so complex can function reliably enough to put on a plane. Thank you :)
I have been wondering that too.
Beautiful engine 👌
Beautiful intake cone
Some people call it, "the dog pecker".
whenever that rpm revs up I feel the g-forces pushing me back into my chair.
🤨
Below temp, higher thrust, and low vibration. What is the main cause for that? Is it just more modern components like modern and better bearings? Or better balancing? Or all of the above? That's pretty neat.
Stock parts, careful assembly, and "boutique" balancing procedure, as our manager calls it.
The thrust is always great with the Orendas, because I think the factory was very conservative in their ratings.
@@AgentJayZ that is awesome. Interesting about the orendas being low estimates. Now I really want to see what that Iroquois can do!
@@AgentJayZ oh. And thank you for answering my question.
You have one of the best jobs in the world
amazing work, any chance we get to see the jet it goes into?
I made a video of a Sabre in Texas that another Orenda I built was installed in.
It's called Orenda 14 in the Sabre6
@@AgentJayZ NICE! Thanks!!
Congrats!
You must have done a damn good job to get the thrust above spec and both the temp and vibration below spec. I was under the impression it was near impossible to get all 3.
Think the owner would sell that? I'm looking for something to swap into my VW Bus
You need a T58. 1200 Hp, shaft output. 350 lbs. Fit in your van easily. We can build you one!
@@AgentJayZ Need something faster than that- I have a long commute
Watch Krugtech's Chrysler minivan with a 750 Hp RR Nimbus in it.
@@bobqzzi won't be with one of these........
Am happy with you because of good work
Well done.
totally engrossed in those engines ,.. Wanted to work on jets when I joined up , but they decided I should dangle from a parachute and walk everywhere..
Fascinating
A very good watch AgentJayZ also wondering how was the jet engine for the ENA jet going, any information
A good demonstration of why I try to avoid using jargon...
@@AgentJayZ Sorry about that I thought it was genuine, but not to be, my big mistake believing
What I meant was... I have no idea what ENA means, and I'm not going to ask.
@@AgentJayZ ENA (Ecole Nationale De aerotechnique) school who helped Mikey Mcbryan with his dc3 restoration, The school aquired a jet plane I think they were/are going to save. Cheers
Why would you abbreviate that? Is that a household word? Even in the aviation community? Jeez.
I offered those people two engines for the CF-100. They never got back.
I think they realized the project is more than they could handle and lost interest in ever getting it flying.
Thanks....AgentJayZ...Sounds good...No vib's much awesome...!
Sabre is one of my favorite airplanes thank you. Can I have a general question for any Jet engine. When a turbine ingests moisture in the form of a cloud or rain is there any thrust advantage from the expansion of the water from liquid into vapor? When I was a kid in Colorado we used to use vapor injection in our old gasoline motors to get a little bit of performance at high altitude above 6000 feet. Just curious thank you
Cloud or rain, no matter how heavy, will have no effect at all on any turbojet.
Injecting a lot more into the combustor, will lower the temp and produce steam, so even more fuel can be sprayed in. Result, more power.
Nice
Bad little boys giving thumbs down. I guess they don't know what the real world is.
Sabre jets make me get tingley...just sayin....nice work
Brilliant 👍👍👍
Magic Wand will come in handy at the shop.
always great to see a fine piece of engineering restored and put back into service! Any idea how big the stock of these engines is, and whether the owners of F-86s might have to consider fitting other engines?
If you blow up a balloon and release it, is it the high velocity air coming out the hole pushing against the air that makes it move, or is it the pressure difference inside the balloon?
Neither.
Once the balloon is filled with air, it tries to contract due to the nature of the rubber. But is resisted by the air traped inside, which is under a slight amount of additional pressure than the atmosphere on the outside of the balloon. This contained pressure creates no thrust because the balloon is sealed.
When the balloon is released, the pressure-differential between the inside of the balloon and the outside atmosphere causes the air to eject out the neck of the balloon. The balloon continues to compress the remaining air, causing a continuation of the air moving from inside the balloon out the neck of the balloon.
The acceleration of the air from inside the balloon is what caused the thrust, as air has mass, and every action creates and equal and opposite reaction. That is, every time a mass is accelerated, it resists, or pushes back.
It has nothing to do with the escaping air "pushing against" the air that is outside the balloon. Because it will work in outer space where there is no atmosphere at all. The air mass inside the balloon escapes at a velocity, which means it accelerated, it has mass, and it accelerated, therefore it creates an equal and opposite reaction.
Rockets generate more thrust in outer space than they do at sea level because there is no air resistance in space. The air resistance around the rocket at takeoff actually robs it of some thrust.
Watch a video of the spaceX Falcon 9, as it reaches outer-space the rocket plume gets wider and wider in the thin air.
That's a pretty good answer, right there.
@@Triple_J.1 Thanks Justin that was an amazing answer I appreciate it! I thought about the space scenario as well.. since we have a smart guy on the line, I wanted to ask you about this.. for years I have watched the depiction of lift on an airfoil as a stationary wing with streamlines of air passing over. I dont think this in any way an accurate rep of what is actually happening. The stationary air molecules get moved by a wing blasting through them, moved up, object in motion wants to stay in motion creating a vacuum.. idk thanks again!
@@Triple_J.1 I’m renowned for giving long-winded answers, but yours is even longer than I would have given, and I’m going to contradict your “neither”.
This is an example that I have used recently in my STEM presentations to primary schools here in the UK - and the answer is BOTH, because you can’t have one without the other. However, while the air is being expelled from the neck of the balloon, it is NOT producing any resultant force on the balloon. This is a basic misunderstanding in the minds of so many people.
The potential energy stored in the membrane tension in the balloon envelope is converted into kinetic energy in the expulsion of the air through the neck, resulting in a classic demonstration of Newton’s Third Law. The air is propelled in one direction, the balloon in the other.
That answer might satisfy a physicist, but it doesn’t satisfy an engineer like me. So what about Newton’s First and Second Laws? There must be an unbalanced physical force acting on the balloon somewhere to cause it to be accelerated from rest in a direction opposite to the air being expelled. So what and where is that force applied?
The answer is simple: it is the internal pressure (which is greater than atmospheric pressure) acting on the projected area of the balloon neck on the interior of balloon envelope opposite the neck - and nothing else! However, this cannot happen unless and until air is expelled through the neck of the balloon, where there is obviously no pressure being exerted on the balloon envelope.
@@paramtrx9558 Please see my contradiction of Justin J’s “neither” - and you have hit upon an issue I’ve raised in another STEM presentation that I’m giving next week.
We see videos of wind tunnels with flow visualisation smoke trails around aerofoils, aircraft, cars, etc. However, they are stationary, while the air is moving and has kinetic energy, which means that it wants to continue on its way, induced by a fan somewhere downstream.
That is not what actually happens in the real world, where the air is stationary until the aircraft or the car arrives. In this case, it is the aircraft or car that possesses kinetic energy, some of which is transferred to the air transiently, with some of the air being dragged along in the slipstream - the “hole in the air” to which motor racing commentators so often refer.
If you want to see a graphic demonstration of what an aircraft actually does to the air, look for photos taken of aircraft flying just above the cloud tops (I’ve included a couple in my presentation). You will see that the aircraft produces a deep ‘trough’ in the cloud tops, with a distinct downward ‘curl’ at the sides, as a result of the wingtip vortices.
It’s a classic demonstration of Newton’s Third Law: the wings are producing a downward force on the air, the result of which is an upward force on the wings ie, ‘lift’.
Of course, there is the matter of where the force is actually applied on the wing (and how). The greater proportion of the lift force is applied to the upper surface of the wing, as a result of a reduction in pressure. The increase in pressure on the underside of the wing is a relatively smaller proportion of the total lift force.
If you want an explanation (none of that ‘equal transit time’ nonsense), check out Professor Holger Babinsky of the University of Cambridge.
Only Canuck could appreciate that free workshop heating... I am more accustomed to a fully ducted exhaust in the test cell.
Great Sucess!!!!! aNyeiice!!
...Thank You.
Hey mate , love all your videos, I’ve learnt so much .
Love the way you explain everything. Its easy to understand,
Can I ask ,what does a turbine stater/nozzle do ? I understand the gas pathways through the turbine itself and how it changes the direction and speed of the gases to make a or multiple turbines turn but can you tell me what do the staters do in regards to how the gases are changed and how does it impact the flow of gases to the turbine behind it ?
Thanks in advance from Australia
Part of the stators function is the way they guide the gases to flow into the turbine blades at an angle that makes the energy transfer happen most effectively.
The other part of the stators function is how they form a narrowing passage between each other, so the gases flowing through them accelerate before they encounter the turbine.
Luckily, the angle at which each individual stator vane needs to be set in order to direct the gases at the right angle, and also create a narrowing pathway between them, seem to coincide nicely, when combined with the design of the thicknesses, shapes and curvatures designed into the individual nozzle guide vanes.
There are some excellent diagrams out there. The search bar is your friend!
The turbine stators, commonly referred to as nozzle guide vanes (NGVs), are what the three words suggest.
They are nozzles: they convert the pressure of the hot gas into velocity in a converging passage. They are guides: they guide the accelerated hot gas in a circumferential direction.
They are vanes, obviously: the term vane is conventionally used for a stationary aerofoil, and the term blade is used for a rotating aerofoil.
Having been turned, or 'whirled', in a circumferential direction, the accelerated hot gas then encounters the turbine blades, which also have converging passages. The turbine blades turn the hot gases in the opposite circumferential direction, extracting power in the process, with a further reduction in pressure. The amount of power a turbine stage extracts is measured by the change in the whirl velocity, ΔVw.
As AgentJayZ has told you, there are excellent diagrams out there: you need to get your head around velocity triangles.
PS At the design point of the turbine(s), the angle of the hot gas exiting the NGV row, and entering the row of rotor blades, matches the inlet angle of the blades, and the outlet angle of the blades ensures that the angle of the gas entering the following NGV row matches the inlet angle of the vanes, and so on. Now get your head round velocity triangles!
I have a question: how thrust is measured? It is a sensor on the engine, outside the engine, or a estimation based on engine parameters like revs and fuel flow?
I could be mistaken, but I believe the grey rectangle with the yellow wire coming from it at 8:16 is a thrust cell mounted on the stand.
Yes, they are piezoelectric load sensors connecting the engine in a pivoting saddle to the fixed structure of the stand,
Thanks for the video agent JZ. I just bet it was very nerve-wracking. Old stuff is less perfect in it's understanding. Jury rigging is a big part of making this prime time. I am not sure what it's thrust was but you can bet it was not very much maybe double on afterburner and still less than 10,000lbs. No way could this engine pull the Sabre straight up. You can imagine an f-15 breaking the speed of sound straight up well that ain't this but still a beautiful engine.
1950 technology!!
Why did it take a year to overhaul? Would it take the military or an airline this long?
If I had a large facility and a couple dozen people working on all processes at once, this overhaul could have been done in 30 days.
@@AgentJayZ Quality, Speed, Cheap.. you can't get all 3 just pick two..
Is there an aircraft waiting for this or just a rebuild to put on the market?
This is an overhauled turbojet that will be used in an aircraft.
Is thrust generated and applied in helicopter turbine use? Forward thrust?
No. Helicopter exhaust outlets are divergent, specifically to eliminate any residual thrust from the engine exhaust... which would be an annoyance to the pilot.
If the pilot wants thrust, he/she will ask for it, by using the controls. The cyclic, I think.
I'm sure a few helicopter pilots will let us know...
Does it normally take that long to overhaul one or was this a when you had time overhaul?
This one was more difficult than usual, plus we had to wait a few months more than expected for the fuel pumps.
@@AgentJayZ TY sir, I appreciate the response.
"Total loss lubrication system " is used in any jet engine????
The rear bearing of the J65 is total loss lubed. Very low flow, though.
And with the same ancestry as the J65 (the Armstrong Siddeley Sapphire), all marks of the Armstrong Siddeley/Bristol Siddeley/Rolls-Royce Viper had total loss lubrication for their centre and rear roller bearings.
What is the hole in the tip of the intake cone for?
Cooling air for the hard-working starter...
I didn't know you can rent jet engine starters in Canada.
They make us pay in ice cubes... such a pain...
Dang, I can't imagine all the stuff that can go wrong on one of those things.
You have to remember: it's a combat jet engine, designed to survive all the abuse a young hot dog pilot can dish out, and then some.
It wants to run, and it is very hard to wreck!
Wicked!!
Is there a major loss of energy from the combustion through the turbine ? really glad your still here !
In a simple turbojet like this one, about 2/3 of the energy produced by the combustion of the fuel is "harvested" from the exhaust gas stream by the turbine to supply the power to turn the compressor.
So very roughly 20 thousand Hp to drive the compressor, and 10 thousand left to squirt out the back and provide thrust.
Yes, as AgentJayZ has said, the power is "harvested" to drive the compressor - but it is not "lost". As I have explained numerous times before, it is 'recycled' in the compression/expansion processes.
@@grahamj9101 And I would think that the higher RPM , the more usable thrust from the combustion through the blades exits into the convergent pipe faster , making more thrust , but lower RPM holds up the thrust working the turbine . So like JayZ said in a video , The Engine performs best at full throttle
@@christinadaly7743 The engine "performs best" at full throttle because that is at (or near) its design point. At part-throttle the engine is operating off-design, and both the compressor(s) and turbine(s) are operating inefficiently, in terms of their aerodynamics. The engine is also operating inefficiently as a heat engine, in terms of its thermodynamics, with both the maximum cycle pressure and temperature reduced.
PS As I've explained to someone else, at the design point of the turbine(s), the angle of the hot gas exiting the NGV row, and entering the row of rotor blades, matches the inlet angle of the blades, and the outlet angle of the blades ensures that the angle of the gas entering the following NGV row matches the inlet angle of the vanes, and so on. The same applies at the design point of the compressors: the air angles and the blade angles are matched. Off design they are not, and the angles are mismatched in both the compressor(s) and turbine(s). Consequently, they are operating inefficiently, with increased losses.
@You are correct But Of course it's not a perpetual motion machine.
The work done in the turbine, as a result of the expansion of the hot gas through it, becomes work done on the air in the compression process - with inevitable losses, as a result of inefficiencies, in both the turbine and the compressor.
Nevertheless, what is compressed in the compressor is expanded in the turbine: that is what I mean by 'recycling'.
JJ Abrams star trek seen plenty, is on now film 4 in which AgentJayZ said in the
Engineering room is a LM1500 compressor stage, I normally pick these things up
I cannot watch it again, or I could miss it, have seen before since aware, but missed it!
I wonder if any fans of our Jet Tech, could help me with when or time, might help me, TX
I would love to see this and appreciate the help ? love the might gas-turbine .
Hey, I saw a fella take an automotive turbocharger and run it with compressed air, with the idea to then do steam later on.
He had this interesting idea, after passing the steam through the turbine the plan was to cool it right after the turbine with the air coming out of the compressor end.
Initially I thought it seems dense cause you're just throwing away all that heat, but cooling the steam at the outlet of the turbine would lower the pressure there even more thus giving it to my understanding something equivalent of a vacuum effect potentially gaining you efficiency. Does this compute? if not, could you please enlighten me on why not?
It seems an idea inspired by closed cycle steam turbines, which do condense all the steam, and return it to the source of heat, to boil into steam again to power the turbine.
However, trying to explain what another person thinks they want to do with an old turbocharger is not really possible...
@@AgentJayZ I suppose I asked it poorly. What I meant to ask is, would cooling the steam after it exits the turbine increase the efficiency (or power output maybe?) of the turbine? To clarify, not strictly cooling for recycling but drastically dropping its temperature just at the outlet of the turbine. Which I assume would drop the pressure at the outlet creating a sort of pulling effect for the steam still inside the turbine. Effectively creating more work by dissipating heat?
I'm just trying to understand whether that would be a thing that can work & gain efficiency or is there something in the workings of a turbine that is overlooked and would make this pointless or impossible to do?
I was binging through your videos and I stumbled upon something seemingly similar, unless maybe I misunderstood something and am wrong. The video is.. "Working on a Turbojet: 12" @ about 28min mark
If the steam exit from the turbine is designed properly, the exhaust pressure would be very close to ambient. So cooling the exhaust would do nothing but cause a pool of water to drip on the floor.
The cooling of the exhaust of the turbine shown in my video you mentioned is more for safety reasons. It has no effect on the power made by the turbine.
Also note: it is very difficult to compare combustion turbines with steam turbines.
Apples to pineapples...
Passing air (or steam) through the turbine of a turbocharger, assuming there is a load on it from the impeller, will result in a temperature drop across the turbine. I recall, as a student, doing a lab test on a small air turbine, using compressed air from a large air reservoir. At full load, there was ice forming on the turbine exhaust ducting.
en.wikipedia.org/wiki/Allison_J35#/media/File:GE-Allison-J35-Engine.jpg For what design purpose is the flow divided into those parallel tubes?
Those are combustors. That's the way it was done in the 1940s. Later on, the annular combustor was found to be more efficient, so that's the way it's done now.
Proper combustion is one of the trickiest parts in jet engine design. Flame outs were one of the most dangerous things that regularly happened to early jet engines. Many of these designs had interconnected burn chambers so that a flame out in one cell was quickly reignited by the neigbor. You can see this connection in the picture of your link: The side port of the burn chamber tube. It happens to be easier and more resilient if arranged in multiple smaller units, before the whole tech was mastered sufficiently. So this is what early designs used... for the price of some efficiency.
Fuel has to burn very fast, as the air only spends fractions of a millisecond in the burn chambers, before it enters the turbine section. BUT fuel does not burn fast enough, if it's not in a proper mix ratio with air. Unfortunately the result of perfect air/fuel-combustion is WAY too hot even for modern materials. So you have to shield this overheated gas flow from everything inside the engine by making sure all parts are wrapped by cooler gas flows with the hot gas streaming in between the cooler gas and mixing before entering the turbine stage. It was a permanent ride of the blade between the engine blowing itself out and melting its own guts... ^^
@@AgentJayZLater on? Metrovick's first jet engine had an annular chamber in 1941, which eventually led to Armstrong Siddeley's Sapphire having an annular vaporiser chamber in the late 1940's (years ahead of anything in the States) - and to an obvious technology transfer to the Iroquois.
Within a couple of days of seeing this vid, I happened to come across an airplane-disaster vid about a case where a combustor can that had been repaired, blew its head into the wing, puncturing the fuel tank. So that was a striking coincidence for me to experience, that right after learning what one was, I got to see a doco about one failing catastrophically.
graham, my apologies. I was taking a more North American centric view than I should have, eh?
Jesus! I thought my barbecue was hard to start
minty ol' girl
Just makes you realise why these things are soooo expensive.
Jz is that a F86 Sabre engine?
It's for an Canadair Sabre 6. A slightly modified F86-F, built under license in Canada.
Could someone tell me whats worth a (caterpillar) Solar T-1201 turbine.
Shaft power 800 kw with maintenance documentation.
I think they were 7,000 pounds of thrust
You forgot Zebra. Fun times, Ah.
The Avon Sabre was 10,000
The Avon Sabre was never exported, and is not popular with collectors and owner/pilots.
Some said it was heavy and unreliable. I've never seen an operational example.
@@AgentJayZ you will soon Jay, there’s a restored one near me I’m visiting in a couple weeks at my local RAAF Base museum known as Fighterworld in NSW Australia (Williamtown is the city), I’ll take some photos and send them your way.
That would really be great.
I second that first comment !
Anyone else smell kerosene?
First comment
The Canadian version with the British base centrifugal engine was much more powerful then the axial flow engine used in the American sabres. The engine shown is the centrifugal engine, you can tell by the thrust bottles
No. The Orenda design is a ten stage axial compressor. Also, what you call thrust bottles are the combustor outer cases, often referred to as cans.
"Thrust bottles"? Never heard about that... do you mean the burn chambers?
The Canadair Silver Star had a R-R Nene engine, but AgentJayZ probably knows a lot more about this than me. The Nene was a centrifugal engine, which was reverse-engineered by the Soviet Union as the Klimov VK-1, and used in the MiG-15. It was uprated, relative to the Nene, and produced about the same thrust as the J47 in the F-86 Sabre, but was a lot lighter.
@@jackmclane1826 sorry miss-phrased as a mechanic I make a good carpenter.
PS If the F-86 had been designed for a centrifugal engine, it would have looked fatter, because of the larger diameter of the engine, relative to the J47. In other words, it would have looked more like a MiG-15.