You probably dont give a shit but does someone know of a method to log back into an Instagram account..? I stupidly forgot the password. I love any tips you can give me.
@@acbulgin2 The more I look at turbine blades the more sense they make of velocity, fluid dynamics, power transfer etc. They seem ‘truth-telling’ somehow 🤔
That level of precision engineering is so satisfying. From the ceramic coated blades to the sound of instalment matched with perfect balancing it’s just pure bliss to the mechanically inclined individual.
There is a single stage turbine, which extracts sufficient energy from the combustion gas stream to provide the torque required to turn the 12 stage compressor. Turbine blades have a very different aerodynamic function than compressor blades, and their appearance illustrates this difference.
@MrPocketWatch1 What may look like a turbine that turns the opposite direction is actually the turbine inlet nozzle. It's fixed to the engine cases, and directs combustion gases at the best angle to efficiently drive the single stage of turbine blades in this engine. There are no engines that use a turbine spinning the opposite direction as a nozzle for a subsequent turbine.
Awww, cute little blades. I assembled and serviced industrial turbo pumps for many years, some of the first stage blades were almost a meter long. the biggest was for a gas liquefaction plant on the Sakhalin Islands. It has an axial compressor feeding a radial compressor. The rotor of the axial compressor naked was just on 18 metric tons. Interesting is how the weight scatter on the blades is close to what these little ones are. I love the simple but efficient principles of turbines and how they sound. Thx for the uploads.
I worked machining these exact parts for g.e. pratt and whitney etc,the man hours to produce these things was huge,the tolerances on fit was at times less than .005 of a thousand.of an inch. Precision machining is no joke at this level.
@crazyrum It's a roll pin; it's a spring that is slightly larger than the hole you drive it into... and yes centrifugal force tends to push it into the hole.
From the blade weights that I was able to catch in the video, the blades vary in weight by as much as 12 grams from each other....approximately a third of an ounce. I'm guessing that such difference isn't critical to the integrity of each blade under load, but explains why the need to balance the entire turbine disc. But what variable in the manufacturing or coating process would account for as much as a 3-4% differing finished weight of the blades? In a field driven by high precision, I'm surprised at such variability.
Now that is a question I don't really know the answer to. I would not be surprised if their was that much variability engineered into the production technique. But I don't know.
I would have to guess the 3-4% variability would come from the composition of the materials, depending on manufacturing techniques. the blades generally a made from a single ingot of metal, titanium and/or nickle tin alloys, these you say have a ceramic coating, which could also effect the weight, but specific impurities and imperfections on the alloy compositions could also explain the variance. It is most likely a combination of all three.
It's mostly to do with dimensional variation on the casting of the blades (not sure if these are cast, but similar story for wrought blades too). The alloy composition tends to be very strictly controlled, as does the mass of coatings. For a lost wax casting process you've got variation in wax pattern size, ceramic core size (though these look like solid blades) and ceramic shell size, all of which contribute to a varying size for the final casting. As Jangle points out, the difference does not affect the blade integrity :)
It slows the heat transfer into the blade from the hot gases, but does not affect the heat transfer out of the blade into the disc, and out of the disc into the cooling air it is supplied with. By how much? ...don't know. At the same fired temperature, it greatly prolongs blade and disc life. At the same projected service life, you can increase fired temp by 50F or so, giving increased power output.
What I meant by a partial career is at the moment I have no idea what I'd really like to do in the future. And if it takes more than two tries at finding my goal career, I'll do it. From the beginning I wanted to be an aerospace engineer, Now I want to be an airline pilot. Yet every time I see a turbine engine up close, they just fascinate me. Thanks to your videos that I've watched for a good 2-3 years now I really do understand how they operate. I'd still love to visit FSJ.
The blades and turbine were balanced as an assembly before they were then numbered for position, taken apart... then the turbine was intalled in the engine, then the engine was turned horizontal, then the turbine blades were reinstalled as you see here.
watching such amazing video makes everything clear regarding imagine the flow of gas through stator's and rotor's blades,which is much better than reading ,thank you so much for really precipus video that let me imaging the gas flow through blades,and imagine changes of velocity and pressure of gas through rotor and stator blades
Bee. Ee. Ay. You-tiful. Perfection. Each one a miniature aerofoil, an aircraft wing all its own. Actually, given its function, ‘glider wing’ might be more appropriate because *like* a glider wing, the turbine is reliant entirely upon the accelerated airflow incident upon it for lift; or in this case, rotation. Thanks JayZ for all the years of awesome content. And greater thanks for fielding and even *attempting* to answer *some* of the hundreds of questions sent your way. Actually, I’ll rephrase that, to be more accurate: translating so many inquiries into questions that are answerable………and answering them. Thank you.
I have made those type of blades before. I worked in a machine shop that used electro chemical machining. It lets the finish and an shape form easy without stressing the metal
When this engine was produced, the turbine blades were uncoated. We have applied a modern process to improve the heat tolerance of the blades. I believe a J47 back in the day went for about 55,000.00US
Dear, AgentJayZ and MrPocketWatch. You guys are so close in your conversation when it comes to the next generation of tubine engines. I'll say no more because the patent is still in the works, and I don't have a Pending Patent, but you'll be pleasantly suprised at the simplitcity and also the complexity of things to come.
I'm surprised the weight varies so much blade to blade. I wouldn't expect more than a gram or two difference in high precision, identical and relatively small parts but there is more than 10g between some of them.
The high nickel alloy is quite heavy, and each blade is cast with a single use mould. There is no area on the blade where material van be removed to adjust the weight.
@@AgentJayZ Can't you drill a little 1mm diameter hole into the face that's facing you when you insert the blades at 2:44? (I mean hypothetically. I know you can't ignore the repair manual IRL)
В 46. Году. Слесарь ..КОВАЛЕВИЧ за 4 месяца. Вручную сделал. 52. Лопатки на турбину. Разница в весе составила. Миллиграмы. Ну о размерах и говорить нечего....
I find this video incredibly relaxing when the blades are being installed, that must be one of the most satisfying jobs when resurrecting a jet engine. Love the vids, keep it up!
The ceramic coating to the turbine blades of this J47 is an example of "hot rodding". We have taken a modern thermal barrier coating, and have applied it to increase the performance of this old engine. It was never a service bulletin because the technology was developed after the manufacturer stopped supporting the engine. As far as I know, this is the only J47 ever given this upgrade in thermal protection.
@1metiz New? 2500.00 but you can't get these anymore. To obtain one as a souvenir... their value is not measured in money, but in resoucefulness, courage, and a willingness to thrash back the boundaries of the great unknown. An aviation scrap yard would sell them for the price of their mostly nickel content.
The best I can figure is that there is something amazing about the symphony of mechanical components working together that makes this so appealing... Of which, mostly men understand.
@@AgentJayZ You're right.... I guess I gotta throw my two cents in because men never hear the end how we are holding women back. Great Video's ... glad you take to the time...
Seems the blades on the back have much more aggressive profiles than the blades on the front...plus less rows on the back...must be so as to be able to extract more torque so as to run all the rows on the front?
..once as a thesis, developed a computer program in NPS, Monterey, blade sequence for minimum imbalance, since they weigh slightly different than each other, (i.e.,166blades, 166! factorial different way to place them), yet program used a heuristic way, also this video was very nicely put together....
OK, just wondering. I'm used to thinking of ceramics as very hard and brittle, although I admittedly don't know much of anything about them... Is it aluminum oxide?
That coating is called TBC thermal barrier coating which is plasma spray coating. You should never hit them together like that fool did it chips really easy and expensive to repair.
Love new old stock!!. I bought a nos mechanical wind up german alarm clock made in 1977,, i wanted back up in case my mobile died on me,,couldnt resist buying clock made when i was in first year of junior school!!
So well balanced that adding the miniscule weight of a single blade causes the entire assembly to rotate. Very cool stuff, makes me want to build a functional miniature gas turbine engine.
As a Quality Engineer who takes pride in providing quality product to my customers, it bothers me that when we manufacture these blades with the ceramic coating, we have to wear clean white cotton gloves and absolutely no part to part contact.. The specs alone on handling of these parts is crazy, and just to watch you slap 2 parts together and manhandle them with your bare hands is very unnerving.
Are you referring to the forward stub shaft or the distance piece? Perhaps you're referring to bucket wheels which have radial slots for bucket cooling air.
I think the coating here is on a stage of the compressor section and that the coating is to prevent erosion on the blade surfaces that wears them down to where they will not function. You know like when you have someone sandblast your teeth to a fine point. I hate when that happens.
The J47 is a first generation axial flow turbojet. Low compression, low temps, low power... compared to todays engines. Air-cooled nozzles and turbine blades were developed along with higher compression more than a decade after this engine was designed.
@AgentJayZ So there is no locking mechanism such as thread? Does it expand when the temp goes up such that is stays in the position? Or they are hold in place just by centrifugal force? Thanks
That is only true of the turbine blades. Compressor blades are not required to withstand extreme heat, so are manufactured differently, out of different materials.
I have a question, what temperature do these blades withstand? I assume that if there's fuel burning without lack of oxygen, it would melt most materials, like a gas welder.
Hi Jay, What is the turbine inlet temperature of the J47? How come those blades do not have those air cooling holes that are common in more recent jet engines? Would like to here your expert opinion.
I wonder what the part number is on those blades, I work for a facility that heat treats a substantial amount of ge Dayton blades. Although we specialize in inconel and titanium treatment
In my childhood I got a fan blade from a pilot from the legendary aerobatic team Frecce Tricolori during an airshow, because I was sitting in the cockpit of his aircraft and told him all about it and how it is functioning and how to fly this aircraft! He was simply so astonished and fascinated from my knowledge about it and I told him that I am addicted to aircraft's and I am very excited to be in this cockpit and I am twelve years old! He said I should go with him to his car and as we went on his car he opened a suitcase and picked the fan blade out and gave it to me and he said it is a gift for me because I am so interested and well educated in flying and on the attachment point to the engine was a little hole in it with a ring inside and since this day I carry this little fan blade on a dogs collar on my neck and I eat sometimes my ice-cream or yogurt with it! The pilot told me that this little thing was once inside the engine of one of his aircraft's right behind the hottest part of the engine and it was from a Pratt&Whittney engine! I love it so very much and I am so proud to have it! 😍😍😍😍😍Lovely greetings from Sarah 🙋💖😍✈️👍
There is no power turbine in a turbojet like the J47. And the J47 uses a single stage turbine, so this is the first, last, and only stage... The alloys have not changed a whole lot, but engines are firing hotter because of advancements in blade-cooling technology. Beyond the scope of my little channel, really.
you have such a cool job dude would love a job like that but why don't you put a carpet on the floor could only help if u drop one or are you really that crazy good at ur job. love the video learned a lot
@@AgentJayZthere are two “common” methods of manufacturing these coatings. Thermal Spray literally sprays the coating onto the blades. EBPVD grows it on the blade like a crystal. YSZ is a very common material used in either process.
Can you comment on how the turbine was balanced and then in turn how the blades were numbered? I’ve read somewhere that RR sell fan blades in a pair so no balancing needed.
Turbojet turbine blades are very different from Turbofan fan blades. The blades are weighed, the weight is written on them, and that is used in the balancing process. Then, once the assembly is balanced, sometimes the blades are numbered consecutively to indicate their position in the disc, which would have the slots also numbered.
Not sure why you would put thermal barrier coating on a an uncooled blade? It can lower the bulk temperature circa 80 C on a cooled blade but it only delays the heating up of a solid blade......
Solid blades are cooled by conduction through the root to the turbine disk, which in this engine, is cooled by airflow from the compressor. See my recent vid: Turbine Cooling Air in a Jet engine. Then you will be sure.
@@AgentJayZ Thanks for the explanation, I have to be honest I can't conceive there is sufficient cooling in the turbine disc wheel space to absorb that amount of heat but I'm happy to be corrected.....maybe if it's a very low firing temp this would be the case but I still can't understand what TBC gives you on an uncooled blade?
It's not an uncooled blade. See previous response. What you or I perceive was not a concern to the engineers who created this fighter jet engine in the early 1950s, nor does it change how it functions now.
@@AgentJayZ Unless there is a cooling flow through the root then, by definition, it's uncooled. I'm not spoiling for an argument only hoping to increase my knowledge of turbomachinery....happy to be corrected but the heat flux into the blade could never be cooled by the disc. PS I love you vids.
Air cooling is better, but the solid blades are not uncooled. Funny thing about metals... they conduct heat very well. I just rechecked the description of turbine blade cooling in the Orenda overhaul manual: "Baffles fitted between the extended necks of the blades meter the flow of cooling air between the necks, and ensure a sufficient supply of cooling air over the root of each blade". So I was not completely right. Most of blade cooling happens by air flow on the roots, not conduction to the disc. Thanks for getting me to look it up!
I suppose... most sources call the turbine mounts firtee because they look like fir trees. The mounts on most compressor blades are called dovetail because, like the carpentry joint, they look like doves' tails. Calling a turbine blade a bucket, and calling the mount a dovetail is a bit like calling the rear gate on a pickup a hatchback... not totally wrong, but just different enough to raise a questioning eyebrow.
Actually, these were called buckets back then, as they were designed by steam turbine engineers. s3.amazonaws.com/dsg.files.app.content.prod/gereports/wp-content/uploads/2015/08/11203510/tumblr_inline_nsxs3jaQ031qzgziy_540.jpg
What is the advantages of ceramic turbine blades in this case? I have read that the use of ceramics allows for a much higher operating temperature of the turbine, thus increasing efficiency. However, seeing that the disk is made of metal, thus not having the same temperature stability, is temperature not the reason why ceramic blades are used in this case?
It protects the blades from transient temp spikes on startup, which these old turbojets are prone to do, and it lengthens the service life of the blades.
@@AgentJayZ I am guessing only the blades are suceptible to those heat spikes due to their thin geometry? Or are the heat spikes only occuring locally at the blades and not the disk? Interesting none the less😃
Heat enters the blades from their contact with combustion gases. Heat leaves the blades through their contact with the disk, which is not exposed to the combustion heat. If we put a resistor on the input, and don't change the output... we run cooler, and lower any spikes on the input side.
Any chance that convex & concave sides of the blades may get reversed during assembly? Also please make a video if you come across clockwise and counter clockwise rotors in 2spool engine. Thanks a lot /Jay
+Jayaram Murthy You edited your comment because you got the names backwards. Ironic, isn't it? Although in this engine the blades will fit either way, it's very obvious which way they are facing. Only complete incompetence and lack of effort put into inspection of one's work would allow a turbine or compressor rotor to be put together with a backwards facing blade. I'm not saying it never happens, but I've never done it. I will say that in the past, some people who have think little of me have indeed made this blunder themselves. What does that say about their level of ability? Ha!
AgentJayZ Murphy's law - "If an aircraft part(*) can be installed 2 ways and one of them is the wrong way, someone will do it." I am surprised that they're not keyed to make it impossible. (*) Or a spacecraft part - which is why Stardust's return pod never opened its parachute. Someone put the gravity sensor in upside down.... WRT your comment about pistons being installed in engines upside down - it happens more often than you'd think.
Yes. Many people complain that I don't use the moment weight, which takes into account the distance from the root base of the center of mass, but they can bite down hard, because my engines run as smooth as a dream. Typically with less than 20% of the max allowable vibration.
is there an wear coeffecient for the buckets as they spin through air? does a ceramic coating reduce it? if so is the wear dependent on temperature and humidity ?
Imagine forgetting to install just 1 pin lock for the blades, just 1 is enough to destroy the engine!, this is some super delicate stuff that I do not ever wanna mess with.
Hi AgentJayZ, i really love your channel ! i have a question that perplexes me for some time. some applications use this fir tree root with z-lock shrouds. i never understood how are they assembled. must they be assembled all together ?
It's very hard that TBC I spent many hours polishing them with diamond pads, what a few of you watching may not know is each one of those buckets (blades ) is weighed and that data is fed it a computer that works out where on the wheel they go in relation to each other for perfect balance hence the numbers
Making those blades is a Herculean task. GE perfected it.. They denied us the core engine tech. Never mind! We still admire their hardwork, skill, and finesse.
4 года назад
Were the numbers written on the blades their weight? How much can they vary without causing a balance problem?
Yes. They vary by up to 5% or so. The weight variation allows us to balance the assembly by moving blades. I have made several videos about balancing. There's a search bar on my channel page.
4 года назад
@@AgentJayZ Thanks! That looks like a very interesting job, but one for someone very meticulous and careful. I had no idea that turbine blades as old as 1952 were still able to be reused.
The blades were made in 1952, out of an alloy consisting mostly of nickel. If left outside in the sun of Death valley, or dropped into the ocean, these blades would look and function as new after a hundred thousand years in those environments. In a sealed container, at room temperature, they have a shelf life of at least one million years. Long after the steel can was not even dust, the blades would be new.
The lock pin slot is positioned so that it would not be possible to lock a blade in place backwards. Plus, part of being a turbine engine technician is to check each and every blade in your hand to make sure you have it oriented correctly. A bit like pistons in a car engine. Mechanics don't put them in upside down, do they?
Since this is an old video, I may not get an answer. Anyway, I'm assuming you numbered the blades because you wanted to keep the balance of the whole assembly. If those blades were recoated, wouldn't that make the numbering unnecessary? I would assume you'd have to balance the whole thing again since the blade weights would be different -- or would they?
+Mark - The turbine was removed from the engine, then de-bladed. The blades were sent out for TBC coating. The turbine disk was carefully cleaned for at least a day. When the blades returned, they were weighed, and the weight printed on them. The blades were sorted to provide a reasonably even distribution of their weights. The turbine was placed on the balance machine. The blades were installed without locks. The assembly was balanced by moving blades around, and the positions of the blades was recorded 1-2-3 in the disk locations 1-2-3. The blades were removed and placed in storage. The engine was then reassembled in the vertical position to facilitate alignment of the turbine shaft with its bearings and the connection to the compressor. The engine was then placed in the horizontal position, the blades reinstalled in their recorded position ( this video), and locked into place. All this is necessary because the turbine can't be balanced while it is in the engine, and it's easier to install the turbine when the blades are not in it.
AgentJayZ Now that I understand the sequence, makes sense. Thanks for the explanation -- and for all the videos. I worked on round motors; never got to the turbines, so it's nice to see the work.
I would imagine there's alot of force trying to push those blades out to the back of the engine. Is that tiny pin the only thing that prevents that or am I missing something?
AgentJayZ Thanks for the reply. The more I think about it though, it seems like the torque produced by the gas flowing past the blades would "lock" the blade in by friction from the fir tree slot. Maybe I'm wrong, look forward to the video.
Hey, is the turbine stage impulse or reaction? Also, do you know any reasons why they would use a single stage of turbine to drive 12 compressor blades, other than weight savings? Thanks
Nate Baker Turbine blades are combination of impulse and reaction.As for the single stage of turbine driving 12 stages of compressor it's because of the high torque that gets developed on the turbine rotor blades from the high velocity and temperature gas coming out of the combustion chamber. These rotor blades are rotating at about 2000 ft/sec.
Turbine blades are things of beauty, I got a Harrier Pegasus engine turbine blade, it has pride of place on my mantelpiece.
Agreed. It is as if they are 'designed by nature'
You probably dont give a shit but does someone know of a method to log back into an Instagram account..?
I stupidly forgot the password. I love any tips you can give me.
@Jesse Steven instablaster ;)
@@acbulgin2 The more I look at turbine blades the more sense they make of velocity, fluid dynamics, power transfer etc. They seem ‘truth-telling’ somehow 🤔
@@acbulgin2 Wonderful observations. Your post is also crafted beautifully. Made my day, though it is night here.
its kind of hypnotic how perfect blades fit
Watching the blades get inserted was so satisfying.
Thanks for sparing me the comment. :)
Yeah, but no, really. What is that?
I came down to write the same thing.
That level of precision engineering is so satisfying. From the ceramic coated blades to the sound of instalment matched with perfect balancing it’s just pure bliss to the mechanically inclined individual.
Bearings so smooth that the weight of a blade being added to one side makes it turn a bit.
Jack Bruce yup I was amazed by that
perpetual motion
Lol
I wonder what kind of bearings those are
Amazingly smooth
@rickey5353 Blades made in 1953 out of high nickel refractory alloy. Coated with ceramic Thermal Barrier Coating by Avanti Aerospace in 2011.
They were made from some variant of Inconel?
@@nicholasmaude6906 yes. There are a bunch of names for nickel based super-alloys.
There is a single stage turbine, which extracts sufficient energy from the combustion gas stream to provide the torque required to turn the 12 stage compressor.
Turbine blades have a very different aerodynamic function than compressor blades, and their appearance illustrates this difference.
@MrPocketWatch1 What may look like a turbine that turns the opposite direction is actually the turbine inlet nozzle. It's fixed to the engine cases, and directs combustion gases at the best angle to efficiently drive the single stage of turbine blades in this engine.
There are no engines that use a turbine spinning the opposite direction as a nozzle for a subsequent turbine.
Awww, cute little blades. I assembled and serviced industrial turbo pumps for many years, some of the first stage blades were almost a meter long. the biggest was for a gas liquefaction plant on the Sakhalin Islands. It has an axial compressor feeding a radial compressor. The rotor of the axial compressor naked was just on 18 metric tons. Interesting is how the weight scatter on the blades is close to what these little ones are.
I love the simple but efficient principles of turbines and how they sound.
Thx for the uploads.
I worked machining these exact parts for g.e. pratt and whitney etc,the man hours to produce these things was huge,the tolerances on fit was at times less than .005 of a thousand.of an inch. Precision machining is no joke at this level.
@crazyrum It's a roll pin; it's a spring that is slightly larger than the hole you drive it into... and yes centrifugal force tends to push it into the hole.
From the blade weights that I was able to catch in the video, the blades vary in weight by as much as 12 grams from each other....approximately a third of an ounce. I'm guessing that such difference isn't critical to the integrity of each blade under load, but explains why the need to balance the entire turbine disc. But what variable in the manufacturing or coating process would account for as much as a 3-4% differing finished weight of the blades?
In a field driven by high precision, I'm surprised at such variability.
Now that is a question I don't really know the answer to. I would not be surprised if their was that much variability engineered into the production technique.
But I don't know.
AgentJayZ Thanks. I couldn't even begin to guess. I'd be very interested in hearing the thoughts from others. Grahamj9101?
I would have to guess the 3-4% variability would come from the composition of the materials, depending on manufacturing techniques. the blades generally a made from a single ingot of metal, titanium and/or nickle tin alloys, these you say have a ceramic coating, which could also effect the weight, but specific impurities and imperfections on the alloy compositions could also explain the variance. It is most likely a combination of all three.
It's mostly to do with dimensional variation on the casting of the blades (not sure if these are cast, but similar story for wrought blades too).
The alloy composition tends to be very strictly controlled, as does the mass of coatings.
For a lost wax casting process you've got variation in wax pattern size, ceramic core size (though these look like solid blades) and ceramic shell size, all of which contribute to a varying size for the final casting.
As Jangle points out, the difference does not affect the blade integrity :)
I wonder why they wouldnt just have a spot for balancing on the base or something then. Or if it's the blade itself's weight that's more critical?
@crazyrum They are a high temp roll pin. You gently tap them into their mounting holes until they protrude into the slots in the base of the blades.
It slows the heat transfer into the blade from the hot gases, but does not affect the heat transfer out of the blade into the disc, and out of the disc into the cooling air it is supplied with.
By how much? ...don't know.
At the same fired temperature, it greatly prolongs blade and disc life.
At the same projected service life, you can increase fired temp by 50F or so, giving increased power output.
This is truly the most fascinating video on the web.
This channel rules! This is what I really want to see, not just compilations of the same recycled videos.
What I meant by a partial career is at the moment I have no idea what I'd really like to do in the future. And if it takes more than two tries at finding my goal career, I'll do it. From the beginning I wanted to be an aerospace engineer, Now I want to be an airline pilot. Yet every time I see a turbine engine up close, they just fascinate me. Thanks to your videos that I've watched for a good 2-3 years now I really do understand how they operate. I'd still love to visit FSJ.
The blades and turbine were balanced as an assembly before they were then numbered for position, taken apart... then the turbine was intalled in the engine, then the engine was turned horizontal, then the turbine blades were reinstalled as you see here.
watching such amazing video makes everything clear regarding imagine the flow of gas through stator's and rotor's blades,which is much better than reading ,thank you so much for really precipus video that let me imaging the gas flow through blades,and imagine changes of velocity and pressure of gas through rotor and stator blades
Bee. Ee. Ay. You-tiful. Perfection. Each one a miniature aerofoil, an aircraft wing all its own. Actually, given its function, ‘glider wing’ might be more appropriate because *like* a glider wing, the turbine is reliant entirely upon the accelerated airflow incident upon it for lift; or in this case, rotation.
Thanks JayZ for all the years of awesome content. And greater thanks for fielding and even *attempting* to answer *some* of the hundreds of questions sent your way. Actually, I’ll rephrase that, to be more accurate: translating so many inquiries into questions that are answerable………and answering them. Thank you.
I have made those type of blades before. I worked in a machine shop that used electro chemical machining. It lets the finish and an shape form easy without stressing the metal
When this engine was produced, the turbine blades were uncoated. We have applied a modern process to improve the heat tolerance of the blades.
I believe a J47 back in the day went for about 55,000.00US
It looks like thermal barrier coating based on zirconia
Dear, AgentJayZ and MrPocketWatch. You guys are so close in your conversation when it comes to the next generation of tubine engines. I'll say no more because the patent is still in the works, and I don't have a Pending Patent, but you'll be pleasantly suprised at the simplitcity and also the complexity of things to come.
I know this is an old video but what is the name of thermal ceramic barrier coating?
The manufacturer of the materials is unknown to me. The coating was applied by an engineering service by the name of Avanti Aerospace.
Cool to think they were stored since a year before my father was born.. thanks for the video👍
I'm surprised the weight varies so much blade to blade. I wouldn't expect more than a gram or two difference in high precision, identical and relatively small parts but there is more than 10g between some of them.
The high nickel alloy is quite heavy, and each blade is cast with a single use mould.
There is no area on the blade where material van be removed to adjust the weight.
sounds like a great field of research: Making a blade that is adjustable after being cast
@@AgentJayZ Can't you drill a little 1mm diameter hole into the face that's facing you when you insert the blades at 2:44? (I mean hypothetically. I know you can't ignore the repair manual IRL)
В 46. Году. Слесарь ..КОВАЛЕВИЧ за 4 месяца. Вручную сделал. 52. Лопатки на турбину. Разница в весе составила. Миллиграмы. Ну о размерах и говорить нечего....
I find this video incredibly relaxing when the blades are being installed, that must be one of the most satisfying jobs when resurrecting a jet engine. Love the vids, keep it up!
The ceramic coating to the turbine blades of this J47 is an example of "hot rodding". We have taken a modern thermal barrier coating, and have applied it to increase the performance of this old engine.
It was never a service bulletin because the technology was developed after the manufacturer stopped supporting the engine.
As far as I know, this is the only J47 ever given this upgrade in thermal protection.
I don’t know why I feel comfortable and relaxed watching this😊
@1metiz New? 2500.00 but you can't get these anymore.
To obtain one as a souvenir... their value is not measured in money, but in resoucefulness, courage, and a willingness to thrash back the boundaries of the great unknown.
An aviation scrap yard would sell them for the price of their mostly nickel content.
The best I can figure is that there is something amazing about the symphony of mechanical components working together that makes this so appealing... Of which, mostly men understand.
Oh, we have some pretty awesome gearhead girls on the team.
@@AgentJayZ You're right.... I guess I gotta throw my two cents in because men never hear the end how we are holding women back. Great Video's ... glad you take to the time...
Don't know for sure... but I would guess it is just the way things go in production.
Beautiful. I’m dreaming about that job 😍
Seems the blades on the back have much more aggressive profiles than the blades on the front...plus less rows on the back...must be so as to be able to extract more torque so as to run all the rows on the front?
..once as a thesis, developed a computer program in NPS, Monterey, blade sequence for minimum imbalance, since they weigh slightly different than each other, (i.e.,166blades, 166! factorial different way to place them), yet program used a heuristic way, also this video was very nicely put together....
sliding the blades back in looks like such a satisfying thing!!
1:26 Just curious, why is the guy tapping the blades together? Aren't you supposed to ever-so-carefully avoid such things?
To demonstrate how durable the ceramic coating really is, and to emphasize that the answer to your second question is no.
OK, just wondering. I'm used to thinking of ceramics as very hard and brittle, although I admittedly don't know much of anything about them... Is it aluminum oxide?
That coating is called TBC thermal barrier coating which is plasma spray coating. You should never hit them together like that fool did it chips really easy and expensive to repair.
@@stevenfoulds6883 What's the actual material? I thought it was a metal oxide and not a pure metal
Love new old stock!!. I bought a nos mechanical wind up german alarm clock made in 1977,, i wanted back up in case my mobile died on me,,couldnt resist buying clock made when i was in first year of junior school!!
2:37 You can hear the tensile strength.
4:34 I'm puzzled as to why there doesn't seem to be an impact mat in case something gets dropped.
Sort of the same reason delivery rooms don't have rubber floors, in case the doc drops the newborn. A large part of my job is being careful.
So well balanced that adding the miniscule weight of a single blade causes the entire assembly to rotate. Very cool stuff, makes me want to build a functional miniature gas turbine engine.
Chromalloy has a joint-venture in Middletown, NY which is one of the largest operations of its type for surface treatment of turbine blades...
It's a thing of beauty to see a well made machine.
I love how informational this is!
As a Quality Engineer who takes pride in providing quality product to my customers, it bothers me that when we manufacture these blades with the ceramic coating, we have to wear clean white cotton gloves and absolutely no part to part contact.. The specs alone on handling of these parts is crazy, and just to watch you slap 2 parts together and manhandle them with your bare hands is very unnerving.
Please note it was not me you had to watch. It's not a movie, and I do not direct the actions of others.
Thanks.
Worked on Rolls Wood group.. High standard... and I know exactly what you are saying.
We do our best tho..
Yeah, these guys aren't very bright. You can tell
Are you referring to the forward stub shaft or the distance piece? Perhaps you're referring to bucket wheels which have radial slots for bucket cooling air.
I think the coating here is on a stage of the compressor section and that the coating is to prevent erosion on the blade surfaces that wears them down to where they will not function. You know like when you have someone sandblast your teeth to a fine point. I hate when that happens.
The turbine blades have a ceramic thermal barrier coating.
The function is in the name.
The J47 is a first generation axial flow turbojet. Low compression, low temps, low power... compared to todays engines. Air-cooled nozzles and turbine blades were developed along with higher compression more than a decade after this engine was designed.
@AgentJayZ So there is no locking mechanism such as thread? Does it expand when the temp goes up such that is stays in the position? Or they are hold in place just by centrifugal force? Thanks
JayZ. When you say ceramic blades, /do you mean metallic blade with a ceramic coating? Wow! and from 1953? Incredible!
Dare I ask what that set of new old stock blades cost before the ceramic treatment? After the ceramic treatment? Awesome work! :)
i buy that for a dollar!
Thanks. Its hard to get a get a look at that end.
Excellent soundtrack for the assembly video
wait did you use a commercial grade felt tip marker? or can you actually use that on ceramics in the hot section.
the ceramic can witstand heat but isnt it BRITTLE??
That was one of the best videos I ever saw explaining how this thing really works! Thanks!
I can see the pins going in, but what about coming out for repairs?
My understanding is that today even large fan jet blades are cast as one monolithic metalic crystal from the root... have I understood that right?
That is only true of the turbine blades. Compressor blades are not required to withstand extreme heat, so are manufactured differently, out of different materials.
If you would have drop a blad (of course you wouldn´t) would that be scrapped even if there wouldn´t be a ny noticable cracks or similar?
I have a question, what temperature do these blades withstand? I assume that if there's fuel burning without lack of oxygen, it would melt most materials, like a gas welder.
I'm looking for a turbine blade that contains platinum. Are they available for purchase? Thank you.
Want see that bearings of main shaft. How its cooled and lubricated ? If flames throw aroun half part of engine.
Have a look at my video: jet engine lube system.
I am guessing it's the hot section post combustion chamber part?
How do you skim-cut the turbine wheel assembly to make it all concentric if you are installing blades on an installed disc?
There is no cutting, grinding or trimming of the blades or wheel.
Hi Jay,
What is the turbine inlet temperature of the J47? How come those blades do not have those air cooling holes that are common in more recent jet engines? Would like to here your expert opinion.
Now I know how the blades fit into the main disk. Awesome. I am going to subscribe. Can’t wait for more video’s.
I wonder how far back TBC ceramics goes if they did these in 1953. what stage was this?
The J47 has one turbine stage. It was developed with TBC. We had them applied, when rebuilding this engine.
I wonder what the part number is on those blades, I work for a facility that heat treats a substantial amount of ge Dayton blades. Although we specialize in inconel and titanium treatment
In my childhood I got a fan blade from a pilot from the legendary aerobatic team Frecce Tricolori during an airshow, because I was sitting in the cockpit of his aircraft and told him all about it and how it is functioning and how to fly this aircraft! He was simply so astonished and fascinated from my knowledge about it and I told him that I am addicted to aircraft's and I am very excited to be in this cockpit and I am twelve years old! He said I should go with him to his car and as we went on his car he opened a suitcase and picked the fan blade out and gave it to me and he said it is a gift for me because I am so interested and well educated in flying and on the attachment point to the engine was a little hole in it with a ring inside and since this day I carry this little fan blade on a dogs collar on my neck and I eat sometimes my ice-cream or yogurt with it! The pilot told me that this little thing was once inside the engine of one of his aircraft's right behind the hottest part of the engine and it was from a Pratt&Whittney engine! I love it so very much and I am so proud to have it! 😍😍😍😍😍Lovely greetings from Sarah 🙋💖😍✈️👍
There is no power turbine in a turbojet like the J47. And the J47 uses a single stage turbine, so this is the first, last, and only stage...
The alloys have not changed a whole lot, but engines are firing hotter because of advancements in blade-cooling technology.
Beyond the scope of my little channel, really.
Why are all blades mounted in the way that allows them to move a little and make this clicking sound? Is it clearance for heat expansion?
Have a look at a short video I made about your question, called Jet Engine Turbine Blade Noise... Or something like that.
@3:58 are the numbers the weight in grams for each blade? reference used to balance their placement?
Yes. It's explained in detail in my vid called how to balance a compressor rotor
great vids. i create 3d visualizations/animations for geaviation. it's nice to see pros at work. thanks
you have such a cool job dude would love a job like that but why don't you put a carpet on the floor could only help if u drop one or are you really that crazy good at ur job. love the video learned a lot
Is that a YSZ (Yttrium Stabilized Zirconia) coating applied by EB-PVD? It looks like a good coating.
It's described to me as a ceramic thermal barrier coating. I don't have any further knowledge of it.
@@AgentJayZthere are two “common” methods of manufacturing these coatings. Thermal Spray literally sprays the coating onto the blades. EBPVD grows it on the blade like a crystal. YSZ is a very common material used in either process.
Can you comment on how the turbine was balanced and then in turn how the blades were numbered?
I’ve read somewhere that RR sell fan blades in a pair so no balancing needed.
Turbojet turbine blades are very different from Turbofan fan blades.
The blades are weighed, the weight is written on them, and that is used in the balancing process.
Then, once the assembly is balanced, sometimes the blades are numbered consecutively to indicate their position in the disc, which would have the slots also numbered.
Nice video..i m happy that i used to repair those blades...hpc and lpt..Airfoil..
Not sure why you would put thermal barrier coating on a an uncooled blade? It can lower the bulk temperature circa 80 C on a cooled blade but it only delays the heating up of a solid blade......
Solid blades are cooled by conduction through the root to the turbine disk, which in this engine, is cooled by airflow from the compressor. See my recent vid: Turbine Cooling Air in a Jet engine.
Then you will be sure.
@@AgentJayZ Thanks for the explanation, I have to be honest I can't conceive there is sufficient cooling in the turbine disc wheel space to absorb that amount of heat but I'm happy to be corrected.....maybe if it's a very low firing temp this would be the case but I still can't understand what TBC gives you on an uncooled blade?
It's not an uncooled blade. See previous response.
What you or I perceive was not a concern to the engineers who created this fighter jet engine in the early 1950s, nor does it change how it functions now.
@@AgentJayZ Unless there is a cooling flow through the root then, by definition, it's uncooled. I'm not spoiling for an argument only hoping to increase my knowledge of turbomachinery....happy to be corrected but the heat flux into the blade could never be cooled by the disc. PS I love you vids.
Air cooling is better, but the solid blades are not uncooled. Funny thing about metals... they conduct heat very well.
I just rechecked the description of turbine blade cooling in the Orenda overhaul manual:
"Baffles fitted between the extended necks of the blades meter the flow of cooling air between the necks, and ensure a sufficient supply of cooling air over the root of each blade".
So I was not completely right. Most of blade cooling happens by air flow on the roots, not conduction to the disc.
Thanks for getting me to look it up!
I suppose... most sources call the turbine mounts firtee because they look like fir trees. The mounts on most compressor blades are called dovetail because, like the carpentry joint, they look like doves' tails.
Calling a turbine blade a bucket, and calling the mount a dovetail is a bit like calling the rear gate on a pickup a hatchback... not totally wrong, but just different enough to raise a questioning eyebrow.
Actually, these were called buckets back then, as they were designed by steam turbine engineers.
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What is the advantages of ceramic turbine blades in this case?
I have read that the use of ceramics allows for a much higher operating temperature of the turbine, thus increasing efficiency. However, seeing that the disk is made of metal, thus not having the same temperature stability, is temperature not the reason why ceramic blades are used in this case?
It protects the blades from transient temp spikes on startup, which these old turbojets are prone to do, and it lengthens the service life of the blades.
@@AgentJayZ I am guessing only the blades are suceptible to those heat spikes due to their thin geometry? Or are the heat spikes only occuring locally at the blades and not the disk?
Interesting none the less😃
Heat enters the blades from their contact with combustion gases. Heat leaves the blades through their contact with the disk, which is not exposed to the combustion heat.
If we put a resistor on the input, and don't change the output... we run cooler, and lower any spikes on the input side.
Can u give a link to the pdf file for composition of alloys, superalloys being used to make military grade turbine blades.
Sorry, no.
Any chance that convex & concave sides of the blades may get reversed during assembly? Also please make a video if you come across clockwise and counter clockwise rotors in 2spool engine. Thanks a lot /Jay
+Jayaram Murthy You edited your comment because you got the names backwards. Ironic, isn't it?
Although in this engine the blades will fit either way, it's very obvious which way they are facing. Only complete incompetence and lack of effort put into inspection of one's work would allow a turbine or compressor rotor to be put together with a backwards facing blade.
I'm not saying it never happens, but I've never done it.
I will say that in the past, some people who have think little of me have indeed made this blunder themselves. What does that say about their level of ability? Ha!
+AgentJayZ well probably it is better to follow assembly process who works new then.
That is true for this rotor, but most engines do not use this type of blade lock.
AgentJayZ Murphy's law - "If an aircraft part(*) can be installed 2 ways and one of them is the wrong way, someone will do it." I am surprised that they're not keyed to make it impossible.
(*) Or a spacecraft part - which is why Stardust's return pod never opened its parachute. Someone put the gravity sensor in upside down....
WRT your comment about pistons being installed in engines upside down - it happens more often than you'd think.
@FrontSideBus yes, it was the nozzle we opened first...
The written values on the blades 270, 274, 280, etc. is there grams?
Yes. Many people complain that I don't use the moment weight, which takes into account the distance from the root base of the center of mass, but they can bite down hard, because my engines run as smooth as a dream. Typically with less than 20% of the max allowable vibration.
is there an wear coeffecient for the buckets as they spin through air? does a ceramic coating reduce it?
if so is the wear dependent on temperature and humidity ?
Just curious... How were the fir tree attachments machined?
Imagine forgetting to install just 1 pin lock for the blades, just 1 is enough to destroy the engine!, this is some super delicate stuff that I do not ever wanna mess with.
Hi AgentJayZ, i really love your channel !
i have a question that perplexes me for some time. some applications use this fir tree root with z-lock shrouds. i never understood how are they assembled. must they be assembled all together ?
Geezz this is awesome man....i like you re vids .....i like them a lot....very informative....keep up the good work!!!
It's very hard that TBC I spent many hours polishing them with diamond pads, what a few of you watching may not know is each one of those buckets (blades ) is weighed and that data is fed it a computer that works out where on the wheel they go in relation to each other for perfect balance hence the numbers
The computer gives a good starting point. The final balance is achieved by using the balance machine and making very small adjustments.
Sabre? You should try and get work on a MiG-15 or 17. Beautiful planes that i know very little about internally. Would love to see them on here.
What else should I do...?
Making those blades is a Herculean task. GE perfected it.. They denied us the core engine tech. Never mind! We still admire their hardwork, skill, and finesse.
Were the numbers written on the blades their weight? How much can they vary without causing a balance problem?
Yes. They vary by up to 5% or so. The weight variation allows us to balance the assembly by moving blades. I have made several videos about balancing. There's a search bar on my channel page.
@@AgentJayZ Thanks! That looks like a very interesting job, but one for someone very meticulous and careful. I had no idea that turbine blades as old as 1952 were still able to be reused.
The blades were made in 1952, out of an alloy consisting mostly of nickel.
If left outside in the sun of Death valley, or dropped into the ocean, these blades would look and function as new after a hundred thousand years in those environments. In a sealed container, at room temperature, they have a shelf life of at least one million years. Long after the steel can was not even dust, the blades would be new.
I didn't know that Packard built turbojets. Did they make the blades?
Does it matter if you accidentally put every SINGLE blade in backwards?
About as much as putting your car in reverse in a traffic jam and flooring it. Only it would cost more to fix everything.
The lock pin slot is positioned so that it would not be possible to lock a blade in place backwards.
Plus, part of being a turbine engine technician is to check each and every blade in your hand to make sure you have it oriented correctly.
A bit like pistons in a car engine. Mechanics don't put them in upside down, do they?
Since this is an old video, I may not get an answer. Anyway, I'm assuming you numbered the blades because you wanted to keep the balance of the whole assembly. If those blades were recoated, wouldn't that make the numbering unnecessary? I would assume you'd have to balance the whole thing again since the blade weights would be different -- or would they?
+Mark - The turbine was removed from the engine, then de-bladed. The blades were sent out for TBC coating. The turbine disk was carefully cleaned for at least a day.
When the blades returned, they were weighed, and the weight printed on them. The blades were sorted to provide a reasonably even distribution of their weights.
The turbine was placed on the balance machine. The blades were installed without locks. The assembly was balanced by moving blades around, and the positions of the blades was recorded 1-2-3 in the disk locations 1-2-3.
The blades were removed and placed in storage.
The engine was then reassembled in the vertical position to facilitate alignment of the turbine shaft with its bearings and the connection to the compressor.
The engine was then placed in the horizontal position, the blades reinstalled in their recorded position ( this video), and locked into place.
All this is necessary because the turbine can't be balanced while it is in the engine, and it's easier to install the turbine when the blades are not in it.
AgentJayZ Now that I understand the sequence, makes sense. Thanks for the explanation -- and for all the videos. I worked on round motors; never got to the turbines, so it's nice to see the work.
I would imagine there's alot of force trying to push those blades out to the back of the engine. Is that tiny pin the only thing that prevents that or am I missing something?
You are missing something.
It will be a subject of a future video.
AgentJayZ Thanks for the reply. The more I think about it though, it seems like the torque produced by the gas flowing past the blades would "lock" the blade in by friction from the fir tree slot. Maybe I'm wrong, look forward to the video.
So if yer flyin along on a good sunny day and all the fins fall off , then what ??
No fins here. Whaddya talking about.
Hey, is the turbine stage impulse or reaction? Also, do you know any reasons why they would use a single stage of turbine to drive 12 compressor blades, other than weight savings?
Thanks
Nate Baker Turbine blades are combination of impulse and reaction.As for the single stage of turbine driving 12 stages of compressor it's because of the high torque that gets developed on the turbine rotor blades from the high velocity and temperature gas coming out of the combustion chamber. These rotor blades are rotating at about 2000 ft/sec.
@@harixav IDK if I should be amazed at the tech from the 50s/60s or if I should be unimpressed with the tech we have now? XD
Are these blades the same geometrically? Their angles, shapes?
What do you mean? All blades of the same part number are the same shape. After that, no.
what does those numbers on the blades specify or mean..... do they have specific meaning or they are just for counting....
weight of blade... in... grams...
There are a lot looser in the slots than I thought I thought they wage in tighter before the Locking pin