Hot Section Rebuild

[@snaaail]

Those ceramic turbine nozzles look so clean and perfect

[@BlackWolf42-]

Fantastic video of you doing a step by step. I appreciate the time it took for you to make this video with time being devoted to shooting and working on your engine at the same time. Great stuff!

[@jakemj03]

Amazing, beautiful, exciting, precision, metal alloy parts; made by humans, before I was born. I'd love to just hold one! Not many people understand and/or appreciate how amazing this is...

[@ozontm]

My secret favorite channel on KZbin which isn't comedy. Awesome video once again.

[@EdayGone]

It was EXTREMELY satisfying watching you install the last nozzle! Great work.

[@SiblingCreature]

Thanks for making this video. It's always nice to get a glimpse of the actual work while it's in progress.

[@indoorherbivore]

Did someone steal your stairs? Heheh. Nice vid, this is what I look for on your channel.

[@darrenhersey9794]

That engine is beautiful! It looks great.

[@kraz904]

I loved your, "Holy shit" moment. All great techs have them per build...

[@rreiter]

Thanks for another great one, Jay! Really appreciate it.

[@RobertBardos]

rags or paper used to prevent accidentally losing a screw or fastener in the compressor requiring a dissasembly to recover said lost object :) yay! learned that in jet city!

[@rashidminhasbhatti9618]

Beautiful video forever

[@nsemergey]

Man, you are awesome. I watch you for years. Hello from Ukraine :)

[@noisytim]

Bonus question answer: because if you drop anything in there, you'll spend a ton of time taking the whole thing apart again.

[@quakermaas]

+Tim Engel What a nightmare it would be, possibly do damage as well, I think I would just go home and cry if that happened.

[@MrGuvEuroman]

Can you take us on tour of an installed one? We can see it standing, but would be nice to see them in their home and set up :)

[@AgentJayZ]

***** Check out my vid called Orenda 14 in the Sabre6 ...

[@MrLuvOldies]

Thank you. Very interesting.

[@Nighthawke70]

I know it's a bit late, but this might help in installing the inlet vanes, especially the last ones: Take a bit of steel (not spring steel), mill one end to fit the gap on the outer ring vane, then bend it in a 90 degree angle. Hook that onto the outer shield, while holding that out, fit the last vanes in. Adding a clamp to the tool would make it easier especially if you are working on the crazy thing by yourself. This ought to ease the pain of both installing and the risk of chipping the coatings.

[@AgentJayZ]

Nighthawke70 Once I figured out the correct procedure, no special tools were needed, and it was quite straightforward. Thanks for the concern, though!

[@clockman47]

Thanks Jay.

[@boomer9900]

I would like to see one of your nice diagrams on the difference between can, can-annular, annular, etc. flame housings. Have you seen any difference in wear patterns between the varieties during your rebuilding? I assume a perfect ring of fire would be optimal for the turbine's longevity. I enjoy every video you produce. Thanks.

[@AgentJayZ]

+boomer9900 Got a whole series on Combustor liners. Also several videos in the playlist called Your Questions Answered dealing with exactly the subject you've requested. There's a kind of index there.

[@boomer9900]

+AgentJayZ thanks, I'll have to back up and look at those vids again. Index, here i come.

[@damny0utoobe]

This shows exactly why these parts cost so much money, air cooled ceramic coated turbine blades.

[@phensriwood8081]

I called them NGV Nozzle Guide Vane working on JT8D

[@sandkman109]

I would really like to thank you for your time and effort spent making these videos. I've learned so much about gas turbine engines and their components from your channel. Currently a mechanical engineering student at Miami University (in ohio) who hopes to have a career in designing them. All questions I've ever had have been covered in your Question and Answers videos with the exception of one. What do you think could be the next big advancement in these engines? An introduction of air bearings in a industrial engine could potentially reduce wear and cost of ownership while making them less complex, more reliable, and even lighter. Have you had any experience with an air bearing and could you, if possible, share some real world experiences with them. Thanks for your time Jay and hope the question was worth the while! Corey Straker

[@grahamj9101]

+Corey Straker From my very limited experience, air bearings are extremely high precision devices and their surfaces have to have a very fine finish. When I was an apprentice in the 1960s at Bristol Siddeley Engines, Coventry, the company made air bearings for the nuclear industry and they were assembled in a clean room. There are those in the aircraft engine industry who envisage the use of active magnetic bearings, but having done some work on them, unless and until there is some major advance in electro-magnets, they will be heavier and have a much lower load capacity than rolling element bearings.

[@panteradime5150]

Is that O-ring seal placed between what I'm assuming is the compressor section and the combustion chamber just a standard grade nylon rubberized o-ring like you would find sealing an automobiles fuel pump to the fuel tank? If so I'm amazed, a little overkill for what I use them for they usually end up hanging from the shop ceiling.

[@AgentJayZ]

It's a silicone O-ring. The temp it will see is maybe 300F, so the material is more for its softness. The air pressure it will seal against is about 90 psi at maximum.

[@japparin]

I was thinking the rags were for the fuel nozzles, but of course, you don't want shit falling into the compressor blades :)

[@ladams00]

Hey Jay, The next time you guys do another J79 test run, would you be able to run it at night with the AB? I'd like to see the shock diamonds in the exhaust :-)

[@JDALSystems]

+ladams00 YA! I second that if its possible

[@MrBen527]

ladams00 Great vid!!!!!!!!!!!!!

[@AgentJayZ]

ladams00 No

[@coollasice4175]

ladams00 Heck, I'd like to see it tested when it's *snowing or raining* outside. That would be cool seeing the snow or rain swirling around. C'mon, Agent J make it snow.

[@AgentJayZ]

Cooll Asice We are still working on controlling the weather.

[@petestowne]

Hey, thanks for yet another informative video. I am curious whether the engines are secured when standing vertically? I would not want to tip one over..

[@AgentJayZ]

petestowne If you stand a barrel full of water on its end, it will never just fall over. Same idea, only larger and heavier.

[@petestowne]

+AgentJayZ yeah, that makes sense of course. Thanks!

[@gfxindy]

Great videos SuperAgentJayZ ! What is the material of the o-ring that you put between combustion chambers & the engine?

[@AgentJayZ]

Vasileios Koutsovoulos The O-rings are made of silicone. A standard part available through a hydraulic supply house.

[@gfxindy]

Thanks

[@EngDrewman]

The rags are there to prevent FOD. Speaking of which, it looks like that rubber mat you were unpacking the nozzles on was dirty; I would think FOD would be a concern there too with the tiny cooling passages. Why don't you cover it with paper, which is disposable and doesn't hold on to dirt the same way rubber does?

[@AgentJayZ]

KJ6EPL No tiny cooling passages. Plus, even If they were packed in sand, part of the skills of a fitter/technician/builder/mechanic is to ensure they are installed correctly, without damage or contamination.

[@Phoenix-ej2sh]

Another question. You seemed to mention that adding ceramic coating to the turbine nozzles/ blades is "hot rodding". When you make that modification (I'm assuming the modification in question wasn't factory spec), do you adjust the engine to produce more thrust, or is the purpose of ceramic coating simply to add certainty to the lifecycle of the parts in question and/or to extend their service interval?

[@AgentJayZ]

***** Either of those options is possible, and it is up to the owner to decide whether greater performance or longer life is the goal. For industrial engines, the increased service life at the rated power output is usually the reason for adding the thermal barrier coatings.

[@DScottDuncan]

Hi Jay, still catching-up on your latest (well, getting to the 'latest') videos. Learned something, as usual. How costly is the ceramic coating process? Would it benefit my J44 to have its nozzle & turbine blades coated? Maybe it is so costly that it is not practical but thought I would ask. I assume it allows higher temps &/or extends the life of the parts. Thanks for sharing & see you in the next one. DD

[@arthurlejawka6392]

Nice video. What are those thin lines going to the combustion chambers for? Temperature readings?

[@AgentJayZ]

Arthur Lejawka They are drain lines. After shutdown, if any fuel leaks out of the fuel nozzles, it drains out, so there is no fire hazard at the next start-up.

[@CKOD]

The second I saw you snap in the first nozzle on camera, I was like "well shit, that last one is going to be fun" Also, that clunk of it going in is pretty satisfying. Though probably not as much the second time around. :s

[@andrewward9601]

Hi Agent Jz... You mentioned Rolls Royce Avon engines, the later versions and the early versions, have you stripped and rebuilt them also?

[@markb3787]

wouldnt you have the engine tied off to the roof in case some klutz came along and knocked it over which would require a total rebuild ?

[@AgentJayZ]

It's pretty heavy. It would be about as easy to knock over a 55 gallon drum full of sand

[@markb3787]

Oh Ok, so its pretty stable I used to hang out with my Dad at the hangar, he was a aircraft mechanic he passed away last week :( I work nightshift and enjoy watching your videos, im no mechanic but find jet engines fascinating. Cheers From Aus

[@DiveTunes]

White rags--because they look and perform so much better than old shoes?

[@lwrii1912]

LWR II4 hours ago Hi "J", this is lwrii here, I was watching one of your earlier question videos and an issue of interest to me came up. Someone asked about air starting a jet engine in flight and you said it wasn't done and if a pilot told you about it you may address this issue, or something similar to that. I am not a pilot but I served 13 years in the USAF as an aircraft mechanic. I do know of a procedure that required the starting of an engine in flight. It was referred to as an FCF, functional check flight. A pilot of advanced qualification would take an aircraft that had major maintenance performed on it that required a checkout of ALL systems, this was not usually done under normal circumstances. This was done on the aircraft I crewed. The FCF pilot takes the aircraft up to a very high altitude and shuts off one engine and puts the aircraft into a dive and uses the air speed to spin up the engine and starts it. He then gains altitude and does it to the other engine. This is only done by a qualified pilot to ensure the engine could be started in case of a wartime emergency. The aircraft in particular was an EF-111A with TF30-P-109 engines. I would like to see if you think this meets your criteria for mentioning the procedure in a future question episode. Thank you for your work on these videos, you certainly put forth great effort and are a wealth of knowledge and entertainment. Well done sir. Show less

[@fastone942]

have you done a video of damage from a hot start to the Hot section and what happens to the blades yet ?

[@AgentJayZ]

I take a look inside a T-58 that was damaged from excessive heat, similar to a hot start, in a video called Bad news, good news with a T-58.

[@stanleycarter6275]

Jay I have a question what are the hp turbines made of because I know they have to be a metal that is resistant to heat and don't expand and hit the case

[@13megaprime]

Jay, i remember vaguely about 4 years ago i spoke to a student jet mechanic and he was telling me about afterburner. like i said, this was years ago, but i think he said something like there is a certian point in time that can be calculated that you can put your hand in the afterburner disc without anything happening to you, but any other time you can hold a frying pan up into that exhaust and it would melt. was he just full of crap? is there such a phenomenon? thanks and keep up the good video content

[@AgentJayZ]

13megaprime What the heck is an afterburner disc? That point in time would be when the engine is not running.

[@ratride1]

What type of commuter bicycle did you buy? I was a bike mechanic for 17 years. Nothing like you do but I enjoyed fixing bikes and working with my hands. Thanks for the vids.

[@AgentJayZ]

ratride1 I am fairly sure it's a 2007 or 2008 model of the Marin Point Reyes. I got it from the used rack out front of Reds Shreds bike shop in Williams Lake, BC. They are really nice there, and you should visit them when you go there to ride the hundreds of miles of trails right around this town in the foothills of the rocky mountains.

[@arthurlueck5709]

I'm assuming you send the turbine blades out for ceramic coating. After coating, do they test for blocked cooling passages at the coating facility, or do you need to inspect them when you get them back in the shop?

[@arthurlueck5709]

I'm talking about the LM2500 first stage blades...

[@AgentJayZ]

Arthur Lueck Every part that goes into an engine is inspected.

[@elanjacobs1]

Are the rags in there to avoid hearing the wonderful noises from "Dropped into a turbine engine"? Also, what happened to the Iroquois rebuild?

[@AgentJayZ]

Elan Jacobs Yes. The Iroquois made a quest appearance at the FSJ air show. People seemed interested.

[@waterlover30]

Hi Jay. Another great video. Really appreciate your efforts! Just read that there was a 4.6 earthquake in Jet City. Did you notice it or was lost in the background of your normal earth shaking activities?

[@AgentJayZ]

waterlover30 I found out about it from the news. Nobody I know felt anything.

[@Hein223]

Hi there AgentJayZ Is there a difference between engines which are able to supercruise and other turbojet engines? To my knowledge the exhaust gasses need to exit the nozzle faster than the velocity of the aircraft to produce thrust. That means the aircraft's nozzle must be in the converging diverging "afterburner" position for the gasses to exit at Mach > 1, and generate thrust. Please shed some light on this topic! Frequent viewer from South Africa. supercruise : (aircraft velocity > Mach 1, without afterburner)

[@grahamj9101]

+Hein Joubert (Hein-ZA) I'll take the liberty of answering this, having worked on one of the few engines, the Olympus 593 in Concorde, that was capable of supercruise. This term is commonly used in industry to denote supersonic cruise without reheat/afterburner. You are quite correct in stating that the exhaust velocity of a jet engine must always exceed the forward speed of the aircraft to produce thrust. If the jet velocity equalled the forward speed, then propulsive efficiency would be 100percent, but there would be no thrust! The 593 had a convergent-divergent nozzle and a reheat/afterburner system, but this was used only during transonic acceleration. There was a project design for an uprated 593 with an enlarged LP compressor that would not have needed reheat, but it would still have had a con-di nozzle. There was nothing special about the 593 as a turbojet, other than its size and the fact that it had to be designed to cope with an intake air temperature of 127degC in supercruise at 58,000ft. Perhaps you're tempted to ask why the 593, being a turbojet, didn't become an industrial gas generator, like its predecessor, the Olympus 200? The answer is, it very nearly did, but the project was cancelled with at least one development engine running and design well under way.

[@Hein223]

+grahamj9101 Thanks grahamj9101, so you basically just need a very big engine capable of supplying the mass flow rate and turbine outlet pressure as I understand (since the turbine outlet temperature is fixed and will drop as the gasses accelerate through the nozzle). Would supersonic flow out of a J79 or similar turbojet without an afterburner be possible, by adding a smaller converging diverging nozzle for interest sake?

[@grahamj9101]

+Hein Joubert (Hein-ZA) You've posed a very good question! You don't necessarily need a "very big engine", just a big enough engine, in relation to the aircraft - and you are on the right lines thinking in terms of mass flow. I'm no performance engineer, just a retired engine designer, so I'm doing some revision in answering. The pressure ratio of the Olympus 593 at 15.5:1 wasn't much higher than that of the J79 at 13:1 and supersonic flow from a 'dry' J79 with a suitably sized con-di nozzle should, therefore, be theoretically possible. However, we need to understand what 'supersonic flow' means in this context. What it doesn't mean is a flow velocity of over 768mph or 1,126 ft/sec, which is the speed of sound in air at 20degC. The speed of sound in the hot exhaust gas is directly proportional to the square root of its absolute temperature in degK (or degR for US readers): so let's do some rough and ready maths (sorry, but I am a Brit!). For an EGT of, say, 600degC, I make the local speed of sound in the exhaust gas as over 1,325mph. If you add on the temperature rise with reheat/afterburning, then the local speed of sound will be considerably higher. That is why reheated engines such as the Avons in the RAF's Lightnings and the Speys in the UK's Phantoms, both of which had variable (but not con-di) nozzles that could not produce a supersonic flow, could nevertheless power their respective aircraft to well over 1,000mph.

[@Hein223]

Hahaha, Yesssss, it's wonderful when something makes such clear scene. Its funny because i know the theory but did not piece everything together. I wrote a thermo-fluid dynamics exam today, we are currently doing converging diverging nozzles, normal and oblique shock waves, stagnation conditions, reheat and fanno flows ect. Very interesting stuff.

[@grahamj9101]

+Hein Joubert (Hein-ZA) I do not wish or mean to be patronising, but I do not necessarily know the technical background and knowledge of individual subscribers. Consequently, I try to give answers that can be more widely understood.

[@gregeconomeier1476]

I see that some type a marker is used to write "balance" weights on ceramic turbine and compressor blades in this video and in others. It seems this would cause differential heating on the blade surface similar to skin oil from fingerprints. Is this correct?

[@AgentJayZ]

No. There is a problem with using a carbon or graphite based marker on steel blades, as the heating could cause diffusion hardening and an increase in the likelihood of a crack forming, but steel blades are rare, and we don't use such marking devices...

[@gregeconomeier1476]

BTW, great videos. I love the educational component.

[@gundamm5]

In normal operation without misshap or accident (with good maintinece) what parts in the engine usally gets worn down durning the lifespan of a jetengine. I would guess berrings gasket and seels and blades or am I wrong ?

[@AgentJayZ]

gundamm5 The parts under the most stress, and the ones most frequently replaced, are the combustor liners and the turbine nozzles, also called the NGVs. It should be remembered that each engine design has its own pattern of wear, and these generalities apply to the GE LM1500.

[@G3rain1]

How much of a difference in performance does ceramic coating the turbine blades actually make?

[@MrShobar]

Jay, are the igniters in all of the combustors?

[@AgentJayZ]

MrShobar No.

[@superdau]

Are the turbine (or compressor) blades completely fixed axially after the lock strips have been installed? Or is it like in the radial/tangential direction, where the blades can wiggle a little in the dove tail/fir tree root and only lock when the engine is spun up?

[@AgentJayZ]

superdau Your second sentence describes it well.

[@jont4504]

Thanks for the video, question, I noticed this engine had 2 turbine blade cooling air pipes but there were extra holes in the casing with blanking plates attached. Are these blanked holes for additional cooling feeds or another purpose?

[@Phoenix-ej2sh]

Can you describe the differences between the Orenda 10 and 14?

[@AgentJayZ]

***** The ten was for multi-engined aircraft, like the CF-100, and the fourteen was for the single engine Sabre series of Canadian built F-86 air frames. For single engine use, there are more backup systems controlling the fuel. Also the 14 was more powerful by a thousand pounds of thrust or so, It has a two stage turbine, while the 10 has a single stage, like the J47. Structurally they appear so similar that one is tempted to use the 14 manual for reference, yet they are different enough to make that a bad idea...

[@Phoenix-ej2sh]

AgentJayZ Thank you for such a deeply insightful and informative answer! I wish I had caught the 2 turbine thing. I should have seen that.

[@elijahgutierrez3159]

nuoooice vidueeeo, muooatey!

[@Alim92usaman]

How are you planning to move the engine later on?

[@AgentJayZ]

With two cranes to horizontal, then on stands on a trailer, or into an engine shipping container for shipping. Here's what they look like kzbin.info/www/bejne/m4nWnJqZqpx8Z6M

[@Ducksauce33]

does the ceramic ever crack from the heat causing the metal to expand, and contract. Or are they so strong that can never really happen. BTW is the answer about the rags so you don't drop anything in there?

[@skyhop]

***** To the best of my knowledge it prevents the metal it is coated with from getting hot.

[@AgentJayZ]

***** From our experience with ceramic coated industrial turbine blades, it never cracks or wears off. It makes the blades immortal.

[@AgentJayZ]

***** You were the first to answer the bonus question correctly!

[@Ducksauce33]

Yeah I remember you saying something along the lines of the worst thing you can hear is the song a dropped bolt plays as it tings off all the turbine blades.:)

[@grahamj9101]

+Ducksauce It depends on how 'hard' a ride the coating gets. In base load industrial operation, as AgentJayZ suggests, it should last almost for ever. However, put it in an engine that gets a lot of thermal cycling, it can become eroded and sometimes spall off in patches. I know it as thermal barrier coating (TBC): it is a barrier and not a total insulation, so it cannot stop the coated parts getting hot. In the case of the LM2500 HPT1 blade, it will reduce the metal temperature significantly, by acting as an external insulation layer, with the blade being cooled internally, plus some external film cooling from the rows of small holes either side of the blade leading edge. The beneficial effect on an uncooled aerofoil will be more of a second order. It will reduce the thermal shock and it should reduce the peak metal temperature, to give a more uniform temperature gradient both chordwise and spanwise. And yes, there could even be a small reduction in the average metal temperature, with the TBC reducing the heat flux into the aerofoil and allowing the blade root or vane platform to act as a heat sink.

[@mikezaq1]

Why where you wearing gloves when unpacking the new blades? I know working on engines can get dirty sometimes but that looked to be clean work. Is there a reason that you need them such as oils on your hands or was it just personal preference?

[@AgentJayZ]

Michael Carroll I had 'em on, and never thought to take them off. No real reason.

[@jfan4reva]

Glad you work for a boss/in a shop/in an industry where having to spend two hours re-doing something is OK. In some industries management doesn't understand the pitfalls of working with very complex things....

[@AgentJayZ]

jfan4reva I work for me, I run the shop. It would be great but my boss can be a jerk!

[@jfan4reva]

LOL! I hope he isn't so big a jerk that he won't take you out for a beer after a long day ;)

[@spowyou]

what happened whit the pit?? that you use lathers ?

[@AgentJayZ]

spowyou No pit in the new shop. Ladders and cranes it is!

[@louigi6001]

To prevent dust and stuff from falling in ?

[@AgentJayZ]

louigi600 It's more about the stuff than the dust. Much like everything in life.

[@seq165432]

You probably know that P&W PT-6 engines "fly backwards". Any others?

[@selwinlisand3125]

Help me a lot with my design.

[@toddp442]

My Guess is the rags are there to prevent a repeat of a long past, hard learned lesson.

[@MrBranboom]

No turbine rain-sticks!

[@Braeden123698745]

I see you struggling with things sometimes, like putting in that nozzle and when you had to put lock wire down in pit of an engine a while back. Makes you wonder how much different complex objects like engines would be if the designers had to also build them XD

[@grahamj9101]

+Braeden Hamson Many designers (like me) did apprenticeships or traineeships that included placements in engine assembly shops and we did think about the engine fitters, as we would be called into the build shop if/when there were problems. These days, there are more formal processes, such as 'design for manufacture' and 'design for assembly', which are intended to do what they say. Lockwire or safety wire has been a 'no, no' on new designs for many years, thank goodness: the sharp ends aren't good for the fingers.

[@lusher00]

Holly ceramic coated turbine nozzle Batman

[@code123ns]

Yey! A non-Q video! :)

[@karemmosa2300]

ممتع

[@karemmosa2300]

جيد

[@collingtech1]

hot rod turbine engine

[@tracyrreed]

I can just imagine the wailing and gnashing of teeth that must have occurred when you realized you had missed a step and had to take all of those nozzles back out and put them in again. I hope no women, children, or others of delicate sensibilities were within earshot.

[@grahamj9101]

+Tracy Reed It happens - I've done such things a time or two in the days when I could work on my car, for instance. And, if I recall correctly, AgentJayZ has told us that he doesn't have repair and overhaul manuals for this engine, which would give him a step-by-step procedure.

[@jasonmskidmore]

Not specifically related to this video - but saw this fascinating fire-fighting tank that uses jet engines to help put out fires & thought you'd enjoy: kzbin.info/www/bejne/a3a8g4OAnL-XppY

[@mtnbiker310]

Not sure where to post this, so this might be as good a place as any. Check out this article that is on the GE Reports website. I guess they have no editors or AgentJayZs there to correct their writers. Prepare yourself; it's really bad. www.gereports.com/post/126449265200/the-first-american-jet-engine-was-born-inside-a

[@AgentJayZ]

mtnbiker310 It's about what one can expect from a PR media department. Really great old photographs, some of them mislabeled, and a great story featuring a few facts compounded with a lot of errors, and some plain old spelling mistakes. Great for PR, but misleading and useless for anyone interested in what really went on.

[@grahamj9101]

+mtnbiker310 At least it gives some credit to Frank Whittle, who really was s**t on by the powers-that-be in the UK at the end of the War (WWII, that is).

[@Phoenix-ej2sh]

Answer to the bonus question - so this won't happen: kzbin.info/www/bejne/aqiugYeNjallkJI

[@SirDeanosity]

If at first you succeed, read the directions.

[@AgentJayZ]

SirDeanosity Did you miss the part where I explained there are no instructions? There are no instructions.... Over.

[@AgentJayZ]

AgentJayZ And maybe... proof-read your condescending comment before hitting that blue button...

[@heavymental70]

SirDeanosity If at first you succeed, move on to the next step.