I was a gas turbine systems tech in the Navy. The Oliver Hazard Perry (FFG-7) class frigate I was on used two LM2500s for main propulsion. I was lucky enough to work in close proximity to these beasts but we never got too deep inside them. If it came to that, up and out and back to GE she went, and a replacement was installed. We had that happen once. I was on watch when they called down that there was some kind of high temp alarm going off, I think it was a bearing, don't remember exactly. Anyway, I did a visual and there was white smoke pouring from the sump vent (I wanna say "C" sump) so we shut it down, and when we got back to port, out she went. Other than that, they were just remarkable. I remember during our sea trials we did like a 12 hour full speed run. If you turned out the lights in the enclosures, you could see the area around the combustor was glowing cherry red. Love these machines. Thanks for your videos.
To your knowledge, do any of the USN ships that are use gas turbines carry spare engines? I know from a TV show I saw a few years back that some Royal Navy ships carry a spare engine, and in this case they did and engine change whilst the ship was under way! From memory, it was HMS Illustrious from before she was converted from being a light aircraft carrier to a helicopter carrier
daniel2001 Having been a member of the Marine Olympus design team back in the 60s, my understanding was that the three Royal Navy Invincible class aircraft carriers each had a spare Olympus gas generator stored in the engine room area. I was given to understand that a gas generator change was carried out in the south Atlantic1982 during the Falklands conflict.
I have to say, that shot of you guys popping the stator housing away from the rotor was quite awesome. That's some real "things that fit perfectly into other things" porn right there.
Sorry if you've answered this question, but I haven't seen it anywhere. I even looked through all the Q&A topics. When you send the turbine blades or turbine stator vanes out to get ceramic coated, how do they keep the ports clean (on blades w/ holes)? My best guess: dip each blade, blow air through the pathways while coating is still soft, then fire to harden the coating. I suppose the labor in making sure the holes are clear is the highest cost in coating.
Why do they use a "torque cone" on the turbine discs instead of just bolting or keying them to a straight externally splined shaft? (What is the purpose of the cone that a regular shaft couldn't accomplish?) Shown at 4:30. Also do the H.P.T. air cooled blades separate? They're paired (seem to be anyway) and I could see what I thought was a seam but never saw any separated to aid in cleaning.
Chase Murry A solid shaft is much heavier, and still would not be as stiff torsionally. This does not really matter for a ground-based powerplant, but these engines were derived from an aircraft design. It worked well in the air, and may be ovekill for the ground, but it costs a lot of research and money to redesign an engine.
Chase Murry 1: Instead of a bolted shaft (no idea what your image of it looking like is) a solid piece cone shaft (like is there) with a smooth shape reduces the overall stress due to torque *A LOT*. 2: Using bolts for torque transfer is a *BAD* idea. Bolts don't do well with shearing stress. It causes them to rip or shear out their screw thread (dictionary translated word). Shearing stress on bolts is worse than compression or tension stress (as that is what bolts are designed to take). If you want to transfer stress through a component a couple things are important: -smooth shape. Any edges are areas with increased stress. surface roughness increases internal stresses too. -no force flow interruptions (lack of better translation). drilling holes, cut outs, diameter changes, sharp edges and that stuff are stress hot spots. Parts are going to fail there. And on a 7200 rpm rotating 1 ton shaft a component faliure is very catastrophic.
Achim Hanischdörfer It's not solid, but actually made of quite thin material. It's purpose is to be strong and light. If it was solid it would weigh a literal half ton.
Chase Murry The manner in which a turbine disc is attached to the shaft that drives the compressor is largely down to the 'design style' of the manufacturer and the engine 'architecture' (ie, the bearing arrangement, etc), which can change over the years as materials and technology develop - and another Chief Designer has his way. There is no one 'correct' way to do it. GE have used the 'drive cone' arrangement seen in the CF6 and LM2500. I think that the volume within the cone may also be providing a 'plenum' for the HPT1 blade cooling air feed. R-R tried this drive cone arrangement in one mark of the RB211-524, but rapidly reverted to discs with integral drive arms and bolted flanges. Where bolted flanges are used, it should be noted that the torque is not being carried by the bolts in shear, but through the friction between the clamped flanges. In addition, care has to be taken with the inevitable stress concentrations around the bolt holes, particularly with bolt holes through a turbine disc, which is one of the most highly stressed components in the engine. For comparison, P&W have used drive arm extensions on their discs, which are splined onto the compressor drive shaft and clamped in place with a big ring nut.. What you may not realise is that the inner portion of the disc is effectively retaining the outer portion. For each disc, at its design rotational speed, there is a certain radius, which I knew as the 'free ring radius': the material outside this radius is being held together by the material below it. If the disc were to be bored out to this radius and spun up, then the remaining ring would just fly apart. Going back to your original question, the bore of a disc, whether compressor or turbine, is the last place to incorporate a discontinuity, such as a spline or a keyway. For minimum weight, the bore hoop stress is designed to be as high as practicable for an acceptable cyclic life. Stress concentrations in the bore, even small scratches, are potentially disastrous as a potential source of crack initiation and propagation. With some discs that I was involved with during my career, I had to 'invent' the equivalent of a calibrated fingernail to pick up unacceptable scratches. If a fingernail would 'catch', then the scratch was unacceptable and had to be very carefully polished out, using a prescribed and approved process.
Why do they have two so different bleed stages in the compressor? (around 1:40) Or was it that they needed the much larger stator vanes (compared to the preceding/following blades) at that stage? But why would that be?
When looking at the front of the LM1500 at around the 1:00 mark, there is a little coil visible at around the 4 o'clock position that looks to my untrained eye like a high tension spring. What is the purpose of that and why does it protrude into the air path?
Excellent video! Question for you! What is involved with paperwork for each engine you work on!? Are you responsible for completing the logs after completing inspection and overhaul!? Thanks for the awesome videos! Dan DeZinna
Hay Jay, what does the cases of the 2500 weigh? How much heavier are they over the 1500? They seem a lot beefier the way you handling them. Cool can't wait for more.
AgentJayZ A bit lighter? how did they manage that? mostly the same materials being nickel alloys and titanium right? Really impressive to hake something that much larger and more powerful and yet even lighter.
That dust is crazy, does it 'shellac' on the hot blades at all? Is there a way for the user to inspect them without opening the case? (edit: i think you answered this with the boroscope vid, missed that one) Thanks for the vid!
A little off topic, but how many man hours would you say go into a rebuild? And does an LM2500 take longer than a LM1500 due it's larger size? Also, does one single person work on an engine? Or does each person in the shop have a specialty and just work on certain parts? P.S. Long time fan. Keep up the great work!
08ttimlin It usually takes a couple of months by a team of 3 or 4 people. It also depends a lot on how much repair work is needed. We see a wide range of "received condition" in the industrial engines.
I was wondering myself if you did ultrasonic cleaning. I almost got myself a nice ultrasonic cleaning unit, before the guy who had it destroyed the power supply.
+AgentJayZ that's a Fixed Lens right? Shame. I was going to suggest some manual focus macro lenses to make filming up close easier, but this camera's pretty good as is!
***** I love SLR's. In the film days, I had a vintage Pentax.Nowadays, I would like one, but I honestly don't need one. Also, all but my "camera one" units need to be good, but not so expensive that I'll cry if they go sailing or eat dirt.
AgentJayZ Oh man. I love my Canon AE. Feels like its gonna be a great year for some Kodak Ektar. But yea. If you ever look into getting a new "main" camera, look to the Panasonic GH3 or GH4. The GH3 is one of the best amature video enabled "mirrorless" camera's you can get. The GH4 shoots full 4K video. Its pretty amazing, but a bit pricy. Both support ad-on mics though, which is something you may be interested in.
i work in a musical instrument retail store and when i saw that clogged cooling air hole my first thought would have been to try and clear it with the end of a guitar string. our non-wound, solid steel strings range from .008" to .022" in .001" increments so it seems like it would be easy to find an appropriate size to do the work needed. Not sure how stiff they would have to be though, that clog looked pretty stubborn.
almfreak Excellent idea. I happen to be a newb with a Stratocaster, so I will try this. The blockage appears to be metal, and is proving to be a bit difficult.
Alright, I think I have a good question, I know in aircraft there are no filters on the intake of these engines, but they also spend most of their time running at an altitude where there's not much dirt in the air. But in industrial use is the air ever filtered before it gets to the engine? Does dust damage the engine much, or would filtering the air just add more equipment and cost with no real benefit to engine life?
I'm guessing that anyone who's been to school already knows this, but after watching the disassembly, I just have to ask. How many fasteners are there holding the cases together, and how long does it take to remove them for disassembly, and reinstall them when reassembling? It looks like they've put the maximum number in the space available. BTW thanks for all the videos!
jfan4reva It took a week to get to the point where we could split the cases of the compressor. There are as many bolts along the flanges as GE could fit. A more even clamping of a flat joint that holds in about 275psi, and many small bolts can hold more load than few large ones.
In an earlier vid (Q55 I think. I watched several in a row to get caught up so I'm not sure. Sorry) you mentioned that the Iriquois was Half Complete. Does that mean it has been worked on or was that just a comment about how many parts it has to this point?
Why didn't you use a small handheld-drill at once, as it remained blocked after an ultrasonic washing with a bit just similar to the target hole, and forcely drill it over? Is that so critical to keep the hole intact?
Eltardo Wut and another question: do you deal with APU's? It would be very interesting to see one of that small engines from inside, if you have one in the near)
Sorry about that, yes I noticed after watching a second time! How many air bleeds are there? I mean probably one at high pressure for the HP turbine NGVs, and then is there another one at lower pressure for other purposes? Thank you for your answer!
Looks tedious. Baked clay; actually ceramic plugging the hole is a tough one. If you push the foreign material into the blade, can you get it out of the central cavity/passage? I got the LM1500 1st stage turbine blade (split) out of my curio cabinet to look at those holes. They are tiny! Hope you get it cleared. Thanks for sharing. DD
Why is the Lm2500 in the shop ? Any specific repair or General overhaul ? How many hours does it have ? I hope These are no secret Informations--- I don´t even ask what it is used for :)
Would it be possible to free the Blade holes from dirt my using sink-eroding? I assume it won't, because the dirt needs to be at least a little bit electrical conductiv. But I am curious if it would nevertheless work. In an eroding process you don't have the risk to break a drill inside your workpiece
Outstanding video! This is so cool. So dust... When used for industrial purposes, don't these have air filters on the inlets. I know massive HVAC systems pull air from a large chamber with walls of filters, sometimes two stages depending on the air quality required, or is the amount of air these units require too much to make it practical to filter...
William Garrett Yes, as metioned before, gigantic filters. But notice how fine the dust is. It can squeak through the filtersI think this engine ran a long time before being shut down.
Very understandable how dust can cause problems with all the intricate air passages on the HPT blades. Dust and heat, not a good combination for any system.For some reason this video has made if very clear to me how the compressor truly works. The variable stages actuating each vain is a beautiful piece of mechanics. I could also see the seal material quite clearly on the case and the rotor. It is interesting to see substantial wear marks at the case "seam". Will this seal material be replaced? Considering the tight clearance, this has got to be tricky. Thanks again Jay, I can't wait to see more.
Interesting you call it extraction. It's more like complete engine disassembly, to the point where you remove the HPT. The step by step instructions are in the overhaul manual. You will need the special tooling. It's a big job. The split nut will take up to 8,000 ft-lbs of torque to break free. It's reverse thread.
0.3g of dust multiplied by how many air cooled blades (three thousand blades? 900 grams of dust?) must add up to a lot of reduced cooling and reduced performance. Are the stater blades air cooled, were any of them blocked with grime? Or are the stater blades less prone to buildup of grime.
With all the high precision, complicated, critical, important stuff you've shown us in these jet engines, how is it possible that they are so reliable? Just saw a video of a British plane that threw a piece of combustor can on takeoff right thru the wing which then gushed out fuel right on to a burning engine. Pilot unfortunately did not figure out what happened fast enough and stopped on runway with wind blowing flames under the fuselage and about half the passengers died cause they couldn't get out in less than 90 sec. cause of the panic. Investigation revealed that the combustor had been repaired by welding up several cracks but one of them was a bit long and maybe they should have replaced it. Just hard to know when some little thing like dust in a tiny hole is going to cause a bad day.
Well it is dust building up over time, remember that these engines blow air so a lot of dust would be blown away, but over time more will build up because they are air engines not dust engines
AgentJayZ - @ 2:40 Grazia Mille! I appreciate seeing this. I presume that joining the case and rotor assembly is a much trickier process. Future video?....pretty please?
I have a large range of printed circuit board drills the range in size to very small I am not sure how small exactly your blade holds are but it might be worth a visit to your local electronic parts store. I have not idea what is available in Canada. I think careful use of such a drill only using careful hand pressure might shift the dirt although I am not sure how soft that metal is and if the drill might present a risk of enlarging or otherwise damaging the blade. Message me if you want to know the details of the drills I have.
Systemrat2008 We're going to try this and the dental tools. The main problem I have discovered here is that the debris is very hard. It may be a bit of rock, which is going to make things interesting.
AgentJayZ Jay,i was about to suggest the same... Ask for dental canal files (pics URL below so you know wat i mean), they're cheap, resistant in it's axial direction (pull/push movement), and thou i never breaked one cleaning my airbrush when it's heavely clogged, (Once i was cleaning it wit a toothpick, it broke inside, i drilled into the toothpick and it screw there, allowing me to pull it back) they bend very easely, to follow the teeth root without damaging it's walls. Good thing is that you don't need to forcely push the clogging by force, just gently turning it with the tip of your fingers, it will drill the dust out, pulling it OUTSIDE, avoiding the dirt falling into the blade. You can find in many sizes, my airbrush is 0.15mm in diameter, my smallest file goes straigh trhu it...www.odontologiaintegradars.com.br/blog/uploads/endodo.jpg www.noticiasdematogrosso.com.br/fotos-noticias/imagem-dente-tratamento-de-canal.png Regards!
Systemrat2008 I hope you don't mean PCB drills made out of tungsten carbide, because using them there would be quite silly. You don't want something that drills the hole bigger, just remove the dirt. But even more importantly tungsten carbide drills are so brittle that without proper mounting of the blade and the tool (which is almost impossible here) they will immediately break. The last thing you want is something almost as hard as diamond stuck in that hole.
Your tear-down and shop work videos are my favorite. It's fascinating to see the guts of these machines. Thanks for sharing!
This is why i love youtube, and people like you who take time off your job to educate people like us. Much appreciated!!
"...the real answer is: Very carefully."
I love this channel.
Thanks.
Hi Jay, great video, please thank your colleagues for allowing it. It's was so cool to see you at work.
Kind Regards to your Boss.
Its nice to see the shop working in that cut when you opened the compressor case, as in the tests you are mainly floating around
I was a gas turbine systems tech in the Navy. The Oliver Hazard Perry (FFG-7) class frigate I was on used two LM2500s for main propulsion. I was lucky enough to work in close proximity to these beasts but we never got too deep inside them. If it came to that, up and out and back to GE she went, and a replacement was installed. We had that happen once. I was on watch when they called down that there was some kind of high temp alarm going off, I think it was a bearing, don't remember exactly. Anyway, I did a visual and there was white smoke pouring from the sump vent (I wanna say "C" sump) so we shut it down, and when we got back to port, out she went. Other than that, they were just remarkable. I remember during our sea trials we did like a 12 hour full speed run. If you turned out the lights in the enclosures, you could see the area around the combustor was glowing cherry red. Love these machines. Thanks for your videos.
To your knowledge, do any of the USN ships that are use gas turbines carry spare engines? I know from a TV show I saw a few years back that some Royal Navy ships carry a spare engine, and in this case they did and engine change whilst the ship was under way! From memory, it was HMS Illustrious from before she was converted from being a light aircraft carrier to a helicopter carrier
daniel2001 I got out in 1990, and they didn't then.
daniel2001 Having been a member of the Marine Olympus design team back in the 60s, my understanding was that the three Royal Navy Invincible class aircraft carriers each had a spare Olympus gas generator stored in the engine room area. I was given to understand that a gas generator change was carried out in the south Atlantic1982 during the Falklands conflict.
I have to say, that shot of you guys popping the stator housing away from the rotor was quite awesome. That's some real "things that fit perfectly into other things" porn right there.
im Addicted to dis guy's vids!! Thumbs UP !!!
Nice footage of splitting the case, Ive always wonder how that was done.
great to see inside the 2500,i think the compresser whent in to the ge 90.
Sorry if you've answered this question, but I haven't seen it anywhere. I even looked through all the Q&A topics.
When you send the turbine blades or turbine stator vanes out to get ceramic coated, how do they keep the ports clean (on blades w/ holes)?
My best guess: dip each blade, blow air through the pathways while coating is still soft, then fire to harden the coating. I suppose the labor in making sure the holes are clear is the highest cost in coating.
+cheeto4493 It's not a process that we do, and I have not witnessed it. so I can't answer your question.
Why do they use a "torque cone" on the turbine discs instead of just bolting or keying them to a straight externally splined shaft? (What is the purpose of the cone that a regular shaft couldn't accomplish?) Shown at 4:30. Also do the H.P.T. air cooled blades separate? They're paired (seem to be anyway) and I could see what I thought was a seam but never saw any separated to aid in cleaning.
Chase Murry A solid shaft is much heavier, and still would not be as stiff torsionally. This does not really matter for a ground-based powerplant, but these engines were derived from an aircraft design. It worked well in the air, and may be ovekill for the ground, but it costs a lot of research and money to redesign an engine.
Chase Murry 1: Instead of a bolted shaft (no idea what your image of it looking like is) a solid piece cone shaft (like is there) with a smooth shape reduces the overall stress due to torque *A LOT*.
2: Using bolts for torque transfer is a *BAD* idea. Bolts don't do well with shearing stress. It causes them to rip or shear out their screw thread (dictionary translated word). Shearing stress on bolts is worse than compression or tension stress (as that is what bolts are designed to take).
If you want to transfer stress through a component a couple things are important:
-smooth shape. Any edges are areas with increased stress. surface roughness increases internal stresses too.
-no force flow interruptions (lack of better translation). drilling holes, cut outs, diameter changes, sharp edges and that stuff are stress hot spots. Parts are going to fail there. And on a 7200 rpm rotating 1 ton shaft a component faliure is very catastrophic.
Achim Hanischdörfer It's not solid, but actually made of quite thin material. It's purpose is to be strong and light. If it was solid it would weigh a literal half ton.
AgentJayZ
It's hollow shaft, correct?. Oops. Same design rules still apply. Hollow shafts are good for torque transfer.
Chase Murry The manner in which a turbine disc is attached to the shaft that drives the compressor is largely down to the 'design style' of the manufacturer and the engine 'architecture' (ie, the bearing arrangement, etc), which can change over the years as materials and technology develop - and another Chief Designer has his way. There is no one 'correct' way to do it. GE have used the 'drive cone' arrangement seen in the CF6 and LM2500. I think that the volume within the cone may also be providing a 'plenum' for the HPT1 blade cooling air feed. R-R tried this drive cone arrangement in one mark of the RB211-524, but rapidly reverted to discs with integral drive arms and bolted flanges. Where bolted flanges are used, it should be noted that the torque is not being carried by the bolts in shear, but through the friction between the clamped flanges.
In addition, care has to be taken with the inevitable stress concentrations around the bolt holes, particularly with bolt holes through a turbine disc, which is one of the most highly stressed components in the engine. For comparison, P&W have used drive arm extensions on their discs, which are splined onto the compressor drive shaft and clamped in place with a big ring nut..
What you may not realise is that the inner portion of the disc is effectively retaining the outer portion. For each disc, at its design rotational speed, there is a certain radius, which I knew as the 'free ring radius': the material outside this radius is being held together by the material below it. If the disc were to be bored out to this radius and spun up, then the remaining ring would just fly apart.
Going back to your original question, the bore of a disc, whether compressor or turbine, is the last place to incorporate a discontinuity, such as a spline or a keyway. For minimum weight, the bore hoop stress is designed to be as high as practicable for an acceptable cyclic life. Stress concentrations in the bore, even small scratches, are potentially disastrous as a potential source of crack initiation and propagation.
With some discs that I was involved with during my career, I had to 'invent' the equivalent of a calibrated fingernail to pick up unacceptable scratches. If a fingernail would 'catch', then the scratch was unacceptable and had to be very carefully polished out, using a prescribed and approved process.
Hmmm. If that dust was sand, and when it was initially blocked it created a hot spot... I wonder if the thing in the hole is now actually glass. :)
Why do they have two so different bleed stages in the compressor? (around 1:40)
Or was it that they needed the much larger stator vanes (compared to the preceding/following blades) at that stage? But why would that be?
Great videos thank you!
When looking at the front of the LM1500 at around the 1:00 mark, there is a little coil visible at around the 4 o'clock position that looks to my untrained eye like a high tension spring. What is the purpose of that and why does it protrude into the air path?
SiblingCreature That's the CIT sensor. Every engine has one. It measures the temperature of the air at the compressor inlet.
Excellent video! Question for you! What is involved with paperwork for each engine you work on!? Are you responsible for completing the logs after completing inspection and overhaul!? Thanks for the awesome videos!
Dan DeZinna
Hay Jay, what does the cases of the 2500 weigh? How much heavier are they over the 1500? They seem a lot beefier the way you handling them. Cool can't wait for more.
hommie789 The LM2500 compressor cases are about the same, maybe a bit lighter than the LM1500s.
AgentJayZ A bit lighter? how did they manage that? mostly the same materials being nickel alloys and titanium right? Really impressive to hake something that much larger and more powerful and yet even lighter.
That dust is crazy, does it 'shellac' on the hot blades at all? Is there a way for the user to inspect them without opening the case? (edit: i think you answered this with the boroscope vid, missed that one) Thanks for the vid!
A little off topic, but how many man hours would you say go into a rebuild? And does an LM2500 take longer than a LM1500 due it's larger size?
Also, does one single person work on an engine? Or does each person in the shop have a specialty and just work on certain parts?
P.S. Long time fan. Keep up the great work!
08ttimlin It usually takes a couple of months by a team of 3 or 4 people. It also depends a lot on how much repair work is needed. We see a wide range of "received condition" in the industrial engines.
I was wondering myself if you did ultrasonic cleaning. I almost got myself a nice ultrasonic cleaning unit, before the guy who had it destroyed the power supply.
Jay, new camera mount/ stabilization?
Alan Caraway Got a good tripod last year. replaced an injured soldier with a nice new Canon G7x.
+AgentJayZ that's a Fixed Lens right?
Shame. I was going to suggest some manual focus macro lenses to make filming up close easier, but this camera's pretty good as is!
***** I love SLR's. In the film days, I had a vintage Pentax.Nowadays, I would like one, but I honestly don't need one. Also, all but my "camera one" units need to be good, but not so expensive that I'll cry if they go sailing or eat dirt.
AgentJayZ Oh man. I love my Canon AE.
Feels like its gonna be a great year for some Kodak Ektar.
But yea. If you ever look into getting a new "main" camera, look to the Panasonic GH3 or GH4. The GH3 is one of the best amature video enabled "mirrorless" camera's you can get. The GH4 shoots full 4K video. Its pretty amazing, but a bit pricy.
Both support ad-on mics though, which is something you may be interested in.
You can 'lock focus ' right . So that on close ups the focus doesn't mess you about plus you can unlock it so it focuses auto as well
i work in a musical instrument retail store and when i saw that clogged cooling air hole my first thought would have been to try and clear it with the end of a guitar string. our non-wound, solid steel strings range from .008" to .022" in .001" increments so it seems like it would be easy to find an appropriate size to do the work needed. Not sure how stiff they would have to be though, that clog looked pretty stubborn.
almfreak Excellent idea. I happen to be a newb with a Stratocaster, so I will try this. The blockage appears to be metal, and is proving to be a bit difficult.
That must be frustrating to try and get into that tiny hole. What other method might you try?
Keith Burr I know what my brother would suggest.
Alright, I think I have a good question, I know in aircraft there are no filters on the intake of these engines, but they also spend most of their time running at an altitude where there's not much dirt in the air. But in industrial use is the air ever filtered before it gets to the engine? Does dust damage the engine much, or would filtering the air just add more equipment and cost with no real benefit to engine life?
are the struts solid?
Kalimerakis They are all cast that way, and then some are cored through to contain oil lines, radial driveshafts, electrical leads, etc.
AgentJayZ makes sense, thank you :)
I'm guessing that anyone who's been to school already knows this, but after watching the disassembly, I just have to ask. How many fasteners are there holding the cases together, and how long does it take to remove them for disassembly, and reinstall them when reassembling?
It looks like they've put the maximum number in the space available.
BTW thanks for all the videos!
jfan4reva It took a week to get to the point where we could split the cases of the compressor. There are as many bolts along the flanges as GE could fit. A more even clamping of a flat joint that holds in about 275psi, and many small bolts can hold more load than few large ones.
You should try and use a set of dentist's tools to clean out those little holes. That's what we use in situations like that.
GreenNarwals Yeah, they are stonger than lame pins and torch cleaners.
I now appreciate that flying though a smoking volcano is going to result in a lot of cleaning work.
In an earlier vid (Q55 I think. I watched several in a row to get caught up so I'm not sure. Sorry) you mentioned that the Iriquois was Half Complete. Does that mean it has been worked on or was that just a comment about how many parts it has to this point?
Why didn't you use a small handheld-drill at once, as it remained blocked after an ultrasonic washing with a bit just similar to the target hole, and forcely drill it over? Is that so critical to keep the hole intact?
Eltardo Wut and another question: do you deal with APU's? It would be very interesting to see one of that small engines from inside, if you have one in the near)
Could you show where the air bleeds are (which stages) and how they are made along the compressor of the lm2500? Cheers
Ad Koordihey I do that in this very video. Did you notice?
Sorry about that, yes I noticed after watching a second time! How many air bleeds are there? I mean probably one at high pressure for the HP turbine NGVs, and then is there another one at lower pressure for other purposes? Thank you for your answer!
Looks tedious. Baked clay; actually ceramic plugging the hole is a tough one. If you push the foreign material into the blade, can you get it out of the central cavity/passage? I got the LM1500 1st stage turbine blade (split) out of my curio cabinet to look at those holes. They are tiny! Hope you get it cleared. Thanks for sharing.
DD
Why is the Lm2500 in the shop ? Any specific repair or General overhaul ? How many hours does it have ? I hope These are no secret Informations--- I don´t even ask what it is used for :)
How many time can you spend to cleaning one blade, before it's cheaper to use a new one?
Wumpsi In good used condition, these blades are a couple thousand each. I'm scared to find out what they are new...
AgentJayZ i heard that the turbine blades in modern jet engines are worth their weight in gold.
Would it be possible to free the Blade holes from dirt my using sink-eroding? I assume it won't, because the dirt needs to be at least a little bit electrical conductiv. But I am curious if it would nevertheless work.
In an eroding process you don't have the risk to break a drill inside your workpiece
And it's used to remove drills as well! In this case spark erosion definitely wouldn't work to clear those holes.
Outstanding video! This is so cool. So dust... When used for industrial purposes, don't these have air filters on the inlets. I know massive HVAC systems pull air from a large chamber with walls of filters, sometimes two stages depending on the air quality required, or is the amount of air these units require too much to make it practical to filter...
William Garrett Yes, as metioned before, gigantic filters. But notice how fine the dust is. It can squeak through the filtersI think this engine ran a long time before being shut down.
Very understandable how dust can cause problems with all the intricate air passages on the HPT blades. Dust and heat, not a good combination for any system.For some reason this video has made if very clear to me how the compressor truly works. The variable stages actuating each vain is a beautiful piece of mechanics. I could also see the seal material quite clearly on the case and the rotor. It is interesting to see substantial wear marks at the case "seam". Will this seal material be replaced? Considering the tight clearance, this has got to be tricky.
Thanks again Jay, I can't wait to see more.
Hello, how can i extract the hpt in a lm2500? Thanks
Interesting you call it extraction. It's more like complete engine disassembly, to the point where you remove the HPT.
The step by step instructions are in the overhaul manual. You will need the special tooling. It's a big job.
The split nut will take up to 8,000 ft-lbs of torque to break free. It's reverse thread.
0.3g of dust multiplied by how many air cooled blades (three thousand blades? 900 grams of dust?) must add up to a lot of reduced cooling and reduced performance. Are the stater blades air cooled, were any of them blocked with grime? Or are the stater blades less prone to buildup of grime.
@AgentJayZ I would love to discuss over LM2500 engine repair possibilities. Is it possible to share an email address?
email is on channel page
With all the high precision, complicated, critical, important stuff you've shown us in these jet engines, how is it possible that they are so reliable? Just saw a video of a British plane that threw a piece of combustor can on takeoff right thru the wing which then gushed out fuel right on to a burning engine. Pilot unfortunately did not figure out what happened fast enough and stopped on runway with wind blowing flames under the fuselage and about half the passengers died cause they couldn't get out in less than 90 sec. cause of the panic. Investigation revealed that the combustor had been repaired by welding up several cracks but one of them was a bit long and maybe they should have replaced it. Just hard to know when some little thing like dust in a tiny hole is going to cause a bad day.
Well it is dust building up over time, remember that these engines blow air so a lot of dust would be blown away, but over time more will build up because they are air engines not dust engines
your videos are great but is it possible to put the tradutceur in french
AgentJayZ - @ 2:40 Grazia Mille! I appreciate seeing this. I presume that joining the case and rotor assembly is a much trickier process. Future video?....pretty please?
I must say, with all them blades in all them stages,all with them holes, it must be very repetitive and boring, but very important
If only we could get the Americans to say turbine instead of turBIN
I have a large range of printed circuit board drills the range in size to very small I am not sure how small exactly your blade holds are but it might be worth a visit to your local electronic parts store. I have not idea what is available in Canada.
I think careful use of such a drill only using careful hand pressure might shift the dirt although I am not sure how soft that metal is and if the drill might present a risk of enlarging or otherwise damaging the blade.
Message me if you want to know the details of the drills I have.
Systemrat2008 We're going to try this and the dental tools. The main problem I have discovered here is that the debris is very hard. It may be a bit of rock, which is going to make things interesting.
AgentJayZ Jay,i was about to suggest the same... Ask for dental canal files (pics URL below so you know wat i mean), they're cheap, resistant in it's axial direction (pull/push movement), and thou i never breaked one cleaning my airbrush when it's heavely clogged, (Once i was cleaning it wit a toothpick, it broke inside, i drilled into the toothpick and it screw there, allowing me to pull it back) they bend very easely, to follow the teeth root without damaging it's walls. Good thing is that you don't need to forcely push the clogging by force, just gently turning it with the tip of your fingers, it will drill the dust out, pulling it OUTSIDE, avoiding the dirt falling into the blade. You can find in many sizes, my airbrush is 0.15mm in diameter, my smallest file goes straigh trhu it...www.odontologiaintegradars.com.br/blog/uploads/endodo.jpg
www.noticiasdematogrosso.com.br/fotos-noticias/imagem-dente-tratamento-de-canal.png
Regards!
Systemrat2008
I hope you don't mean PCB drills made out of tungsten carbide, because using them there would be quite silly. You don't want something that drills the hole bigger, just remove the dirt. But even more importantly tungsten carbide drills are so brittle that without proper mounting of the blade and the tool (which is almost impossible here) they will immediately break. The last thing you want is something almost as hard as diamond stuck in that hole.