Many have asked over the years if testing jet engines is a dangerous thing to do. Let's look into that and try to come up with some sort of answer...
Пікірлер: 399
@joevignolor4u9493 жыл бұрын
In the Air Guard we had F-100's that used J-57 engines with afterburners. We didn't have a test cell so we had to install the engines into an F-100 to test them. Then we would tow or taxi the whole airplane minus the tail assembly out to a pad and chain it to two anchor points sunk into the ground. Then we'd fire it up. We would walk all around it while it was running. The only safety rule was to avoid standing in line with the turbine. It was amazing being that close to a running jet engine, especially while it was in afterburner.
@jadefalcon0013 жыл бұрын
"Like liquid thunder." That's some poetry, man!
@lsdzheeusi3 жыл бұрын
The pace of advancement in the 1940s and 1950s was incredible. In two decades, we went from the first jet engines, to the SR-71 and Concorde. I wonder if the engineers who designed models like the Orenda and J79 had any idea or expectation that their efforts would still be relied upon in the third decade of the 21st Century? That’s a testament to brilliant design.
@morphius20033 жыл бұрын
At the company i work, we overhaul large and small airliner engines. Fan diameters from 60 to 100 inches. The company exists more than 30 years. in this time, we tested many thousands of engines. Of course, sometimes a leak or some other small quirks happen, but never something serious. After initial startup we let the engine run for some time, and make sure everything is okay. At this stage, the cowling is still open. Then a technician puts on some safety gear (a LOT of ear protection, and safety goggles), opens a small door leading directly in the testcell and enters it (all while the engine is running on idle). He will go up to the running engine from the side. Looking for oil or fuel leaks and any other problems. He will inspect the first side, the underside. Then he will will walk underneath the fan case to the other side, and finish his inspection. I did that once on a PW 4000 100 inch, with 68000 pounds of thrust. It was amazing and frightening at the same time. Even running at ground idle such an engine produces amazing amounts of energy. You feel the power in every fiber of your body. Every single cell resonates with it. After this idle leak check the technician exits the testcell and the cowlings are closed. Then the real testing starts. (seal break in, low and high power runs, vibration survey, performance survey, takeoff run and other stuff). This procedure is really safe, if you stay away from: hot parts, the intake stream, the bypass stream and the exhaust stream. My workplace is about 200 meters away from the test cell. The testcell is well insulated, so you cant really hear the sound of an engine being tested. But if one goes to takeoff thrust, you will feel the rumbling through the floor and in the air. Humbles me every time i feel it. This is the old school way it is done. Most testcells these days have cameras installed, to do the idle leak check. But where is the fun in that :)
@Dontworryimaprofessional3 жыл бұрын
"Liquefied thunder" 😂 thank you my friend.
@Mrsournotes3 жыл бұрын
I love that one also!
@crabcake430113 жыл бұрын
When I worked at RR, we used to say we stand behind our engines, but never beside them!
@zapfanzapfan3 жыл бұрын
It's like the opposite of a trebuchet :-)
@riflebone3 жыл бұрын
"Given 'er" - Is there a more eponymous Canadian expression for maximum effort? "Let's take that Orenda out fer' a rip dere bye and we'll giver". Love it! Great vid as always JayZ.
@drthik13 жыл бұрын
Nothing like anchoring 30,000 hp to the ground and letting it rip
@FoxDuece3 жыл бұрын
Anything is dangerous if you don’t treat it with respect
@quiescentnexus3 жыл бұрын
"It's idlin' " at 4:45 sounded exactly like "it's restin'" in the Monty Python parrot sketch.
@AgentJayZ3 жыл бұрын
Why that's a compliment, sir! We don't actually handle compliments here. That's across the hall...
@sski3 жыл бұрын
@@AgentJayZ LOL!!
@marshallblythe7240 Жыл бұрын
If you examine photos of old jet aircraft like the F-86 you'll see that many of them have a thin red stripe that encircles the fuselage somewhere in the rear. This indicates the location of the turbine disk, so ground crews can remain clear of it while the engine is running.
@AgentJayZ Жыл бұрын
Also on the start carts.
@grahamj91013 жыл бұрын
Testing both repair and overhaul and production engines is usually a very routine event, but as AgentJayZ has mentioned, development testing can be a different matter. The failure of a Olympus 22R engine, back in 1962 , is still remembered locally. The engine, destined to power the ill-fated TSR2, was slung under the belly of a Vulcan FTB, and was being run up to full power on the airfield at Filton. The LP turbine shaft failed, the turbine disc was released whole and sliced into the fuel tanks in the aircraft's wing. The fuel pooled on the ground and caught fire, destroying both the aircraft and a brand-new fire engine. The disc bowled across the airfield for several hundred yards, reportedly bouncing every 150 feet, coming to rest just a few feet short of the Bristol T188 research aircraft (which I actually saw coming in to land a few years later). I also heard another story of an engine test that was carried out by Bristol Aero Engines in a disused railway tunnel, where a turbine disc was deliberately released. The disc reportedly ran around the tunnel several times before running out of energy and falling to the floor.
@jurepecar90923 жыл бұрын
Fuel flow regulators is a super interesting topic. Yes, they're all digital these days, but that's what makes the old mechanical ones so much more interesting. I see them essentially as analog mechanical computers, designed to do a specific task. Understanding how they work exactly is very interesting, another dimension of interesting is tracing their development through history, probably goes back to 18th century steam technology. Would you mind to talk more about these at some point? Thanks.
@dozer16423 жыл бұрын
If it wasn’t for the comment section of KZfaq, we would never be told how dangerous everyday actions are by people that have never done them.
@AgentJayZ3 жыл бұрын
Oh, you bet, Dozer !
@jonginder54943 жыл бұрын
This guy understands energy *with great clarity*. So very rare. Respect.
@donaldstanfield88623 жыл бұрын
The earth turns a little faster when AgentJayZ gooses those J-79s - WHEEEEEEEEEE!
@markrichards96463 жыл бұрын
Another great video from the boss. Thank you sir, for taking the time to makes these videos. You really help people understand what you’re doing and why you do it. Like the first stage of compression, I’m a big fan.
@lllateralus2 жыл бұрын
Always find myself back at your channel and enjoy the videos Ive missed. Thank you for taking the time.
@Fragaut3 жыл бұрын
Basically, a jet engine is built to the operation standards of an industrial diesel, not those of a car engine.
@AgentJayZ3 жыл бұрын
I guess you could say it is built for 100% duty cycle.
@1320fastback3 жыл бұрын
@@AgentJayZ My old school Cummins diesel is rated to run at governor speed at 1,200EGT all day long.
@eddean66633 жыл бұрын
I saw a CFM-56-3 that had sucked an fiberglass and aluminum ladder into it. The test cell crew had forgotten it. Two millon dollar damage.
@IcthioVelocipede3 жыл бұрын
Wow. That's a hell of an expensive ladder!
@crabcake430113 жыл бұрын
Ouch
@MatthijsvanDuin3 жыл бұрын
Whoopsiedoodle
@QueenOfPessimism3 жыл бұрын
These videos are so cool. Been binging for a while. I have a weird phobia of...well, let’s just say “large machinery” but seeing them broken down and having their purpose explained really helps.
@nicksexton63793 жыл бұрын
AgentJayZ, your humour is amazing, so well delivered. Thanks for a little bit of a chuckle in these depressing times
@mcgherkinstudios3 жыл бұрын
Of course it's not going to blow up on the stand. It's just been pulled apart and inspected in minute detail, balanced, checked and then assembled using only good parts. For a machine to fail it has to have a defect, and in many cases a pretty serious one. Given the attention to detail used in overhauling a jet engine, it's probably the least likely thing to fail during testing after a nuclear reactor. The fact that the team who put it together are perfectly happy to stand next to it whilst running shows the amount of care taken. Also, nobody panics when their plane is taking off because the engines are running at takeoff power.
@jenniferwhitewolf37843 жыл бұрын
People that use automotive internal combustion engines in marine applications also endure highly elevated failure issues because of extended time at higher power output levels. Excellent discussion on the principles of %power.
@hananc3 жыл бұрын
Something else that you could have said was that turbine engines DO fail, but it happens after much use and good/bad maintenance in the field. The engines you are testing went through a rebuild, checking and calibrating so they are in the best condition they can possibly be.
@MrWirebrain3 жыл бұрын
I love his last remark, that should apply to everything!
@danlemke64073 жыл бұрын
Some of us old jet engine mechanics that worked on the older jets such as the T-33 (F-80) were Leary of the blades egressing the aircraft, as you could see the patches on the empennage where it happened a few times. It is the reason most military jets had a red line painted where the turbine blade was, as it was not a spot where you wanted to hang out at. Military jet engines are trimmed (tuned) for the mission they are used for. For example, there is a peace time trim, and a war time trim for most military applications for obvious reasons, so 100% isn't always the norm. Jet engines as I knew them generally idle at 60%, so like he mentioned in the video, it is very unlike a car that idles at about 10%. Jet engines are usually not throttled about simply due to exhaust temps, but they do need to set them at less than 100% most of the time. Not sure about the light switch rational, but he was trying to make a point. There is an application where the jet is run at two speeds, idle and 100%, and that is a constant speed, with a variable pitched propeller affixed to a gearbox that is mounted on the front of the jet. So, the speed is adjusted only by the pitch of the prop, even allowing it to reverse. There are so many variations and applications of the jet engine, that it would be difficult to encapsulate all of them in one video on the dangers of working on jets, but I would say from my many hours in a test cell, that the most dangerous part is the very beginning of the start up on an engine that has been apart. It would be fuel leaks (we burned up a 2million dollar J-75), and vibration of something that is unbalanced mostly in the turbine section. We use vibration pickups to monitor this and would immediately shut down an engine that exceeded norms. In conclusion, jet engines are very safe to be around, or they wouldn't be around. In public anyways...
@sionekulu79123 жыл бұрын
Jay how s you re going ? Thanks for sharing this video appreciated , now I learn more and more about jet engines on and off for about 2 years now , I work fulltime in the constructions and building industry , on my spare time specially in weekends and sometimes during the week , if I got nothing to do at home first thing pop up in my mind is you re videos , its a kind of entertainment I love to watch and learn while I m off from work or nothing to do , I always get my note book and pens ready before I start watch it , as I said before I never knew anything about jet engines but now it becoming very bright in my head , I watched other videos as well but nothing kick in my head and fired up some basic knowledge for a start and go from there like youre videos , beautiful , you never stop learning right , its for my own interests not for a career I love youre videos , very educational , my son loved it too , thank you cheers mate .
@SkyhawkSteve3 жыл бұрын
your test cell is fairly similar to the diesel engine test cells at my former employer. Thick armored glass so you can see if anything has gone wrong (fuel or oil leaks, piston flying through the engine block, etc), some sound-proofing material on the walls, lots of instrumentation, and a way to control the engine being tested. I imagine the tests were similar too... kinda fun at first, but then a bit tedious.
@ajaychoudhary98173 жыл бұрын
love it so much cant believe its been 10 years since i began following this channel
@nopamineLevel100 Жыл бұрын
I used to think I was the only one curious about all the other (less exciting) things like the engine stands. This is awesome!
@AgentJayZ Жыл бұрын
I have a playlist called Our Engine Test Cell. Also, there's a search feature on my channel page.
@nopamineLevel100 Жыл бұрын
@@AgentJayZ hahahaha thank you, I actually fell asleep watching the whole playlist - it was after midnight here in Australia! I'm about 10-15 years too late, but I'm glad I came across your channel. You explain engineering concepts in such a great way - even mathematically challenged archaeologists like myself can understand what's going on 👍📚
@SeanBZA3 жыл бұрын
Remember the engine test cell where I was in the military. 2m of concrete as sides and floor, and then a roof of thin sheet steel, there only to keep the sun off. Input side you had a massive concrete pad to keep the airflow, and a nice chain link fence to act as debris filter around it. Output side you had a set of diffusers cast out of concrete, to direct the airflow upwards and dissipate the energy. Drive the engine in on a trailer, then attach to the slide rails there, and slide forward till you can attach to the mounting points as on the airframe, and then connect all the cables and hydraulic lines, and the fuel supply, using the locations as in the airframe. OHS came there one day, and they measured over 130dB at a point 100m away from the test cell, directly down exhaust. They were not happy with that.... It was loud for the local buildings, despite having walls that were a half metre thick reinforced concrete on all the sides. Yes it also had it's own fuel supply tanks underground, but was fed from the fuel farm on the other side of the base as well, as the pipeline was not capable of supplying 200l/m at the required pressure. Full power test for an hour or more were common.
@lwilton3 жыл бұрын
In the 1970s I worked for a short while at the GE jet engine division developing some engine balancing programs. They had 3 or 4 "old" test cells for the military engines, and one newer large cell for the huge turbofan engines. The old test cells were literally 2x4's and 1x6 vertical siding and tarpaper roofing over 1x6 boards, having been built in the late 1940s and still used. Air came straight in one end and went straight out the other end. Noise started inside and went everywhere. The new test stand (where I was working) was about 30 feet away from the old stands and was made from concrete block, with some attempt at sound proofing the control room. The old stands just had a wooden shed on the side for a control room. The big fans weren't all that loud when they were testing. But oh my, those military engines were just amazingly loud inside the supposedly soundproofed control room, even with hearing protection on. I sure wouldn't have wanted to be in one of those old test sheds when they were in use.
@perwestermark89203 жыл бұрын
The sound of a military jet on afterburner is quite violent. The sound just moves through the bones.
@joefzd40402 жыл бұрын
Watched your videos a few years back and have just come across them again. Love them, sort of hypnotic and relaxing. I used to fly on lots of piston planes and early jets, Comets and 707's' as a boy, My last flight was in a Stratocruiser. The whole Jumbo thing just passed me by! Anyway very interesting videos, thanks.
@georgepbriles6963 жыл бұрын
Nice channel man 👍 I love the vids, u can learn a lot on this channel, great work Jay!
@StonehouseCinema3 жыл бұрын
I seem to remember an old tool box at the Pratt & Whitney test cell that was cut in half by a runaway fan blade. They also had steel plate they put over the cell room window when they ran up new models for the first time. They may have been messing with me, the computer guy, but I loved the place. It was all kinds of awesome for an 18 year old computer nerd.
@AgentJayZ3 жыл бұрын
Yes, research and development testing is far more dangerous than what we do.
@DeliveryMcGee3 жыл бұрын
There's a reason airplanes have red lines on the sides. If the turbine comes apart, you're ... going to have a bad day if you're on the same geometric plane with it. (I believe the technical term is "turbof*cked") See Quantas Flight 32, where #2 (left inboard) RR Trent's turbine decided it wanted to be somewhere else. Somehow it didn't cut the fuselage in half, and Quantas spent more than it would cost to buy a replacement A380 to fix it, because their advertising is based on never having written off a jet.
@SeanBZA3 жыл бұрын
@@DeliveryMcGee Quantas themselves did not pay fully for the repairs, RR did put in a big chunk of the cost, because those engines are leased units.
@grahamj91013 жыл бұрын
@@DeliveryMcGee Qantas also got a lot of money out of R-R in compensation. Interestingly, that Trent engine failure seems to get referred to frequently in this sort of discussion, while there seems to be some selective amnesia when it comes to similar failures of US engines. Let me remind you and others of the Sioux City disaster back in 1989. Then there was the near-miss at Las Vegas in 2015, when a GE90 on a BA B.777 had an uncontained failure. And there was the Air France GP7000 engine failure over Greenland in 2017. Thankfully, such failures are very rare and there are always lessons to be learned.
@StonehouseCinema3 жыл бұрын
@@AgentJayZ the best part of that operation was the computer that sampled the hundred or so vacuum sensors in the prototype engines. Its hard to explain, but it step rotates sensors very fast and can sample hundreds of vacuum and pressure sensors inside the engine.
@Bergstaller013 жыл бұрын
My dad at Rolls Royce used to put his hand on the engine to feel for vibration in test cells. Not alot of people can or will do that these days.
@AgentJayZ3 жыл бұрын
Come to our test cell, and you can do that. At full, earth-ripping power if you want. We all do. You will love it.
@jadefalcon0013 жыл бұрын
@@AgentJayZ That sounds addictive!
@grahamj91013 жыл бұрын
@@AgentJayZ As a young designer, I went into the test cell with the prototype Industrial RB211 running at idle. That was awesome enough. My colleague development engineer did the same on another day, when a high pressure compressed air line let go. A compression fitting joint failed: nothing to do with the engine. Another time, I visited the control room when the engine was running. It meant walking around the back of the exhaust detuner to climb the steps to the control room. Exactly 24 hours later, when I was taking time out for a visit to the dentist, the engine flamed out for some reason. The development fuel system sensed the decay in speed and increased the fuel flow. The engine pumped vaporised kerosene into the diffuser, where it was probably ignited by a glowing speck of soot. The whole detuner was blown back several feet.
@AgentJayZ3 жыл бұрын
Graham... I once was allowed to slightly open the door and peek into the test cell when an industrial RB211 was at full power. The door was about 30m to the front and 5m to the right of centerline. I opened the steel door about 30cm, and I was frozen with a combination of fear and awe. Fifty thousand Hp will do that to you. Some expletives were involuntarily exclaimed. I went back to the control room, and said "that thing is one very angry machine!"
@Bergstaller013 жыл бұрын
@@AgentJayZ My dad told me a story where a Spey was being test run in a cell, one of the turbine disks let go, and buried itself into the concrete of the cell several inches. Needless to say, not a place you'd want to be in when an uncontained failure occurs...
@aaraspensor3 жыл бұрын
I used to measure the pursentage of used engine power driving in the town in my car. That was not the quite powerful car and the result was even less than 30%. The more poweful car the less power is used in everyday life. Those vipers and camaros hardly use 10% of their power. The overall car efficiency as a transport with internal combustion engine is 2...10%.
@fuzzy1dk3 жыл бұрын
it only takes some thing like 15hp to do 100km/h in car on flat a road
@aaraspensor3 жыл бұрын
@@fuzzy1dk you are right. It is even less than 10% of average car engine maximum power.
@aaraspensor3 жыл бұрын
@@fuzzy1dk the less power has the engine of a car the more effectively it runs.
@manifold14763 жыл бұрын
Spoken like a true mule driver.
@dronexfun8469 Жыл бұрын
My motto in life," just don't be in the way."
@AgentJayZ Жыл бұрын
I tell every visitor to make sure they are never the closest one to the engine.
@thomasbelmont8103 жыл бұрын
I love the fuel controller as a great example of ‘slide rule engineering’. It’s really magnificent what they managed to accomplish in the early jet age in such a short period of time. Separately, I suppose a classic automatic transmission is also an analog computer, although much simpler.
@GEFanuc21t2 жыл бұрын
We vacuum spin pit all of our impellers and turbine disks with big air motors to spin it at 1.5 times their max RPM they would ever run in the engine before the governor would shut down the engine...New or rebuilt in Axial compressors and impellers. So if the maximum RPM in the engine is 42,000 RPM at shutdown, we spin test them to 63,000 RPM. We want them to fail in the pit if they are going to fail at all, and not in the engine while in service. We do that with all of our engine rotating components, either APU's or Propulsion. Just the facilities to spin stuff costs an incredible amount of money. Last cost was quoted at 2 million dollars for us to build another vacuum overspeed pit from scratch.
@Breadmason3 жыл бұрын
Dear Agent jayZ, Love your stuff, just an old printer from down under, but have learnt SO MUCH, from you. Hope you & yours are safe and well. Thank you. Les
@C-M-E3 жыл бұрын
Other than looking like it might be dangerous because most people don't know jack all about unusual devices, anything can be dangerous with context. People walk all the time without issue, but the moment they decide to do so with a phone in their hand and attempt to challenge physics by stepping out in front of a bus...
@HimanshuShekhar12 жыл бұрын
You're the best teacher ever.
@Ratlins93 жыл бұрын
This is great stuff, thanks for showing your testing room.
@arronhyde3 жыл бұрын
Turbine disc failures, when they go they go! eg, QF32 on the A380. Passengers were very very lucky it went under them and up through the wing, and the disc severed the controls to the outboard engine lol Its just something you try not to think about but unfortunately they happen and when your times up, its up.
@MatthijsvanDuin3 жыл бұрын
Last november an An-124 had a fan disk failure at full take-off thrust, with one fragment going straight into the fuselage leaving a big exit hole on the other side. Fortunately it's a cargo plane and none of the crew sustained any injuries, I imagine it could have been pretty gruesome if it had been a passenger airliner. Kudos to the crew for getting the plane safety down on the ground despite complete loss of electrical systems (including instrumentation) as a result of frag damage.
@rickblackwell64353 жыл бұрын
Love flying in a Dash-8 beside the propeller! Does not bother me in the slightest.
@alsmith56043 жыл бұрын
Great video, but one thing that's not quite right... Aeroplane manufacturers do design for turbine disc failures. They can't stop the disc from going through the structures, but the trajectory of the "high energy debris" of the disc fragments is modelled, and no "singe point of failure" can be within these zones.... i.e. Structures in those zones have to have multiple redundant load paths, and systems (electrics, hydraulics etc.) are routed to either avoid these debris hazard zones or are duplexed to ensure continued functionality.
@AgentJayZ3 жыл бұрын
Well, that's a good idea. Not exactly moving the seats out of the plane of turbine rotation, because that would be expensive. A fore-and-aft 777 would be hard to make, and for such a statistically small risk. Still, if you wanted to, you could get yourself to think that wires and hydraulic lines might be more important to airliner designers than nerves and blood vessels... eh?
@apegues3 жыл бұрын
The engines I worked on (P&W F100-100 & -200, for F-15s & F-16s) all had what we called a “belly band” to contain a disk failure, didn’t always work but mostly
@alsmith56043 жыл бұрын
@@AgentJayZ It's not what I think, that is the way that aircraft are designed and its mandated in law by the Airworthiness Authorities. I know that because I spent 15 years working on gas turbine engine design and development, working closely with both Airbus and Boeing. One of the things the engine manufacturers have to provide to the airframers is the trajectories of high energy debris for exactly that purpose. Generally, if a disc fails, it will split into three pieces and exit the engine at 120s to each other. Because of the size and speed, these will punch a hole through pretty much anything... but in reality, its actually a pretty small hole! (There are quite a few photos of the top surface of the wing of QF32). If the worst case was to happen and it goes through the fuselage, then at worst one or two people would be hit, maybe a small number getting injuries from secondary debris... if the disc segment takes out a wing spare or completely wipes out an entire hydraulic system then all 350 people die. So the unfortunate reality is that wires and hydraulic lines are actually more important than nerves and blood vessels.
@AgentJayZ3 жыл бұрын
EGL: One answer: they don't have to be.
@grahamj91013 жыл бұрын
@@leontierralta Water injection permits an increase in thrust, without an excessive increase in turbine entry temperature, for a short period, on take-off. Its function is to provide a cooling effect on the combustion products, a by-product of which may be the production of smoke, to a greater or lesser degree. B-52s had it, which is why they produced so much smoke on take-off in those old film clips. BAC 1-11 airliners also had it and Harrier jump jets still have it. If you see a clip of a Harrier performing a vertical take-off, with visible smoke coming from the 'hot' nozzles, it will be using water injection. Operationally, it should normally be used for a 'short lift wet' take-off rating, with a maximum load of stores, when performing a rolling take-off, with partially deflected nozzles. My recollection is that the Harrier carried enough water/methanol for a maximum of 90 seconds usage.
@grahamhaynes42843 жыл бұрын
It's a lot safer now that remote cameras are used. The manufacturers won't allow folks into the cell when engines are running these days, especially at high power settings. Unfortunately, it can hamper the investigation of leaks etc. We had a turbine disc let go once. A piece of the disc smashed through the observation window, grazed the operators head and bounced off the control room wall. The operator was severely shaken and got a transfer to detail inspection. The test cell was used for testing three different engine types. Unfortunately, the HP turbine of one of those types lined up with the observation window. The window was subsequently modified!
@epicspacetroll13993 жыл бұрын
Wow that's scary! Glad the operator made it. I wonder, why wasn't the window already armored? Or was it armored, just not for large pieces of turbine disk?
@grahamhaynes42843 жыл бұрын
@@epicspacetroll1399 It happened in the 1970's. A lot of lessons have been learned since then.
@epicspacetroll13993 жыл бұрын
@@grahamhaynes4284 Fair enough. Lots of lessons in engineering/test history have been learned through injury/loss of life. Glad this one wasn't! Hope you have a good day! :)
@bobroberts23713 жыл бұрын
And then the engine is attached to the side of a tin can flying at 35,000 Ft.
@rodgermiller2970 Жыл бұрын
The glass block used to observe the engine in a test cell that was used by a major airline was 4 feet thick. The rest of the cell was reinforced concrete and they have had a major failure of the unit under test. But this is the last test before unit is mounted on an aircraft and would rather see them fail in the test cell than the aircraft.Cool stuff.
@AgentJayZ Жыл бұрын
Our test is the last run before installation. In 15 years, no failures. If there was ever such an event, our control room is not in the plane rotation of the turbines. The best strategy for dealing with high energy debris is not to be in the way of it.
@rodgermiller2970 Жыл бұрын
@@AgentJayZ Hi , When I say the at this test cell it was in the 1960's when jet engines were not as reliable as they try to make them now but you some of them still come apart in flight. Good channel!
@xBIGMUSCLEx3 жыл бұрын
Please answer this: So why is it more efficient to use the exhaust flow to drive a big fan (Turbofan engine) than it is to just simply allow it to flow freely out of the nozzle (TurboJet engine)??
@AgentJayZ3 жыл бұрын
The greater the difference in speed between the propellant gas stream and the flight speed of the aircraft, the more energy is wasted on the turbulent mixing of the gas stream with the atmosphere.
@xBIGMUSCLEx3 жыл бұрын
@@AgentJayZ Ah! I see, thanks for the explanation.
@OVRxNxOUT2 жыл бұрын
On turbofan & turbojet engines, if the exhaust flow didn’t pass through the turbine fins the there wouldn’t be anything driving the compressor side to make compression in the 1st place. Ramjet & Scramjet engines don’t use rotating or many moving parts, if any at all.
@donrideout49193 жыл бұрын
Worked on the Sabre when I was stationed in Germany, a groundcrew was doing a full run up on sabre another groundcrew made the mistake of crawling between nosewheel and intake, he was sucked into engine never survived.
@antidecepticon3 жыл бұрын
AgentJayZ, @ 14:38 I am curious about the altitude sensor - acceleration module, and how it works, Also do you have to calibrate it? Furthermore, when testing do you influence it, by making it think is at another atmosphere to see if it reacts appropriately? Just wondering how it's checked for operational standards. Thanks I have had many questions I never knew I had answered by you before I though of them.
@Josectre3 жыл бұрын
Yes, refrigerators are tested at the end of the production line. All of them are. I have worked in that industry for many years now.
@77bubba003 жыл бұрын
Hi Jay! Good video as usual. I'm way behind.... need to spend a couple weeks catching up if I ever have enough time. We've been testing engines back to back for months. Keep up the great work!
@rcom98803 жыл бұрын
Curious as to your pretest FOD check in the test cell and the path of intake air in those close quarters. Great videos, thanks!
@AgentJayZ3 жыл бұрын
That's the subject of an upcoming vid. Stay tuned!
@StealthMode139 Жыл бұрын
Ty For Sharing this Worx of art. Awesome to see her run again. FL
@sski3 жыл бұрын
LOL! Love that last bit. So many people these days seem to prefer the helmet/basement corner/lights out lifestyle these days. Especially over this sweet & sour shivers nonsense. Thanks for going over the basics of the test cell. Stuff does happen, rarely. But if you do your job correctly from the git-go, that rarely turns into an improbability.
@dougbourdo25893 жыл бұрын
Absolutely. Best description ever... especially for our current times !!!
@Cletrac305 Жыл бұрын
Great video, good teaching! A big sidetrack, but a very good point you made is the fact of being designed for 100% power at 100% duty cycle! This is something i cannot drive through most peoples heads when they speak of "modern" "high tech" piston car engines being so small for their HP. Firstly, its all been done before. We always knew that more flow, rpm, or boost or all 3 make power, BUT, There's a direct relationship between power and time an engine of a certain displacement can operate period. That has to do with thermal mass and heat rejection and transfer, and unit loading. In other words how much pressure and speed is one square inch of any bearing surface absorbing? Again a direct relationship. 1/2 the speed, 2x the life, same true for loading. So 2x the surface speed, and 2x the loading even at cruise, and 1/4 the life. The only 2 things modern that has allowed this is CNC machining making a 100yr old 4 valve design practical, and having a computer that keeps the loose nut behind the wheel from blowing it up before warranty, metallurgy also plays a lesser part. I have racing, pulling, flying And heavy duty gasoline engine experience and can tell you thats why we raced the only brand of the big 3 that DIDN'T have a separate heavy duty gasoline engine department. No, its not GM. those famous early hemis and big blocks had to power tug boats and semis and irrigation pumps and some did so at 1hp/ ci with 2 4bbls hour after hour. In 13 yrs, a 440+6 had 2500+ dragslip passes, lifting the front wheels at 4860lb, with $500 invested, 40 top eliminator trophies and using it for daily transport and it was the farm truck, NO failures of anything but spark plugs! Then into 3 more cars no overhaul just bearings 1 time. A 1960 GMC 305ci V6 truck engine weighs around 1000lb to make 175hp continously compared to the weight of a 305 smallblock. Bigger thermal mass. More cooling and probably 3x the bearing area. Contrary to popular belief, thats why good heavy duty gasoline engines have SHORT strokes big bores, and huge valves with a semi lopey cam. The biggest limitation is actually compression, worse before modern fuels. Less piston travel with short stroke and less bearing speed. Make hp with rpm. Gasoline heavy duty engine Torque is Starting at lower rpms than a diesel (except Detroit 2 cycles), even worse with a turbo diesel because if you pull it down it suddenly falls out of the turbo or hasn't spooled it yet. Those gas engines drink alot of gas but run like electric motors from bottom to top. a 478 gas V6 is a 5.125" bore x 3.86" stroke with 2.3" valves and a 306deg duration aggressive mechanical cam! It will run 600,000 miles at 4,000 rpm and pull down so slow an electronic tach won't read it! It makes 254 hp. An 855ci 6cyl cummins (with about the same bore) at 240hp runs from about 1200rpm to 2100 (900rpm) and uses a turbo. The 478s peak torque is at 1400 rpm. Hp is at 4,000 (2600+ useable rpm) less gears in trans. Bearings never touch the crank only oil, i can pour any "modern oil' in any engine. So unit loading really hasn't changed alot. At some point to be reliable it has to get bigger and heavier on the outside too! But to go from NY to LA with 80,000lb even if i couldn't haul as much net, due to engine and driveline 2x the weight, if i had to feed it I'd want the Cummins! Or better yet the Detroit with an (gasp, sacrilidge!) Allison Automatic trans.
@Cletrac305 Жыл бұрын
P.S. my 2009 honda CRV had more stroke than either the 440 big block V8, or that 478 V6! But not the 478s 7" rods!
@wishusknight3009 Жыл бұрын
Its a similar comparison to the Ford Ecoboost v6 in their trucks vs the 7ish liter v8 gaspot they just put out a couple years ago. Both have similar HP and torque numbers, but if you try to use both engine for actual work like pulling a 5th wheel travel trailer through the mountains, the v6 will eat itself alive far sooner.
@GarageSupra3 жыл бұрын
cool video! I didn't know about those throttle control automatic restrictions, nifty.
@andrealoi44263 жыл бұрын
Racecars on a track, bullets on a firing range, bulls running through the streets in Pamplona... Staying out of the way is almost often the best safety measure.
@andrealoi44262 жыл бұрын
@@FyreSturmOfficial What i meant is that you don't stay in front of those things. Guns are fun, if you're behind the sights, not in front of them. Racecars are fun, if you're in one of them or behind the guard rail, not if you're on the side of the road in the Portugal WRC in 1985.
@sless69283 жыл бұрын
You mentioned that you use propane in the test cell instead of natural gas which is used in service. Doesn't that throw out all of the fuel flow settings and mean that the fuel system needs to be re-tuned when the engine is put in service on natural gas?
@AgentJayZ3 жыл бұрын
Industrial engines that use natural gas have a simplified fuel control. Basically it supplies enough fuel to get to the required exhaust temp, while staying under the limits of rpm and vibration programmed into it. So if the caloric value of propane is less than natural gas, the fuel control just opens the valve more until the desired temp is reached. It's a closed loop system. No adjustments needed to switch between those two fuels.
@sless69283 жыл бұрын
@@AgentJayZ Thankyou.
@MrAsBBB Жыл бұрын
Great explanation
@altinfoil5923 жыл бұрын
It's only dangerous if you hold your hot dog by your fingers, or if you leave it in the exhaust stream too long. Other than that, the only danger is that your hot dog might taste a bit like burning kerosene once its cooked.
@thelightninghunter233 жыл бұрын
A few years back at O'Hare there was a Boeing 767 that caught fire before takeoff... no one died and the plane never even took off so I didn't really think much of it. Only a few days ago I watched a video by TheFlightChannel that showed the event... turns out that the right engine had the Stage 2 HP turbine disk break apart into two main pieces during the takeoff roll... the smaller of these pieces went through the engine, right through the wing and the fuel tank which caused the fire, out the top of the wing and then through the roof of a warehouse over half a mile away. It was very fortunate that A. this happened when the pilots could abort takeoff and B. that the pieces of the turbine missed the fuselage. If it happened just 15sec later, you would have hundreds dead... there's no way the plane would make it back with the fire. kzfaq.info/get/bejne/eqiGeM-JmqfNhX0.html
@noochification3 жыл бұрын
If it had happened 15 sec later, the plane would have taken off on the one good engine, completed in flight engine failure checklists, and landed back at the airport. All passenger aircraft are designed for this exact case.
@rjtoten3 жыл бұрын
"If it happened just 15sec later, you would have hundreds dead... there's no way the plane would make it back with the fire." that airplane is designed, tested, and certified to be able to take off with one engine completely disabled (beyond the certification reject airspeed). Even with that engine on fire. Every single day, for every single takeoff that airplane ever made, it's performance was calculated and programmed for the failure of one of its engines after takeoff. The crew knows the procedures for an engine failure. They know the procedures for an engine fire. They know the procedures for a takeoff with both at the same time. They are trained on them. They are tested on them in full motion, full cockpit simulators about every single year. Those procedures are published, trained, and checked by the airline. Both are overseen by the government. ....in short, there's about as close to a guarantee that the plane would make it back on the ground with that fire. It was purpose built to do it.
@thelightninghunter233 жыл бұрын
@@rjtoten The WING was on fire because a ruptured fuel tank was gushing jet fuel. Did you see the video? Fire crews came as fast as they could and still the wing was completely burned off by the time the fire was out. You can see photos and video from this incident. This was basically the Concorde crash except the fire happened before V1.
@rjtoten3 жыл бұрын
@@thelightninghunter23 "You can see photos and video from this incident." If it's still up, you can watch the entire response from the POV of ARFF dashcam video. It was a tremendous and life threatening event but your characterization is still melodramatic. No, the wing was NOT on fire. The engine was on fire. The wing was punctured. The wing was pouring fuel uncontrolled onto the burning engine. The ignited fuel was on fire BELOW the wing. The inferno raging below the wing ON THE GROUND is what destroyed that wing. You don't do us any favors by saying "oh my gosh if it was in the air everybody would be dead **shudder**!!!"
@thelightninghunter233 жыл бұрын
@@rjtoten That's possible ... I didn't really do a thorough analysis. Maybe there was a chance. But taking off with one engine with a hole in the wing, reduced aerodynamics and possibly the loss of flight controls on that wing, a massive fuel leak and a possible fire? It's not your typical landing due to a compressor stall.
@Mrsournotes3 жыл бұрын
Excellent video AgentJayZ. Excellent!
@khaledyousfi71603 жыл бұрын
I've been following these lessons but unfortunately I couldn't get a chance in one of the aircraft maintenance companies😢😢, I wish I can get a chance some day
@AgentJayZ3 жыл бұрын
If you keep trying, you will.
@khaledyousfi71603 жыл бұрын
@@AgentJayZ ❤️❤️
@High_Alpha3 жыл бұрын
Turbines in modern aircraft are designed to contain failures. This is why uncontained failures are big news. But to achieve this they generally use materials like kevlar to handle the stupid energy involved. Also with FADEC they tend to use software to help. Example the Trent900 on the A380 had a software change post QF32's uncontained failure (when the second spool turbine disk burst following a failure that decoupled it second spool compressor... with the insane RPM increase that would result!) from the inter that would prevent a similar disk burst by using the processing speed of the FADEC to cut the fuel flow when the turbine speed exceeded a certain RPM (which was well above normal operation but would ensure run down prior to reaching failure rpm).
@High_Alpha3 жыл бұрын
Also an important point for the Jay's test cell is that not only does the J79 WAY predate the containment requirements... And in its flight version it was a military engine which has different standards. But the cowling on a modern turbine is also part of the containment system. This is why test cells for commercial engines use the same principles as this cell, the turbine is offset from the control window. They also tend to have much thicker walls and glass... But I believe this is more the volume of testing they need to do in commercial engines and the desire to have the test team not needing hearing protection. The bigger cells at major airports also tend to be sound proofed so you can test your average commercial engine and make no more noise than a vacuum cleaner. This allows them to use the cell 24hrs a day as there is virtually no external noise. Of course it's easier to sound proof when you don't need to test afterburning engines!
@grahamj91013 жыл бұрын
There are no casings on any engines flying today that can contain the total failure of a disc, whether that of a fan, compressor or turbine disc. The design philosophy is to make such an event extremely improbable, through careful design, rigorous control of manufacture and extensive testing. If engines had containment shields capable of containing such a failure, they would be incapable of flying, as they would be far too heavy. In fact, it would be impossible to come up with a sensible design. However, there are engines out there that, in certain cases, have containment shields intended to contain multiple blade failures. And, of course, the big turbofans have containment features, such as Kevlar, around their fan casings, which are designed to contain the release of a single fan blade. You may be interested to know that the last mark of the Pegasus engine in the Harrier jump jet, has an Armco containment ring fitted into the aluminium casing above the first stage of the three-stage fan. This is designed to contain the release of the portion of a single blade from above the snubber (aka mid-span shroud in N America). The engine would fail, of course, but the design intent is to prevent major damage to the airframe, including a fuel tank, and give the pilot enough time to eject.
@High_Alpha3 жыл бұрын
Awesome thanks Graham! Thanks for the for the clarity. I should have been explicit... Jay would not approve. I did mean blade failure for the casing. Of course the idea being that anything escaping goes out the back in the exhaust flow. Disks can't be contained physically. The software is designed to sense when they are approaching dangerous speeds and shut the fuel flow off to prevent the burst in the first place.
@grahamj91013 жыл бұрын
@@High_Alpha Some engines also have a mechanical shut off, in the event of an LP turbine failure. The Olympus 593 did and so did one mark of the Trent.
@hadinossanosam44593 жыл бұрын
Why is a turbine failure so much more damaging than a compressor failure? Are the required heat resistant materials that much heavier?
@kjdude87653 жыл бұрын
The individual compressor blades are much lighter in mass and material than the turbines. Less rotational mass is less energy at the same speed. And lower inertial mass is easier to stop.
@builtrodewreckedit3 жыл бұрын
yea but what if a large bird that had just eaten a bunch of titanium bolts and flew threw the front door? then what?
@pauldatche84103 жыл бұрын
Bro, that would be a new species of bird...straight out of the "Jurassic Park", which means its not happening anytime soon...
@crabcake430113 жыл бұрын
Now that’s a risk assessment right there!
@andreabuzzolan98073 жыл бұрын
Great video! I've a question, since sometimes you need to take apart the engine and then test it; all the procedures of unmounting parts are done in a different building closeby? can metallic dust be a problem for the engine? are dusty places a problem when working on jet engine? Thank you for your work!
@DinoAlberini3 жыл бұрын
“Yes it is, but we’re badasses and laugh danger in the face!”
@paulpaul9914 Жыл бұрын
Is the throttle setting on a passenger jet engined aircraft routinely anywhere between 51.23% & 95.67% on most normal flying days? & The engine is at its most efficient at around the 84.56% throttle setting? It seems that the future of all jet engine parts involves lightweight materials - ceramic matrix composites which are made in the same way as infused epoxy fibreglass boat hulls & 3d printing, just imagine that!
@fascistpedant7583 жыл бұрын
It has to be safer standing beside the engine on the ground than sitting beside it in a pressurized tin can at 35,000 feet.
@AgentJayZ3 жыл бұрын
The safety is equal. Maybe safer in the plane, because the engine is being force-fed, and is therefore happier.
@c-stofft-stoff85313 жыл бұрын
How much "propulsion/lift/anti-thrust?" does the low pressure zone at the compressor inlet generate by "sucking" the engine forward in comparison to the thrust generated by the jet exaust
@pudmina3 жыл бұрын
for most turbojets the majority of the propulsive power of the engine is from what I've heard provided by the exhaust. The J58 turbo-ramjet used by the SR71 is different though. According to Wikipedia "The propulsion system consisted of the intake, engine, nacelle or secondary airflow and ejector nozzle (propelling nozzle).[11] The propulsive thrust distribution between these components changed with flight speed: at Mach 2.2 inlet 13% - engine 73% - ejector 14%; at Mach 3.0+ inlet 54% - engine 17.6% - ejector 28.4%". So at top speed most of the power is provided by the inlet. So it could be said that at top speed the J58 'Sucks' :)
@AgentJayZ3 жыл бұрын
There is no such thing as suction. Look into that before you call me an idiot, as so many before you have... shaming themselves in the process.
@c-stofft-stoff85313 жыл бұрын
@@AgentJayZ Im completely aware i just don't know the correct terminology to describe my question properly hence the misnomer "suction" in quotation marks sorry about that....the closest approximation to what i was attempting to say is how much aerodynamic lift is generated on the lip of the compressor inlet i figured asking how much lift was generated would be confusing since lift is usually in the vertical not horizontal axis
@AgentJayZ3 жыл бұрын
Dear Mr Wilson: There is no such thing as suction. You can quote anything you want. Nobody is talking about the J58 here. The inlet does not cause any thrust, no matter how you want to think about it. Thank you for your amusingly erroneous contribution. It will serve as an exhibit, until you delete it.
@ASJC273 жыл бұрын
@@pudmina The power is not "provided" by the intake. The intake is a passive device. It is always provided by the engine. It just sometimes happens that most of the force is located there, by the action of the pressures distributed throughout the engine, and made possible by the engine's operation. If a car is accelerated by the push of the tires against the road, are the tires or the engine responsible for that power? Obviously it's the engine. Same thing. This is also not exclusive to the SR-71. In most supersonic jets at speeds of around Mach 2+ the thrust is mostly at the intake. For example, in the A-5 at Mach 2.2 75% of the total thrust was located in the diverging section of the inlet, while in the converging section it was -12%, for a total of +63% of the thrust in the intake. Only 8% was located within the engine, and the final 29% in the nozzle.
@changefromabill16373 жыл бұрын
A stock engine corvette holds three world records for continuous top speed of thirty hours. Set in 1990 or so. Saw a video of it at the museum in Bowling Green. The new ones are dyno tested for much longer during development. Several days if I remember correctly
@griffinfaulkner3514 Жыл бұрын
Set by a C4 ZR-1 with the Lotus-designed, Mercury-built LT5 DOHC V8.
@grahamj91013 жыл бұрын
I've looked at the video clips of the failed engine on the United Airlines B.777. However, I can't make out whether there is a fan blade missing, but the fan is obviously still rotating, and there is a heavy unbalance, consistent with a fan blade off. Please also see my comment about a fan blade failure on an Air Asia A330.
@AgentJayZ3 жыл бұрын
Sheila, wherever that engine ends up, it will be disassembled to the last nut and washer. The big pieces will be inspected dimensionally for plastic deformation due to the monstrous forces they endured. If they are out of spec, they will be destroyed. If not, they will be inspected for cracks. If any are found that are outside the repair schemes, they will be scrapped. Then, millions of dollars of new parts will be used to reassemble the engine into zero timed overhauled condition. It will be identical to a new engine.
@grahamj91013 жыл бұрын
@Sheila Walker I found the clip to which you refer and, yes, it does appears that there are portions of two blades missing. Where they went, I wouldn't like to guess: I'll wait for the NTSB report, as we all should. I will acknowledge that the Air Asia A330, to which I referred, was in cruise when it lost a fan blade, as it was about an hour out of Perth, Western Australia. If you check the ATSB report, you will find that about three-quarters of a fan blade was missing. In comparison, United flight 328 was reported to be at around 13,000ft, which looked about right from the video clips of the aircraft, the puff of smoke and the falling debris. Consequently, compared to the Trent 700 failure, the fan speed and the energy levels of the blade release in that PW 4000 would have been somewhat higher. I am, nevertheless, perturbed by the gross loss of engine cowling panels, and the apparent disruption of something that fed the fire. The Trent 700 does appear to have been somewhat more robust in this respect. In terms of what might and might not be re-used from that engine, while it will be stripped and minutely examined, my guess is that much of the fan, fan booster and HP compressor sections will end up in the scrap bin. The fan casing and the static structure around the front bearing housing, in particular, will have taken a considerable amount of damage. The design philosophy with which I am familiar is that, in the event of a fan blade off, the FBH support structure is actually designed to fail at a structural 'fuse', to allow the unbalanced fan rotor to rotate about its new centre of mass. The NTSB report will tell us how much damage there is in the engine, and it will make interesting reading. Did you ever read the report on the engines from US Airways flight 1549, or the ATSB report on the engine from QF32? And the AAIB report on the investigation into flight BA38, which crash-landed at LHR, was fascinating - for an engineer.
@tocarules3 жыл бұрын
The youth got confused at "Chevette", knock off of the Rabbit.
@robmeekel91983 жыл бұрын
What's a rabbet? lol
@tocarules3 жыл бұрын
@@robmeekel9198 LOL. The VW Rabbit was I think the very first hatch back. Chevy made the Chevette and Doge made the Omni. Omni made a special edition the GLH for Goes Like Hell. They put in a 2.2 with a turbo. Doesnt sound like much, but the HP to rate ratio was pretty speedy. I've only seen one in real life and that was a couple years ago.
@robmeekel91983 жыл бұрын
I know what a Rabbit is, i also know the Chevette. The rabbit was the golf. badged for North America. My cousin from Holland visited Canada and bought and took back all the badges for his
@robmeekel91983 жыл бұрын
@@tocarules Ever notice the steering column in a chevette. Its off perpendicular to the line of the car by several degrees. They angled it to clear the crap under the hood.
@tocarules3 жыл бұрын
@@robmeekel9198 Never owned a Chevette, but my insurance company jacked my insurance up for crashing one. I called them up and they said it must have been a "computer glitch". Ya, everything was a glitch like you would tell the cops you though the sign meant 100 MPH as you didnt know they changed the signs to KMH. Then the cop told me that I was still doing 142, so no matter the unit of measurement I would have been breaking the kmh limit too. PS. 142 mph was impressive back in 81, but now the Ford Escorts will do that.
@CMDRSweeper3 жыл бұрын
So these non FADEC engines do have nannies? Then how come that there is a warning for non FADEC aircraft to not slam the throttles forward to max power "Because you could exceed something"? A classic example is the takeoff thrust and one of the bragging rights of the Concorde back in its day was that they just smacked the thrust lever to full power for the takeoff while a DC-10 similarily had to be eased up to it.
@AgentJayZ3 жыл бұрын
1 - there are warnings about throttle control in the old jets, in the pilots manual. The rest of your comment is not true. The DC-10 had the CF6-6, and it would respond nicely to having the throttles instantly moved to 100%. No sweat. Any modern engine will do that. There are other reasons why airline pilots never so that. Even Concorde would never apply full power right at a standstill, but ease into it after moving forward some distance. The FADEC in modern engines performs the same duties as the FCU on the older ones. It does a much better job at it.
@alandaters85473 жыл бұрын
Hey! I just found the "Orenda" plaque which was missing from one of the engines outside. It is hanging on the wall above the pegboard, next to a couple of wrenches!
@AgentJayZ3 жыл бұрын
That one is from ser #2052. Sadly, she didn't make it.
@micstonemic696stone3 жыл бұрын
AgentJayZ I never considered an example that a 10,000hp engine could use up to around 5,000hp to run the compressor blades, I'd heard a gearbox may limit some of, like Mike Patey's STOL Aircraft Draco, which had P&W PT-6 turbo-prop.........mmmmm bacon, funny fascinating......
@AgentJayZ3 жыл бұрын
A 10,000 Hp jet is using 20,000Hp to run the compressor.
@micstonemic696stone3 жыл бұрын
@@AgentJayZ confused for a moment, but then I knew exactly what you meant, I really do enjoy learning about these awesome engines, thankyou for finding the time to reply and enhance my knowledge of jet engine, thrust or shaft. just great.
@briancox27213 жыл бұрын
If a turbine disk lets go, I'd imagine anyone in the control room is going to have an emotional experience and browned pants. Hopefully, that is the limit of "effects" on them.
@LouT15013 жыл бұрын
Good video. And I've been to Fort St Johns, stopped and got fuel on my way to Alaska. There's risk in everything, impossible to eliminate it, just have to manage it best you can and it appears that you have. Every been up the road to Shepherd's Inn? One of my favorite spots.
@mikelagaffe3 жыл бұрын
man, id like to learn to do maintenance and rebuilds like that.. is there a school for this or somewhere to get a job in it and all?? my dream was to fly but i couldnt become a pilot for medical reasons... namely, extremely poor eyesight beyond a couple meters....
@AgentJayZ3 жыл бұрын
Watch my video called So you want to work on jets...
@tomminystrom11 ай бұрын
I have seen airline engines being tested for blade failure and casing contained that blade. Im sure that large fan blade contains more energy that smaller turbine blade and that turbine blades are also contained by modern airline engine casing/housing in the event of failure.
@AgentJayZ11 ай бұрын
The most dangerous failure, and that is not tested for... because nothing can contain the energy, is breakup of a turbine disk. Very rare, but usually causes loss of the aircraft. And it's important to distinguish the testing talked about in this video, from design proof testing. We test our work on the engines to ensure proper function before returning them to the customer. Design testing is done by the manufacturer while development of the product is still taking place.
@DeliveryMcGee3 жыл бұрын
Idle on a piston engine is ~10% of max rip-em's (~600RPM, and most modern V8s start putting windows in the block at 7000). Idle on a jet is, what, 90%?
@AgentJayZ3 жыл бұрын
Ground idle is about 65%, but it takes forever to get into the power, so flight idle, which is the lowest rpm you ever want to see while in the air, is about 85% of max. Cruise is about 93 to 95%. Max continuous is 100%. Take off power ( limited to 5 minutes) is about 103 to 106%, depending on which engine we are talking about. Just for fun: the engines of the C-130 Hercules idle at 100% rpm. They also produce max power at 100% rpm. Pilot controls prop pitch, and the FCU adjust fuel flow to maintain prop rpm. I told you it would be fun.
@SeanBZA3 жыл бұрын
@@AgentJayZ The C130 also has a reverse gear selection. You better be wearing a seat belt though, if you are landing on a short runway where they are going to use it, it is rather brutal. You are not quite going to stop in the length of the aircraft, but it sure feels that way.
@josephschaefer91633 жыл бұрын
A goodwrench 350 will do 7000 rpm at least a few times. Redlines these days are limited to valve train control. Of course this is a case by case basis depending on part selection
@ENTK873 жыл бұрын
@@AgentJayZ Sure it's fun redlining a car's engine, while deciding the acceleration rate only by feathering the clutch! 😂
@AgentJayZ3 жыл бұрын
Sean, you may call it a reverse gear but it's not that. The prop pitch goes into the negative, so it pushes air forward, but everything continues rotating in the same direction... always.
@micstonemic696stone3 жыл бұрын
Thanks for video
@roybm31243 жыл бұрын
Have you every seen powerturbine blades coming through the casing?
@AgentJayZ3 жыл бұрын
You can see in my recent power turbines video, that those cases are several inches thick of steel. PTs are stressed much less than the engines, and are built far heavier.
@nicholasoliver Жыл бұрын
Excuse any duplication but...why would the turbine blades come flying out with more energy than compressor blades?
@AgentJayZ Жыл бұрын
They are turning the same speed, but they weigh ten times as much. And the turbine disc weighs about a hundred times as much as a compressor disk.
@nicholasoliver Жыл бұрын
@@AgentJayZ Thanks JZ I presume due to the temp difference between compressor and turbine sections.
@hootis83 жыл бұрын
What makes the turbine disks more dangerous than the compressor stages? They're spinning at the same speed?
@AgentJayZ3 жыл бұрын
They are much thicker and heavier, and under much greater stress due to the much heavier blading... and they are running at close to a thousand degrees F.
@bhargavdesai79843 жыл бұрын
@@AgentJayZ do compressor and turbine blades rotate at same speed???
@AgentJayZ3 жыл бұрын
Did you watch the video....Where I mentioned that?
@samcana3494 Жыл бұрын
Okay how much horse power does j_49 engine has
@davidsavage6227 Жыл бұрын
How difficult would it be to get an RB211-22? These engines powered the L-1011, and people could hear the low hum this beauty made while starting from a mile or more away. I’d love to hear this engine start up - and watch it too. They’d smoke like crazy when the weather was cold.
@AgentJayZ Жыл бұрын
Not difficult at all. It would take some money. Getting an engine into the test cell, even if we do no work on it in preparation, is a procedure involving several people and a couple of days. For an engine we don't normally deal with, a lot of reconfiguring and fabrication of new equipment is done, and so the process of a first time run would take weeks. All paid time. Never mind the cost of the engine. And, a large turbofan engine is not within the capabilities of our test cell. Sorry.
@westtex36753 жыл бұрын
One of my coworkers was telling of a time where an industrial turbine disc flew off during a mishap. I don’t remember if he was at the site during the incident or after the fact, but he said that the disc had sliced through the engine casing, then through the external engine enclosure, then through a few other building walls and ended up halfway across the power plant site.
@AgentJayZ3 жыл бұрын
Yes, that was probably me that told you that.
@westtex36753 жыл бұрын
@@AgentJayZ Perhaps. I haven't been on your channel in 5-6 yrs tbh, so maybe was an old video. But I am pretty sure it was from my coworker who has been a site manager working on gas turbine power plants for many decades, both on new builds and rebuilding sites after accidents. He had some crazy stories (people closing a high voltage circuit-breaker out-of-phase, etc).
@oldmech6193 жыл бұрын
American Airline’s lost a disk on an high power maintenance run to check for vibrations. B767 LAX. The aircraft suffered a lot of fire damage.
@AlessandroGenTLe3 жыл бұрын
It's funny that "Orenda" sounds a lot like Italian word "orrenda" which translates into "hideous" or "horrendous" adjective for a female noun :D
@bobrice39573 жыл бұрын
I my experience the HP compessor case is the only thing to fail. It runs the cowling and often wraps it round the slats as take off is when it is most likely to fail. I've never heard of the turbine letting go. If the fan blades fail they are restrained by the fan case.
@grahamj91013 жыл бұрын
In 2010, the No.2 Trent engine of Qantas flight QF32 had an uncontained failure of its IP turbine disc (it's discussed elsewhere here). This was not because of any defect in the disc, but was as a result of a raging oil fire that grossly overheated the drive arm of the disc, which then twisted itself off the turbine shaft. The IP turbine was then driven to overspeed and burst in around 120 miliseconds. There are no casings on any jet engines flying that will resist a major disc failure, whether compressor or turbine. As I've mentioned elsewhere, there were uncontained failures of both fan and HP turbine discs in the early days of the RB211 on Tristars - and to maintain some balance, there have been similar failures on engines of US origin. Fortunately, such failures are extremely rare.
@MatthijsvanDuin3 жыл бұрын
The Progress D-18T turbofan engine of the An-124 has also seen two uncontained failures last year, one in March 2020 with no details known other than that it was traced to the second-stage disk of the intermediate pressure compressor, and the more publicized fan disk failure in November
@easternwoods43783 жыл бұрын
Juan is going to be so upset that the engine decides what it's going to do
@MarkRose13373 жыл бұрын
One thing pilots transitioning to turbine power learn is turbine spool up time. You have to anticipate the power you'll need ahead of time. ICE engines are actually the same way, either mechanically or electrically, but they tend to respond faster.
@publicmail23 жыл бұрын
The Southwest uncontained failure that killed the woman was quite away from direction of rotation, given many factors I believe a piece of case hit window...
@AgentJayZ3 жыл бұрын
No. It was a piece of the nacelle that hit the window. That's airplane parts, not engine.
@dinosaurcomplaints23593 жыл бұрын
Sounds like a detroit diesel, wind it up till it stops screaming, shift a gear, stand on it.
@AgentJayZ3 жыл бұрын
Years ago, when I was racing bikes, we would race at night at a little track that also held stock car races on the same night. A car crew chief wanders through the pits, over to my buddy who rides a Yamaha R6 with a screaming open exhaust collector. Chief says "What the heck is the redline on that thing?" Jed says "Fifteen five" Chief: " What do you shift at?" Jed: "Fifteen five!" ... I am still smiling at that exchange between the car world and the bike world.
@TheAnubite3 жыл бұрын
Does the fuel freeze?
@burntchickennugget1913 жыл бұрын
I dont think it can freeze in any w3ather
@AgentJayZ3 жыл бұрын
Engine is rated for nominal performance at -50F to plus 150F. You can look up the freezing point of JetA, and get back to me.
@darrensworkshop67833 жыл бұрын
Silly question time - do you point the engine opposite to the Earths rotation fearing slowing/ speeding up the rotation of the Earth with the engines on full power? LoL...
@michaeljones6256 Жыл бұрын
Awesome test cell. Seems to me its always the uncontained compressor failure with the turbofan engines not the turbine section.
@AgentJayZ Жыл бұрын
Good thing we do not work on high bypass turbofan engines, then, eh?