Is Testing Jet Engines Dangerous ?

[@joevignolor4u949]

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.

[@jadefalcon001]

"Like liquid thunder." That's some poetry, man!

[@lsdzheeusi]

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.

[@riflebone]

"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.

[@Dontworryimaprofessional]

"Liquefied thunder" 😂 thank you my friend.

[@Mrsournotes]

I love that one also!

[@drthik1]

Nothing like anchoring 30,000 hp to the ground and letting it rip

[@jurepecar9092]

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.

[@markrichards9646]

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.

[@crabcake43011]

When I worked at RR, we used to say we stand behind our engines, but never beside them!

[@zapfanzapfan]

It's like the opposite of a trebuchet :-)

[@morphius2003]

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 :)

[@FoxDuece]

Anything is dangerous if you don’t treat it with respect

[@jonginder5494]

This guy understands energy *with great clarity*. So very rare. Respect.

[@QueenOfPessimism]

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.

[@nicksexton6379]

AgentJayZ, your humour is amazing, so well delivered. Thanks for a little bit of a chuckle in these depressing times

[@quiescentnexus]

"It's idlin' " at 4:45 sounded exactly like "it's restin'" in the Monty Python parrot sketch.

[@AgentJayZ]

Why that's a compliment, sir! We don't actually handle compliments here. That's across the hall...

[@sski]

@@AgentJayZ LOL!!

[@lllateralus]

Always find myself back at your channel and enjoy the videos Ive missed. Thank you for taking the time.

[@grahamj9101]

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.

[@sionekulu7912]

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 .

[@marshallblythe7240]

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]

Also on the start carts.

[@jenniferwhitewolf3784]

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.

[@donaldstanfield8862]

The earth turns a little faster when AgentJayZ gooses those J-79s - WHEEEEEEEEEE!

[@antidecepticon]

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.

[@danlemke6407]

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...

[@MrWirebrain]

I love his last remark, that should apply to everything!

[@joefzd4040]

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.

[@dozer1642]

If it wasn’t for the comment section of KZbin, we would never be told how dangerous everyday actions are by people that have never done them.

[@AgentJayZ]

Oh, you bet, Dozer !

[@georgepbriles696]

Nice channel man 👍 I love the vids, u can learn a lot on this channel, great work Jay!

[@SkyhawkSteve]

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.

[@ajaychoudhary9817]

love it so much cant believe its been 10 years since i began following this channel

[@mcgherkinstudios]

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.

[@nopamineLevel100]

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]

I have a playlist called Our Engine Test Cell. Also, there's a search feature on my channel page.

[@nopamineLevel100]

@@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 👍📚

[@xBIGMUSCLEx]

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)??

[@AgentJayZ]

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.

[@xBIGMUSCLEx]

@@AgentJayZ Ah! I see, thanks for the explanation.

[@OVRxNxOUT]

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.

[@Breadmason]

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

[@Fragaut]

Basically, a jet engine is built to the operation standards of an industrial diesel, not those of a car engine.

[@AgentJayZ]

I guess you could say it is built for 100% duty cycle.

[@1320fastback]

@@AgentJayZ My old school Cummins diesel is rated to run at governor speed at 1,200EGT all day long.

[@hananc]

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.

[@eddean6663]

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.

[@IcthioVelocipede]

Wow. That's a hell of an expensive ladder!

[@crabcake43011]

Ouch

[@MatthijsvanDuin]

Whoopsiedoodle

[@StonehouseCinema]

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.

[@AgentJayZ]

Yes, research and development testing is far more dangerous than what we do.

[@DeliveryMcGee]

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.

[@SeanBZA]

@@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.

[@grahamj9101]

@@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.

[@StonehouseCinema]

@@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.

[@sski]

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.

[@dougbourdo2589]

Absolutely. Best description ever... especially for our current times !!!

[@andreabuzzolan9807]

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!

[@rcom9880]

Curious as to your pretest FOD check in the test cell and the path of intake air in those close quarters. Great videos, thanks!

[@AgentJayZ]

That's the subject of an upcoming vid. Stay tuned!

[@jmikronis7376]

As an electronics tech, I’ll throw in - the mems sensors that are almost too tiny to see, are what’s governing the engines parameters today. They are micro mechanical sensors.

[@sless6928]

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?

[@AgentJayZ]

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.

[@sless6928]

@@AgentJayZ Thankyou.

[@c-stofft-stoff8531]

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

[@pudmina]

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' :)

[@AgentJayZ]

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-stoff8531]

@@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

[@AgentJayZ]

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.

[@ASJC27]

@@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.

[@GEFanuc21t]

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.

[@Cletrac305]

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]

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]

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.

[@Ratlins9]

This is great stuff, thanks for showing your testing room.

[@SeanBZA]

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.

[@lwilton]

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.

[@perwestermark8920]

The sound of a military jet on afterburner is quite violent. The sound just moves through the bones.

[@oscarzt1652]

6:36 212 horsepower? are you thinking of a 2004 ford focus RS or a 2004 honda civic type R

[@77bubba00]

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!

[@HimanshuShekhar1]

You're the best teacher ever.

[@arronhyde]

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.

[@MatthijsvanDuin]

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.

[@StealthMode139]

Ty For Sharing this Worx of art. Awesome to see her run again. FL

[@Bergstaller01]

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.

[@AgentJayZ]

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.

[@jadefalcon001]

@@AgentJayZ That sounds addictive!

[@grahamj9101]

@@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.

[@AgentJayZ]

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!"

[@Bergstaller01]

@@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...

[@alsmith5604]

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.

[@AgentJayZ]

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?

[@apegues]

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

[@alsmith5604]

@@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.

[@AgentJayZ]

EGL: One answer: they don't have to be.

[@grahamj9101]

@@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.

[@thomasbelmont810]

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.

[@C-M-E]

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...

[@donrideout4919]

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.

[@Mrsournotes]

Excellent video AgentJayZ. Excellent!

[@mikelagaffe]

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....

[@AgentJayZ]

Watch my video called So you want to work on jets...

[@VinceWaldon]

Curious about how engine thrust is measured in your test cell, as I don't see any obvious load cell instrumentation. At the engine mounts, perhaps?

[@AgentJayZ]

Yes, we built a thrust test stand years ago for the J79. It is actually easier to use than this old clunker, which it replaced. I don't know why the crew used this mount, and I didn't ask. The usual, and correct one has a pivoting cradle, to which the engine is attached. The cradle transfers the thrust through piezoelectric links to the rigid anchor. Here, they have used the old anchor to hold the engine directly.

[@VinceWaldon]

​@@AgentJayZ Thanks for the response.... yep I was thinking the cradle in your older videos looks like it can pivot, which would be more suitable for load cell measurements. Once an engineer always an engineer I guess.Thanks again!

[@TheAnubite]

Does the fuel freeze?

[@burntchickennugget191]

I dont think it can freeze in any w3ather

[@AgentJayZ]

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.

[@LouT1501]

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.

[@paulpaul9914]

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!

[@VirtualJMills]

20:45 -- Not mentioned explicitly, but I'm guessing y'all also have safety / exclusion-zone policies about who is allowed to be in the spaces co-planar with those discs during tests (ideally no-one), even outside of the skin of the building. :-)

[@grahamj9101]

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.

[@AgentJayZ]

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.

[@grahamj9101]

@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.

[@aaraspensor]

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%.

[@fuzzy1dk]

it only takes some thing like 15hp to do 100km/h in car on flat a road

[@aaraspensor]

@@fuzzy1dk you are right. It is even less than 10% of average car engine maximum power.

[@aaraspensor]

@@fuzzy1dk the less power has the engine of a car the more effectively it runs.

[@manifold1476]

Spoken like a true mule driver.

[@tomreid9326]

So can I ask what your view is in regards to the QUANTAS Flight 32, ( about 10yrs ago) which had turbine disk failure which resulted in an uncontained engine failure . ? Just want to know what your thoughts are on this? Please respond

[@AgentJayZ]

Having read an excellent summary of the incidence on the Wiki page, There's really not much I can say. One thing that is not really mentioned is that is was by pure chance and great luck that the three fragments of the turbine disk all manage to depart following paths that did not cause them to impact the fuselage of the aircraft. The energy contained in a turbine disk at operating speed is tremendous, and any of those fragments would have travelled completely through the fuselage. That would result in several passenger fatalities, and the possibility of breakup of the fuselage, which would likely leave no survivors.

[@alandaters8547]

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!

[@AgentJayZ]

That one is from ser #2052. Sadly, she didn't make it.

[@cliftonbrown911]

Are there a series of tests you can perform on a jet engine (CJ-610 series) to determine the engines health, without any teardown? Such that you might perform prior to purchasing a Lear 25.

[@AgentJayZ]

The manual will list boroscope locations. Any competent A&P tech with experience on the CJ-610 is worth a couple hundred bucks an hour to talk to about this, and to hire to perform the inspection. Any Competent A&P tech without experience on the CJ-610 is worth150 an hour...

[@nicholasoliver]

Excuse any duplication but...why would the turbine blades come flying out with more energy than compressor blades?

[@AgentJayZ]

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]

@@AgentJayZ Thanks JZ I presume due to the temp difference between compressor and turbine sections.

[@GNX157]

JZ I watched the whole video about is it safe but I’ll ask you this. On a turbofan engine, such as the recent Southwest Airlines uncontained engine failure where one person died, would you feel safe walking around in your test cell or in the control booth if that engine had been in your shop, with its shroud on?

[@AgentJayZ]

Wrong question. Would I feel safe testing a freshly overhauled CFM56 turbofan? Yes. We could "what if" to the back side of infinity. Not doing that. Too busy living in the world...

[@silasmarner7586]

He never proposed walking around it while at rated power did he? Or did I miss something?

[@samcana3494]

Okay how much horse power does j_49 engine has

[@dronexfun8469]

My motto in life," just don't be in the way."

[@AgentJayZ]

I tell every visitor to make sure they are never the closest one to the engine.

[@GarageSupra]

cool video! I didn't know about those throttle control automatic restrictions, nifty.

[@whoyoulookingatabs1028]

hey Jay, I have a question. You said in Jet Questions 67 that water goes through the Bypass Duct on a Turbofan because of Centrifugal Force, what about a Turbojet?

[@AgentJayZ]

You need to clarify what you mean by "water" ... what amount. All of it will go through the core of a turbojet, but no naturally occurring amount of rain will impair the function of the engine. The heaviest rainfall in the world: a turbojet does not care.

[@grahamj9101]

@@AgentJayZ In the limit, I believe it is possible that a turbojet could be made to flame out as a result of an extreme water ingestion event - and I think it may have actually happened in flight, in the dim and distant past. I have previously told the story of the Proteus turboprop in the Bristol Britannia, which suffered flame-outs during test flights in unusual icing conditions over Africa (I think it was), in the early 1950s. If you find a cross-sectional GA of the engine, you will see that it has a reverse-flow arrangement and a radial air intake, similar to that of the P&W PT6 engine. This arrangement resulted in a long inlet duct around the engine, with a 180degree turn of the air forward into the compressor. It was discovered, the hard way during flight tests, that under certain conditions, ice would build up in the intake and large lumps would drop off, to be harmlessly 'minced' by the compressor. However, the combustors didn't like the experience of a large amount of water suddenly being delivered to them and they flamed out. It was soon established that the icing phenomenon only occurred occasionally under predictable atmospheric conditions, and that it only needed the igniters to be switched on to alleviate the problem, with no more than a momentary loss of power. Nevertheless, BOAC, the prime customer for the aircraft, demanded that an anti-icing solution for the intake be developed and tested, which delayed EIS by two years and the loss of sales to other airlines.

[@whoyoulookingatabs1028]

@@AgentJayZ I Meant during the Extreme Engine Water ingestion test where they Dump Hundreds of gallons into an engine

[@hadinossanosam4459]

Why is a turbine failure so much more damaging than a compressor failure? Are the required heat resistant materials that much heavier?

[@kjdude8765]

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.

[@rickblackwell6435]

Love flying in a Dash-8 beside the propeller! Does not bother me in the slightest.

[@rodgermiller2970]

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]

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]

@@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!

[@listerdave1240]

What are the three thick electrical cables going in to the front of the engine for?

[@DarenPage]

Looks the connections for a three phase starter/alternator

[@micstonemic696stone]

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......

[@AgentJayZ]

A 10,000 Hp jet is using 20,000Hp to run the compressor.

[@micstonemic696stone]

@@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.

[@Josectre]

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.

[@orcasea59]

Okay, this might be a stupid question, but (in a single shaft turbojet) why does the turbine section (turning at the same RPM) have so much more energy than the compressor section? Is it the material of the blades? That, alone, doesn't seem like enough of a difference to create such a difference in energy...?

[@AgentJayZ]

It's all just a lot heavier. A compressor disc weighs about 10 lbs, and has about that much in blades attached to it. A turbine disc is ten times as thick. It weighs over a hundred lbs, and has about 50lbs in blading attached. Going five hundred mph, a garbage can lid is going to really damage a car. A manhole cover is going to go right through ten cars in a row. Sorta like that.

[@orcasea59]

@@AgentJayZ Thanks, that makes sense. F = M*V. I should have remembered that!

[@manifold1476]

@@orcasea59 momentum = M*V^2

[@DinoAlberini]

“Yes it is, but we’re badasses and laugh danger in the face!”

[@kurt74ful]

Hi Agent Jayz Question! You have answered a ton of them already that I never thaught to ask. I'm just a carpenter down in new Zealand no such career in avionics or turbine generators.. So the question remains to me unanswered.. In say the jet boat and or a helicopter how does the turbine engage with the jet unit or propeller and be totally controlled as desired in relation to the turbine spinning at x thousand rpm ?

[@AgentJayZ]

1 power turbine 2 reduction gearbox 3 the main fuel control is quite sophisticated.

[@imchris5000]

how much would we have to raise for you to get a engine that is on its way out and play will it blend with it

[@AgentJayZ]

The test cell charges a 20K fee. It takes three techs a day to install the engine and get it ready to run. We would need about a hundred gallons of fuel You supply the engine You put up a bond to cover any damage to the test cell. You need to give me some incentive i.e. why am I doing this? Another day do get it out of the cell. However long it takes to clean up any mess and or damage. So as a rough guess, a half mil oughta cover it. So that's why we don't play around like that.

[@imchris5000]

@@AgentJayZ well I guess im buying lotto tickets and if I win your going to run the worlds most powerful blender lol

[@thelightninghunter23]

@@AgentJayZ So we just need all of your subscribers to pitch in a few bucks and we get to see what FOD damage looks like. I have a high speed camera that I use for lightning research... I'm more than happy to lend it if the money gets raised!

[@haraldhannelius]

Isn't there a temperature sensor controlling fuel flow too? Both the temp of the fuel and the outside air?

[@AgentJayZ]

There is an inlet air temp sensor, but fuel temp does not matter.

[@haraldhannelius]

@@AgentJayZ interesting, thanks. Fuel metered by weight?

[@AgentJayZ]

Fuel is pumped in until the fuel control is happy. It monitors EGT, RPM, and power level requested. Unlike EFI in a car, it is a closed loop system. Amount of fuel flowing is measured as a convenience to allow the crew to calculate what they have left.

[@haraldhannelius]

@@AgentJayZ thank You!

[@ASJC27]

@@AgentJayZ Modern EFI is also a closed-loop system. The loop is closed around the reading of the lambda sensor, i.e. it actively adjusts the amount of fuel injection to reach a desired air-fuel ratio.

[@khaledyousfi7160]

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

[@AgentJayZ]

If you keep trying, you will.

[@khaledyousfi7160]

@@AgentJayZ ❤️❤️

[@darrensworkshop6783]

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...

[@LK-pc4sq]

A few years ago I was flown by a company into Quesnel BC for work. Now I get a idea just how remote your life is in FSJ. I do not live in Vancouver anymore. I moved back to Washington. Cost was out of control. Should have moved north :( but it is what it is. Love your explanation of this engine. BTW is air injected into the oil and is there a air/oil separator like that of a T58-GE engine?The more modern T58 used a carbon carbon seal. Care to explain what that type of seal is?

[@roysegal4594]

Hello Agent, are you able to refer to the United airlines engine fire video and explain what was going on there?

[@AgentJayZ]

That will be happening soon. I have watched the same clip you have seen, but I think I might wait until Blancolirio supplies us with a few more details.

[@Alexander470815]

I guess the propane has to be very hot to not condense back into a liquid under these pressures? Because ist must overcome the pressure inside the combustor to even get it in, or is there some kind of special injector in it? For natural gas this is of course not a problem.

[@joevignolor4u949]

Jet engines used in airplanes don't run on propane or natural gas. They run on jet fuel, which is basically liquid kerosene. In some cases turbine engines are converted for industrial use and they do burn natural gas instead of jet fuel. In any case the compressor discharge pressure and the discharge pressure of the fuel supply (using either liquid or gaseous fuel) must be higher than the pressure inside the combustion section so as to maintain positive flow going into the combustors.

[@AgentJayZ]

The propane is heated to about 100C. The fuel nozzles used can be seen in my videos called Jet Fuel Nozzles

[@ivarbiermann9278]

Hows the dutch starfighter engine??

[@AgentJayZ]

Shipped quite a while ago.

[@ivarbiermann9278]

@@AgentJayZ havent heard of it from the dutch side but good to hear!

[@grahamhaynes4284]

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!

[@epicspacetroll1399]

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?

[@grahamhaynes4284]

@@epicspacetroll1399 It happened in the 1970's. A lot of lessons have been learned since then.

[@epicspacetroll1399]

@@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! :)

[@bobroberts2371]

And then the engine is attached to the side of a tin can flying at 35,000 Ft.

[@davidsavage6227]

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]

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.

[@changefromabill1637]

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]

Set by a C4 ZR-1 with the Lotus-designed, Mercury-built LT5 DOHC V8.

[@CMDRSweeper]

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.

[@AgentJayZ]

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.

[@bobrice3957]

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.

[@grahamj9101]

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.

[@MatthijsvanDuin]

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

[@MrAsBBB]

Great explanation

[@tomminystrom]

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.

[@AgentJayZ]

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.

[@altinfoil592]

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.