Building the RR Trent 700 and 1000 (video, 59:11)

Thanks for sharing.

I had seen that a while ago. You have to love youtube..anything you can think of is on there somewhere. There is a great one (mega factorys i think) on the Lear Jet Company.

Great stuff

 

That was a great show. Very interesting all the way thru. Some key points for me;

The tig welding being performed by the older gent was the most difficult job there. I learned tig welding years ago at a trade school for a hobby type of thing. It is fun, but that position was almost impossible that he had to do, he should be paid a large amount of money for the skill/difficulty/responsibility. (similar to another discussion)


I have always been amazed that these engines can stay lit with all that water passing thru them.

I learned that these engines are not really "jets" but really jet powered modernized propellers pushing lots of air that never goes into the jet.

And businesses like these are important to countries and everybody as they are things to marvel at and elevate everyone. That is why it was so bad to see a lot leave the US over the last 30 years but happy to see a lot coming back now. I worked during school break at a similar aircraft industry heavy manufacturer once and watched large pieces coming out of furnaces glowing orange and being pounded by presses into shape.

 

Fanjet... sort of a turbojet with a fan on the front...

Then there's the turbojet, as in the Concorde.

And the turboprop, sort of a turbojet with a propeller instead of a fan... the propeller is not ducted...


I still remember when Rolls Royce went under (and took Lockheed commercial avaition with it) many years ago.
The L-1011 was a better plane than the DC-10.

 

For fan engines (like the one shown) most of the water doesn't really go through the core of the engine. What happens is that the core gets its air from an area near the hub of the fan, and that inlet is behind a "hump" in the flow path behind the fan. In order to get through the fan the water has to accelerate to fan speed or to put it in another way it has to spin with the fan. This rotation tends to sling the water (and other foreign objects in the flowpath out from the hub. As a result, most of the water gets "centrifuged" away from the core inlet and it doesn't go through the core, it just goes out of the fan duct and out the exhaust.

If a lot of water goes through the core it can do a lot more than just put the flame out. There was a DC-9 that lost both engines in a thunderstorm and consequently crashed. The engines ingested water into the core and the water turned to steam, causing the turbines to overspeed and that shucked all the blades. Pratt tried to recreate the failure and had big fire hoses spraying at the fans and couldn't cause the engines to fail. They were stumped. Then they left the hoses on and brought the engine to idle, and the engine blew up. When the speed went down the water went through the core and caused the failure, since at lower fan speed the water wasn't going out the fan duct anymore.

Turboshaft and turboprops can ingest a lot of water, and in these engines it all goes through the core, but it's not like a fan engine, but P3's are used in the hurricane hunters for the last 50 years and never had problems with putting the engine out with water, but the inlet is smaller and not as much water is captured by the smaller inlet.

 

Hmmm, I was waiting to see them shoot chickens into the running engine... (or geese)...


Also, they talked a lot about the engine casing being able to withstand a blade.

I remember a DC-10 that had a whole fan disc come off (Sioux City)... it went right through the case, severing hydraulic lines. That was much older engine technology, though, and GE engines.

 

Bird ingestion is always a tough test. The basic requirement is to be able to shut the engine down successfully after a 5 pound bird, but it does nasty things to the blading.

The requirement is to be able to contain a fan blade if one were to fail. Nowadays they use a kevlar wrap around the fan case to "catch" the blade before it gets out. There's a huge amount of energy in a rotating blade, so containment is always a problem. Turbine cases are also designed to contain a blade failure.

If a disk fails you aren't going to contain it in any engine, the criteria hasn't changed. There is simply way too much energy. If you designed it to contain it the engine would literally weigh tons more, so you design for a specific LCF life with the largest allowabe flaw and then inspect to insure you never get a crack or flaw that big. If you do you take the part out of service.

The GE engine that failed a disk had a manufacturing flaw in the hub that grew into a low cycle fatigue crack and then the disk broke into three pieces (a classic "tri-hub" burst failure). The flaw should have been caught in the manufacturing process, but it apparently wasn't.

The disk in the RR engine that burst on the A380 also broke into three pieces, same type failure, but this was caused by higher temperature in the disk cavity due to the oil leak, the higher temp reduced the material strength and the disk burst. Different mechanism, same result.

The fact that we are talking about two very isolated instances out of the thousands of successful flights per day, and lots of years between failures shows that the process is actually pretty good, but there really isn't any way you are going to contain a disk failure.

 

thanks for the info ^^, water - kinda like the amusement park barrel ride where the floor falls out when spinning fast enough.


Here is a cool little vid I bookmarked that goes with this one -

[ame=http://www.youtube.com/watch?v=mLGqrsjILo4]Making the Boeing 777-300ER . - YouTube[/ame]

 

And the only commercial jet cooler imo than the 777 is the 747-800, another great quick video;

[ame=http://www.youtube.com/watch?v=CdDN3v4eiSQ]Our new arrival the 747-8 Freighter - YouTube[/ame]

 

I just watched a very interesting hour long vid produced by Australia's Four Corners about the trouble on Qantas Flight 32 from Singapore to Sydney. Very interesting and related to this thread.