Boeing 787 engines
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50 twin-engine 787's - One hundred installed T1000's. If retrofit is needed, it will also no doubt include spare engines. Any Idea how many spares?
If a couple come off every day and a spare goes on per aircraft it doesn't seem like any more spares than usual are needed.
In the end the risk analysis should ensure that its extremely unlikely that more than one engine loses power or has to be shut down in the life of the retrofit program.
On the other hand if one becomes too aggressive in swapping out engines like two at a time. human error becomes a more significant risk
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Based on ANA statements initial problem was noticed in long haul fleet, later found in short haul fleet. This contradicts initial reports claiming ANA high-cycle short haul was unique. What about other Trent 1000 operators.
RR fanboys are not happy with ANA demanding RR to fix all engines, same fanboys who quickly claimed GE was the reason for BA276@LAS.
RR fanboys are not happy with ANA demanding RR to fix all engines, same fanboys who quickly claimed GE was the reason for BA276@LAS.
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OLD RED DAMASK
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It is disturbing.......that one or two posters don't know the difference between Fan, Compressor & Turbine blades.
Did 500's, 700's and 1000's. Plus discs for the BR710 series. A lot of it has transferred to Singapore now.
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lasernigel,
Let's get the terminology correct. This thread isn't about fan blades, it is about an intermediate turbine blade that is apparently problem on the Trent 1000 as experienced by ANA.
Fan blades are in the very front of the engine and run cool. Turbine blades are towards the rear of the engine, aft of the combustor and run hot. Fan blades, some early stages of the compressor (low pressure) and some discs in the fan or early stages of the compressor may very well be made of titanium. In the turbine, there are no titanium blades, vanes or turbine discs because of the high temperatures being experienced. There may be titanium aluminide turbine blades in the very last stage of a five or six stage low pressure turbine of certain engines dependent on temperatures being experienced, but that is only because titanium aluminide has somewhat improved high temperature capability verses common titanium alloys.
Main fan blades are not intermediate turbine blades.
Let's get the terminology correct. This thread isn't about fan blades, it is about an intermediate turbine blade that is apparently problem on the Trent 1000 as experienced by ANA.
Fan blades are in the very front of the engine and run cool. Turbine blades are towards the rear of the engine, aft of the combustor and run hot. Fan blades, some early stages of the compressor (low pressure) and some discs in the fan or early stages of the compressor may very well be made of titanium. In the turbine, there are no titanium blades, vanes or turbine discs because of the high temperatures being experienced. There may be titanium aluminide turbine blades in the very last stage of a five or six stage low pressure turbine of certain engines dependent on temperatures being experienced, but that is only because titanium aluminide has somewhat improved high temperature capability verses common titanium alloys.
Main fan blades are not intermediate turbine blades.
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lasernigel:
Could you share with us the approximate dimensions of these blades?
Worked for a company that used a l@ser to harden the 1000 blades. I can assure you that they are titanium.
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Seems to be some disagreement re the engine components. This may help: How jet engine is made - material, manufacture, history, used, parts, components, dimensions, product, industry and http://www.azom.com/article.aspx?ArticleID=11454
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Wow. Ugh. The How Products Are Made article has several factual and historical errors that need to be addressed. I've seen better stuff in Popular Science.
I didn't even get as far as the manufacturing processes; i hope this section is more accurate & up-to-date.
I didn't even get as far as the manufacturing processes; i hope this section is more accurate & up-to-date.
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Well after reading the linked explanations above it would seem that you can't even trust the internet to know the differences between fan, compressor and turbine blade materials or manufacturing.
Now back to the thread subject. Suffice it to say that the Subject engine problems are turbine blades which are quite different in design, manufacturing, operation and repair from the blades in fans or compressors.
Now back to the thread subject. Suffice it to say that the Subject engine problems are turbine blades which are quite different in design, manufacturing, operation and repair from the blades in fans or compressors.
Thread Starter
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As one might expect from a publication that specialises in Materials Science, in fact.
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Pity, apart from that one unfortunate typo/spellcheck fail the rest of the article is actually a pretty reasonable rundown on what materials are used in which parts of a turbofan.
I've yet to hear of a common usage of the "lost wax" process in compressor blades
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They did fine with materials, but not the where they are used part, which seems to have misled some folks in this thread
Turbine blades are investment cast because of the high temperature materials now required. In the olden days, turbine blades were forged, but the forged alloys didn't have the higher temperature or the internal air-cooling sophistication capabilities that investment cast turbine blades can provide made with ceramic cores, forming the intricate internal cooling passages. Investment cast turbine blades can be produced with random equiax grain control, directionally solidified grain control or as a single crystal where the entire turbine blade contains no grain boundaries.
Fan blades have been made for many years using titanium alloys and forging processes. Today fan blades on newer engines are being produced using composite materials to reduce weight, improve strength and improve resistance to foreign object damage (bird strike, etc.).
Hope this information is helpful as the articles referenced left quite a bit to be desired and are misleading in some instances.
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The challenge for forging turbine blades (in the old days) and turbine discs, is that the materials used are the ultimate available in resisting deformation at high temperature. Sort of Catch 22!
