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WholaLottaLove
Topic Author
Posts: 55
Joined: Sat Sep 24, 2016 10:46 pm

Why wouldn't the Trent 1000-TEN problems also show up in the Trent XWB?

Mon Feb 17, 2020 8:32 pm

I have a question for the engine experts on this forum: Why wouldn't the Trent 1000-TEN problems also show up in the Trent XWB?

As a recap, there are three problems with the Trent 1000-TEN:

  • IP compressor (vibrations can cause the blades to crack)
  • IP turbine (corrosion-related fatigue cracking of intermediate-pressure turbine blades)
  • HP turbine (durability issue, mainly coating related)

Conceptually, the Trent XWB and the Trent 1000-TEN can be compared like this:

Trent XWB
Compressor 8-stage IP, 6-stage HP
Combustor 20-off fuel spray nozzles
Turbine Single Stage HP, 2-stage IP, 6-stage LP

Trent 1000-TEN
Compressor 8-stage IP, 6-stage HP
Combustor 18-off fuel spray nozzles
Turbine Single Stage HP, 1-stage IP, 6-stage LP

When the Trent 1000-TEN was released, RR stated the following: "The single biggest contributor to improved fuel burn in the TEN comes from the new compressor system. It employs a scaled version of the IP and HP compressors from the Trent XWB-84. The HP turbine architecture is shared with the Trent XWB-97 and will provide better component life results for the Trent 1000 in service."

This leads to three questions/remarks:

  • As can be seen, the compressor design seems to be pretty much the same, in fact, the Trent 1000-TEN "features a scaled version of the Airbus A350's Trent XWB-84 compressor". What makes RR confident not to endure the same issues on the XWB as they encountered on the Trent 1000-TEN with regards to the compressor?
  • There are differences in the turbine section, notably the 1-stage IPT in the Trent 1000 versus a 2-stage IPT in the Trent XWB which makes it unlikely that RR will witness the same ITP.
  • Both engines use a single-stage HP "turbine architecture [which] is shared with the Trent XWB-97". On the Trent 1000-TEN the HPT is already showing durability issues, wouldn't we expect these issues also to crop up in the XWB given its even higher thrust rating?

RR's counterargument taken from another article is this:

"While acknowledging the difficulties experienced by some operators of Trent 1000 engines on Boeing 787s, relating to compressor blade durability, Cholerton says he has "very high confidence" that the Trent XWB will not face similar or related issues.

He says that the XWB has a different architecture, and adds: "[The] magnitude of testing, the magnitude of experience we have, and the experience to date in the fleet – of those 1.3 million flying hours – has been exceptional."

For the -1000 the XWB-97 incorporates an improved, higher-speed fan, a larger core, and new materials and coatings for protection.

The manufacturer ran 10 XWB-97 development engines over 3.5 years, exposing them to extreme conditions in five countries, and logging over 11,000 simulated flight cycles, as well as 1,600h of flight tests."


Especially regarding the IPC and the HPT, there seem to be commonalities between the TEN and the XWB which makes me wonder whether the same problems will not crop up in the XWB as well? - Yes, so far the XWB has not really suffered any meaningful IFSDs, but then again only a very small percentage of the installed base has reached their 5th year yet.
 
ILikeTrains
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Re: Why wouldn't the Trent 1000-TEN problems also show up in the Trent XWB?

Mon Feb 17, 2020 8:37 pm

Biggest difference I could tell is that the Trent 1000 and 787 don’t use bleed air. Other than that, I would guess the XWB is just a big 1000.
 
goosebayguy
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Re: Why wouldn't the Trent 1000-TEN problems also show up in the Trent XWB?

Mon Feb 17, 2020 9:02 pm

The Trent 1000 has had a few problems since introduction, These will be sorted, However the XWB is a massive success story. Its a huge success. It makes the A350 fabulous.
 
Waterbomber2
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Re: Why wouldn't the Trent 1000-TEN problems also show up in the Trent XWB?

Mon Feb 17, 2020 9:17 pm

There could be several reasons,from slightly different materials/alloys being used, to different vendors for similar parts with the XWB vendors sticking to specs and the TEN ones not. It could also be that the XWB engines have more margins built in to them.
There could also be conspiracies, sabotage by the competing engine options which you dont have on the XWB. Unlikely but not impossible.
 
VSMUT
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Re: Why wouldn't the Trent 1000-TEN problems also show up in the Trent XWB?

Mon Feb 17, 2020 9:47 pm

The 787 doesn't use bleed air. That means putting more generators on it, causing more mechanical friction. Jet engines never did well with mechanical friction. The 787 was also rushed, with the planned rollout in 2007 and EIS not too long after. That caused unneccesary rush by Rolls Royce. Had they had the 3 extra years to develop it from the get go, the final result would likely have been better.
 
WholaLottaLove
Topic Author
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Re: Why wouldn't the Trent 1000-TEN problems also show up in the Trent XWB?

Tue Feb 18, 2020 9:40 am

VSMUT wrote:
The 787 doesn't use bleed air. That means putting more generators on it, causing more mechanical friction. Jet engines never did well with mechanical friction. The 787 was also rushed, with the planned rollout in 2007 and EIS not too long after. That caused unneccesary rush by Rolls Royce. Had they had the 3 extra years to develop it from the get go, the final result would likely have been better.


Thank you for your reply. I totally see your point regarding bleed air and the certainly rushed (and by Boeing upsized) development. However, what does concern me is that there are some commonalities between the Trent 1000 and the XWB since they employ essentially the same IP and HP compressors as well as HP turbine architecture, both of which (compressor and HPT) causing the big problems on the Trent 1000. Hence why wouldn't those issues also show up in the XWB?
 
VSMUT
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Re: Why wouldn't the Trent 1000-TEN problems also show up in the Trent XWB?

Tue Feb 18, 2020 10:56 am

WholaLottaLove wrote:
VSMUT wrote:
The 787 doesn't use bleed air. That means putting more generators on it, causing more mechanical friction. Jet engines never did well with mechanical friction. The 787 was also rushed, with the planned rollout in 2007 and EIS not too long after. That caused unneccesary rush by Rolls Royce. Had they had the 3 extra years to develop it from the get go, the final result would likely have been better.


Thank you for your reply. I totally see your point regarding bleed air and the certainly rushed (and by Boeing upsized) development. However, what does concern me is that there are some commonalities between the Trent 1000 and the XWB since they employ essentially the same IP and HP compressors as well as HP turbine architecture, both of which (compressor and HPT) causing the big problems on the Trent 1000. Hence why wouldn't those issues also show up in the XWB?


Jet engines have historically used bleed air to regulate airflow in the engine, to prevent stalls and surges. A compressor surge could result in the damage seen on the RR 787 engines. IMO, it could be that the bleedless technology in combination with the added force from the generators are not up to that task.

We just aren't seeing the A350 engines fall apart like the 787 engines are. The cause clearly lies with the 787 specific modifications. The A350 has seen 5 years of service with minimal issues. You already had 787-10s with RR engines falling apart just 1 year after that variants entered service.
 
mxaxai
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Re: Why wouldn't the Trent 1000-TEN problems also show up in the Trent XWB?

Tue Feb 18, 2020 11:39 am

VSMUT wrote:
Jet engines have historically used bleed air to regulate airflow in the engine, to prevent stalls and surges. A compressor surge could result in the damage seen on the RR 787 engines. IMO, it could be that the bleedless technology in combination with the added force from the generators are not up to that task.

787 engines still use bleed air internally, they just don't provide bleed air to the aircraft systems.

Further, it doesn't matter much how you extract energy from the engine, i.e. by bleed air or by electrical generators. Jet engine derivatives have been used for centuries as electrical power generators without issues, in stationary applications as well as for ship propulsion.

Corrosion and coating durability point towards slightly different materials and/or slightly different operating conditions (higher temperature/pressure or different combustion products). Also, the 1-stage IP on the T1000 probably has to do more work, per stage, than the 2-stage IP on the T-XWB for the same number of IPC stages, so likely higher forces on each blade and thus higher susceptibility to fatigue.
 
787SIN
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Re: Why wouldn't the Trent 1000-TEN problems also show up in the Trent XWB?

Tue Feb 18, 2020 11:51 am

The main issues with the Trent 1000/Ten engine are with the IP section both IPC and IPT. I've not seen this mentioned much but the power offtake for the generators/gearbox is from the IP section on this engine due to the genys and believe the XWB reverts back to Roll's traditional location for power offtake being the HP section. This certainly could be a consideration as is quite a significant difference.
Last edited by 787SIN on Tue Feb 18, 2020 11:51 am, edited 1 time in total.
 
VSMUT
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Re: Why wouldn't the Trent 1000-TEN problems also show up in the Trent XWB?

Tue Feb 18, 2020 11:51 am

mxaxai wrote:
VSMUT wrote:
Jet engines have historically used bleed air to regulate airflow in the engine, to prevent stalls and surges. A compressor surge could result in the damage seen on the RR 787 engines. IMO, it could be that the bleedless technology in combination with the added force from the generators are not up to that task.

787 engines still use bleed air internally, they just don't provide bleed air to the aircraft systems.


I know they do, but I do speculate if they maybe made some changes to that too. Without the need to bleed air off to pressurize the cabin and run air conditioning, the total bleed capacity must be somewhat smaller.

mxaxai wrote:
Further, it doesn't matter much how you extract energy from the engine, i.e. by bleed air or by electrical generators.


Yes it does.
 
mxaxai
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Re: Why wouldn't the Trent 1000-TEN problems also show up in the Trent XWB?

Tue Feb 18, 2020 12:02 pm

VSMUT wrote:
mxaxai wrote:
Further, it doesn't matter much how you extract energy from the engine, i.e. by bleed air or by electrical generators.


Yes it does.

No it doesn't. The turbine provides power to its shaft. This power is used by devices connected to the shaft, like the compressor, electrical generators and other auxiliary devices. Turboprops use turbines where 100% of their power output is used by the prop, with none of the air passing through that going to the turbine (like bleed air wouldn't either). Electrical power stations use turbines that are only connected to a generator. The turbine doesn't care what's connected on the other end of its shaft.
 
WholaLottaLove
Topic Author
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Re: Why wouldn't the Trent 1000-TEN problems also show up in the Trent XWB?

Tue Feb 18, 2020 1:06 pm

787SIN wrote:
The main issues with the Trent 1000/Ten engine are with the IP section both IPC and IPT. I've not seen this mentioned much but the power offtake for the generators/gearbox is from the IP section on this engine due to the genys and believe the XWB reverts back to Roll's traditional location for power offtake being the HP section. This certainly could be a consideration as is quite a significant difference.


That is very interesting! Does this also have to do with the bleed-air differences between TEN/XWB?
 
Dalmd88
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Re: Why wouldn't the Trent 1000-TEN problems also show up in the Trent XWB?

Tue Feb 18, 2020 1:47 pm

787SIN wrote:
The main issues with the Trent 1000/Ten engine are with the IP section both IPC and IPT. I've not seen this mentioned much but the power offtake for the generators/gearbox is from the IP section on this engine due to the genys and believe the XWB reverts back to Roll's traditional location for power offtake being the HP section. This certainly could be a consideration as is quite a significant difference.

All three; 1000, 7000 and the XWB have the same gearbox shaft arrangement which is connected to the IP module. The 1000 and the 7000 also are having HPT blade issues while the 7000 IPT are not having problems at this time.
 
lowbank
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Re: Why wouldn't the Trent 1000-TEN problems also show up in the Trent XWB?

Tue Feb 18, 2020 4:16 pm

The best way it’s been described in layman’s term’s to me. RR employee.

The T1000-ten is akin to a Ferrari V12 F1 engine.
The XWB is more like a Camaro V8 road engine.

I have had the privilege of sitting through some lunch and learn presentations on the T1000 component issues, the work that’s gone into finding the true root cause and the fixes.
In every case it is the work establishing the true root cause that takes all the time and is the most interesting. I apologise I cannot go into detail.

So the short answer is that the T1000-ten has pushed all areas of the engine harder hence showing up any issues quicker and higher frequency.
Hence it’s not expected to see similar issues with the XWB.
Every days a school day.
 
WholaLottaLove
Topic Author
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Re: Why wouldn't the Trent 1000-TEN problems also show up in the Trent XWB?

Tue Feb 18, 2020 4:47 pm

lowbank wrote:
The best way it’s been described in layman’s term’s to me. RR employee.

The T1000-ten is akin to a Ferrari V12 F1 engine.
The XWB is more like a Camaro V8 road engine.

I have had the privilege of sitting through some lunch and learn presentations on the T1000 component issues, the work that’s gone into finding the true root cause and the fixes.
In every case it is the work establishing the true root cause that takes all the time and is the most interesting. I apologise I cannot go into detail.

So the short answer is that the T1000-ten has pushed all areas of the engine harder hence showing up any issues quicker and higher frequency.
Hence it’s not expected to see similar issues with the XWB.


But wouldn't this mean that the problems will also show up on the XWB, just later? (Given the design communality and similar root-causes).
 
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Erebus
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Re: Why wouldn't the Trent 1000-TEN problems also show up in the Trent XWB?

Tue Feb 18, 2020 5:15 pm

WholaLottaLove wrote:
lowbank wrote:
The best way it’s been described in layman’s term’s to me. RR employee.

The T1000-ten is akin to a Ferrari V12 F1 engine.
The XWB is more like a Camaro V8 road engine.

I have had the privilege of sitting through some lunch and learn presentations on the T1000 component issues, the work that’s gone into finding the true root cause and the fixes.
In every case it is the work establishing the true root cause that takes all the time and is the most interesting. I apologise I cannot go into detail.

So the short answer is that the T1000-ten has pushed all areas of the engine harder hence showing up any issues quicker and higher frequency.
Hence it’s not expected to see similar issues with the XWB.


But wouldn't this mean that the problems will also show up on the XWB, just later? (Given the design communality and similar root-causes).


I guess what he means is that everything ends up with some wear and tear at some point. Just a matter of when. F1 engines barely last more than a couple of races and operate within very small margins of error. Road engines are built to be longer lasting even though some wear and tear will be expected during normal use.
 
dc10lover
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Re: Why wouldn't the Trent 1000-TEN problems also show up in the Trent XWB?

Tue Feb 18, 2020 5:21 pm

Can you attach a Trent XWB Jet Engine to the Boeing 787?
Last edited by dc10lover on Tue Feb 18, 2020 5:23 pm, edited 1 time in total.
Why endure the nightmare and congestion of LAX when BUR, LGB, ONT & SNA is so much easier to fly in and out of. Same with OAK & SJC when it comes to SFO.
 
dstblj52
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Re: Why wouldn't the Trent 1000-TEN problems also show up in the Trent XWB?

Tue Feb 18, 2020 5:21 pm

WholaLottaLove wrote:
lowbank wrote:
The best way it’s been described in layman’s term’s to me. RR employee.

The T1000-ten is akin to a Ferrari V12 F1 engine.
The XWB is more like a Camaro V8 road engine.

I have had the privilege of sitting through some lunch and learn presentations on the T1000 component issues, the work that’s gone into finding the true root cause and the fixes.
In every case it is the work establishing the true root cause that takes all the time and is the most interesting. I apologise I cannot go into detail.

So the short answer is that the T1000-ten has pushed all areas of the engine harder hence showing up any issues quicker and higher frequency.
Hence it’s not expected to see similar issues with the XWB.


But wouldn't this mean that the problems will also show up on the XWB, just later? (Given the design communality and similar root-causes).

Depends not all stress on parts result in linear damage some are exponentially and some follow other damage patterns it's possible when they designed the Trent xwb they did an end run around a fairly core problem with the Trent 1000 that their still trying to patch
 
rbavfan
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Re: Why wouldn't the Trent 1000-TEN problems also show up in the Trent XWB?

Tue Feb 18, 2020 5:29 pm

WholaLottaLove wrote:
I have a question for the engine experts on this forum: Why wouldn't the Trent 1000-TEN problems also show up in the Trent XWB?

As a recap, there are three problems with the Trent 1000-TEN:

  • IP compressor (vibrations can cause the blades to crack)
  • IP turbine (corrosion-related fatigue cracking of intermediate-pressure turbine blades)
  • HP turbine (durability issue, mainly coating related)

Conceptually, the Trent XWB and the Trent 1000-TEN can be compared like this:

Trent XWB
Compressor 8-stage IP, 6-stage HP
Combustor 20-off fuel spray nozzles
Turbine Single Stage HP, 2-stage IP, 6-stage LP

Trent 1000-TEN
Compressor 8-stage IP, 6-stage HP
Combustor 18-off fuel spray nozzles
Turbine Single Stage HP, 1-stage IP, 6-stage LP

When the Trent 1000-TEN was released, RR stated the following: "The single biggest contributor to improved fuel burn in the TEN comes from the new compressor system. It employs a scaled version of the IP and HP compressors from the Trent XWB-84. The HP turbine architecture is shared with the Trent XWB-97 and will provide better component life results for the Trent 1000 in service."

This leads to three questions/remarks:

  • As can be seen, the compressor design seems to be pretty much the same, in fact, the Trent 1000-TEN "features a scaled version of the Airbus A350's Trent XWB-84 compressor". What makes RR confident not to endure the same issues on the XWB as they encountered on the Trent 1000-TEN with regards to the compressor?
  • There are differences in the turbine section, notably the 1-stage IPT in the Trent 1000 versus a 2-stage IPT in the Trent XWB which makes it unlikely that RR will witness the same ITP.
  • Both engines use a single-stage HP "turbine architecture [which] is shared with the Trent XWB-97". On the Trent 1000-TEN the HPT is already showing durability issues, wouldn't we expect these issues also to crop up in the XWB given its even higher thrust rating?

RR's counterargument taken from another article is this:

"While acknowledging the difficulties experienced by some operators of Trent 1000 engines on Boeing 787s, relating to compressor blade durability, Cholerton says he has "very high confidence" that the Trent XWB will not face similar or related issues.

He says that the XWB has a different architecture, and adds: "[The] magnitude of testing, the magnitude of experience we have, and the experience to date in the fleet – of those 1.3 million flying hours – has been exceptional."

For the -1000 the XWB-97 incorporates an improved, higher-speed fan, a larger core, and new materials and coatings for protection.

The manufacturer ran 10 XWB-97 development engines over 3.5 years, exposing them to extreme conditions in five countries, and logging over 11,000 simulated flight cycles, as well as 1,600h of flight tests."


Especially regarding the IPC and the HPT, there seem to be commonalities between the TEN and the XWB which makes me wonder whether the same problems will not crop up in the XWB as well? - Yes, so far the XWB has not really suffered any meaningful IFSDs, but then again only a very small percentage of the installed base has reached their 5th year yet.



The single stage IPT could be causing vibration issues in the IPC due to only 1 stage driving the IPC.
 
WIederling
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Re: Why wouldn't the Trent 1000-TEN problems also show up in the Trent XWB?

Tue Feb 18, 2020 6:12 pm

mxaxai wrote:
VSMUT wrote:
mxaxai wrote:
Further, it doesn't matter much how you extract energy from the engine, i.e. by bleed air or by electrical generators.


Yes it does.

No it doesn't. The turbine provides power to its shaft. This power is used by devices connected to the shaft, like the compressor, electrical generators and other auxiliary devices. Turboprops use turbines where 100% of their power output is used by the prop, with none of the air passing through that going to the turbine (like bleed air wouldn't either). Electrical power stations use turbines that are only connected to a generator. The turbine doesn't care what's connected on the other end of its shaft.


With bleed air you take away from the adiabatic compression path and thus touch on overall pressure ratio.
This cuts into efficiency. ( Just like open bleeds to give surge margin to mismatched compressor sections. ask LS )

Obviously, and In the end any kind of power take off increases fuel burn.
What is more efficient?
create shaft power at minimally better sfc but an overall higher powerlevel ( the E generation power delta incl. efficiency issues )
or
derate sfc by compressed air offtake but no power offtake at shaft level.

I would not be surprised if this isn't a wash with niggly details making the difference.
Murphy is an optimist
 
uta999
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Re: Why wouldn't the Trent 1000-TEN problems also show up in the Trent XWB?

Tue Feb 18, 2020 6:18 pm

dc10lover wrote:
Can you attach a Trent XWB Jet Engine to the Boeing 787?


You can but due to the fan size, you would need to mount it further forward and higher. Oh wait....

We have software that can deal with that.
Your computer just got better
 
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Revelation
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Re: Why wouldn't the Trent 1000-TEN problems also show up in the Trent XWB?

Tue Feb 18, 2020 6:48 pm

lowbank wrote:
So the short answer is that the T1000-ten has pushed all areas of the engine harder hence showing up any issues quicker and higher frequency.
Hence it’s not expected to see similar issues with the XWB.

Thanks, that's a far better answer than the boss gave ( https://www.flightglobal.com/systems-an ... 59.article ).

Of course the next question would be why aren't they pushing XWB harder? ;)

Hopefully these T1000 fixes are finally settling down and it can become as well regarded as TXWB is.
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Wake now, discover that you are the song that the morning brings
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marcelh
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Re: Why wouldn't the Trent 1000-TEN problems also show up in the Trent XWB?

Tue Feb 18, 2020 7:35 pm

uta999 wrote:
dc10lover wrote:
Can you attach a Trent XWB Jet Engine to the Boeing 787?


You can but due to the fan size, you would need to mount it further forward and higher. Oh wait....

We have software that can deal with that.

I see what you did there :mrgreen:
 
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novarupta
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Re: Why wouldn't the Trent 1000-TEN problems also show up in the Trent XWB?

Tue Feb 18, 2020 7:54 pm

mxaxai wrote:
VSMUT wrote:
mxaxai wrote:
Further, it doesn't matter much how you extract energy from the engine, i.e. by bleed air or by electrical generators.


Yes it does.

No it doesn't. The turbine provides power to its shaft. This power is used by devices connected to the shaft, like the compressor, electrical generators and other auxiliary devices. Turboprops use turbines where 100% of their power output is used by the prop, with none of the air passing through that going to the turbine (like bleed air wouldn't either). Electrical power stations use turbines that are only connected to a generator. The turbine doesn't care what's connected on the other end of its shaft.


What you’re saying only holds true for a single shaft motor. The RR Trent is a triple shaft motor. Simply unloading one shaft and loading another can and does make a difference. Most turbine motors in service today are dual or triple shaft designs.
 
lowbank
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Re: Why wouldn't the Trent 1000-TEN problems also show up in the Trent XWB?

Tue Feb 18, 2020 7:55 pm

Revelation wrote:
lowbank wrote:
So the short answer is that the T1000-ten has pushed all areas of the engine harder hence showing up any issues quicker and higher frequency.
Hence it’s not expected to see similar issues with the XWB.

Thanks, that's a far better answer than the boss gave ( https://www.flightglobal.com/systems-an ... 59.article ).

Of course the next question would be why aren't they pushing XWB harder? ;)

Hopefully these T1000 fixes are finally settling down and it can become as well regarded as TXWB is.


All I can say is the root cause analysis I have witnessed and the fixes were comprehensive, after 39 years in the industry I certainly had no questions. Which I normally do !!
Every days a school day.
 
lowbank
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Re: Why wouldn't the Trent 1000-TEN problems also show up in the Trent XWB?

Tue Feb 18, 2020 8:08 pm

All I can say to you guys is, as I understand it.

We are given a fan diameter and a power output required, SFC etc.
Normally the power request goes up but the fan size stays the same.

Go figure what happens.

Going back to the XWB, as I remember it.

The initial request was around 80k and 90k thrust but airbus wanted the same engine just an engine management tweak to change the power output.
GE and RR offered a solution on that basis.
The power out put rose to 97k , GE bugged out as it didn’t want to design two engines.
RR offered to hurry a design of a 97k engine but the Airbus restriction was it had to fit into the 84k nacelle. That still today is giving us issues on my component in particular.
The 84k engine is still running 6k below the initial design ask, therefore it’s less stressed.


Does that explain it better???
Every days a school day.
 
9Patch
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Re: Why wouldn't the Trent 1000-TEN problems also show up in the Trent XWB?

Tue Feb 18, 2020 8:20 pm

VSMUT wrote:
The 787 doesn't use bleed air. That means putting more generators on it, causing more mechanical friction. Jet engines never did well with mechanical friction. The 787 was also rushed, with the planned rollout in 2007 and EIS not too long after. That caused unneccesary rush by Rolls Royce. Had they had the 3 extra years to develop it from the get go, the final result would likely have been better.

The 787 was three years late so RR did had an extra three years to develop it!
Why aren't GE on the 787 having similar problems?
 
Okcflyer
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Re: Why wouldn't the Trent 1000-TEN problems also show up in the Trent XWB?

Tue Feb 18, 2020 8:40 pm

The talk about larger 787 generators consuming more shaft power being the root cause of these durability problems is nonsense. It may well be an intermediate cause due to poor engineering and testing by RR but it’s definitely not a root cause. GENx has proven the unique 787 architecture is reliable, regardless of whether it was worth the investment for the architecture change.

Either RR was unintentionally lucky on the XWB or there were intentional factors and risks they knowingly took on the TEN update. Personally, I suspect the XWB has a couple of small changes that, through dumb luck, made it a more durable design than what the TEN ended up with. Now the root cause investigations are going and determining what those dumb luck factors were in the XWB but not in TEN.

Make no mistake, these are massively complex projects and difficult to manage. Easy to sit back and point out the flaws. Not arguing they didn’t attempt to prevent the problems. Clearly they did. But not everything’s works out as hoped.
 
dstblj52
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Re: Why wouldn't the Trent 1000-TEN problems also show up in the Trent XWB?

Tue Feb 18, 2020 8:50 pm

9Patch wrote:
VSMUT wrote:
The 787 doesn't use bleed air. That means putting more generators on it, causing more mechanical friction. Jet engines never did well with mechanical friction. The 787 was also rushed, with the planned rollout in 2007 and EIS not too long after. That caused unneccesary rush by Rolls Royce. Had they had the 3 extra years to develop it from the get go, the final result would likely have been better.

The 787 was three years late so RR did had an extra three years to develop it!
Why aren't GE on the 787 having similar problems?

Except they didn't plan around having them once parts of a design get frozen. Those extra years aren't worth nearly as much as people think if their not planned for. And the shorter the design cycle the higher the risk that something goes wrong so it can come down to getting lucky and picking the right approaches and solutions based on what you have available. Plus GE weren't building a wholly new engine it was based on an older engine so they likely had much less work todo. Just a whole lot of factors
 
lowbank
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Re: Why wouldn't the Trent 1000-TEN problems also show up in the Trent XWB?

Tue Feb 18, 2020 8:55 pm

Okcflyer wrote:
The talk about larger 787 generators consuming more shaft power being the root cause of these durability problems is nonsense. It may well be an intermediate cause due to poor engineering and testing by RR but it’s definitely not a root cause. GENx has proven the unique 787 architecture is reliable, regardless of whether it was worth the investment for the architecture change.

Either RR was unintentionally lucky on the XWB or there were intentional factors and risks they knowingly took on the TEN update. Personally, I suspect the XWB has a couple of small changes that, through dumb luck, made it a more durable design than what the TEN ended up with. Now the root cause investigations are going and determining what those dumb luck factors were in the XWB but not in TEN.

Make no mistake, these are massively complex projects and difficult to manage. Easy to sit back and point out the flaws. Not arguing they didn’t attempt to prevent the problems. Clearly they did. But not everything’s works out as hoped.


Dumb luck!!!

FFS, every single specialist writes a report in support of the design of every single component.

Be that stress, aero, air systems, thermal, iceing, materials, and more. There can be over twenty specialist reports for each component in the engine.
Every days a school day.
 
VSMUT
Posts: 4454
Joined: Mon Aug 08, 2016 11:40 am

Re: Why wouldn't the Trent 1000-TEN problems also show up in the Trent XWB?

Tue Feb 18, 2020 9:18 pm

9Patch wrote:
VSMUT wrote:
The 787 doesn't use bleed air. That means putting more generators on it, causing more mechanical friction. Jet engines never did well with mechanical friction. The 787 was also rushed, with the planned rollout in 2007 and EIS not too long after. That caused unneccesary rush by Rolls Royce. Had they had the 3 extra years to develop it from the get go, the final result would likely have been better.

The 787 was three years late so RR did had an extra three years to develop it!


It doesn't work like that. Rolls Royce had to have the engine ready by 2007. Those 3 subsequent years were only good for rectifying issues, not for making radical design changes.


9Patch wrote:
Why aren't GE on the 787 having similar problems?


Because they somehow didn't screw up somewhere.
 
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Revelation
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Re: Why wouldn't the Trent 1000-TEN problems also show up in the Trent XWB?

Tue Feb 18, 2020 9:43 pm

lowbank wrote:
The initial request was around 80k and 90k thrust but airbus wanted the same engine just an engine management tweak to change the power output.
GE and RR offered a solution on that basis.
The power out put rose to 97k , GE bugged out as it didn’t want to design two engines.
RR offered to hurry a design of a 97k engine but the Airbus restriction was it had to fit into the 84k nacelle. That still today is giving us issues on my component in particular.
The 84k engine is still running 6k below the initial design ask, therefore it’s less stressed.

Does that explain it better???

Yes, that and the preceding post explains things quite well, thanks!

Okcflyer wrote:
Either RR was unintentionally lucky on the XWB or there were intentional factors and risks they knowingly took on the TEN update. Personally, I suspect the XWB has a couple of small changes that, through dumb luck, made it a more durable design than what the TEN ended up with.

The TXWB and the T1000 are different architecturally and operate at different power levels.

TTEN is just a back port of some things learned on TXWB but T1000 still is a different architecture that operates at different power levels.

As above T1000 is pushing the limits whereas TXWB (and TXWB-84 in particular) is not.

I feel we're pretty lucky to have an insider giving us some insights that we can learn from.
Wake up to find out that you are the eyes of the world
The heart has its beaches, its homeland and thoughts of its own
Wake now, discover that you are the song that the morning brings
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lowbank
Posts: 511
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Re: Why wouldn't the Trent 1000-TEN problems also show up in the Trent XWB?

Tue Feb 18, 2020 10:10 pm

Revelation wrote:
lowbank wrote:
The initial request was around 80k and 90k thrust but airbus wanted the same engine just an engine management tweak to change the power output.
GE and RR offered a solution on that basis.
The power out put rose to 97k , GE bugged out as it didn’t want to design two engines.
RR offered to hurry a design of a 97k engine but the Airbus restriction was it had to fit into the 84k nacelle. That still today is giving us issues on my component in particular.
The 84k engine is still running 6k below the initial design ask, therefore it’s less stressed.

Does that explain it better???

Yes, that and the preceding post explains things quite well, thanks!

Okcflyer wrote:
Either RR was unintentionally lucky on the XWB or there were intentional factors and risks they knowingly took on the TEN update. Personally, I suspect the XWB has a couple of small changes that, through dumb luck, made it a more durable design than what the TEN ended up with.

The TXWB and the T1000 are different architecturally and operate at different power levels.

TTEN is just a back port of some things learned on TXWB but T1000 still is a different architecture that operates at different power levels.

As above T1000 is pushing the limits whereas TXWB (and TXWB-84 in particular) is not.

I feel we're pretty lucky to have an insider giving us some insights that we can learn from.




I wish I could share just one lunch and learn.

People would be blown away about the in depth detail. Majority would not understand 50% of it and I say that because I don’t as specialist presentations just go way beyond a manufacturing Engineers knowledge.

However I think it just might stop on line comments of dumb luck.
Every days a school day.
 
RB211trent
Posts: 158
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Re: Why wouldn't the Trent 1000-TEN problems also show up in the Trent XWB?

Tue Feb 18, 2020 10:13 pm

9Patch wrote:
VSMUT wrote:
The 787 doesn't use bleed air. That means putting more generators on it, causing more mechanical friction. Jet engines never did well with mechanical friction. The 787 was also rushed, with the planned rollout in 2007 and EIS not too long after. That caused unneccesary rush by Rolls Royce. Had they had the 3 extra years to develop it from the get go, the final result would likely have been better.

The 787 was three years late so RR did had an extra three years to develop it!
Why aren't GE on the 787 having similar problems?

GE are having issues with premature wear and loads of engine removals, I was with a GE 787 operator a few weeks ago and they are not impressed with their performance. GE seem better prepared to deal with it.
 
LDRA
Posts: 328
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Re: Why wouldn't the Trent 1000-TEN problems also show up in the Trent XWB?

Wed Feb 19, 2020 12:12 am

How is RR structured organization wise? Are the same people doing TEN doing the XWB?
 
9Patch
Posts: 579
Joined: Wed Mar 13, 2019 10:38 pm

Re: Why wouldn't the Trent 1000-TEN problems also show up in the Trent XWB?

Wed Feb 19, 2020 12:30 am

RB211trent wrote:
GE are having issues with premature wear and loads of engine removals, I was with a GE 787 operator a few weeks ago and they are not impressed with their performance. GE seem better prepared to deal with it.

What exactly constitutes 'loads'?
Sorry, anecdotes are no substitute for facts.
 
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Slug71
Posts: 1485
Joined: Wed Jan 04, 2017 6:08 am

Re: Why wouldn't the Trent 1000-TEN problems also show up in the Trent XWB?

Wed Feb 19, 2020 1:53 am

Revelation wrote:
lowbank wrote:
The initial request was around 80k and 90k thrust but airbus wanted the same engine just an engine management tweak to change the power output.
GE and RR offered a solution on that basis.
The power out put rose to 97k , GE bugged out as it didn’t want to design two engines.
RR offered to hurry a design of a 97k engine but the Airbus restriction was it had to fit into the 84k nacelle. That still today is giving us issues on my component in particular.
The 84k engine is still running 6k below the initial design ask, therefore it’s less stressed.

Does that explain it better???

Yes, that and the preceding post explains things quite well, thanks!

Okcflyer wrote:
Either RR was unintentionally lucky on the XWB or there were intentional factors and risks they knowingly took on the TEN update. Personally, I suspect the XWB has a couple of small changes that, through dumb luck, made it a more durable design than what the TEN ended up with.

The TXWB and the T1000 are different architecturally and operate at different power levels.

TTEN is just a back port of some things learned on TXWB but T1000 still is a different architecture that operates at different power levels.

As above T1000 is pushing the limits whereas TXWB (and TXWB-84 in particular) is not.

I feel we're pretty lucky to have an insider giving us some insights that we can learn from.


Thanks for saving me from typing this.

Just as the two engines borrow from each other, the TTEN also exchanges with the upcoming Advance3. If I'm not mistaken, the Advance uses the T1000 LP Turbine and the XWB-84 fan. The Ultrafan is yet a further development of the Advance3.
 
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Slug71
Posts: 1485
Joined: Wed Jan 04, 2017 6:08 am

Re: Why wouldn't the Trent 1000-TEN problems also show up in the Trent XWB?

Wed Feb 19, 2020 2:06 am

uta999 wrote:
dc10lover wrote:
Can you attach a Trent XWB Jet Engine to the Boeing 787?


You can but due to the fan size, you would need to mount it further forward and higher. Oh wait....

We have software that can deal with that.


Not too mention quite a bit more heavier too.
 
WIederling
Posts: 9307
Joined: Sun Sep 13, 2015 2:15 pm

Re: Why wouldn't the Trent 1000-TEN problems also show up in the Trent XWB?

Wed Feb 19, 2020 9:01 am

RB211trent wrote:
GE are having issues with premature wear and loads of engine removals, I was with a GE 787 operator a few weeks ago and they are not impressed with their performance. GE seem better prepared to deal with it.


Protected.

They don't get the (negative) media exposure RR does.

Just Imagine LH (vs Air France ) having lost the front of an A380 engine.
Beyond some "we've found more fragments under the ice" things are rather quiet around the GP7200 failure.

( and the analyst attack on RR in the right moment ( reflexive reaction : reduce workforce to vie share holders ) was insidiously well timed.)
Murphy is an optimist
 
mjoelnir
Posts: 9386
Joined: Sun Feb 03, 2013 11:06 pm

Re: Why wouldn't the Trent 1000-TEN problems also show up in the Trent XWB?

Wed Feb 19, 2020 10:41 am

Slug71 wrote:
Revelation wrote:
lowbank wrote:
The initial request was around 80k and 90k thrust but airbus wanted the same engine just an engine management tweak to change the power output.
GE and RR offered a solution on that basis.
The power out put rose to 97k , GE bugged out as it didn’t want to design two engines.
RR offered to hurry a design of a 97k engine but the Airbus restriction was it had to fit into the 84k nacelle. That still today is giving us issues on my component in particular.
The 84k engine is still running 6k below the initial design ask, therefore it’s less stressed.

Does that explain it better???

Yes, that and the preceding post explains things quite well, thanks!

Okcflyer wrote:
Either RR was unintentionally lucky on the XWB or there were intentional factors and risks they knowingly took on the TEN update. Personally, I suspect the XWB has a couple of small changes that, through dumb luck, made it a more durable design than what the TEN ended up with.

The TXWB and the T1000 are different architecturally and operate at different power levels.

TTEN is just a back port of some things learned on TXWB but T1000 still is a different architecture that operates at different power levels.

As above T1000 is pushing the limits whereas TXWB (and TXWB-84 in particular) is not.

I feel we're pretty lucky to have an insider giving us some insights that we can learn from.


Thanks for saving me from typing this.

Just as the two engines borrow from each other, the TTEN also exchanges with the upcoming Advance3. If I'm not mistaken, the Advance uses the T1000 LP Turbine and the XWB-84 fan. The Ultrafan is yet a further development of the Advance3.


One advance demonstrator uses the T1000 LP turbine and I think a new fan, carbon fibre fan and fan casing AFAIK. Otherwise part of the Advance program is redistributing the load between the hp unit and mp unit, so big changes in the core.
While the demonstrators uses available components, we can assume an Trent Advance production engine, if ever build, will use it's own components.
 
abies111
Posts: 16
Joined: Mon Feb 29, 2016 6:15 pm

Re: Why wouldn't the Trent 1000-TEN problems also show up in the Trent XWB?

Wed Feb 19, 2020 11:46 am

Revelation wrote:
lowbank wrote:
The initial request was around 80k and 90k thrust but airbus wanted the same engine just an engine management tweak to change the power output.
GE and RR offered a solution on that basis.
The power out put rose to 97k , GE bugged out as it didn’t want to design two engines.
RR offered to hurry a design of a 97k engine but the Airbus restriction was it had to fit into the 84k nacelle. That still today is giving us issues on my component in particular.
The 84k engine is still running 6k below the initial design ask, therefore it’s less stressed.

Does that explain it better???

Yes, that and the preceding post explains things quite well, thanks!

Okcflyer wrote:
Either RR was unintentionally lucky on the XWB or there were intentional factors and risks they knowingly took on the TEN update. Personally, I suspect the XWB has a couple of small changes that, through dumb luck, made it a more durable design than what the TEN ended up with.

The TXWB and the T1000 are different architecturally and operate at different power levels.

TTEN is just a back port of some things learned on TXWB but T1000 still is a different architecture that operates at different power levels.

As above T1000 is pushing the limits whereas TXWB (and TXWB-84 in particular) is not.

I feel we're pretty lucky to have an insider giving us some insights that we can learn from.


Could the airframe itself (A359) be helping also by means of allowing more derating when taking-off and climbing for the average flight?
 
kurtverbose
Posts: 581
Joined: Thu Jun 26, 2014 9:33 pm

Re: Why wouldn't the Trent 1000-TEN problems also show up in the Trent XWB?

Wed Feb 19, 2020 12:11 pm

lowbank wrote:
All I can say to you guys is, as I understand it.

We are given a fan diameter and a power output required, SFC etc.
Normally the power request goes up but the fan size stays the same.

Go figure what happens.

Going back to the XWB, as I remember it.

The initial request was around 80k and 90k thrust but airbus wanted the same engine just an engine management tweak to change the power output.
GE and RR offered a solution on that basis.
The power out put rose to 97k , GE bugged out as it didn’t want to design two engines.
RR offered to hurry a design of a 97k engine but the Airbus restriction was it had to fit into the 84k nacelle. That still today is giving us issues on my component in particular.
The 84k engine is still running 6k below the initial design ask, therefore it’s less stressed.


Does that explain it better???


Hence why the A330NEO is not having engine problems and they don't expect any. The 7000 is a de-rate of the 1000-TEN. Nothing to do with bleed air.

Thanks for the feedback Lowbank. Really enjoy reading your posts.
 
StTim
Posts: 3714
Joined: Thu Aug 08, 2013 7:39 am

Re: Why wouldn't the Trent 1000-TEN problems also show up in the Trent XWB?

Wed Feb 19, 2020 12:40 pm

There will be a slight imbalance in the air flows between a bleedless and bleed engine.

In a bleedless the air that would normally be bled off to power the packs etc will now flow through the combustors and turbines.

Small but will be noticeable to these fine tuned machines.
 
mjoelnir
Posts: 9386
Joined: Sun Feb 03, 2013 11:06 pm

Re: Why wouldn't the Trent 1000-TEN problems also show up in the Trent XWB?

Wed Feb 19, 2020 1:14 pm

mjoelnir wrote:
Slug71 wrote:
Revelation wrote:
Yes, that and the preceding post explains things quite well, thanks!


The TXWB and the T1000 are different architecturally and operate at different power levels.

TTEN is just a back port of some things learned on TXWB but T1000 still is a different architecture that operates at different power levels.

As above T1000 is pushing the limits whereas TXWB (and TXWB-84 in particular) is not.

I feel we're pretty lucky to have an insider giving us some insights that we can learn from.


Thanks for saving me from typing this.

Just as the two engines borrow from each other, the TTEN also exchanges with the upcoming Advance3. If I'm not mistaken, the Advance uses the T1000 LP Turbine and the XWB-84 fan. The Ultrafan is yet a further development of the Advance3.


One advance demonstrator uses the T1000 LP turbine and I think a new fan, carbon fibre fan and fan casing AFAIK. Otherwise part of the Advance program is redistributing the load between the hp unit and mp unit, so big changes in the core.
While the demonstrators uses available components, we can assume an Trent Advance production engine, if ever build, will use it's own components.


I have to correct myself. You were right, The Trent advance core demonstrator uses a T1000 LP turbine and the TXFW84 fan. The HP and IP sections differ.
The composite fan is tested on a T1000 core.
 
WholaLottaLove
Topic Author
Posts: 55
Joined: Sat Sep 24, 2016 10:46 pm

Re: Why wouldn't the Trent 1000-TEN problems also show up in the Trent XWB?

Wed Feb 19, 2020 1:32 pm

kurtverbose wrote:
lowbank wrote:
All I can say to you guys is, as I understand it.

We are given a fan diameter and a power output required, SFC etc.
Normally the power request goes up but the fan size stays the same.

Go figure what happens.

Going back to the XWB, as I remember it.

The initial request was around 80k and 90k thrust but airbus wanted the same engine just an engine management tweak to change the power output.
GE and RR offered a solution on that basis.
The power out put rose to 97k , GE bugged out as it didn’t want to design two engines.
RR offered to hurry a design of a 97k engine but the Airbus restriction was it had to fit into the 84k nacelle. That still today is giving us issues on my component in particular.
The 84k engine is still running 6k below the initial design ask, therefore it’s less stressed.


Does that explain it better???


Hence why the A330NEO is not having engine problems and they don't expect any. The 7000 is a de-rate of the 1000-TEN. Nothing to do with bleed air.

Thanks for the feedback Lowbank. Really enjoy reading your posts.


Whilst I cannot comment on the bleed air issue, the Trent 7000 does suffer from some of the same problems as the Trent 1000-TEN, albeit to a lesser degree. The intermediate-pressure compressor (IPC) has to be swapped and there is also a fairly low cycle limit (between 1,000 and 1,500 cycles) on the high-pressure turbine (HPT) blades. The problems are though not as bad as on the Trent 1000-TEN, since the Trent 7000 does indeed run at a lower temperature (roughly 50 centigrades lower) which means less degradation and there are more spare engines available which reduces the number of AoGs.

The IPC (fixed, but not retrofitted to the whole fleet until 2021) and HPT problems (no fix yet, expected from mid 2021) on the Trent 7000 are real though - on the bright side, at least the IPT seems to be fine though.
 
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Revelation
Posts: 24313
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Re: Why wouldn't the Trent 1000-TEN problems also show up in the Trent XWB?

Wed Feb 19, 2020 2:53 pm

WIederling wrote:
RB211trent wrote:
GE are having issues with premature wear and loads of engine removals, I was with a GE 787 operator a few weeks ago and they are not impressed with their performance. GE seem better prepared to deal with it.

Protected.

They don't get the (negative) media exposure RR does.

Just Imagine LH (vs Air France ) having lost the front of an A380 engine.
Beyond some "we've found more fragments under the ice" things are rather quiet around the GP7200 failure.

( and the analyst attack on RR in the right moment ( reflexive reaction : reduce workforce to vie share holders ) was insidiously well timed.)

Tell us how this "media protection" works.

AF A380 with GE engines flies CDG-LAX, a fatigue crack in the titanium fan hub spreads and fan is shed, engine suffers IFSD and plane lands safely at wind swept CFB Goose Bay in Atlantic Canada rather than glorious LAX right next to Tinseltown.

All around the world media members run through their pre-trained checklist:
    1) Air France not Lufthansa? Check!
    2) American engines, not European? Check!
    3) PROTECTION ON!
Wake up to find out that you are the eyes of the world
The heart has its beaches, its homeland and thoughts of its own
Wake now, discover that you are the song that the morning brings
The heart has its seasons, its evenings and songs of its own

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