https://www.yahoo.com/finance/news/airc ... 38633.html


Fascinating article about the Trent 1000 engines and the technical problems posed. It certainly raises some interesting questions. I would love to know folks opinions on this who have some technical expertise.


Key quote from the article:


"The high-pressure turbine blades in a Trent 1000 passenger jet engine have to withstand temperatures far above the melting point of the nickel alloy from which they’re made. It’s a fiendish technical challenge for the engine’s British manufacturer, Rolls-Royce Holdings Plc — comparable to trying to stop an ice cube melting inside a kitchen oven on full blast. The solution found by the company’s engineers was to blow cool air through tiny holes in the blades. Unfortunately this clever approach has encountered some unexpected problems.

Boeing 787 aircraft operated by British Airways, Norwegian Air Shuttle, Virgin Atlantic and others have been grounded in recent months for inspections and repairs because the Trent 1000 engine blades have been degrading faster than anticipated. It’s the type of problem that’s becoming common in the industry as the demands placed on engines become ever greater."

Wait till the Utlrafan comes out. Maybe unrealistic demands are being placed on these aerospace companies.

The only material i know if that can reliably handle the core temperatures of newer engines are cremarics. However cremarics are exceeding brittle and difficult to machine. I am not a gas turbine expert but simple physics says the greater the temperature difference between the hot internal core and the cold air bypass the greater "work" i.e. efficiency of the engine.

However my assumption is the core temps of these new generation engines are hitting the limits of existing standard materials. I would love Lightsaber or others with genuine knowledge to comment.

ElroyJetson wrote:

https://www.yahoo.com/finance/news/aircraft-engines-hitting-technical-limits-073538633.html


Fascinating article about the Trent 1000 engines and the technical problems posed. It certainly raises some interesting questions. I would love to know folks opinions on this who have some technical expertise.


Key quote from the article:


"The high-pressure turbine blades in a Trent 1000 passenger jet engine have to withstand temperatures far above the melting point of the nickel alloy from which they’re made. It’s a fiendish technical challenge for the engine’s British manufacturer, Rolls-Royce Holdings Plc — comparable to trying to stop an ice cube melting inside a kitchen oven on full blast. The solution found by the company’s engineers was to blow cool air through tiny holes in the blades. Unfortunately this clever approach has encountered some unexpected problems.

Boeing 787 aircraft operated by British Airways, Norwegian Air Shuttle, Virgin Atlantic and others have been grounded in recent months for inspections and repairs because the Trent 1000 engine blades have been degrading faster than anticipated. It’s the type of problem that’s becoming common in the industry as the demands placed on engines become ever greater."

This article acts like every other HPT blade in existence doesn't have cooling holes. Its all a matter of designing it properly, not inherently the idea of cooling blades with air.

ElroyJetson wrote:

The solution found by the company’s engineers was to blow cool air through tiny holes in the blades. Unfortunately this clever approach has encountered some unexpected problems.

Not sure what is so special about this, it’s found in all large engines that I am aware of.

The issue with the blades has nothing to do with cooling, it is the new coating that they have on the blades that is being eaten away by acid in the atmosphere as a result of pollution.

zeke wrote:

The issue with the blades has nothing to do with cooling, it is the new coating that they have on the blades that is being eaten away by acid in the atmosphere as a result of pollution.

Are you sure about that? A lot of airlines have grounded their 787's due to RR engine issues... and many of them are not in areas that are considered highly polluted like parts of Asia and India are.

It seems to me that the Trent 1000 could not handle even some of the cleanest air...

Have a great day,

2175301 wrote:

zeke wrote:

The issue with the blades has nothing to do with cooling, it is the new coating that they have on the blades that is being eaten away by acid in the atmosphere as a result of pollution.

Are you sure about that? A lot of airlines have grounded their 787's due to RR engine issues... and many of them are not in areas that are considered highly polluted like parts of Asia and India are.

It seems to me that the Trent 1000 could not handle even some of the cleanest air...

Have a great day,

Yes it has been widely reported that pollution is causing acid which is eating the protective coating on the blades, and this is causing issues with the blades as the coating is designed to protect them. The largest source for this pollution is power stations and where oil and gas are produced, the worst areas are China, India, NW USA, and the Middle East.

https://so2.gsfc.nasa.gov/

zeke wrote:

ElroyJetson wrote:

The solution found by the company’s engineers was to blow cool air through tiny holes in the blades. Unfortunately this clever approach has encountered some unexpected problems.

Not sure what is so special about this, it’s found in all large engines that I am aware of.

The issue with the blades has nothing to do with cooling, it is the new coating that they have on the blades that is being eaten away by acid in the atmosphere as a result of pollution.

Just to be clear the quote you cited is not from me but the actual Bloomberg article. I also agree with the other poster that atmospheric pollution is likely a factor, but far from the only factor. The GE engines on 787's do not appear to be having the same issues as the Trent 1000. The question is why?

zeke wrote:

2175301 wrote:

zeke wrote:

The issue with the blades has nothing to do with cooling, it is the new coating that they have on the blades that is being eaten away by acid in the atmosphere as a result of pollution.

Are you sure about that? A lot of airlines have grounded their 787's due to RR engine issues... and many of them are not in areas that are considered highly polluted like parts of Asia and India are.

It seems to me that the Trent 1000 could not handle even some of the cleanest air...

Have a great day,

Yes it has been widely reported that pollution is causing acid which is eating the protective coating on the blades, and this is causing issues with the blades as the coating is designed to protect them. The largest source for this pollution is power stations and where oil and gas are produced, the worst areas are China, India, NW USA, and the Middle East.

https://so2.gsfc.nasa.gov/

Zeke: While I have no doubts about current day China and India the information about NW USA is out of date. Power Plants are my historic industry and I lived though the changes from high sulfur coal, adding scrubbers or changing to low sulfur coal, precipitators and baghouses too for particulates. I know how much power plants and oil refineries have had to reduce and control sulfur in the last 40 years.

If you take that NASA diagram and click on any of those boxes.... I suggest you click on the box in the Eastern USA. It will show you a running video of the changes from 1980 to 2015. Its almost all cleaned up now.

The air over the USA, Canada, the Northern Atlantic, and Europe is largely free of any historic sulfur and other pollution issues now. So why were the Trent 1000 engines failing? Your pollution argument does not hold up there.

Have a great day,

ElroyJetson wrote:

"The high-pressure turbine blades in a Trent 1000 passenger jet engine have to withstand temperatures far above the melting point of the nickel alloy from which they’re made. It’s a fiendish technical challenge for the engine’s British manufacturer, Rolls-Royce Holdings Plc — comparable to trying to stop an ice cube melting inside a kitchen oven on full blast. The solution found by the company’s engineers was to blow cool air through tiny holes in the blades. Unfortunately this clever approach has encountered some unexpected problems.

Here my 20 years knowledge of what I learned as graduated material scientist.
The coating on the blades is called TBC, Temperature Barrier Coating, usually ceramics. Below you have bonding coating usually made of refractory metals like Ta or Pt or an intermetalic compound (with high melting point) and then the single crystalline Nickel based superalloy blades.
So what is written in the article is nothing special for RR. The goal is always to go to the highest temperature as possible.
The material system is very complex. I guess there are 10000 PhDs based on that topic and 100000 papers;-)

ElroyJetson wrote:

[The GE engines on 787's do not appear to be having the same issues as the Trent 1000. The question is why?

Who said they don’t suffer from premature erosion of the blade coatings ? It is still is very much an active area of research for GE.

2175301 wrote:

[the information about NW USA is out of date.

I should have written NE, it is not out of date, you can see individual known bad power plants in this map

https://bit.ly/30inNie

Or try this link

https://www.google.com/maps/d/u/1/viewe ... 094853&z=4

While the US has improved, the issue is the shear volume of power plants.

2175301 wrote:

The air over the USA, Canada, the Northern Atlantic, and Europe is largely free of any historic sulfur and other pollution issues now. So why were the Trent 1000 engines failing? Your pollution argument does not hold up there.

Doesn’t matter, even aircraft in New Zealand where the air is significantly cleaner than the US or Europe have eroded blades, as the aircraft fly to areas of high pollution.

The engines are not failing very often at all these days, your premise “ So why were the Trent 1000 engines failing?” is not true. The engines are being picked up on inspections and getting changed out, but that is not unique to RR.

zeke wrote:

ElroyJetson wrote:

The solution found by the company’s engineers was to blow cool air through tiny holes in the blades. Unfortunately this clever approach has encountered some unexpected problems.

Not sure what is so special about this, it’s found in all large engines that I am aware of.

... since before then end of World War II!

Best regards
Thomas

zeke wrote:

ElroyJetson wrote:

[The GE engines on 787's do not appear to be having the same issues as the Trent 1000. The question is why?

Who said they don’t suffer from premature erosion of the blade coatings ? It is still is very much an active area of research for GE.

2175301 wrote:

[the information about NW USA is out of date.

I should have written NE, it is not out of date, you can see individual known bad power plants in this map

https://bit.ly/30inNie

Or try this link

https://www.google.com/maps/d/u/1/viewe ... 094853&z=4

While the US has improved, the issue is the shear volume of power plants.

2175301 wrote:

The air over the USA, Canada, the Northern Atlantic, and Europe is largely free of any historic sulfur and other pollution issues now. So why were the Trent 1000 engines failing? Your pollution argument does not hold up there.

Doesn’t matter, even aircraft in New Zealand where the air is significantly cleaner than the US or Europe have eroded blades, as the aircraft fly to areas of high pollution.

The engines are not failing very often at all these days, your premise “ So why were the Trent 1000 engines failing?” is not true. The engines are being picked up on inspections and getting changed out, but that is not unique to RR.

Zeke: I think we may have to agree to disagree... From a jet age historical perspective the S02 emissions of the US and Europe are at an all time low. These are not areas of "high pollution" You should have seen the data from the 1970's.

Within the USA sulfur reductions started in the early 1970's. The US Navy changed their ships from "Bunker C" - the high sulfur residue oil from refineries, and certain specific high sulfur crude oils, which had to be heated to even pump it, to "Navy Distillate (ND)." I know that as a fact as I reported onboard a ship in the fall of 1975 as a new US Navy " A-School" graduate from their steam propulsion school (a few months after graduating from High School). The ship had been converted to ND 2 years earlier and was still struggling with fuel leaks (Bunker C self sealed small leaks; ND ate out those Bunker-C based seals); and we still had Bunker C residue in the bottom of the fuel tanks that had to be cleaned out in the 1977 overhaul period.

I've started working in coal fired power plants in 1982... when the industry was being forced to retrofit scrubbers and convert to lower sulfur coals. As a Power Plant Superintendent in the late 1980's (small municipal power plant) I made the decision to change to a higher cost but significantly lower sulfur coal for my plant. The State Public Utility Commission accepted that as a reasonable decision without asking any questions except why had the fuel prices gone up - and automatically passed the increased fuel cost onto the customers. That plant was closed a few years later due to other issues... and that was my last time on staff in a coal fired power plant (I've been in them as a contractor). I then moved to Nuclear Power after a stint working for vendors, etc. Many of the plants I worked at had Gas Turbine generating units, and older boilers that had been converted to either clean oil or natural gas - which were mainly used for short term operations and peaking units (did not run most of the time).

Right now there are less than half the number of coal fired power plants in the USA (and I presume Europe) as there was back in the mid 1980's; and their numbers keep dwindling in the USA as relative low cost natural gas with higher efficiency combined cycle power plants are replacing them.

So you see "high levels" of SO2 pollution. I see historic lows... and I also see that the previous generation of jet engines did not have these kinds of problems up to recent times even when the SO2 levels were much higher.

I agree with you that the issue is the blade coating is not standing up to the higher temperatures in the engines. I do not agree with you that the problem in the United States, Europe, and certain other parts of the world are from "highly" polluted air; given how much the pollution levels have declined. I think its more that the RR engineers missed on designing this coating for realistic applications.

Now China, India, and certain other parts of the world are different. I had personal friends who in the late 1980's to early 1990's went to China and India to build new coal fired power plants. No precipitators or bag-houses for particulate control. High sulfur coals. No SO2 scrubbers of any kind. When I asked them didn't the Chinese and Indians know about Power Plant pollution effects and how most of it could be controlled at a reasonable cost... (you could cut about 75% of the emissions towards the US and European standards with modest additions to a plant, it tripled the added cost to go for the next 25% which was required in the US and I presume Europe) and was told that "they" didn't care. They wanted old fashioned just send everything up the stack - cheapest to build (and lower efficiency too) power plants as they needed all the electrical generation they could get. Those governments did not even try to control pollution at any level, or even buy the highest efficiency coal fired power plant technology. Had they just done the easy and relatively cheap 75% reductions it would have massively changed what they have now. You see the results now of those decisions in the late 1980's and early 1990's in China and India (and a few other areas).

Have a great day,

Edited to add: In the 1970's and 1980's the parts of the Midwest and Eastern US had what was called "Acid Rain" and it obviously was affecting a lot of buildings, forests, lakes, rivers, etc.

If I travel to those areas now the old timers will remember it if you ask about it... but, I have not heard anyone talk about "acid rain" in a couple of decades now in the USA.

2175301 wrote:

zeke wrote:

ElroyJetson wrote:

[The GE engines on 787's do not appear to be having the same issues as the Trent 1000. The question is why?

Who said they don’t suffer from premature erosion of the blade coatings ? It is still is very much an active area of research for GE.

2175301 wrote:

[the information about NW USA is out of date.

I should have written NE, it is not out of date, you can see individual known bad power plants in this map

https://bit.ly/30inNie

Or try this link

https://www.google.com/maps/d/u/1/viewe ... 094853&z=4

While the US has improved, the issue is the shear volume of power plants.

2175301 wrote:

The air over the USA, Canada, the Northern Atlantic, and Europe is largely free of any historic sulfur and other pollution issues now. So why were the Trent 1000 engines failing? Your pollution argument does not hold up there.

Doesn’t matter, even aircraft in New Zealand where the air is significantly cleaner than the US or Europe have eroded blades, as the aircraft fly to areas of high pollution.

The engines are not failing very often at all these days, your premise “ So why were the Trent 1000 engines failing?” is not true. The engines are being picked up on inspections and getting changed out, but that is not unique to RR.

Zeke: I think we may have to agree to disagree... From a jet age historical perspective the S02 emissions of the US and Europe are at an all time low. These are not areas of "high pollution" You should have seen the data from the 1970's.

Within the USA sulfur reductions started in the early 1970's. The US Navy changed their ships from "Bunker C" - the high sulfur residue oil from refineries, and certain specific high sulfur crude oils, which had to be heated to even pump it, to "Navy Distillate (ND)." I know that as a fact as I reported onboard a ship in the fall of 1975 as a new US Navy " A-School" graduate from their steam propulsion school (a few months after graduating from High School). The ship had been converted to ND 2 years earlier and was still struggling with fuel leaks (Bunker C self sealed small leaks; ND ate out those Bunker-C based seals); and we still had Bunker C residue in the bottom of the fuel tanks that had to be cleaned out in the 1977 overhaul period.

I've started working in coal fired power plants in 1982... when the industry was being forced to retrofit scrubbers and convert to lower sulfur coals. As a Power Plant Superintendent in the late 1980's (small municipal power plant) I made the decision to change to a higher cost but significantly lower sulfur coal for my plant. The State Public Utility Commission accepted that as a reasonable decision without asking any questions except why had the fuel prices gone up - and automatically passed the increased fuel cost onto the customers. That plant was closed a few years later due to other issues... and that was my last time on staff in a coal fired power plant (I've been in them as a contractor). I then moved to Nuclear Power after a stint working for vendors, etc. Many of the plants I worked at had Gas Turbine generating units, and older boilers that had been converted to either clean oil or natural gas - which were mainly used for short term operations and peaking units (did not run most of the time).

Right now there are less than half the number of coal fired power plants in the USA (and I presume Europe) as there was back in the mid 1980's; and their numbers keep dwindling in the USA as relative low cost natural gas with higher efficiency combined cycle power plants are replacing them.

So you see "high levels" of SO2 pollution. I see historic lows... and I also see that the previous generation of jet engines did not have these kinds of problems up to recent times even when the SO2 levels were much higher.

I agree with you that the issue is the blade coating is not standing up to the higher temperatures in the engines. I do not agree with you that the problem in the United States, Europe, and certain other parts of the world are from "highly" polluted air; given how much the pollution levels have declined. I think its more that the RR engineers missed on designing this coating for realistic applications.

Now China, India, and certain other parts of the world are different. I had personal friends who in the late 1980's to early 1990's went to China and India to build new coal fired power plants. No precipitators or bag-houses for particulate control. High sulfur coals. No SO2 scrubbers of any kind. When I asked them didn't the Chinese and Indians know about Power Plant pollution effects and how most of it could be controlled at a reasonable cost... (you could cut about 75% of the emissions towards the US and European standards with modest additions to a plant, it tripled the added cost to go for the next 25% which was required in the US and I presume Europe) and was told that "they" didn't care. They wanted old fashioned just send everything up the stack - cheapest to build (and lower efficiency too) power plants as they needed all the electrical generation they could get. Those governments did not even try to control pollution at any level, or even buy the highest efficiency coal fired power plant technology. Had they just done the easy and relatively cheap 75% reductions it would have massively changed what they have now. You see the results now of those decisions in the late 1980's and early 1990's in China and India (and a few other areas).

Have a great day,

Edited to add: In the 1970's and 1980's the parts of the Midwest and Eastern US had what was called "Acid Rain" and it obviously was affecting a lot of buildings, forests, lakes, rivers, etc.

If I travel to those areas now the old timers will remember it if you ask about it... but, I have not heard anyone talk about "acid rain" in a couple of decades now in the USA.

Thanks for noting your experiences. I did 4 years after college doing engineering around the steel and auto industries in Detroit, then 3 years on what is still the tallest high rise in Denver, Republic Plaza, then 35 years in Bremerton with lots paper industry, docks & piers, and naval base work including projects both for SP as well as naval nuclear power. In the 70's the water in parts of the Puget Sound was so polluted the divers had to wear dry suits or their skin would itch for weeks. Untreated wood piling would last decades in the water as there was plenty of 'preservative', by the early 90's sufficiently clean for the little critters to eat the tasty wood in less than 2 years.

There is a 2nd corrosion issue that is probable with NZ and other tropical coastal areas, salt air. It causes both mechanical erosion like fine sand along with intense chemical corrosion. With stainless steels in salt exposure it will act as both an anode and cathode depending on strain such as a bent corner compared to the field adjacent.

2175301 wrote:

Now China, India, and certain other parts of the world are different.

More different than you suggest. The reporting I read on India's smog said a large part of it was because many people still cooked their food on wood fires, and because farmers still burn their fields to clear them.

This thread kinda got derailed talking about pollution versus the problems with the Trent 1000. If pollution was the sole causal factor wouldn't all engines suffer the same blade erosion as the Trent?

The GE engines in the 787 are not having the same issues to anywhere near the degree of the Trent 1000. Again why?

Maybe RR should stop to bother building engines and focus on derivatives trading instead?

ElroyJetson wrote:

This thread kinda got derailed talking about pollution versus the problems with the Trent 1000. If pollution was the sole causal factor wouldn't all engines suffer the same blade erosion as the Trent?

The GE engines in the 787 are not having the same issues to anywhere near the degree of the Trent 1000. Again why?

Because RR and GE use different types of blade coatings?

Thermal protection is a key technology, each company develops its own approach and protects the resulting IP.

RR went down a path that ended up being more vulnerable in high sulfur environments than they realized.

Unfortunately for them, it took a few years of in service data to see the problem, and from what we just read, their first attempt at a fix for the HPT did not produce a satisfactory result so the problem will stretch well in to 2021 ( ref: https://www.flightglobal.com/news/artic ... 21-462054/ ).

The reason for the failure is not clear. It could be that RR missed something in design or test, or they knew they were taking a risky approach and just misjudged the ultimate outcome.

ElroyJetson wrote:

This thread kinda got derailed talking about pollution versus the problems with the Trent 1000. If pollution was the sole causal factor wouldn't all engines suffer the same blade erosion as the Trent?

The concentration of failures doesn't seem to have any correlation with air pollution levels, Air China's 787s are trents and they don't seem to be suffering more issues with them than the other Trent 787s. This isn't GTF where 6E is getting roasted by the DGCA and everyone else seems to be getting by.

The A330NEO's engines are a derivative of the Trent 1000. Will those engines also experience degradation? Will TP face the same engine issues? If not, why not?

Also, Boeing touted how the 787 can perform engine swaps during the 787 design phase. This is predominantly for lessors? Did that feature make its way to production? If so, why haven't airlines opted for this? RR must be on top of this issue. I know they lost NZ as they chose GE for their 787-10.

RR do have a new format of cooling holes introduced on the T1000 (i believe its no the TXWB too) whereby the holes are cut into the blades to be round where they meet the internal path and migrating to rectangular the closer to the surface of the blade they get and creating a slot whereby they all effectively join up along(near) to the leading edge of the blade. This in theory creates a more uniform and laminar flow over the surface.
https://www.soue.org.uk/souenews/issue7/osney.html
So whilst all (pretty much) aero turbines have cooling there are subtle differences and nuances.

Fred

boeingbus wrote:

The A330NEO's engines are a derivative of the Trent 1000. Will those engines also experience degradation? Will TP face the same engine issues? If not, why not?

Also, Boeing touted how the 787 can perform engine swaps during the 787 design phase. This is predominantly for lessors? Did that feature make its way to production? If so, why haven't airlines opted for this? RR must be on top of this issue. I know they lost NZ as they chose GE for their 787-10.

Excellent point that I failed to mention. NZ has been a long time RR engine buyer, yet opted to change to GE for their latest 787 order, which had to be a significant blow to RR.

To be clear, I am a big RR fan. I think their later generation RB211-535 on the 757 were outstanding and once they ironed out initial problems on the RB211-524 in the 747 it turned to be a solid power plant. But the problems in the Trent 1000 are clearly hurting them in a big way.

flipdewaf wrote:

RR do have a new format of cooling holes introduced on the T1000 (i believe its no the TXWB too) whereby the holes are cut into the blades to be round where they meet the internal path and migrating to rectangular the closer to the surface of the blade they get and creating a slot whereby they all effectively join up along(near) to the leading edge of the blade. This in theory creates a more uniform and laminar flow over the surface.
https://www.soue.org.uk/souenews/issue7/osney.html
So whilst all (pretty much) aero turbines have cooling there are subtle differences and nuances.

Fred

Fred, thank you for link. Excellent information.

Revelation wrote:

The reason for the failure is not clear. It could be that RR missed something in design or test, or they knew they were taking a risky approach and just misjudged the ultimate outcome.

Half-assed time & budget constrained testing.

But the program managers will continue to think they are "delivering excellence" or some similar sh|te.


Far too many folks in decision making positions that are either technically clueless or ignore the realities of delivering a technically complex product.

zeke wrote:

I should have written NE, it is not out of date, you can see individual known bad power plants in this map

https://bit.ly/30inNie

Or try this link

https://www.google.com/maps/d/u/1/viewe ... 094853&z=4

While the US has improved, the issue is the shear volume of power plants.

I have to question the validity of your data here. Your links indicate dozens of oil power plants in the US. That is simply not the case. Oil is less than 1% of US electricity production and that is mostly in Alaska and Hawaii. The one supposed oil plant I looked into on that map (Gibson City Energy Center) is actually a gas plant.

boeingbus wrote:

The A330NEO's engines are a derivative of the Trent 1000. Will those engines also experience degradation? Will TP face the same engine issues? If not, why not?

Do you really think that if you would get the answer in detail by RR you would be able to understand?

william wrote:

Wait till the Utlrafan comes out. Maybe unrealistic demands are being placed on these aerospace companies.

Going to be a long wait!!

mham001 wrote:

zeke wrote:

I should have written NE, it is not out of date, you can see individual known bad power plants in this map

https://bit.ly/30inNie

Or try this link

https://www.google.com/maps/d/u/1/viewe ... 094853&z=4

While the US has improved, the issue is the shear volume of power plants.

I have to question the validity of your data here. Your links indicate dozens of oil power plants in the US. That is simply not the case. Oil is less than 1% of US electricity production and that is mostly in Alaska and Hawaii. The one supposed oil plant I looked into on that map (Gibson City Energy Center) is actually a gas plant.

Actually, Zeke's and others statement that the problem is pollution (and specifically SO2) flies in the fact that with the exception of China/India and perhaps the middle east that North America, Europe, and many other parts of the world at at historic lows in SO2 and other pollutants due to almost 50 years of reductions. Its a Straw Man argument. It sounds good until you look at the background and facts.

Neither Air nor Water is perfectly clean - anywhere in the world. There are not unusual levels in most of the world - yet the Trent 1000 has had problems in areas without unusual levels. Any designer is held responsible for not accounting for normal conditions.

Have a great day,

sciing wrote:

boeingbus wrote:

The A330NEO's engines are a derivative of the Trent 1000. Will those engines also experience degradation? Will TP face the same engine issues? If not, why not?

Do you really think that if you would get the answer in detail by RR you would be able to understand?

He is not going to get an answer. I understand that the T7000 is not going to work as hard on the 330neo.


The article is being way to simplistic. The RB211-524 has turbine blades with cooling holes drilled in them.

If you google about the 524 that flew through a volcanic cloud, all four engines cut out.

I spoke to a couple of guys that stripped those engines, all the cooling holes had been blocked and they were amazed the blades didn’t melt after the pilots got the engines relit and got them to an airport.

Turbine temperatures are key to turbine life.

Talking in general terms, a turbine life is 5000 cycles. 10 degrees over temp in the turbine is going to reduce your life around 800-1000 cycles.

Now the T1000 does not have that issue, but just illustrate what we are dealing with.

When the turbine is running at over 2000 degrees it’s a small increase, but a big impact.

On the App Store there is Trent XWB pilot guide with lots of geek info.

Not sure who can register to get in but if you can it’s really good.

boeingbus wrote:

Also, Boeing touted how the 787 can perform engine swaps during the 787 design phase. This is predominantly for lessors? Did that feature make its way to production?

IIRC even before flight test it became clear that the engine swap is not possible as originally advertised.

lowbank wrote:

sciing wrote:

boeingbus wrote:

The A330NEO's engines are a derivative of the Trent 1000. Will those engines also experience degradation? Will TP face the same engine issues? If not, why not?

Do you really think that if you would get the answer in detail by RR you would be able to understand?

He is not going to get an answer. I understand that the T7000 is not going to work as hard on the 330neo.


The article is being way to simplistic. The RB211-524 has turbine blades with cooling holes drilled in them.

If you google about the 524 that flew through a volcanic cloud, all four engines cut out.

I spoke to a couple of guys that stripped those engines, all the cooling holes had been blocked and they were amazed the blades didn’t melt after the pilots got the engines relit and got them to an airport.

Turbine temperatures are key to turbine life.

Talking in general terms, a turbine life is 5000 cycles. 10 degrees over temp in the turbine is going to reduce your life around 800-1000 cycles.

Now the T1000 does not have that issue, but just illustrate what we are dealing with.

When the turbine is running at over 2000 degrees it’s a small increase, but a big impact.

I already wrote how complex the material system of an blade is. Load and heat is the next complex topic. So for me as material scientist it is clear that I have no glue about the topic. Even people working in the field would have some trouble to understand. But some people here with much lower background think they would be able to understand anything.
The Bloomberg article is an example of this absolutely misunderstanding of the complexity. It suggest that the basic challenges of turbine blades are the problem of RR now.

boeingbus wrote:

The A330NEO's engines are a derivative of the Trent 1000. Will those engines also experience degradation? Will TP face the same engine issues? If not, why not?
.

The early build 7000 engines will need HPT and IPC blade replacements in the coming months. The blades installed in these motors are similar to the old Pack C T1000 I believe. The fix for those T1000 blades came out right after the early build 7000 were completed. I don't know where in production they changed to the newer blades. I don't think the service bulletins for the change are published yet.

I doubt the 330neo fleet will see the groundings like the 787. There are enough spares and ample time to run the fleet through shop visits. We are still seeing the 787 groundings because there just isn't a large enough spares fleet. Engines are getting turned by the shops but the current rate is only keeping up with removals and not getting ahead. I heard that the Rolls Royce Montreal facility will start doing T1000 visits soon to help with the back log. They usually work the BR 700 series engines found on biz jets I think.

It seems kinda like most of the engine manufacturers all have products with problems.
RR: problems with Trent 1000 equipped on B787.
PW: bunches of problems on GTF engines that are installed on A220 and A320neo families.
GE: facing troubles on the gigantic GE9x, which delayed the B777X's development.

sciing wrote:

ElroyJetson wrote:

"The high-pressure turbine blades in a Trent 1000 passenger jet engine have to withstand temperatures far above the melting point of the nickel alloy from which they’re made. It’s a fiendish technical challenge for the engine’s British manufacturer, Rolls-Royce Holdings Plc — comparable to trying to stop an ice cube melting inside a kitchen oven on full blast. The solution found by the company’s engineers was to blow cool air through tiny holes in the blades. Unfortunately this clever approach has encountered some unexpected problems.

Here my 20 years knowledge of what I learned as graduated material scientist.
The coating on the blades is called TBC, Temperature Barrier Coating, usually ceramics. Below you have bonding coating usually made of refractory metals like Ta or Pt or an intermetalic compound (with high melting point) and then the single crystalline Nickel based superalloy blades.
So what is written in the article is nothing special for RR. The goal is always to go to the highest temperature as possible.
The material system is very complex. I guess there are 10000 PhDs based on that topic and 100000 papers;-)

Thank you for the information. It is clear from your answer the materials element is highly complex. The actual physics of gas turbine engines is fairly simple thermodynamics. Internal combustion and steam engines work on the identical principles. Multiple chambers, with the greater temperature variance between the chambers creating more efficiency. Hot must always flow to cold, never the reverse. Hence your statement about getting the highest temperature as possible in the internal core of the engine, and why jet engines are more efficient at altitude (colder bypass air) versus, say on the ground in Dubai in summertime.

My question for you is do you think the problem with the Trent 1000 is a materials issue, a design issue, or both? Also, are the newest generation engines hitting the limits of existing materials technology?

Thank you for your expertise.

Ronaldo747 wrote:

boeingbus wrote:

Also, Boeing touted how the 787 can perform engine swaps during the 787 design phase. This is predominantly for lessors? Did that feature make its way to production?

IIRC even before flight test it became clear that the engine swap is not possible as originally advertised.

The common pylon went the way of the Dodo long before test flights commenced, from the engine OEM's perspective, this is what they preferred.
Imagine if the common pylon was used, how many RR customers with a/c sitting on the ground would have switched to GE?

How has the A350 version of the Trent avoided all these problems?

Can’t the tech there make its way to the 787 somehow?

How did Boeing get the very short straw from RR?

uta999 wrote:

How has the A350 version of the Trent avoided all these problems?

Can’t the tech there make its way to the 787 somehow?

How did Boeing get the very short straw from RR?

Because Boeing is quite cozy with GE.


A couple of factors is that the tech was evolving so the A350 version (Trent 7000) is a later variant with improved reliability. But it is also likely that the A350 engines still have lower on average hours and cycles. Things like coatings tend to fail at say 75% of their expected life. So the Trent 7000 troubles may only be arriving, but not as bas as the 1000 had.

The domestic coal in India has a high sulphur content and the old plants do not remove the pollutants efficiently from the flue gasses.
Options are changeover to more expensive low sulphur imported coal. A difficult commercial decision.
Or Close all old plants and run only the newer clean coal plants.
But India reached power surplus status in generation just a few years back. So shutting down the old thermal plants might start now, like the local Delhi government closes the local plant during winters to reduce pollution. But unless the grid is better integrated and newer plants come up in proximity of the demand centres, these plants will be running for some more years.

But I doubt corrosion through so2 is the primary reason for the rolls Royce issues. Probably its the effect of erossion. The blades are not heat treated/coated properly.
These high temperature engines have their origins in fighter jet engines, which have a much more punishing duty.

Antaras wrote:

It seems kinda like most of the engine manufacturers all have products with problems.
RR: problems with Trent 1000 equipped on B787.
PW: bunches of problems on GTF engines that are installed on A220 and A320neo families.
GE: facing troubles on the gigantic GE9x, which delayed the B777X's development.

Big difference is RR and PW are seeing IFSDs, AOGs and groundings.
All that adds a big cost and reputational hit.
For unrelated reasons 777X customers aren't in a hurry to bring 777X in to their fleets right now.
You can't say the same thing about 787 and A320neo customers.

ElroyJetson wrote:

The solution found by the company’s engineers was to blow cool air through tiny holes in the blades.

Antaras wrote:

It seems kinda like most of the engine manufacturers all have products with problems.
RR: problems with Trent 1000 equipped on B787.
PW: bunches of problems on GTF engines that are installed on A220 and A320neo families.
GE: facing troubles on the gigantic GE9x, which delayed the B777X's development.

Seems like we are getting to the limit of turbine technology. What is next?

Contra-rotating variable pitch geared propellers bolted on the back of a turbofan. Oh wait....

ElroyJetson wrote:

The only material i know if that can reliably handle the core temperatures of newer engines are cremarics. However cremarics are exceeding brittle and difficult to machine. I am not a gas turbine expert but simple physics says the greater the temperature difference between the hot internal core and the cold air bypass the greater "work" i.e. efficiency of the engine.

However my assumption is the core temps of these new generation engines are hitting the limits of existing standard materials. I would love Lightsaber or others with genuine knowledge to comment.

I just watched a documentary about Project Pluto. And they had to use ceramics for the ramjet due to the heat from the nuclear reactor. I thought the same thing when reading the quote. But a ram jet is a lot different than a gas turbine.