RR Builds Next-Gen "Advance 3" Demo Engine

Revelation · Thu May 19, 2016 10:19 pm

http://aviationweek.com/commercial-avia ... emo-engine says:

The demonstrator, dubbed the Advance 3, is being assembled in the company’s Bristol, England, facility and will fire up for the first time in Derby in the August-September time frame, he adds.
...
The Advance demonstrator is a hybrid combining a Trent XWB-84 case and fan system and the LP turbine from a Trent 1000. “In the middle is the all-new core, both in terms of architecture as well as new technology [that] includes the two new compressors [HP and IP], a lean-burn combustor, ceramic matrix composite [CMC] seal segments and advanced cooled turbine blades. The demonstrator brings them together in a system context,” Newby says.

Compared to the current Trent family, the Advance core “changes the work split significantly,” says Newby. “We will do much more work on the HP compressor with a two-stage HP turbine driving it and a lightly loaded IP compressor. This allows us to grow the pressure ratio in a very efficient manner but also provides a core which leads us to the UltraFan.” Rolls believes the plan takes advantage of the three-shaft configuration in ways that have not been possible before. “You can have a very lightly loaded HP spool with a decent pressure ratio in the IP compressor because it runs at its optimum speed,” Newby says. This provides the launch platform for the UltraFan because “then you take the HP spool and combine that with a geared LP system, and it allows you to grow the bypass ratio as well.”

Lots more details in the article. Good to see this R&D program is moving forward.

kurtverbose · Fri May 20, 2016 7:02 am

Thanks for posting. Shame it's behind a paywall.

Okie · Fri May 20, 2016 1:14 pm

Interesting to see that many of the same new materials are in the GE 9X and Roller Advanced 3.
Just a GE seems to be chasing 2 shaft and RR chasing 3 shaft.

Makes you wonder if the limited number sales for the 777 is the driving force for GE to continue with the 2 shaft vs 3 shaft on the 9X.

Okie

speedbored · Fri May 20, 2016 1:43 pm

Quoting Okie (Reply 2):
Makes you wonder if the limited number sales for the 777 is the driving force for GE to continue with the 2 shaft vs 3 shaft on the 9X.

I think the fact that RR hold multiple patents for 3-shaft configurations has a lot more to do with why GE are sticking with 2 shafts rather than moving to 3.

Good to see that RR are still working, and making progress, on the Advance architecture. I still have a feeling that the first engine that will evolve out of all of this work will be an Advance engine for the A380, with a new Advance core, re-using other modules from various existing engines.

Revelation · Fri May 20, 2016 2:43 pm

Quoting kurtverbose (Reply 1):
Shame it's behind a paywall.

Sorry, I hadn't noticed it wasn't in the "free if you register" section of AvWeek. Note that even if you subscribe, a lot of the jucier content is for AWIN subscriptions only, which is $$$$. I did subscribe at the basic level when I was bored a few weeks ago and thought I'd spend more time drooling over the hardcopy magazines, but so far it's not happening.

Quoting speedbored (Reply 3):
I think the fact that RR hold multiple patents for 3-shaft configurations has a lot more to do with why GE are sticking with 2 shafts rather than moving to 3.

Interesting point. However we're reading that Advance is moving more work to the HP spool in preparation for the UltraFan where they will in essence be using the GTF architecture.

There's an interesting tidbit on the UltraFan whose design freeze is targetted for late 2017:

Quote:

Rolls has also signed a joint venture with Liebherr on the gear system. “That is up and running and delivering the first parts for testing and will begin in the third quarter of 2016,” he says.

It could be that the Advance is the last three spool we see.

Quoting speedbored (Reply 3):
Good to see that RR are still working, and making progress, on the Advance architecture. I still have a feeling that the first engine that will evolve out of all of this work will be an Advance engine for the A380, with a new Advance core, re-using other modules from various existing engines.

The article mentions the Advance technology would be ready in the right time frame for the Boeing "New Midsize Airplane" currently being studied, although above we see they are using a TXWB-84 engine to host the new Advance core. Another section mentions that the "HT3 (high-temperature turbine technology) program" is using a TXWB-97 engine to host a new HP turbine section made of CMCs and other advanced metals. Also the article says, with regard to the "CTi (composite titanium) fan system":

Quote:

“We are also testing bigger blades. The last was 112 in., which is Trent 1000 size and now we are testing blades beyond 120 in. We have thrown birds at them and are testing them in extremes of environmental conditions to make sure the material properties stay good. The final back-to-back engine test in Berlin on the new 61 bed is to validate performance with the standard titanium and new composite fan.”

All of this suggests to me that they're targeting the A380's market segment rather than the NMA/MOM/whatever.

[Edited 2016-05-20 07:49:27]

flipdewaf · Fri May 20, 2016 3:17 pm

Quoting Revelation (Reply 4):
All of this suggests to me that they're targeting the A380's market segment rather than the NMA/MOM/whatever.

Or the T7 replacement

Revelation · Fri May 20, 2016 3:57 pm

Quoting flipdewaf (Reply 5):
Or the T7 replacement

Yes, it'll be pretty interesting to see how GE will respond as it's clear RR is doing an awful lot of R&D that can easily address the T7 space, and the GE9x is mostly GEnX tech.

Revelation · Fri May 20, 2016 7:25 pm

Too late to update the earlier post, so I'll point out that the May 23rd AvWeek:

http://aviationweek.com/aviation-week-space-technology/2016-05-23

is just loaded with what many of us here at a.net refer to 'engine porn'.

The Advance article is just one of several interesting ones.

So, some of you who don't subscribe might want to see if you can get it via a library etc.

I may summarize some of the other articles if I find them interesting or if there are suitable requests here.

[Edited 2016-05-20 12:27:37]

Amiga500 · Mon May 23, 2016 9:26 am

Quoting Revelation (Reply 4):
It could be that the Advance is the last three spool we see.

Ah, I dunno. I wasn't exactly reading that out of it.

With the addition of a gear to the LP shaft, they can better break down the 4 "compressor" speeds amongst the 3 turbine speeds.

Right now, the LP is only running the fan, meaning the IP is running the bulk of the compressor.

With a gear on the LP shaft, you can shift one or two compressor stages from IP to LP - allowing better tuning of IP and HP to their remaining stages.

Lightsaber would probably have a better gut feeling for how much difference it might make to performance.

Obviously, as usual, it'll all come down to a trade-off of complexity, cost, weight, reliability, performance etc etc - but I definitely wouldn't put much money on a gearbox in an RR engine automatically signalling the death of their triple spool architecture.

speedbored · Mon May 23, 2016 12:33 pm

Quoting Amiga500 (Reply 8):
Obviously, as usual, it'll all come down to a trade-off of complexity, cost, weight, reliability, performance etc etc - but I definitely wouldn't put much money on a gearbox in an RR engine automatically signalling the death of their triple spool architecture.

For the Ultrafan, it seems that RR have decided that the trade-off works out in favour of a 2-shaft design, with the fan attached via a gearbox to the second (LP) shaft:
http://www.rolls-royce.com/products-...ucts/future-products/ultrafan.aspx

Though, just to make it easier for a good a.net argument, they are referring to it as a "geared 3-shaft" design - the 3rd shaft being the one emerging from the front of the gearbox, I presume.

Given that the major reason why the 3rd shaft was introduced will now be handled by the gearbox, I doubt that there would be sufficient benefit from a third core shaft to drive the gearbox. I certainly don't claim to be an engine expert, but it seems to me that the faster the LP turbine is run, the smaller, and lighter, it can be so, with a gearbox, there is no point in using a slower 3rd shaft. I'm sure that lightsaber will be able to shed more light on this.

Amiga500 · Mon May 23, 2016 3:38 pm

Fair 'nuff.

Looks like its a 2 shaft design for Rolls in future then.

KarelXWB · Tue Aug 01, 2017 9:33 am

Update.

RR is getting ready to fly the Advance 3 demonstrator, ahead of schedule.

Rolls-Royce this month plans to test Advance3 engine demonstrator

https://twitter.com/R_Wall/status/892295735735181312

parapente · Tue Aug 01, 2017 12:57 pm

Interesting thread indeed.this demonstration engine does not include the gearbox I assume.ie Simply to test the new core with known 'front and back' parts? I assume this test engine is the one people hope might become a NEO engine for the 380?

uta999 · Tue Aug 01, 2017 1:07 pm

Will RR ever return to the narrowbody A320 / 737 market? With the problems the other two manufacturers are in, now might be time to look at the business case.

seahawk · Tue Aug 01, 2017 1:20 pm

Looks like a serious PiP for Trent 7000, XWB and Ten.

Revelation · Tue Aug 01, 2017 2:13 pm

KarelXWB wrote:
RR is getting ready to fly the Advance 3 demonstrator, ahead of schedule.

It's not clear if this is intended to fly or not. Do you have a clear reference? All I could find is https://www.ainonline.com/aviation-news/air-transport/2017-06-18/rolls-royce-advance-test-engine-readied-testing which says:

Chief engineer and head of program for Advance 3, Andy Geer, said that the Advance 3 test engine would be trucked to Derby “in July” and would then be put on a test pylon before installing in one of the site’s large test cells. Tests will include water ingestion, noise surveys, X-ray examination, “rumble” survey and core zone thermal surveys, with the engine running at speeds of up to 15,000 rpm.

No mention of installation on flying testbed, etc.

EDIT: http://aviationweek.com/caring-engines- ... rt-forward says:

The Advance3 programme will not include a flying phase.

so it seems the tweet was misleading.

Revelation · Tue Aug 01, 2017 2:32 pm

seahawk wrote:
Looks like a serious PiP for Trent 7000, XWB and Ten.

If the goal is as mentioned ( "move overall gas generator pressure ratio from 50-odd to one in the latest Trent families to 60-odd to one", ref: http://aviationweek.com/caring-engines- ... rt-forward ), we aren't talking about a PIP.

speedbored · Tue Aug 01, 2017 2:45 pm

parapente wrote:
Interesting thread indeed.this demonstration engine does not include the gearbox I assume.ie Simply to test the new core with known 'front and back' parts? I assume this test engine is the one people hope might become a NEO engine for the 380?

The Advance engines were never designed to have a gearbox - they are a stepping stone on the way to the Ultrafan engines, where a gearbox will be introduced.

parapente · Tue Aug 01, 2017 5:22 pm

I appreciate that this test engine is a 'one off' (to quote RR) but have they stated what power output they are expecting from this hybrid engine?

WIederling · Tue Aug 01, 2017 7:01 pm

seahawk wrote:
Looks like a serious PiP for Trent 7000, XWB and Ten.

The Trent 1000 TEN and thus Trent 7000 too already got TXWB and "Advance 3" elements implanted.

seahawk · Tue Aug 01, 2017 7:22 pm

WIederling wrote:
seahawk wrote:
Looks like a serious PiP for Trent 7000, XWB and Ten.

The Trent 1000 TEN and thus Trent 7000 too already got TXWB and "Advance 3" elements implanted.

And I guess it is likely that more technology will find their way into those engines. Which I consider the most likely application for the technology.

WIederling · Wed Aug 02, 2017 7:35 am

seahawk wrote:
WIederling wrote:
seahawk wrote:
Looks like a serious PiP for Trent 7000, XWB and Ten.

The Trent 1000 TEN and thus Trent 7000 too already got TXWB and "Advance 3" elements implanted.

And I guess it is likely that more technology will find their way into those engines. Which I consider the most likely application for the technology.

The TEN already is a serious revamp. IMU only 25% parts commonality to the original model.
The TEN and 7000 will, Afaics, go forward with "simple" PIPs only. Another major revamp would be too expensive by far.

But I could see some major changes to the TXWB retracing the TEN redo.
On the other hand: the TXWB never appeared to be such a shortchanged design that the original
Trent1000 seems to have been. ( Same for the GEnX base engine.)
There may not be much pressure for change beyond further "simple" PIPs.

KarelXWB · Wed Aug 02, 2017 7:44 am

Revelation wrote:
KarelXWB wrote:
RR is getting ready to fly the Advance 3 demonstrator, ahead of schedule.

It's not clear if this is intended to fly or not. Do you have a clear reference? All I could find is https://www.ainonline.com/aviation-news/air-transport/2017-06-18/rolls-royce-advance-test-engine-readied-testing which says:

Chief engineer and head of program for Advance 3, Andy Geer, said that the Advance 3 test engine would be trucked to Derby “in July” and would then be put on a test pylon before installing in one of the site’s large test cells. Tests will include water ingestion, noise surveys, X-ray examination, “rumble” survey and core zone thermal surveys, with the engine running at speeds of up to 15,000 rpm.

No mention of installation on flying testbed, etc.

EDIT: http://aviationweek.com/caring-engines- ... rt-forward says:

The Advance3 programme will not include a flying phase.

so it seems the tweet was misleading.

You are right, Advance 3 demonstrator will not fly. I must have misinterpreted the tweet.

Revelation · Wed Aug 02, 2017 12:00 pm

WIederling wrote:
seahawk wrote:
Looks like a serious PiP for Trent 7000, XWB and Ten.

The Trent 1000 TEN and thus Trent 7000 too already got TXWB and "Advance 3" elements implanted.

Since the T-TEN is in testing and A3 is not, it'd be more accurate to say Advance 3 has T-TEN elements in it!

No fair counting twice...

WIederling wrote:
The TEN already is a serious revamp. IMU only 25% parts commonality to the original model.
The TEN and 7000 will, Afaics, go forward with "simple" PIPs only. Another major revamp would be too expensive by far.

But I could see some major changes to the TXWB retracing the TEN redo.
On the other hand: the TXWB never appeared to be such a shortchanged design that the original
Trent1000 seems to have been. ( Same for the GEnX base engine.)
There may not be much pressure for change beyond further "simple" PIPs.

I'm not sure what you are trying to say. Both T1000 and GEnX were anything but short changed. They were huge and costly development efforts that produced generational engines with big architectural changes such as contra-rotation. Both initially did not meet projected numbers, but that's because (a) the bar was set so high and (b) it took so long to mature all that new tech.

KarelXWB wrote:
You are right, Advance 3 demonstrator will not fly. I must have misinterpreted the tweet.

No problems. Thanks for posting the picture, it's interesting news.

WIederling · Wed Aug 02, 2017 8:47 pm

Revelation wrote:
[quote="WIederling"The Trent 1000 TEN and thus Trent 7000 too already got TXWB and "Advance 3" elements implanted.

Since the T-TEN is in testing and A3 is not, it'd be more accurate to say Advance 3 has T-TEN elements in it!

[/quote]

From the horses echo chamber:
Combining Advance3 core technology and features from the Airbus A350’s Trent XWB program, the hybrid engine will become the standard Rolls 787 powerplant beginning this year.
ref: http://aviationweek.com/commercial-avia ... es-1639711 last paragraph.

Revelation · Wed Aug 02, 2017 10:02 pm

WIederling wrote:
From the horses echo chamber:
Combining Advance3 core technology and features from the Airbus A350’s Trent XWB program, the hybrid engine will become the standard Rolls 787 powerplant beginning this year.
ref: http://aviationweek.com/commercial-avia ... es-1639711 last paragraph.

In other words, it's horse droppings. I've been off reading the various press clippings of the various T1000 derivatives and it all gets very circular very quickly.

parapente · Tue Aug 15, 2017 5:46 pm

The have been reports of the Royal Dubai visit to Airbus and the associated rumour of a x20 A380 plus order.All conjecture of course.But if such an order took place then it would happily take the programme to 2020.But we know what they really want is a NEO...

This Advance test bed engine has been clearly stated not to fly.But.The Txwb was tested on an A380 and the power of this hybrid engine has gotta be somewhere between the txwb and the T7000.Couldnt be closer to a T900 if you tried...Or am I taking things too far!

They clearly state that the geared Ultra will be around 50k thrust so that would be for any MOM type aircraft.So it would never go on an A380.

KarelXWB · Tue Nov 14, 2017 12:06 pm

Small update on the progress:

The next milestone in the development of our next generation civil aerospace engines is due shortly with the first run of the Advance3 demonstrator.

...

The demonstrator engine is now complete and is being readied for test in Derby, UK. Testing will initially confirm operational parameters with future tests designed to gather data on the performance of the engine across more than 2,800 parameters.

http://www.rolls-royce.com/products-and ... ducts.aspx

And for the first time RR included a photo of the Advance3 demonstrator:

lightsaber · Tue Nov 14, 2017 6:19 pm

The switch to a 2 stage HP turbine implies a dramatic increase in pressure ratio. This looks like a MoM technology demonstrator... Just the right timing to get Boeing's attention...

Lightsaber

parapente · Wed Nov 15, 2017 1:00 pm

Hopefully will have 6 months test data by Farnborough!Plus of course the power gearbox and carbo-titanium wide cord fan blades.
One imagines that the 797 will be launched then.It does seem to be gathering a head of steam.

kitplane01 · Sat Nov 18, 2017 1:42 am

speedbored wrote:
Quoting Okie (Reply 2):Makes you wonder if the limited number sales for the 777 is the driving force for GE to continue with the 2 shaft vs 3 shaft on the 9X.
I think the fact that RR hold multiple patents for 3-shaft configurations has a lot more to do with why GE are sticking with 2 shafts rather than moving to 3.

Good to see that RR are still working, and making progress, on the Advance architecture. I still have a feeling that the first engine that will evolve out of all of this work will be an Advance engine for the A380, with a new Advance core, re-using other modules from various existing engines.

Can you tell me more about these patents? I note that the F104 jet engine had three spools, was made in 1968 (the RB-211 was 1969) , and patents last 14 or 20 years (depending on type).

kitplane01 · Sat Nov 18, 2017 1:44 am

lightsaber wrote:
The switch to a 2 stage HP turbine implies a dramatic increase in pressure ratio. This looks like a MoM technology demonstrator... Just the right timing to get Boeing's attention...

Lightsaber

My understanding is that (1) Yes, they are going to increase the overall pressure ratio and (2) They are offloading work from the IP onto the other spools. Both things will make the pressure ratio of the HP higher.

WIederling · Sun Nov 19, 2017 10:58 am

kitplane01 wrote:
I note that the F104 jet engine had three spools, was made in 1968 (the RB-211 was 1969) , and patents last 14 or 20 years (depending on type).

Which engine do you mean?

https://en.wikipedia.org/wiki/Category: ... an_engines

Rush of engines around 1969.. 1972: Euro RB199/RB211 and Soviet (.Lotarev D-36, Kuznetsov NK-25 )
I suppose prepping started earlier all around.

kitplane01 · Mon Nov 20, 2017 7:01 am

WIederling wrote:
kitplane01 wrote:
I note that the F104 jet engine had three spools, was made in 1968 (the RB-211 was 1969) , and patents last 14 or 20 years (depending on type).

Which engine do you mean?

https://en.wikipedia.org/wiki/Category: ... an_engines

Rush of engines around 1969.. 1972: Euro RB199/RB211 and Soviet (.Lotarev D-36, Kuznetsov NK-25 )
I suppose prepping started earlier all around.

Speedbored wrote that RR had lots of patents around the three spool concept. I wondered what they were. And I mentioned that there were lots of three spool engines from long ago. Any patents on those would have long since expired.

Faro · Mon Nov 20, 2017 10:00 am

There was talk somewhere of RR starting to engage in CFRP technology for the fan...when may we expect this to bear fruit...the Advance3 pic shows 22 blades against the GE9X's 16...

Faro

speedbored · Mon Nov 20, 2017 10:02 am

kitplane01 wrote:
Speedbored wrote that RR had lots of patents around the three spool concept.

But not the concept itself, I didn't.

As the first to introduce a large 3-spool commercial engine (which technically bankrupted them), RR has taken out many patents over the years relating to the implementation, many of which have made it difficult, and expensive, for other manufacturers to introduce competing 3-spool designs.

kurtverbose · Mon Nov 20, 2017 11:47 am

kitplane01 wrote:
And I mentioned that there were lots of three spool engines from long ago.

I can't think of any three spool engines outside of Russia that were built in any significant numbers without Rolls Royce involvement.

You said the F-104. I don't know an engine called that - who makes it? There is an aircraft, but this is powered by a GE J79 turbojet, which is a single spool engine.

Wiederling posted a wikipedia link for you.

WIederling · Mon Nov 20, 2017 1:22 pm

kitplane01 wrote:
WIederling wrote:
kitplane01 wrote:
I note that the F104 jet engine had three spools, was made in 1968

Which engine do you mean?

Speedbored wrote that RR had lots of patents around the three spool concept.

I wanted to know which "F104" engine your were referencing.
( if there are valid patents around they are probably younger and cover detail solutions on 3spool engines?)

Slug71 · Tue Nov 21, 2017 10:02 pm

Vladex wrote:
I am just curious as to the case in layman terms for for Rolls Royce Advance engine for A380?
I know there is talk of ultrafan but that is long time away and it would be too much range for this A380 , that maybe for a stretch. Besides I don't hear about any other application for Advance right now. How much efficiency would there be with the advance engine compared to the current operating engines?
Advance - 60:1 pressure ratio , 11:1 bypass ratio
GP7000 - 43:1 pressure ratio, 8.8 bypass ratio
Trent 900 - 39:1 pressure ratio, 8.7 bypass ratio.

It's probably to soon for much info considering it's still in development. The first demonstrator has only just been recently completed.

IIRC, the Advance is supposed to be 20% more efficient than the Trent 700 and the Ultrafan 25% more efficient than the Trent 700. Not sure how that relates to the T900 or GP7200 though.

Copied your question over to this thread in "Technical/Operations" too as its probably most appropriate over here.

Revelation · Wed Feb 07, 2018 2:24 am

http://aviationweek.com/singapore-airsh ... olls-royce gives a nice status update on the Advance 3 demo engine, the new gearbox (i.e. heart of "RR GTF"), the advanced low-emissions combustion system (ALECSys), and the advanced low-pressure system (ALPS).

All are making good progress. Advance 3 has reached 90% of core power.

The later (ALPS) was of most interest to me:

Rolls-Royce is also poised to begin runs of the advanced low-pressure system (ALPS) engine, which, for the first time on one of the company’s powerplants, combines tests of a composite fan with a composite fan case. “We have just got to pop the fan blades in the front and we will be putting that on test later this year. That’s a good step forward because that is all about understanding not just the composite blade but also the performance of the composite case with the fan,” says Curnock. Testing is expected to be complete by year-end.

KarelXWB · Sun Feb 11, 2018 7:18 pm

Since when does Advance 3 demo has a gearbox? Because 6 months ago we read:

speedbored wrote:
parapente wrote:
Interesting thread indeed.this demonstration engine does not include the gearbox I assume.ie Simply to test the new core with known 'front and back' parts? I assume this test engine is the one people hope might become a NEO engine for the 380?

The Advance engines were never designed to have a gearbox - they are a stepping stone on the way to the Ultrafan engines, where a gearbox will be introduced.

Revelation · Sun Feb 11, 2018 7:45 pm

KarelXWB wrote:
Since when does Advance 3 demo has a gearbox?

http://aviationweek.com/singapore-airsh ... olls-royce tells us RR's third gear box is being tested, but that is a separate effort from Advance 3 (which is a core demonstrator), ALPS (a fan demonstrator) and ALEsys (a combustor demonstrator).

The plan of record stays the same:

The new core, which began tests in November in a hybrid demonstrator, will run initially in the Advance, a direct-drive turbofan with a fuel-burn level at least 20% better than the current Trent 700. However the Advance is a stepping-stone to the UltraFan, a very high bypass design that marries the same core to a large gear-driven fan to improve fuel burn by at least another 5% over the Advance.

Sorry if I misled anyone.

kurtverbose · Thu Apr 26, 2018 12:20 pm

Flight reporting Airbus is helping with the necelle and pylon to flight test ultrafan, even though it'll be mounted on RR's own 747 flight test aircraft.

parapente · Thu Apr 26, 2018 1:25 pm

They also mentioned that they have submitted a variant to Boeing for the 'proposed' 797 .Tight on timescales but probably possible.

Revelation · Mon Jul 16, 2018 11:38 am

http://aviationweek.com/propulsion/ultr ... s-new-core says:

“The Advance3 is doing really well. The technology is performing as we thought it would, and it has now run at full take-off power,” says Andy Geer, project director for the UltraFan demonstrator program. Although the UltraFan and the new core are scalable to thrust levels from 25,000 lb. up to 100,000 lb. and beyond, the Advance3 and initial UltraFan demonstrators are designed to run at 80,000 lb.-plus to take advantage of the existing Trent 1000 and Trent XWB hardware used to make the hybrid demonstrator powerplants in the test effort. Full power for the Advance3 is therefore set at 84,000 lb. to match the fan system of the Trent XWB-84 donor engine.

Advance is also a stepping stone to the UltraFan, a very high bypass design which marries the same core to a large gear-driven fan to improve fuel burn by at least a further 5%. The UltraFan is targeted at entry-into-service in the mid-2020s and is aimed at Boeing’s new midsize airplane (NMA), as well as next-generation Airbus twin-aisle designs.

On UltraFan, the manufacturer “recently passed through the Stage 1 exit gate,” says Geer. “This essentially means the concept for the engine is frozen and locked, so we can move to the next stage of more detailed design and then component manufacture. So, this is a significant and exciting time for the program.” Initial ground tests of the UltraFan are set to begin in 2021.

That's a lot of solid information, and the source article has even more.

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