Leeham News and Analysis
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Leeham News and Analysis
- Bjorn’s Corner: New engine development. Part 4. Propulsive efficiency April 19, 2024
- Boeing unlikely to meet FAA’s 90-day deadline for new safety program April 18, 2024
- Focus on quality not slowing innovation, says GKN April 18, 2024
- Boeing defends 787, 777 against whistleblower charges April 17, 2024
- Dissecting Boeing CEO’s statement next new airplane will cost $50bn April 15, 2024
Pontifications: March is a critical month for engine OEMs
By Scott Hamilton
Feb. 25, 2019, © Leeham News: Even as Boeing put off a decision whether to launch the New Midmarket Aircraft until 2020, next month could be an important milestone—not only for the program but especially for the engine makers.
Unless delayed, engine down-select is supposed to be made in March.
This is a critical decision that could have huge implications to one of the engine OEMs—Rolls-Royce.
Forfeited single-aisle market
In one of the most widely panned corporate decisions in recent memory, Rolls-Royce opted to withdraw from the International Aero Engines consortium, a joint venture that included Pratt & Whitney, RR, MTU and, initially, Japanese Aero Engine Corp and a small Italian company. IAE produced the V2500 (“V” for the Roman numeral five, the original partnership in IAE) engine for the Airbus A320ceo.
As PW moved toward launching the Geared Turbo Fan engine, Airbus wanted IAE to be a partner. IAE produced the core of the V2500. PW’s last attempt at an independently designed engine, the PW6000 for the A318, proved a disaster. Airbus had more confidence in the PW design and RR execution for the GTF than in PW alone.
Rolls nevertheless separated from IAE and with it the lucrative single-aisle transport market. Now it produces only engines for the wide-bodied Boeing 787, Airbus A330ceo/neo, A380 and A350.
We know what has become of the A380. We also know the technical problems of the 787’s Trent 1000 last year and which continue this year. This had a spillover effect to the A330neo.
It’s been an unmitigated disaster for Rolls-Royce.
Making the big bet
Rolls is making a big bet on the NMA to broaden its product base. It’s a hugely risky bet.
The market demand is over 20 years is between 2,000 and 2,500 airplanes. (Boeing continues to talk about the “addressable market,” but internally forecasts about 2,500 in actual demand, an insider told me.) Figure Airbus will get about half this market, weighted toward the A321neo powered in part by the GTF—of which RR has no share.
The business case to any of the engine makers on these numbers is already dicey.
Airlines and Boeing would like dual sourcing for the NMA. But half of one half really sticks the knife into a business case.
This is why the engine makers have bene vociferous about saying they see no business case for them. And why, if they do want the contract, it must be sole-source.
Rolls’ stake
For Rolls, the NMA is a path to broaden its product base beyond the large, long-haul wide-bodies for which there is a limited market.
The NMA is also a way for Rolls to try and get back in Boeing’s good graces.
The 787’s Trent 1000 issues severely strained relations with Boeing. Although the grounded airplanes—numbering around 50 at one point and still about 30 at the beginning of this year—are the fault of Rolls, airlines complained Boeing wasn’t doing enough to try and resolve the situation or find airplanes to lease.
Pratt & Whitney’s stake
For Pratt & Whitney, the NMA is the way back to Boeing.
PW walked away from competing as an engine supplier on the 787 and the 777X. The X was probably a long shot in any event and the market demand for this big airplane certainly didn’t justify dual sourcing.
But taking a pass on the 787 still rankles some at Boeing. Relations with PW haven’t been the same since. (Partnering on the KC-46A tanker, which uses PW engines, apparently didn’t smooth things over.)
There were some within Boeing who wanted to have the GTF as a second choice for the 737 MAX. In the end, GE/CFM made Boeing a sweet commercial terms offer, maintaining its monopoly on the 737.
Boeing then watched as the GTF caused headache after headache for Airbus and on the A320neo. Undoubtedly, Boeing crossed itself in thanks for not putting the GTF on the MAX.
Ironically, the GTF Airbus problems had to do with the engine core and ancillary components and nothing to do with the gear box that is at the heart of the GTF. It was Airbus’ concern over the core that prompted its desire for Rolls to remain part of IAE.
PW doubts the NMA business case and wants sole-sourcing. But with relations with Boeing still poor, it’s an uphill climb.
CFM’s stake
CFM wants sole-source, it doubts the business case and it wants to keep PW and RR off Boeing airplanes. Betting is that CFM has the inside track simply because of the dominate CFM/GE position on the 7-Series airplanes, for decades.
But it’s this very dominance that drives some within Boeing to seek a change, either by bringing in a second engine supplier or switching entirely to a new sole source OEM.
Boeing salesmen complained for years that given its monopoly position, CFM sometimes doesn’t step up with concessions needed to beat the A320. I know of a few deals in which this was the case. PW stepped up and Airbus won, leaving Boeing salesmen fuming in the process, not at Airbus but at CFM.
Winning the deal
Our paywall today discusses some of the commercial terms at stake for the engine OEMs in their quest to win the down-select.
Next month should tell us a lot about how the NMA development will go.
If the A321XLR derails and stops the NMA in its tracks, why should RR bother offering an engine for it?
Also, the single aisle market seems to be almost a factor of ten bigger than the so-called middle of the market for the next 20 years. Wouldn’t it be a better idea for RR to talk Airbus into doing an A32Xneo Mark II — powered by 25-35,000 pounds of thrust UltraFan engines.
I agree. The A32X market is 10 times bigger. Rolls-Royce must be ready and willing when the time comes!
If ands ans buts were candy and nuts we would all have a Merry Christmas .
?
As I said, business analysts are saying Rolls-Royce will out-perform. So @Transworld you are finally right. It’s going to be a Merry Christmas everyday for Rolls-Royce.
The latest news is that Airbus is launching the A321XLR and RR pulls their offer for the Ultrafan for the 797. They say it’s because the timeline Boeing is planing for is hard to fulfill. I think that’s an excuse to keep face for both sides. I assume they rather develop the Ultrafan for more promising projects (A350neo) and not waste time and energy (and money) of the 797 “feasibility study”.
There is no way the aircraft OEMs can keep their strategies mediatight in this world anymore, as trade secrets diffuse freely through whatsoever professional firewalls are conceived to contain their innermost sensitive decisions. In the NMA example here we have engine vendor technology readiness as the upside marker for powerplant selection giving away the smoke from the fire … there’s always somebody who will tell the forbidden tale ! Twitter/Facebook/Google are not helpful either with keeping things mediaproof …
I think Airbus are quietly praying that Boeing don’t select Rolls-Royce’s Ultrafan. Ultrafan will go on the next big iteration of the A320 series, a big iteration is a new wing or a new airplane. It will also go on the A220-500 and the A220 series.
With regard to Rolls-Royce’s future. Business analysts have upgraded the stock to out-perform, noting that the Trent 1000 issues are behind them and the Trent XWB is breaking all sorts of records.
But coming to Advance/Utrafan. Rolls-Royce have skipped a generation. For those who have not been watching, Rolls-Royce was to produce an engine with OPR > 60:1, now it is > 70:1 and could get very close to the magic number of 80:1. An Advance 2 HPC/HPT is running on Pearl 15 with an Advance 3 HPC/HPT to come. The Advance 3 HPC/HPT is running on a Trent XWB based demonstrator engine. Hot materials for the combustor and HPT are in use on the Trent XWB-97. The CTi fan and case is now running on a Trent 1000 based demonstrator engine. And the gearbox is running at full power. A full demonstrator Ultrafan engine will ground run in 2021 and fly in 2022. No other engine will come anywhere near the performance of Ultrafan. And it will be ready by 2025.
Key is the fact that Airbus is designing a pylon and the cockpit/engine interface. I don’t think Airbus would do that unless Utrafan was central to their thinking, both with regard to narrowbodies and widebodies.
I do hope Boeing does put recent history behind them. Rolls-Royce engines on the 747/757/767/777 have the best reputation possible, out-performing their counterparts. Equally the Boeing/GE embrace is for me becoming a suicide pact.
Will it happen, will Boeing put Ultrafan on the NMA? I doubt it. Boeing are risk averse because of the 787, the 737 MAX and the 777X prove that. NMA is looking evermore a moderate solution that will address a moderate market. There will not be any rocket science.
Boeing need to remember that Airlines need flexibility. For example, Delta are happy to replace 767s with A330neos. Expect Delta to buy more A330neos. In the NMA, Boeing have offered airlines a narrow airplane with moderate technology. Airlines have come back and said can it do this and this and this. Boeing have had to say no. So back to the drawing board.
I don’t think there will be an engine selection in march! I’m not even sure that the NMA in it’s current form will happen!
RR did not sell that well onto the 747, 767 and 777. Still quite sucesful on the 757/A330. You are righht that all the RR and Airbus investments into a Advance/Ultrafan hardware and flight test point to a neo program. One is the A350-1000ULR where you can charge customers alot for each % of improved fuel consumption, the other is a A322LR where fuel burn is really important. To reengine the regular A320neo family is not cost effective with a new and expensive Engine is a no go.
The Roll-Royce Trent 800 was market lead on the 777 until GE were given exclusivity. They did very, very well on the 747. They came to the market too late on the 767 to do well.
@claes
An UltraFan powered A32Xneo family would essentially constitute a third engine option for the family — an engine option that would make the two other engine options uncompetitive overnight.
Not really, it would only fit the biggest aircrafts in the A320 family that requires higher thrust (37-42k) and lower SFC. It will be too expensive for the “normal ones”.
Don’t really understand the words, too expensive. Geared fans work down to less than 20,000lb thrust. Ultrafan can be used on the A220 series never mind the A320 series.
If you mesn price, why more expensive.
If you mean efficiency, very high BPR (15:1) is very beneficial especially for slower speed narrowbodies, provided the fan diameter isn’t too big.
Ultrafan will have a very small core, allowing very high BPR (15:1) without excessive fan size.
@claes
Which A320 family member requires 42,000 pounds of thrust?
With an 85 percent learning curve and high-volume production, the production costs will come down dramatically. As I indicated down-thread; it’s all about volume in the single aisle market.
If Airbus would decide to offer the UltraFan as the second or third engine option on the A321XLR and a stretched A322 , it would be commercially wrong-headed to go through all the development, testing and certification expenses and not offering the engine on the A320neo and regular A321neo, as well.
https://www.easa.europa.eu/sites/default/files/dfu/TCDS%20EASA.IM_.E.093%20Issue%2005.pdf
RR did poorly on the A380 as well as the 787 before the debacle.
The Trent 10 suffers from the same core issues that the 1000 had as does the Trent 7000.
As we will not see history on the XWB for a while (which took years to show up on the 1000 in two forms) we don’t know what its long term looks like.
As for records, the XWB is running, I don’t see that as setting all sort of records. So is the GenX, 777 Engines, GP7000 and the CFMs.
I think RR is looking for a common core engine for the 797 and an A322ULR application (like a 757 designed in the 2000’s). Getting into the current A320neo models I think is not feasible but the upper corner in size, payload and range is open. Offering an engine that has more thrust and less fuel burn above the present A321neo engines capabilities is a possibility and can thus be sold for a higher price than a future PW1135G. The 757 was available with 43k engines.
Most gear fan engines had problems initally, anyone remember the Lycoming ALF502? Even the Garret TFE731 has is initial issues.
@TransWorld
“RR did poorly on the A380”
In what way?
“as well as the 787 before the debacle.”
The fault of which lies squarely with the OEM that launched the “Dreamliner” — seemingly in “a drug-like rush” atmosphere — on an irresponsible, truncated and risky four year development schedule from launch to EIS. If the 787 had been developed on the same conservative seven year schedule from launch to EIS as that of the 777X programme — and where GE has been granted ample time to develop the GE9X engine and get it right — I’m quite sure that both the engine OEMs on the 787 would have managed to deliver a much more mature product at EIS. It’s significantly more expensive to fix an immature product post EIS than it is to deliver a fully mature product before EIS.
“The Trent 10 suffers from the same core issues that the 1000 had as does the Trent 7000.”
More ill-informed nonsense.
“As we will not see history on the XWB for a while (which took years to show up on the 1000 in two forms) we don’t know what its long term looks like.”
Long term outlook for the Trent XWB: 2000 plus engines delivered before EIS of the first UltraFan powered A350.
Re: Trent 1000 C-package vs TEN and T7000, the TEN/T7000 has a somewhat different core Engines, so very few of the T1000 C-Engines problems can be red across to the TEN/T7000, the TEN/T7000 has its own problems lika any new Engine type but of a “normal” magnitude.
OV-O99:
That can a pretty good tactic (change the subject) but RR wanted on the program so you are saying its Boeing fault they could not execute but GE could?
Wooheee, fishy smell.
@Philip,
“OPR 60, 70, ‘Magic Number 80’”; “‘Advance 2/3’ HPC/HPT”; “Pearl”; “CRi ‘Fan’, ‘Case’” – OH, MY‼️❓‼️❓‼️❓
For those of us whom are NOT aerospace engineers or trained in the science/physics of jet propulsion, could you, Scott or Bjørn, please offer notations about what these terms are? – and why they matter?/how they apply? in terms accessible to laypersons/professionals in fields outside of science and physics, etc? 😉
Thanks!
OPR – overall pressure ratio.
HPC – high pressure compressor
HPT – high pressure turbine
CTi – carbon fan with titsnium leading edge
Fan – the whirly bit at the front of the engine
Case – the case that surrounds the whirly bit at the front of the engine
Advance 2/3 – the name of Rolls-Royce’s next generation architecture
Pearl 15 – the new engine for Bombardiers Global 5500/6500 airplanes
Magic number 80 – this is all about burning fuel efficiently. Specifically engines don’t burn all the fuel and also fon’t burn fuel efficiently. This means that not all the fuel’s energy becomes thrust. When the OPR get’s to 80:1 then an engine is more likely to burn all the fuel and to burn it efficiently, especially when combined with a lean burn combustor that helps to burn fuel efficiently. It’s a big subject.
Where does “titsnium” come from and and is it soft?
Additional info on the power gear box for the UltraFan:
https://www.ainonline.com/aviation-news/air-transport/2017-06-16/rolls-royce-starts-gearbox-load-tests-new-large-turbofans
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https://leehamnews.com/2017/01/13/bjorns-corner-geared-turbofans/
–
https://www.youtube.com/watch?v=3WhmUSmIPd8
Interesting, butI do think they will be able to keep the fan size down because the core will be small. BPR is the key parameter, not fan size per se.
“meaning the through-ratio of rotational speeds is 4:1 if there sun and planets are the same size (whereas it is 3:1 if drive is through the outer gear”
I’m sorry, but that is not English, that is gibberish. But forgiving that, is there a different ratio if the ring gear is fixed or the sun gear is fixed for the same geometry?
I think both of you are not explaining yourself very well. There are many ways of constructing a gear box. PW and RR have chosen different ways. In both cases, the result is an effective radius which means there is an effective ratio.
I think OV-099 was trying to suggest that RR have chosen a more compact solution meaning the radius of the fan hub is smaller for the same effective radius and therefore the same effective ratio
I don’t know if OV-099 is right, but keeping the radius of the fan hub tight means a higher BPR can be achieved with a smaller overall fan diameter. As I said elsewhere, it’s the BPR not the fan diameter, per se, that improves propulsive efficiency
A ratio of 4:1 does say a lot. It means the IPC can run more efficiently. Good to know OV-099. Thanks.
the difference is if it is the planets that are fixed or one of the rings.
so, for 3:1 you have the sun and universe rotate and the planets fixed, with the core connected to sun and fan to universe, for 4:1 you have the sun and planets rotate and universe fixed and have the core to sun and fan to planets.
the 4:1 configuration introduces some lubrication complexities for the bearings in the planet gears, but nothing that hasn’t been done before.
@Ted @Philip
Not mine words. It was a quote from the linked article:
https://www.ainonline.com/aviation-news/air-transport/2017-06-16/rolls-royce-starts-gearbox-load-tests-new-large-turbofans
–
Bilbo nicely explained the difference between a 3:1 and 4:1 reduction ratio.
Reduction ratio = Driven / Drive
Example:
Sun: 30 teeth
Ring (universe): 90 teeth
Planet carrier= Sun + Ring = 120 teeth
3:1 = Ring (Driven) / Sun (Drive) = 90/30
4:1 = Planet Carrier (Driven) / Sun (Drive) = 120/30
–
Here’s another powered gearbox link:
https://pdfs.semanticscholar.org/4bcd/cba062ffc04b7afe3e16600ad6668a9a28cb.pdf
Thanks for that link.
But let me get this straight:
-PW used a fixed planet, moving ring gear to turn the fan.
3:1 ratio if sun and planets the same diam.
-RR will use a fixed ring, moving planets with planet carrier to turn the fan.
4:1 ratio if sun and planets same diam.
Correct?
After further research, I disagree that the 4:1 versus 3:1 is caused by different ratios of gear teeth. I think it is caused by whether the ring gear is fixed, or the planets are fixed.
If there are 120 teeth on the planets and sun, and 360 teeth on the ring…
When the planets are not fixed and revolve around the sun, one rotation of the sun gear only rotates a planet gear 3/4 of a rotation, since there is a subtraction of a 1/4 from the revolution of the planet.
One rotation of the sun will produce contact with 90 teeth on the sun with 90 teeth on a planet gear, and move the planet 1/4 of the way around the ring.
Here are a few relevant links:
https://www.neugart.com/en/planetary-gearbox/epicyclic-gearing/
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https://en.wikipedia.org/wiki/Epicyclic_gearing
http://www.buseco.net/planetary_gear_ratios/planetary.pdf
Thanks for all those links.
Is RR the first to use the fan driven by the planet carrier for an aircraft engine?
Is the RR planet carrier driven fan a superior solution to the ring driven fan?
It is a cool solution.
Good stuff OV-099!
Scott, what you said about RR and its recent history could also be phrased such as “they gave up on small engines to concentrate on bigger ones and still messed up”.
Now, I see that they did not want to lose time on an A380 upgrade, not even as a spin-off of the RR Advance.
As far as I understand, the RR Ultrafan is based on an XWB engine and Airbus speculates on neo-izing the A350 around 2025 and evolve the plane into a 79m stretch “350-2000”. However, lets be honest, getting the RR Ultrafan market ready will require a hell lot of resources.
So, how should RR be then able to do yet another engine programme in a category they have just abandoned with probably lower margins than in the lucrative wide body market?
Advance/Ultrafan is not based on the Trent architecture and therefore not on the [Trent] XWB. It’s a new architecture. The reason is compressor technology. Compressor speeds used to be ~10,000 RPM. They are now ~20,000 RPM. This invalides the 8/6 stage split of the IPC/HPC of the Trent architecture. Advance/Ultrafan will have a 4/10 stage split and eventually a 3/9 or a 3/8 stage split in the IPC/HPC
@Philip,
Please see my reader comments above.
Thanks!
OK, Philip, wrong wording by me. I did not refer to the engine architecture.
I meant to say, the tests are focused and centred around an engine of the size of an XWB, i.e. 84-97 (-110)000 lbf and not around 30-40000 lbf.
How could they handle 2 completely new engines properly?
@ChrisAustria
Rolls Royce has a great history of scalable technologies such as the three-spool architecture — and now the UltraFan and Advance 3 architecture. Scalable turbofan engine designs leads to lower overall costs when developing the 2nd, 3rd, 4th engine (etc.).
In fact, the Rolls Royce Trent 700 and Trent 800 engines were developed more or less concurrently. The first Trent 700-powered A330 flew in August 1994, and entered service with Cathay Pacific in March 1995. The first Boeing 777 with Trent 800 engines flew in May 1995, and entered service with Cathay Pacific in April 1996.
Rolls-Royce develop the technology then apply it to a range of engine. As it stands Rolls-Royce have spent at least $5 billion on Advance/Ultrafan technology and perhaps a lot more. Each engine then costs them less than $1 billion to develop.
I will be surprised if the Ultrafan demonstrator is in the 100,000 lb bracket for the A350. I think it will be 35,000 lb for the A32X.
@ChrisAustria
The margins may be lower but the volume is much higher.
RR didn’t abandon the single-aisle market for the long term. They just didn’t want to play second fiddle to P&W (i.e. long-term strategy trumps short-term thinking). By re-entering the single aisle market with a vastly superior product RR would not only be killing the margins and possibly put the ROIs into negative territory for P&W and CFM International, respectively, but also force P&W and CFM International to prematurely launch products that can compete with the UltraFan — investments that could be used on other more pressing mid-term engine developments.
And the 7th Calvary o0nly suffered a small setback at the Little Big Horn!
Err we arn’t quitting the battle filed (well other than Custer and 250 troopers? for who it was kind of permanent)
Go Team.
?
I don’t think Rolls-Royce dumped itself out of the narrowbody market because it left IAE. PW were not willing to continue the workshare of IAE because of the GTF. For example, PW had already selected MTU for the HPC, which today is the best HPC in production, 8 stages, 21:1 pressure ratio and all blisk stages. For the record, MTU came to the rescue of the PW6000, but it became irrelevant when Airbus decided to NEO the entire A320 series.
In other words, if Rolls-Royce was to remain a member of IAE, Rolls-Royce had to accept a very minor workshare in PW’S GTF. The other alternative was to go it alone.
With regard to going it alone, Advance 2/3 technology was nowhere near mature enough to produce a new engine in the timescales required by Airbus. Rolls-Royce tried to persuade Airbus to produce a new airplane, claiming a NEO of the A320 series wasn’t anywhere good enough. This would have given Rolls-Royce time to catch up. Airbus somewhat disagreed, resulting in a spat.
It could have been even worse for Rolls-Royce. Remember Airbus choose GE’s GENX for the re-winged A330NEO to compete with the 787.
Thankfully for Rolls-Royce, Airbus came up with the A350. Rolls-Royce offered the Trent XWB. GE refused to match the Trent XWB specification, claiming GENX would suffice. Airbus somewhat disagreed resulting in another spat, this time with GE.
In the end Airbus choose Rolls-Royce to re-engine the A330NEO
So I agree, it was a disaster for Rolls-Royce when it dumped itself out of the narrowbody market. But it could have been even worse for it came close to dumping itself out of the widebody market.
Since then, Rolls-Royce has been ready to re-engine any airplane and has been ready to put an engine on any new airplane. Lesson learnt!
@Philip
Quote: “It could have been even worse for Rolls-Royce. Remember Airbus choose GE’s GENX for the re-winged A330NEO to compete with the 787.”
The “re-winged” A330 (A350 MkI) was also offered with Trent-1700 engines when Airbus officially launched the A350 MkI on October 6, 2005 — or some 9 months before Airbus canned the A350 MkI and launched the A350 XWB programme during the 2006 Farnborough Airshow.
https://www.flightglobal.com/news/articles/rolls-royce-to-develop-trent-1700-for-a350-201998/
But only after GE’s exclusively came to an end. I need to look it up, but my understanding is that the first several hundred airplanes would have to be GE powered
Not really a disaster for RR when it exited IAE.
1) They got a very large divorce payment
2) They got a royalty payment for each additional V2500 engine produced
3)They continued to make ‘their section’ parts.
Continuing with Pratt would just make RR as the ‘second amoung equals’
Considering that RR was making Aero engines in WW1 when Pratt was still in its original product line of industrial lathes, and Pratts first jet engine was a ‘licensed copy’ of a RR design.
Lets see, WWI end 101 years ago, WWII ended 63 years ago?
And that is relevant to what?
The Allison V-1710 was superior to the RR Merlin in every way, but rather than give it a two stage super charger they brought Merlin to the US to build (not that we didn’t do it better but…)
So RR made is fame in WWII on an inferior engine at US expense. Hmmm.
So the V1710 was superior, with it flying with a turbo supercharger in the P38 Lightning and with 2 superchargers in the P63 Kingcobra.
It was only when the Brits who were flying the P51A Mustangs with Allisons , thought we should try this with our advanced Merlin X…and they did with a prototype.
Only then did the USAAF say ‘what a great idea’ lets get that version the Merlin X into production instead of making some changes to the P38/P63
versions of our ‘superior engine’ ?
Of course UK Merlins were built to different ‘grades’ with the lowest being a tank engine and at the top grade for fighters like later Spitfires and run of the mill planes in between.
We saw a similar situation with the early 707 models, with 3 choices of engines . Pratts JT3 ( lowest power needing water injection for takeoff run of 9500ft) , a heavier but more powerful Pratt JT4 ( which Braniff wanted for its higher altitude South American airports and the highest power /most economical Rolls Royce turbofan Conway.
Pretty soon soon Pratt discovered it had to redesign its JT3 into a turbofan variant, with a lot of the early 707s getting the new JT3D version in a swap over [ A hasty NEO !]
Duke: Two speed super chargers were a known solution to performance drop off (over a single speed)
RR put that onto the Merlin, the US Army for unknown reasons did not allow Allison to put it on the V-1710. It was used by the radial engine mfgs.
One of the true mysteries of WWII.
The Allison was deliberately designed as modular and could be configured with drives and aux device output anywhere on the engine.
So rather than ramp up a known engine built to US specs and not that fiddly UK Witworth thing, they elected to go to the huge effort to op0en up an all new engine line with a different engine mfg. Tru8ly nuts and set the war effort back.
What you do not seem aware of is the P-40 was built into 1944, most supplied to British forces and that aircraft could hold its own at lower altitudes with the ME and FW.
It did not need the Turbo on the P-38, it just needed the two speed and it would have been superiors to the Merlin.
While it was a logistical failing, the UK Merlin did not have gaskets sets, the artificer had to cut thous out of bulk material by hand.
The US on the other hand issued standard gasket sets with all equipment.
I have worked on British diesels. They followed exactly what I had read. If you need one medium size faster, lets use 6 small ones.
Far more complex than needed. Much like 3 spools, more costly to mfg, more costly to overhaul and only worth it if you get better SFC (which the GENx on did not)
My favorite one was when RR Car decided to go with an automatic transmission, they wound up a GM (T-400 I believe).
Of course they could not have us supply them, so they got the license and re-engineered it to RR fine tolerance. After a lot of failures they figured out that GM knew what it was doing with those loose tolerance in the auto trany.
They wound up buying them from GM after all.
Don’t get me wrong, the US has its snoot as well. Cat thinks their stuff is vastly superior when in fact Cummins and John Deere match and exceed them.
We did in fact get a fine rifle in WWI from the Brits in the form of a Pattern 14 we turned into the Model of 1917 in 30-06 caliber.
It was vastly superior to the 1903 in mfg as the 1903 was hand built in US Army custom Armories.
About 75% of the US Rifle issue in WWI was a 1917 (1903s took a long time to build).
The US got Packard into building Merlins for UK ( on top of the 2 Rolls factorys and Ford in UK) long before the Merlin Mustang came along.
Having 2 super- chargers arent complicated things, well not compared to weird and wonderful piping for turbo chargers with intercooling on the US other radial fighters- the exhaust piped back behind the cockpit to the turbocharger and then back to the engine ahead of the cockpit and through the supercharger…
What was an interesting might have been was Packard dabbled on its own jet engines towards the end of the war and a bit after.
https://en.wikipedia.org/wiki/Packard_XJ41
I dont think they had enough capital for jet engine development and keep their car business going.
The P40 was built in many versions, substantial airframe differences between the early and late versions…oh the P40F had the Merlin Packard and was the best in a number of areas, according to some people should know
https://ww2aircraft.net/forum/threads/p-40-performance-allison-versus-merlin.14118/
Duke: Now that was something I had not read about (Packard sub contract to Merlin) – that makes some sense then.
Kind of like the Us Model of 1917 that we took over from the Brits who were making the P-14 exclusively in the US.
Still; does not explain why the Army failed to institute the simple tech on the Allison.
“The US got Packard into building Merlins for UK ( on top of the 2 Rolls factorys and Ford in UK) long before the Merlin Mustang came along.
Having 2 super- chargers arent complicated things,”
Duke: In order to compare engine you need to have the same apparatus.
P-38 was outstanding but the engines were picky because of the turbo charger (vs super)
If both Merlin and the Allison had a two stage super charger the Allison was bettter.
That does not get into the complexity of the engines, the Allison was built to simpler US standards vs the complex brits.
I would suspect that Packard probalby produces gasket kits for their Merlins supplied to the US Army but less likely to UK.
The US went with standardized and commonality vs Brits far more into custom hand fit.
Logistics are as big a factor in success as performance.
That was one reason the Sherman was so valuable and the most successful WWII tank, it ran and it was well supported so you could keep it running.
If it isn’t running its not good.
Ford in UK when they started running a large factory in Manchester for making Merlins, said the same thing as Packard- we can make these engines simpler and too higher standards just using well known automotive manufacturing techniques. UK airplane engine makers just hadnt considered mass production techniques as they worked from craftsman principles, their planes even up to the 60s werent much different.
JAEC is still part of the IAE. Avio, now part of GE, went out of IAE in the 90’s but still produces parts for the engine.
Atlas had a 767 Freighter crash outside of Houston.
No reports of any issues from the crew, it appears to have arrowed in.
https://www.flightglobal.com/news/articles/video-shows-atlas-767f-in-steep-dive-prior-to-cras-456054/
Sobering for the 767 fleet.
Scott: Did not Boeing say they would only do two engines on the 787? I don’t recall P&W walked away so much as they were not down selected?
No engine mfg can build an engine that is not going to be taken up, seems like they were removed early in the process
I also disagree that it was the GTF core that has the issues. There have been some seal issues and bearing issues but those are not really what is considered the core (nor hard to get to)
The core is the fan and blades of which RR has had huge issues (on all lines other than XWB and we don’t know on that one yet nor will we if they can cover it up by a fix as they know what they have been on the other lines and possibly can get ahead of it, i.e. err yoo hoo, y’all want to bring your engine in next week and we will put a brand new one on that airplane for youse) .
Considering RRs issues with their recent cores, any condemnation has to be put in perspective.
I think it doesn’t get more core then “knife edge seal in the high pressure compressor”. Sealing the HPC fan blades is very important for efficiency.
https://www.flightglobal.com/news/articles/fixing-faulty-gtf-seal-to-cost-50-million-pw-446840/
This grounded the aircraft if both engines had second attempt of this seal, but limited impact since over half of about 100 engines delivered was still at airbus. But causing engine shutdowns so soon after entry into the flying fleet may cause some to question their design and testing.
I haven’t read anything if they had done a third version of the seal, but that might not make the news.
P&W also had an issue with a knife edge seal in their engine for the F-35, I think the fixin that case may of caused a slight loss in efficiency or perfomance in that case.
The “Core Engine” is normally the HP compressor, burner and HP turbine connected to frames and Engine gearbox so you can test it separate from the LP system (normally in a ram air rigg). For a 3-shaft RR Engine you add the IPC and IPT depending on the location of the Power offtake of the gearbox. (HPC or IPC)
Is a RR NMA geared fan EIS 2025 realistic? Can PW scale up the GTF to 50K for a 2025 EIS?
If a geared fan goes on any A350, I can almost guarantee Boeing will respond with a geared fan on the 787 in short order. I’ll put my bets a little closer to a 2030 EIS for a 70K or 80K geared engine than 2025.
Valid questions.
1. Hard telling, it seems really tight.
2. P&W has been looking at scaling up the GTF since it got off the ground. At one time they made an offer on a Wide body (A330?) . So yes they are ready to do it but also can they do it in the timeline?
The 787 is ‘closer to the ground’ than its peers, both forward fuselage and the bottom of the nacelle. Its a closer match to the A330 neo , which is of course flying with its ‘last’ engine, while the 787 has its ‘first engines’
Good point, fan size limits may be suboptimal in the future. Same with the A350M stretch for fan size and rotation angle. Interestingly, the 764 got longer gear, and maybe this is an option for the 787 and A350.
Duke:
The 787NEO has the RR Trent 10, so its on its second engine.
787, best thing since sliced bread, EIS 2008.
Ultrafan, best thing since sliced bread, EIS 2025.
The 787 is a very expensive slice of bread given it’s losses of > $40 billion ( R&D + deferred costs). It’s now got the A330neo to contend with. We will see.
Are you implying that Boeing’s plan to eventually recoup their 787 overspend could be toast?
Looking at the base cost alluded to by Phillip I think the general consensus is that it will covered over a large accounting block of 1,500 to 2,000. When time value of money ie the need to generate return and cover the financing cost I would suggest there is zero to minimal chance of a positive NPV
It would appear as if the combined development costs (R&D) for the A380 and A350 are close to being in the same ballpark as the total development costs for the 787 (page 6 in the linked paper) — with the deferred 787 production costs not included.
http://zhao.rutgers.edu/787-paper-12-02-2013.pdf
It looks to be that way. The current accounting block over which the deferred production costs are to be amortized is 1500 units, which at present rates (if they can keep that up) would happen around 2025. After which they need to produce hundreds more to recoup the actual development expenses. By which time they will be forced to spend on a re-engined response. So, in its present iteration, they don’t look to be set to earn a return on the program. With a 787MAX, yes.
Post 2025, Airbus might respond with a lighter UltraFan powered A350 family — A350-400/A350-500/A350-600 — that would replace the A330neo and which would force Boeing to develop an all new and lighter wing and a re-optimisation of the entire aircraft — a very expensive undertaking. Meanwhile, the A330neo would have served its purpose of exerting downward pricing pressure on the 787 for over a decade — all the while maintaining a reasonably profitable annual production output.
If the 787-9, for example, were to be re-engined with an Ultrafan-type engine, the aircraft would essentially be turned into an ULR version — or just like the 777-200LR; too heavy and capable.
Of course, one could say the same about the 280 metric tonne (MT) A350-900 (UULR), but a 280 MT A350-900 stretched to the size of the A350-1000 (i.e. A350-800NG) and powered by a 84,000 pounds of thrust UltraFan engines would become a very attractive aircraft.
Here’s an interesting 2008 analysis from Airbus’ engineering intelligence unit: Boeing 787 Lessons Learnt
https://www.planebusiness.com/buzz/airbus2.pdf
As can be seen on page 12 in the report, the Manufacturers Weight Empty (MWE) for the 787-9 increased from 98.5 MT and a MTOW of 230 MT — when Boeing launched the 787 programme in April 2004 — to a MWE of 108,4 MT and a MTOW of 247.2 MT in April 2008.
In fact, the initial unrealistic empty weight estimates for the 787 were IMJ caused primarily by Boeing underestimating the structural complexity of the large scale composite usage on the 787, which required redesigning of the main fuselage and its fasteners, and reassembly of incorrect installation, which had created extensive delays and cost overruns. For example, fuselage design changes required altering joints between sections after barrel mating demonstration, and the outboard wing required a revised wing design to strengthen it (etc.)
Now, let’s assume that an A350-400 would be similar in size to the 787-8; an A350-500 would be similar in size to the 787-9; and an A350-600 would be similar in size to the 787-10. The range for the A350-500 would be similar to the range of 787-9, while the range of both the A350-400 and A350-600 would exceed the range of the 787-8 and 787-10, respectively
The family would be designed using a wing that was slightly smaller in area than the 787 wing — but with a 4 meter larger span — and where the fuel capacity would be optimised for the UltraFan engine — i.e. leading to a significantly smaller, less voluminous and, therefore, a lighter wing box; by far, the heaviest part of the wing —
the MWE for an A350-400/A350-500/A350-600 family would very likely be lower than the initial MWE estimates for the 787-8/-9/-10, respectively.
——————-MWE———-MTOW
A350-400——92 MT———-205 MT
A350-500——100 MT———223 MT
A350-600——110 MT———240 MT
The A350-600 would require about as much thrust as the 787-8 at take-off, while the take-off thrust requirements would be lower for the A350-400 and A350-500. Thus, the sizing and thrust requirements would not be sufficient for the 787-9/-10.
IMJ, therefore, the current 787 family is in risk of being made economically uncompetitive — before, or short after the deferred production costs have been amortised — by a lighter UltraFan powered A350-400/A350-500/A350-600 family.
Expanded UltraFan powered A350 family:
A350-400 (787-8 size class)
A350-500 (787-9 size class)
A350-600 (787-10 size class)
A350-800 (A350-1000 size class)
A350-900 UULR — Ultra Ultra Long range
A350-1000 ULR/UULR (777-8 size class)
A350-2000 (777-9 size class)
Hence, Airbus would be able to offer one family of wide-bodies having two distinctly different wings and engines, while sharing a common fuselage — from the 56m long A350-400 to the 79.5 m long A350-2000.
Interestingly, Airbus has been much derided for going up against the 787 and 777 with one platform. Post 2025, it may appear as if that strategy might not only turn out to be successful, but that it also would be able to permanently take out the 777X while forcing Boeing to make some costly changes to the 787.
But whose GTF would Boeing go with on 787? AFAIK GE aren’t doing one, P&W seem to be getting along better in the small engine business, and only RR seem to be thinking about it for larger engines. So would it be another RR variant? Or are both GE and P&W further ahead than I thought?
The future seems exciting, at least for the non-involved like me.
Matthew: Having followed this, P&W has a design, I don’t know they have done any serious hardware tests. Someone did ask them for a wide body GTF a while back.
GE has not touched GTF hardware at all, RR has prototype hardware (and direction when they dropped the Advanced as a step and used it as a core for their GTF)
And yes its most interesting and (fan boys aside) we can only wait to see what pops out of the engine works in the next few months.
Could we be looking down the road to some fairly major consolidation in the aeroengine business? The situation seems ripe for it.
I have asked that and posted that same question.
Right now GE and PW do have a close connection with the GP7000. They did a bang up job on it.
Its also the missing link for GE, RR has their own GTF approach.
If I was a betting man I would say P&W/GE have the most to win by going in together. GE gets the GTF and P&W gets a partner on the rest (not sure how they broke down the GP.
PW does have partnership with Japanese 4 or 5 mfgs, MTU as well.
RR wanted out of the V2500 program.
Lots of stuff and entities in the air that are not the big 3 as GE also has CFM in the mix.
US Anti trust wont let it happen , let alone the European regulators. US airlines wouldnt be very happy either.
RR got out of the V2500 – with bags of money- when they could see it was coming up to the use-by date around 2020, by Pratts own GTF
GE and PW are direct competitors on nearly every military turbine program. that covers jets, helis and ships, generators… no way would the USG let them merge and not have any competition at all in the Military turbine market.
GE can’t buy RR and PW can’t buy RR (UK govt won’t allow it and EU regulators won’t allow all western civil engine technology to be owned by the US). GE can’t buy PW and PW can’t buy GE (US govt won’t allow it and Pentagon won’t allow a single monopoly supplier of military engines). RR can’t buy GE (Boeing, Airbus, EU regulators, US regulators won’t allow a monopoly at the big end of civil engines). So, there is only one consolidation that can possibly work – RR buys PW. That’s not on the cards soon, and the price would be very high because of the monopoly profits PW will generate from the F35 fighter engine, but RR is betting the farm on Ultrafan. If Ultrafan works, RR will be in a position to do that in the 2030’s. If Ultrafan doesn’t work, RR is toast anyway and it doesn’t matter who buys the wreckage.
Sorry Transworld, there’s been a lot of posts to read through!
I wonder how CFM would evolve should P&W and GE merge? I think it wouldn’t look like good news for Safran. It’s possible that it’s too difficult for GE to walk away from CFM. How about they do a three-way merge?
It’s possible that one of them will successfully develop a big enough technical lead that the others wither and die. RR are heavily and publicly pursuing a number of aggressively ambitious areas, so it might be them. I can’t see Uncle Sam tolerating the aeroengine market shrinking to one supplier, especially if it’s a foreigner.
Tricky though – if this happened, what is the “victor” supposed to do? Give all their IP to the others for free / very cheaply? It’s kinda assumed by governments that the big three (two? One and a half?) will continue to compete more or less evenly, but that’s not really happening anymore. And it’s going to get worse. Perhaps the governments will be forced to accept a managed cartel, otherwise the economic realities might result in no competition at all.
The UK Government have a golden share in RR for national security and strategic concerns. Nobody can own RR except Brits unless the UK Government say so. It doesn’t stop others owning shares, but owning the company, no.
As stated above RR did not really back out of the AIE group,they were forced out ( of their existing position at that time).Indeed it was the CEO of P&W who said less than half of half wasn’t worth having.IE only on one narrowbody and having ( just) less than half the skin in the game of that engine).
They were presenting a complete engine ( with partners) and had perfected the necessary ‘geared’ technology.RR would have been relegated to a subcontractors position.
There was no choice at the time.
History also suggests that it might have been messy considering the blade coating issues that turned up on the T1000 which may well have found there way onto any RR core of a similar time period.
RR actually ended up getting a decent share of the A380 market ( 100% ownership note) btw.
RR are embarking on a new chapter in their history with the Advance/Ultra.It is clear that the development work is aimed at a large engine.The money is on a A350 NEO.
Given the stated timelines of the 797 ( still not launched) Boeing would never offer the project to RR it would be a crazy risk.
I’m afraid I disagree.
Rolls-Royce Germany was specifically set up to be the centre of excellence for engines for airplanes of the size of the A320 series and down. Rolls-Royce Germany has been twiddling their thumbs ever since Rolls-Royce dumped themselves out of the narrowbody market. Rolls-Royce will make a comeback to the narrowbody market sooner rather than later. In other words, Rolls-Royce Germany won’t be twiddling their thumbs for another 10 years (2030)
With regard to timescales. Advance technology is now very mature having been in development for more than 10 year. The Ultrafan demonstrator will run in 2021 and go airborne in 2022. The timescales compare very favourably with other well orchestrated engine programmes (7-8 years).
I think of Pearl 15. Nobody knew of it’s existence until after it was certified. Maybe this is the new norm.
What is for sure is the Ultrafan demonstrstor won’t be a 100,000 Ib engine. The gearbox is rated at 70,000 hp. Not enough for any version of the A350.
RR Germany twiddling their thumbs ?
They have done the Pearl 2 shaft engine and are heavily involved in the Advance technology.
A comparison could be Pratts ‘small business jet engine PW800, which ‘can be thought of’ as the core of the PW GTF without the geared fan. The Pearl could possibly be the basis of a newer single aisle RR GTF?
I agree, but all IAE work was transferred to Rolls-Royce Germany to comply with the agreement. And yes, they led Advance 2 for it was Advance 2 that was to be the basis of a new engine for a narrowbody the size of the A320. Then Ultrafan came along. They are leading the gearbox development.
Rolls-Royce Germany is now doing Trent XWB production to prevent it from twiddling it’s thumbs. Not the original agreement.
And so on … a long story.
Bottom line, they want back in and I don’t think they will wait until ~2030
@Philip
Why would a GTF with a gear box max rated at 70.000 hp not get near to 100.000 lb of thrust?
Maybe I’m misunderstanding, but the gear box on a GTF does not take the full force of the engine, right?
If the gear box would take the full force, I think a 70.000 hp gear box would limit the engine to what’s used by an A330 (hp, and thrust are very different but for the sake of argument I’m assuming 1,15 hp is 1 lb of thrust, which I know is VERY ballpark guestimate).
It is difficult to make assessments with regard to power and force conversions, as perhaps you know. So historical fact is the answer.
The PW GTF gearbox is rated at just over 30,000hp. Can’t be bothered to look up the references. So it’s about a 1000 hp per 1000 Ib of thrust. Yes, I know ~85% comes from the fan, the rest from the core. Then there is margin for safety. And so on. So I’m using just a very simple equivalence.
If RR can create a 100,000 lb engine with a gearbox rated at 70,000 hp then they are far better than I think they are for it would mean 700 hp per 1000 Ib of thrust.
Some think I’m biased toward RR, but I would be beyond pleased if they can do it.
Thanks for the reply.
I kinda assumed 70.000 hp gear box on a GTF could lead to >85.000 lb thrust (what’s currently used on the A350-900). Which is why your assessment surprised me.
I’d still be surprised if a 70,000 hp gearbox can do 100,000 lb of thrust. Rolls-Royce have said the gearbox design can go to 100,000 hp.
According to Aviation Week, the Ultrafan demonstrator will have a fan greater than the Trent XWB. But it isn’t a quote from Rolls-Royce, it is the opinion of Aviation Week.
I didn’t think Rolls-Royce could do it at this point in time. I’ll be stunned if they can and they are!
Perhaps they are prioritizing an A350neo in the 2025 timeframe. But, I don’t see how they can do an NMA engine in the same timeframe. Yes I accept the architecture is scalable, but 100,000 lb and 50,000 lb are very different worlds.
The plot thickens
Airbus wanted the GTF as an IAE ( with RR ) engine.
I suppose they had their reasons. The industrialization issues seem to be hard linked to P&W. Would RR in the background made a adifference?
It’s amazing how so many commenters above just blithely pass over the major headaches/heartaches RR has caused a long list of major world airlines (LATAM, ANZ, ANA, BA, Norwegian, etc.). One of the most ridiculous examples of RR “customer service” was having LATAM fly 6 of their 87-8s over 6,000 miles from Santiago up to Victorville for their Trent 1000 service! I would think most current major airline execs would still be thinking Trent 1000 financial compensation when the name “RR” comes up! LOL
MontanaOsprey and TransWorld, you can keep shouting whatever your shouting about. But people give up listening. GE and PW have had far worse.
It is a blott on an otherwise impeccable record (Merlin and all). But it’s all over bar the shouting.
Move on!
Who’s shouting, you near hysterical clod? Your last thought immediately reminded me of that other fabulous piece of British engineering—the Comet! LOL
The Comet was in passenger service – to South Africa in 1952….while Douglas was aboutto bring the DC7 into airline service., That fabulous piece of American engineering. Those similar US 4 engined planes were so unreliable that the US Coast Guard had ships stationed between West coast and Hawaii for the common occurrence of more than 2 engines failing and the passengers had to swim. LOL.
… and that miracle of engineering called the DC10, which I simply refused to fly in. Etc. Etc anon.
Historically, PW dumped themselves out of the commercial market because of their hot section. With regard to the GTF, early combustors had a life of 500 hours before the lining disintegrated. Newer ones are said to have a few thousand hours, but we will see.
The issue with the GTF is you get two for the price of one for engines are not staying on wing for any great length of time. So nothing is really known about the durability of the hot section.
Elsewhere I said GE are replacing their entire hot section of the GENX with a new design because of durability issues at a cost that will run into $billions. See ainonline. TransWorld as the link!
Etc. Etc. anon.
Rolls-Royce set the standard with later versions of the RB-211 and the Trent 700/800/500, and perhaps the Trent 900. The standard is 30,000 hours on wing or more. The Trent 1000 is 10,000 hours on wing or less. The eigenmode now means a lot less than that. So not good enough. I accept that.
I’ve never been accused of being hysterical. I have been accused of being a clod. Clearly I don’t understand the meaning of LOL. So perhaps I am a clod.
Headaches, heartaches, financial compensation. Words that are also synonymous with the 787’s introduction to service regardless of which engines hung off them.
Philip: You can attempt to re-write history, but the reality is that RR truly mucked up the Trent 1000 and then went onto lay the same eggs in the Ten and 7000.
While all engines have problems, RR has taken it to truly historical proportions.
No commercial jet engine has ever been superseded by a new ever. So RR has set a low for the industry in that regard.
And people do remember debacles. Given a choice no one is going to opt for an RR engine for a long time.
You can add in the arrogance of it having to be done by RR and no where near enough repair shops around the world to keep up with the issues either.
There are behind the scenes issues with the Trent 900 as well.
It did muck up with the Trent 1000.
But let’s divert to the miitary. The lift fan for F35B. It is Rolls-Royce because you boys offer the pond couldn’t do it. The F35B lift fan is a bit good. And yes it it does use gears.
Give it a break, seriously!
the lift fan in the F35B is the answer to a problem that didn’t exist and dramatically compromises all capabilities of that aircraft once it is off the ground.
cubic meters of fuel and thousands of pounds of bombs that are needed for the combat mission must be left behind in order to have that lift fan which is totally dead weight once up and away.
metric tons of money have been spent to make it work and will be spent in the future to maintain it.
the Boeing F-32 was able to haul the same bomb load the same distance without the lift fan, take off and land vertically just the same… sadly it was ugly and not made by Lockheed (of which the US Govt is a wholly owned subsidiary).
The F35A and F35C all dont have a ‘deadweight’ lift fans, but cant compete when it comes to combat sortie rate per day or its short takeoff capability.
You could say the same about an afterburner, deadweight after takeoff and a few occasions
The RR lift fan is still a heck of a piece of engineering.
@dukeofurl yup, the A and C traded the fan weight and volume for bombs and fuel (especially important in a stealth aircraft where external stores are a no-no)
the F-32 on the other hand didn’t have to make those compromises – the direct lift system in the F-32 had minimal impact on fuel volume and bomb load.
the one aspect where the lift fan was advantageous was in vertical landing bringback weight, which is saving pennies at the cost of billions.
is the fan cool? yup. well engineered? yup. needed? nope.
Boeing’s F32 wasn’t the nirvana you think, the F35 cold front lift was more efficient than the hot front lift. The single inlet under the cockpit had to be over sized for all the thrust during vertical flight, (even when not required for the other 2 versions) and with the engine well forward (like the Harrier) so wasn’t as efficient as the Lockheeds twin side intakes and rear engine layout with an extra lift engine behind the pilot only when required. You only get a space saving when you have a central inlet like the F16 that is much further back with the engine the same.
Check the layout of the F32 and see where the engine is…just behind the pilot
@duke – not saying it was nirvana – just massively cheaper (short and long term), met requirements, easier and cheaper to maintain, had significantly longer range in the B model, much greater commonality between versions (F-32 was over 85% common between all versions, F-35 is ~35%)
btw, F-32 was cold front lift. front lift came off the fan just like the harrier, not off the hot section. the Boeing was 3 post lift – 2 off the fan beside the fuselage, one off the hot section at the back, with roll posts at the wingtips also off the fan.
also, it had a variable geometry intake which opened wider for STOVL ops then closed up to optimum cruise size in forward flight. On the prototype (at the direction of the USG) they built it with 2 fixed positions which could only be changed by a mechanic on the ground, as the USG deemed the cost of demonstrating the variable geometry in flight wasn’t worth the cost as it was low/zero risk.
despite the govt having put a hard cap on what Lockheed and Boeing were allowed to spend out of pocket on the contract (to keep it fair) Lockheed spent a ton of extra money to do that one demo flight where they went VTOL to supersonic because they new Boeing’s aircraft couldn’t with the prototype’s fixed inlet. Boeing adhered to the rules of the contract and Lockheed was rewarded for cheating.
TWA, contrary to what you say, RR customer Avianca reported that RR were “very professional” in resolving Trent 1000 issues. https://www.flightglobal.com/news/articles/aviancas-entire-787-fleet-back-in-service-453110/
Hi Scott,
1) Do you see the possibility of Engine Alliance coming into contention for the NMA selection. (similar case to the A380 when Airbus asked PW & GE to combine and offer one engine) or maybe a new partnership between Safran, GE & PW?
2) Do you think RR exclusivity to power the A350 will force them to offer the Advance 3 instead of the Ultrafan for the NMA? Could Airbus limit the use of RR Ultrafan to power only Airbus’ airframes during the first 5 yrs after its introduction?
Back in the mid 2000s, the conventional wisdom was that CFRP fuselage would obsolete the metal fuselage. But now we have the 777x and the A330neo (still selling with a metal wing no less).
Will the geared engine obsolete the non-geared engine in short order? Maybe, or maybe like CFRP the revolution will be less dramatic than predicted. But I see that Boeing has to carefully ponder the risk to exclude a geared engine on the 797 from 2025 to 2045.
cost of converting the 777 to composite fuselage was prohibitive. would have almost as much as a whole new aircraft and it is unclear if the certifying agencies would have accepted it as a “777” requiring a whole new aircraft cert campaign rather than just a mod.
the next generation of widebodies (A360/818) will certainly be CFRP fuselage, probably using the Airbus panel model rather than the 787 whole tube model
Comments were that a composite wing was too much for a small aircraft (single aisle commercial) and BBD did it.
777 with composite is an all new aircraft. You can luge a composite wing onto a metal aircraft (old design) you can’t do the same with a composite fuselage 1 to 1 duplicate.
NASA has done studies and all studies were based on a GTF to get a large improvement.
You can only go so far with heat resistant materials in engines, and its still a trade off on costs for those.
Or you can do a state of the art engine with a GTF and get a big jump.
With all the hoopla, the PW GTF was better than spec, all other engines have just met or failed of recent years.
It also has a solid 3-5% upside in the PIP II P&W is working on.
65 some years went into materials, GTF is just getting started as to what it can do for an engine.
Composites will continue to compete with metal for some time, but at some point they will prevail.
They to are just getting started and out of autoclave curing is here and going to be more so.
First German jet engine was good for 25 hours, that does not mean it was a failure, just needed better material and development and the same is true for composites.
I dont know that anyone seriously said a Cseries was ‘too small’ for a composite wing, as its ideal.
Small fuselages arent composite because the ‘structural thinness’ of the skin has to be increased for other loadings.
the more general picture for fuselage strength was discussed here
https://leehamnews.com/2015/04/02/bjorns-corner-lighter-fuselages-practical-considerations/
This doesnt apply for wing composite structural sections and composite skins.
Boeing said you could not scale a wing down to that level due to the nature of the process.
Clearly Boeing was wrong.
Its all a cost trade off for price, hands on labor, hands off, automation and the materials involved vs the gains.
BBD clearly gained a hell of a wing.
Boeing spun fuselage is costly but it does remove a lot of labor from the costs.
Airbus looks to have more labor and less automation in the building of smaller parts with the farm and skin system.
Elli Whitney proved you could automate a process that was impossible. So it goes.
Anything that automates is a wave of the future. You then deal with fewer cowering workers.
All electric is the wave of the future, that does not mean there are not fits and starts. I did conversion that utilized an existing pneumatics system because that was far more cost effective and did exactly what was needed.
People without pneumatics backgrounds look at you like you are nuts. Yep, but practical about it.
You dont provide evidence of ‘Boeing saying that’, its merely your opinion.
All carbon fibre fuselages, whether barrel or panel use interior carbon fibre frames as stringers and circular frames- that is of course the basis of all semi-monocoque structures.
The stringers are co cured with the skin and then the interior frames added later.
This youtube video made by Seattle Times shows the interior shots of the first 787 – with semi-monocoque shell. ( at about 2:20) The frames are closely spaced, approx after every window !!
https://www.youtube.com/watch?v=67BXUFBFH18
Now you have seen it perhaps you can stop with the nonsense that the A350 is the only one with interior framing.
Duke: Sadly things like the Trent 10 having to get an emissions waiver I have not saved the link to and can’t find again.
Some things we have to take in good faith, not that I expect you to but I have yet to put something up that was not substantiated, sometimes latter but usually yes.
I can remind you that you did not ask for that either? Nah.
It seems that prospects of the NMA launch is more remote than ever. It would be great if LNA could explore at some point the topic of “life after NMA for Boeing Engineering” in an article.
This program didn’t seem viable at any point without some lofty assumptions and self deception, reminiscent of the Theranos saga. Boeing being a public company, it makes me wonder if there will be an internal investigation to hold the responsible parties accountable, who have spent 100s of millions of dollars of shareholder money since 2013 ‘studying’ and ‘marketing’ what now appears to be a non-starter idea from day one.
The A321 is a nominal 200 seat aircraft and relatively the A338 is a 300 seat aircraft. That leaves the 225, 250 and 275 seat aircraft sizes unaddressed for short range 500 to 3,000 nm, and midrange 3,000 to 5,000 nm. Six possible new aircraft variants where no current offerings sell.
I expect the NMA to be built, and either a CFRP rewing A322/3/4 or a new Airbus 2-3-2 aircraft. The large cargo hold of the A300 or 767 is a relic of the past in this segment.
An A321 configured for long ranges may have less than 200 seats but for shorter distances A321neo offers up to 244 seats.
The price tag for an 797 should be between A321XLRand A330. A321XLR’s range is expected to be 4,700 nm. The small aircraft opens the route and than the bigger one steps in. Is a stepping of 50 seats required or just a higher frequency?
It is nice to have a LD3 capability instead of LD2. Why should an airline omit cargo business? I expect at least LD3-45.
Another row and just one seat was already beaten by another row and two seats. 2-3-2 vs. 2-4-2. vs. 3-3-3.
Boeing needs some talk to keep the share holders satisfied.
For high density seating, Airbus offers:
A321 at about 40 rows of 6, 240 seats
A330 at about 50 rows of 8, 400 seats
Wouldn’t that be another case for the
7K7 at about 45 rows of 7, 315 seats?
Ah, the RB211. That marvelous piece of British engineering that put RR in bankruptcy, required a governmental rescue, and pretty much killed the Lockheed Tristar’s prospects and its commercial side! (Beware Boeing! LOL)
Do continue with your fascinating history lesson! I’d love to hear from you how the engine ended up powering the 747 and the 757, including the 757-200 owned by the current resident of the White House!
And CFM continues to struggle
https://www.flightglobal.com/news/articles/cfm-still-battling-leap-1b-production-delays-456147/
Just read FlightGlobal. Rolls-Royce have withdrawn from the NMA. Stunned, but perhaps the right decision!
Better to concentrate on the Ultrafan to NEO the A350, and make sure that they have all previous issues with Trent 1000 well, and truly dealt with.
It does seem to suggest that Rolls were looking very seriously at the Ultrafan for the 797.
They may have decided that the timeline for EIS of the 797 is just too ambitious, better to leave that to the competition to attempt. They may also feel that there wouldn’t be much profit in it for them if BA is squeezing them hard on price, and potentially after a share in the ongoing maintenance revenue.
If BA can produce the 797 for the price the airlines are willing to pay, that’s one thing, but the engines have to be affordable (and reliable) as well. As has been stated before, no engine, no airplane.
Who is in the best position to engine the NMA, GE or Pratt ?
I’m starting to think that if/when the NMA is launched the leasing companies will be disappointed, and it will have a single engine supplier.
How BA close the business case is going to be very interesting.
Better news for BA though, looks like British Airways wants some 777-9s.
Good day for Boeing with regard to British Airways order for 777-9. As Willie Walsh is quoted as saying, paraphrased, the bidding was aggressive. Boeing are stirring the pot on price. Quite right too. But British Airways haven’t over commited. Let’s see how the 777 renewal process works out. Airbus will need to lower the price of the A350, it’s a very expensive lady.
With regard to the NMA. I’ve now read Rolls-Royce’s press release. They have withdrawn from the “current competition”. The word ‘current’ is important.
I do think Rolls-Royce can do an Ultrafan in 7 years and get the maturity there. But that means the clock started ticking towards the end of last year for a 2025 entry into service. As Boeing said they won’t commit, it became a no-brainer.
The Trent 1000 didn’t have the maturity because of the aggressive timescale of the original 787 programme. But Boeing came nowhere meeting that schedule. The irony is that Rolls-Royce would have used Trent XWB technology in the original Trent 1000 if they had known that Boeing were to miss their own schedule by a very, very long way.
Right for Rolls-Royce to say they can’t do it by 2025. But can Boeing?
I’ve never agreed with the NMA. I’ve always taken the view that the prize is the A32X market, a rewinged or new A321 with a stretch, 180-240 seats.
Providing Ultrafan for the NMA would mature the technology in preparation for the A32X. So I took the view that there was nothing wrong in putting Ultrafan on the NMA, provided Rolls-Royce are given the time to do it. But the NMA is a bit player.
We will see what Boeing does. My bet is they will have a rethink.
Once burned (Trent 1000) twice shy. Not good to risk their reputation any further and the cost of not reaching their internal TRL has cost them another £790mn this past year alone on the 1000.
Does seem to imply that Boeing’s EIS requirement is narrowly fixed and not able to swing (a couple of years?) for the potential benefit of an Ultrafan. Or was it simply Boeing framing the terms of participation in a way that only GE/CFM or P&W could accomplish?
Most likely it’s just true. All the engine suppliers want an exclusive for reasons already set out and Boeing want a risk-free new engine (good luck with that). No-one has ever seen an Ultrafan fly and Boeing were never going to give RR an exclusive on an Ultrafan on the NMA. For RR a non-exclusive is risking everything on a half of a half and that just doesn’t work for RR. If Boeing have any sense, they will do a time-limited or volume-limited exclusive with GE/CFM or PW and keep the door open for an Ultrafan development in the 2030’s.
I predict Entry In Service dates,
2025 – 7K7, A321+(2 row stretch), A220-500
2030 – A350neo, 787neo, A321++ rewing/(50m)/5K range
2035 – 737 replacement, A320 replacement or rewing
Could be fairly realistic. Agree with 2025; 2030 possibly a little sooner; 2035 again maybe 2-3 years sooner. But they have so many orders, so maybe they are more inclined towards the later EIS dates.
you may also read these relevant links:
https://www.sciencedirect.com/topics/engineering/epicyclic-gears
https://topgeartransmission.com/planetary-gearbox/
https://journals.sagepub.com/doi/pdf/10.1243/PIAE_PROC_1931_026_022_02
https://journals.sagepub.com/doi/pdf/10.1243/PIME_PROC_1936_134_016_02