Iceman7
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How difficult it is to upscaled GTF

Thu Mar 26, 2020 7:51 am

When i read the A350 page on wikipedia, there is a paragraph that states that A350neo will be developed, where PW is testing with their upscaled GTF.

Questions: how difficult and how long to upscale GTF for WB planes? and how competitive is PW to RR for Geared engines in the future?

Source (Paywall): https://www.bloomberg.com/news/articles ... gined-a350
 
CowAnon
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Re: How difficult it is to upscaled GTF

Thu Mar 26, 2020 8:41 pm

Alternate link, without the paywall (I think): https://www.bloombergquint.com/business ... gined-a350.

Just repeating what I've read on these boards, but it's supposedly much tougher to upscale a geared turbofan than to downscale one. The gearbox efficiency is 99%, but the 1% lost to heat is tricky to dissipate, and more so the higher the horsepower. RR claims its Ultrafan gearbox will be able to handle 100,000 horsepower. PW hasn't published a horsepower claim for its narrowbody GTF, but IIRC it's been estimated to handle up to ~40,000 hp.
 
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Stitch
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Re: How difficult it is to upscaled GTF

Thu Mar 26, 2020 10:09 pm

In May of 2009, Bob Saia, P&W's VP of Next Generation Product Family, spoke about the GTF and he said that their engineers believed that GTFs of up to 100,000 pounds of thrust with fan diameters of 133-138 inches were achievable. He also noted that as the fan grows, the overall engine length shrinks relative to a conventional engine because you can reduce engines stages along with their attendant discs and airfoils. So the bigger the engine, the lighter it gets and the less maintenance it needs compared to a conventional engine.

Development of such an engine would run over $1 billion so Pratt was more interested in offering it as a new engine option for existing in-production models rather than an aftermarket re-fit for existing frames.
 
VSMUT
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Re: How difficult it is to upscaled GTF

Thu Mar 26, 2020 10:32 pm

The engine cooldown issues should be less relevant on a widebody with generally longer turnaround times, or am I mistaken?
 
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Starlionblue
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Re: How difficult it is to upscaled GTF

Fri Mar 27, 2020 12:04 am

VSMUT wrote:
The engine cooldown issues should be less relevant on a widebody with generally longer turnaround times, or am I mistaken?


How long a cooldown are we talking about? On a modern engine it is only a few minutes so no issue on any turnaround. Mostly a longer cooldown affects the ability to do reduced engine taxi in on short taxis.
"There are no stupid questions, but there are a lot of inquisitive idiots." - John Ringo
 
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Faro
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Re: How difficult it is to upscaled GTF

Fri Mar 27, 2020 12:41 pm

Are airlines ready to welcome PW come out of the big-fan leper colony?...Even the GTF was unfortunately not a stellar success...


Faro
The chalice not my son
 
VSMUT
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Re: How difficult it is to upscaled GTF

Fri Mar 27, 2020 12:56 pm

Starlionblue wrote:
VSMUT wrote:
The engine cooldown issues should be less relevant on a widebody with generally longer turnaround times, or am I mistaken?


How long a cooldown are we talking about? On a modern engine it is only a few minutes so no issue on any turnaround. Mostly a longer cooldown affects the ability to do reduced engine taxi in on short taxis.


Wasn't it 7 minutes at one point? They shortened it down somewhat, but the European low-cost carriers weren't too happy about it.
 
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Starlionblue
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Re: How difficult it is to upscaled GTF

Sat Mar 28, 2020 12:47 am

VSMUT wrote:
Starlionblue wrote:
VSMUT wrote:
The engine cooldown issues should be less relevant on a widebody with generally longer turnaround times, or am I mistaken?


How long a cooldown are we talking about? On a modern engine it is only a few minutes so no issue on any turnaround. Mostly a longer cooldown affects the ability to do reduced engine taxi in on short taxis.


Wasn't it 7 minutes at one point? They shortened it down somewhat, but the European low-cost carriers weren't too happy about it.


Thanks for info. 7 minutes would indeed be an issue. You'd frequently have to wait at the bay several minutes before shutting down.
"There are no stupid questions, but there are a lot of inquisitive idiots." - John Ringo
 
Iceman7
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Re: How difficult it is to upscaled GTF

Sat Mar 28, 2020 2:47 am

@Faro That's also one thing to consider if they wish to return WB market, right now RR is also under fire for their Trent 1000 issues, with NH switching to GE for their future orders, as for PW, they need to improve their QC imo, especially that historically, they've been under fire for reliability and performance issue, as in PW4098 and PW4090.
 
strfyr51
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Re: How difficult it is to upscaled GTF

Sat Mar 28, 2020 3:32 am

Iceman7 wrote:
When i read the A350 page on wikipedia, there is a paragraph that states that A350neo will be developed, where PW is testing with their upscaled GTF.

Questions: how difficult and how long to upscale GTF for WB planes? and how competitive is PW to RR for Geared engines in the future?

Source (Paywall): https://www.bloomberg.com/news/articles ... gined-a350

Once the concept is proven? Upscaling the GTF is pretty simple except that PW made a bunch of other changes to the rotating group within the engine that so far seem to have been sketchy. Were they to just update proven technologies? Maybe they might not have had so many problems. they could update proven designs probably easily as their gas generators have always been very well engineered and petty reliable.
 
VSMUT
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Re: How difficult it is to upscaled GTF

Sun Mar 29, 2020 8:31 am

Starlionblue wrote:
VSMUT wrote:
Starlionblue wrote:

How long a cooldown are we talking about? On a modern engine it is only a few minutes so no issue on any turnaround. Mostly a longer cooldown affects the ability to do reduced engine taxi in on short taxis.


Wasn't it 7 minutes at one point? They shortened it down somewhat, but the European low-cost carriers weren't too happy about it.


Thanks for info. 7 minutes would indeed be an issue. You'd frequently have to wait at the bay several minutes before shutting down.


They do it after pushback, prior to taxi. They dry-motor the engines or run them in idle until the core temperature evens out, so the shaft isn't twisted when takeoff power is added.
 
strfyr51
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Re: How difficult it is to upscaled GTF

Sun Mar 29, 2020 11:03 pm

Faro wrote:
Are airlines ready to welcome PW come out of the big-fan leper colony?...Even the GTF was,fortunately not a stellar success...

Faro

Pratt engines are and Have been very reliable from the JT8D, JT9D, PW2000 and,PW4000and have been industry Leaders for many years going back to the Early fighter days. They haven't Bought their way onto any airplane unlike GE has And they're the prime engine for the KC-46 so if they're Not a reliable engine?
Why are they still making them?
 
LyleLanley
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Re: How difficult it is to upscaled GTF

Sun Mar 29, 2020 11:35 pm

strfyr51 wrote:
Pratt engines are and Have been very reliable from the JT8D, JT9D, PW2000 and,PW4000and have been industry Leaders for many years going back to the Early fighter days. They haven't Bought their way onto any airplane unlike GE has And they're the prime engine for the KC-46 so if they're Not a reliable engine?
Why are they still making them?


Many bold statements, there. For a refresher, I'd recommend reading page 1 of "Engine, F-14A Tomcat" and "Engine, 747-100" for just a few examples of when Pratts sucked. As for why the KC-46 has Pratts instead of GE, you'll have to talk to Boeing about that but three words come to mind with government programs: "maintaining industrial base". I hope it works out, but a two-engine jet needs reliable engines when you hit the ETP between CA and HI with 1500 hours between the two pilots.
"I've sold monorails to Brockway, Ogdenville, and North Haverbrook, and, by gum, it put them on the map!"
 
Iceman7
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Re: How difficult it is to upscaled GTF

Mon Mar 30, 2020 8:06 am

@Stitch Do you believe that PW is just playing the waiting game with their GTF, especially with his [Saia] statement that such engine achievable, are they delaying the WB implementation to improve their cash reserve by selling it on NB first?
 
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Faro
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Re: How difficult it is to upscaled GTF

Mon Mar 30, 2020 12:00 pm

strfyr51 wrote:
Faro wrote:
Are airlines ready to welcome PW come out of the big-fan leper colony?...Even the GTF was,fortunately not a stellar success...

Faro

Pratt engines are and Have been very reliable from the JT8D, JT9D, PW2000 and,PW4000and have been industry Leaders for many years going back to the Early fighter days. They haven't Bought their way onto any airplane unlike GE has And they're the prime engine for the KC-46 so if they're Not a reliable engine?
Why are they still making them?



PW have indeed been industry leaders...but unfortunately not for a long time now...the JT8D & JT9D are considered Jet Age paleolithic now...and the PW4000 had it own set of well-publicised problems and pretty much defuncted itself after a while...not to mention the PW6000 of which the total production figure is in the double-digits...


Faro
The chalice not my son
 
CowAnon
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Re: How difficult it is to upscaled GTF

Mon Mar 30, 2020 10:31 pm

You also have to wonder about PW's level of commitment to a widebody GTF. When the current UTC CEO took over in 2014, he said they weren't going to create a new widebody engine. (UTC's merger with Raytheon closes on Friday, but the UTC guy will still be in charge.)

PW sort of outlined an engine roadmap in 2018, describing a GTF2 engine with a bypass ratio of 15. Before that would be a GTF1-Plus, which would've been offered for the MOM, so it's unclear when the GTF2 would follow.

  • New UTC CEO throws cold water on PW GTF growth (Leeham News, December 12, 2014)

    Like all organizations, however, there’s an insatiable appetite to do more, right? What we need to do is figure out a way to do more with less because we cannot continue to afford to invest at these levels. We had $1.1 billion of [R]&D at Pratt, $800 million at the Aerospace Systems.

    That’s not sustainable for us at that level. It’s got to come down closer to 4% or 5% of sales than what it is today. So we’re working on this. Not a surprise, this is one of Alain’s biggest challenges out there. But we’re not going to make some investments. I think, again, we’re not in the wide-body space, right? We’re not going to build a new engine in the wide-body space. Customers would love to take the GTF and scale it up. We’re not going to do that, right?


  • Fantastic beasts: the Pratt and Whitney GTF engine (Australian Aviation magazine, December 2018)

    It may be a decade away, but work is already underway on step changes to the company’s current revolutionary GTF engine, the PW1000G that powers half a dozen single aisle jets, including the Airbus A320neo.
    ...
    With the new GTF in production, the bypass ratio is 12 to 1, the highest available in a contemporary commercial jet engine compared with other widebody large engines offering 10 to 1 or 9 to 1.”

    Going forward, Minor said there are opportunities to introduce additional technology and get more capability out of the engine. “We can go to higher thrust, and higher gross weight airplanes in the future,” he said.

    “Our goal is to get the capability up to GTF2, which is an ultra-high bypass ratio engine … in the range of 15 to 1.
    ...
    As for the future, Minor suggests the move from GTF1 to GTF2 will be a phased process. In between will be what Pratt & Whitney calls the GTF1-Plus, available for improved versions of the A321 and Boeing’s proposed middle-of-the-market jet.

    The Boeing derivative has yet to be launched officially, pitched somewhere between the single-aisle and twin-aisle market. While the GTF is currently carried by narrowbody jets, it will also be developed for widebodies.
 
Iceman7
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Re: How difficult it is to upscaled GTF

Tue Mar 31, 2020 1:04 am

Wow, with their CEO's statement, it shows how pessimistic he is. With his insistence to stop WB engine development, they're falling down the market, and it can't be helped unless they decide to change their mindset. That statement by Hayes is a pure arrogance which undermines growth for the organisation.

As for the GTF itself, atleast they have the ability and the plan, but it's just a matter of their CEO's willingness to approve it or not.
 
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Stitch
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Re: How difficult it is to upscaled GTF

Tue Mar 31, 2020 3:19 pm

Iceman7 wrote:
@Stitch Do you believe that PW is just playing the waiting game with their GTF, especially with his [Saia] statement that such engine achievable, are they delaying the WB implementation to improve their cash reserve by selling it on NB first?


Pratt did submit a 100K GTF for the 777X program when Boeing asked for RFPs from them, GE and RR. So Pratt seemed ready to commit to a high-thrust widebody engine only a few years after the interview with Mr. Saia. I expect Boeing wanted to play it conservative, which is why they chose the GE9X instead of the Rolls RB3025 or the GTF.

Iceman7 wrote:
Wow, with their CEO's statement, it shows how pessimistic he is. With his insistence to stop WB engine development, they're falling down the market, and it can't be helped unless they decide to change their mindset. That statement by Hayes is a pure arrogance which undermines growth for the organization.


I am not sure it is so much "pessimism" as "realism". The days of two engine options on a new large widebody family, much less three, are likely gone. There was some consternation amongst airlines and lessors about the A350 and 777X going single-source for engine supplier, but as a P&W spokesman noted "Engines are no longer commodities...the optimization of the engine and the aircraft becomes more relevant". And RR has noted that it is no longer just "marry the plane with the engine" - designers now need to take into consideration areas including engine/wing close-coupling, short-inlet, pylon-mount, and engine heat-load challenges.

Also, a brand new engine is a very expensive undertaking. On the 777 program, only GE committed to a new engine design with the GE90 - Pratt and RR both went with derivatives of existing designs. As such, GE spent far more, but ended up with a smaller portion of the engine pie (in part due to early technical issues). This is probably one of the reasons they were willing to become a risk-sharing partner on the Longer Range 777 (777-200LR, 777-300ER) to get exclusivity and (hopefully) recover that expense.
 
Dmoney
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Re: How difficult it is to upscaled GTF

Tue Mar 31, 2020 10:22 pm

Oil isn't a scarce resource. Oil prices are going to be low until we stop using it. Efficiency gains are declining, the same percentage decline in fuel burn is less in absolute terms.

All of which is to say new kit struggles to pay for itself with airlines and manufacturers will struggle to justify the investment. Nobody's building new kit.
 
JayinKitsap
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Re: How difficult it is to upscaled GTF

Wed Apr 01, 2020 7:32 am

Improvements in reliability are essential at this time. With low oil prices having 'bulletproof' engines is more important. Look at the T1000 series, still having issues almost a decade after EIS of the 787.

A gearbox is one element, but introducing it changes RPM of everything in the engine, changes turbine and compressor staging. Casually it seems easy, but things like resonance, harmonics, cooling, bearing lubrication, etc all can rear their head. PW would be smart just getting the current GTF to a much higher market share.

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