Leeham News and Analysis
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Leeham News and Analysis
- 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
- Bjorn’s Corner: New engine development. Part 3. Propulsive efficiency April 12, 2024
PW Media Day 2: GTF gets 35,000 lb thrust rating
Pratt & Whitney today confirmed that it will offer a Pure Power Geared Turbo Fan engine with 35,000 lbs of thrust, an increase of two thousand pounds from the previously announced model that powers the Airbus A321neo.
Officials declined to confirm our previously reported thrust bump for the Bombardier CSeries GTF, continuing to stick with its prepared statement.
Thrust bumps are largely considered for hot-and-high operations, where the extra boost is needed to get off the runway with maximum payload. In most operations, the extra thrust isn’t needed. The trade for the extra thrust is higher maintenance costs.
Airlines, according to one engineer, tell engine OEMs that they don’t want the extra thrust as the engine is being designed because of the associated extra costs, but then invariably later say they do.
Market Intelligence tells us CFM is going to provide a 35,000 lb model of the LEAP that powers the A321neo and the Boeing 737-9 MAX.
Separately, PW announced:
- Six prototype V2500 engines built by affiliate International Aero Engines were shipped to Embraer for its KC-390 MRTT tanker. Flight testing will begin this year and certification is expected in the third quarter.
- PW is “significantly” increasing capacity in advance of increased engine production demands for the civil and military markets.
- PW signed $10bn in long-term supplier agreements with 90 companies globally for civil and military engines.
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I am sure that CFM will match the 35klbf with the LEAP-1A.
But I don’t think there is enough margin for 35klbf in the LEAP-1B powering the B737MAX.
That thrust rating seems solely for the LEAP-1A for A321 NEO
E.g. more payload/range for a given, restricted runway length
What’s Boeing have for an equal alternate to the A321neo35K? A 787-8?
I believe that the B739 uses engines with a max trust that is about 2K less than the A321, so if CFM can get the LEAP-1B to about 33K pound of trust, I think Boeing will be very happy.
The 737-9 MAX will only get 28K thrust.
Besides hot and high and runway limitations for A321, what other possibilities are opened up?
If I recall correctly, UAC’s MS-21 seems to have been aiming slightly above A32x, particularly in their stretch model,
Their Pratt engines seem to be nearly direct derivatives of the A32x models, but they could potentially
aim at utilizing this thrust class engine to provide even more seating compared to A321.
35,000 lbs SLST? That’s enough for a 757 replacement. If the 757 were still in production, it would have been a perfect 757NEO engine
PW dimensioned critical parts of the engine (gerabox) to go up to 40,000 klbs in time.
http://www.flightglobal.com/news/articles/gtf-able-to-power-twin-aisle-narrowbody-pratt-amp-338925/
Airbus must have beefed up the A321 wing, which is high loaded already. I wonder if they did any further wingmods, while at it and having several years time.
http://upload.wikimedia.org/wikipedia/commons/c/c6/DSCF0645.JPG
keesje raises the subject of wing loading, which is MTOW divided by wing area. Here are some numbers [based on Wikipedia, so by no means guaranteed 100% accurate]
737MAX -9 = 194900/1341 = 145.5 LB per sq ft
A321NEO = 207000/1320 = 156.8
757-300 = 272500/1951 = 139.7
The A321 number indicates that if this airplane is to move up into the 757’s long thin markets, perhaps the wing needs to be enlarged if not replaced. Not ___ likely mate, but there it is
I presume Airbus is way ahead of us on this subject
“The A321 number indicates that if this airplane is to move up into the 757′s long thin markets, perhaps the wing needs to be enlarged if not replaced.”
Not required if the A321neo would be getting even more efficient engines such as the RR UltraFan, a decade hence.
OV, I’ll leave it to the aero experts to debate the merits of small highly-loaded wings vs larger less-loaded ones. But sometimes no matter how efficient the engine the wing must get bigger to do the longer mission
A recent example is the A340-200 vs A340-500-600: the wing had to be enlarged due to increased cabin size, weight and fuel capacity so as to do the longer-range higher-capacity missions
An early example is the 1960 vintage 707-300 vs the original -100.
oviver, nobody disputes the merits of the much larger less-loaded Category E wings on the 787, A330 and A350. The problem for the vast majority of single aisle operators is the fact that the wing span cannot exceed 36 m as that would exceed the physical limits in the parking box provided for aircraft in Category C. Therefore, a significant increase in the wing span of single aisle aircraft would mean folding wing tips à la the 777X. The difference, though, is that long haul flights won’t stress the airframe nearly as much as short haul flights, hence I’m not sure if a folding wing tip would be that suitable for short duration/high stress flights (i.e. short cycles), at least in the near to medium term.
As I indicated, if the A321neo were to get an engine based on the RR UltraFan concept that would be at least 10 percent more efficient than the A321neo engines in, say 2025, then the A321 would become at least as capable an aircraft, payload/range-wise, as that of the 757-200. If such an engine were to become available at that time, perhaps Airbus could offer two versions of the A32X-series. The heaviest variant which would have the same MTOW as that of the A32Xneo-series and with each family member all having a range exceeding 4000 nm. The new version could have smaller and lighter engines requiring significantly less thrust, and an optimised airframe and a max range of around 2000 nm.
Would this engine fit on the A340-300? This could become the A340-300neo
On the face of it a 35K A321 is pretty well there as a 757 replacement, apart from range. Could the fuel capacity (presumably limited by the wing size) be further boosted to achieve routine TATL operations of the type currently flown by 757s without having to enlarge the wing (eg by a wing root plug)? Auxilliary tanks in the fuselage cost baggage /cargo space so are undesirable, but. could tailplane tanks be added to boost range? (I’m guessing it doesn’t currently have them).
A322 is a + 210″ = + 10 frames = +3 AKH stretch beyond A321, to a total 13 AKH capacity. Applied to 757 typical routes/service, in three-class layouts Premium/E+/Y, the requisition of CIL (checked-in luggage) upon containers underfloor, plus payfreight, would leave room for routinary 3 ACT : 6 CIL + 4 Cargo + 3 ACT = 13 AKH.
But obviously, Roger : agreed, a tail-tank would be quite nice and neat to have ?!
I wonder what Airbus can do to “solve” the wing loading issue without goung to an all new wing.
http://i191.photobucket.com/albums/z160/keesje_pics/AirbusA322NEOconcept_zps13d00dcd.jpg
Slats, flaps, addition milimeters of metal on structural parts, a slight increase in span. No doubt many calculations an d forecasts have been made on the topic, A nd then there is strategy, the backlog is filled and provoking an NSA isn’t a good odea persee..