Leeham News and Analysis
There's more to real news than a news release.
Leeham News and Analysis
- Bjorn’s Corner: Air Transport’s route to 2050. Part 25. June 6, 2025
- New RISE powerplant benefits from decades of GE research and development June 5, 2025
- Engine makers emphasizing durability, reliability June 4, 2025
- Boeing CEO: Lessons learned are key to certification of 737-7/10 and 777X June 2, 2025
- Digital twin is a key to JetZero’s hopes for Blended Wing Body entry June 2, 2025
Bjorn’s Corner: Aircraft engines in operation, Part 4
By Bjorn Fehrm
February 10, 2017, ©. Leeham Co: We now continue our journey how an airline engine is operated during a typical mission.
Last week we explained basics for engine control and Take-Off flat-rating. We now continue with Climb, Cruise and Max Continuous ratings and why these are important.
Figure 1. Principal picture of a direct drive turbofan. Source: GasTurb.
We also touch on de-rating and Cost Index and how these affect how the engine runs.
Assessing the future of COMAC programs
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Introduction
Feb. 6, 2017, © Leeham Co.: China’s effort to become a viable commercial aerospace alternative was filled with rocky fits and starts for its two signature airliner programs, the AVIC ARJ-21 and the COMAC C919.
COMAC, a spin off from AVIC and yet another government-controlled entity, is already casting eyes on a 250-seat, twin-aisle design, the C929—ostensibly in a joint venture with Russia’s United Aircraft Corp.
The ARJ-21 regional jet finally entered service after delays of eight years. The C919 target EIS is now 2019, six years after the original date. The first flight hasn’t even taken place.
Chinese officials set a target EIS for the C929 of 2026.
A rough road remains ahead for each program.
Summary
- Exceedingly slow delivery ramp up for the ARJ-21.
- First flight of the C919 planned this year.
- Wide-body C929 will challenge the Airbus A330 and Boeing 787.
Bjorn’s Corner: Aircraft engines in operation, Part 3
By Bjorn Fehrm
February 3, 2017, ©. Leeham Co: In the last Corner, we went through how our airliner engine reacts to the different phases of flight, including what happens when we operate in a hot environment.
We also showed how engine manufacturers make a series of engines with different thrust ratings by de-rating the strongest version through the engine control computer.
Figure 1. Principal picture of a direct drive turbofan. Source: GasTurb.
We will now look deeper at how engines are controlled and why so-called flat-rating is important. Read more
Bjorn’s Corner: Aircraft engines in operation, Part 2
By Bjorn Fehrm
January 27, 2017, ©. Leeham Co: In the last Corner, we began looking at the in-service operation of a Turbofan. We covered how thrust and fuel consumption varies in the different phases of an airliner’s mission.
Now we will dig a little deeper into how a mission will stress the engine’s different parts.
Figure 1. Principal picture of a direct drive turbofan. Source: GasTurb.
With this knowledge, we will later look at how operators make sure their engines are safe and in good operational condition over the 20 years life of an aircraft. Read more
Bjorn’s Corner: Aircraft engines in operation
By Bjorn Fehrm
January 20, 2017, ©. Leeham Co: We have now covered the technology around airliner turbofans. Now it’s time for the real stuff: their operational life. Most decisions that an engine designer does is about how the engine shall function in practice.
To understand a typical cycle of an airliner engine and the stresses it endures, we will follow an engine during a typical mission.
Figure 1. A principal picutre of a direct drive turbofan. Source: GasTurb.
We chose a single aisle mission because most flights are with single aisle aircraft and the cycle these fly is the most stressful for an engine. Read more
Boeing 737 MAX 10
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By Bjorn Fehrm
Introduction
January 17, 2017, © Leeham Co.: Boeing has given its sales team the “authority to offer” the 737 MAX 10. The aircraft is a stretched version of the 737 MAX 9, designed to compete more successfully with Airbus A321neo.
Boeing worked on the variant for the last year. It started off as a more ambitious change over the 737 MAX 9, but it turned out too expensive and would have taken too long to get to market. The variant that Boeing now offers to airlines is a simple stretch of the 737 MAX 9.
The backing down to a stretched MAX 9 solves the cost and timing problem, but will it solve the competitiveness problem? We make a first analysis.
Summary:
- The offered 737 MAX 10 is a longer fuselage MAX 9.
- The longer fuselage closes the cabin dimensions gap to the A321neo.
- The 737 MAX 10 is longer and heavier than the MAX 9, affecting performance.
- To save field performance, a change to the main landing gear was necessary.
Airbus sets new delivery record for 2016
By Bjorn Fehrm
January 11, 2017, ©. Leeham Co: Airbus Commercial Aircraft presented a new record in yearly deliveries at its Press Briefing in Toulouse today. The division of an integrated Airbus (therefore Airbus Commercial Aircraft, ACA) delivered 688 aircraft during 2016, thereby beating its target of 650 aircraft for the year.
Airbus A321neo with Pratt&Whitney engines was certified end 2016. Source: Airbus.
Orders were also higher than expectations at 731 net orders, giving a Book to Bill of 1.06. The market, including LNC, widely expected Airbus to fall somewhat short of a 1:1 book:bill.
There were no formal forecasts given for 2017. ACA President Fabrice Bregier stated that he expects it to be over 700 deliveries but full details will given at the Airbus Group’s financial press briefing in February.
Bjorn’s Corner: Turbofan developments in 2017
By Bjorn Fehrm
January 06, 2017, ©. Leeham Co: Before we finish of our series on airliner turbofan technology, let’s spend this Corner on what will happen on the airliner engine front during 2017.
While there is no totally new engine that comes into the market during 2017 there are a number of new variants of existing engine families that will be introduced.
Figure 1. GasTurb principal representation of a three shaft turbofan like our reference Rolls-Royce Trent XWB. Source: GasTurb.
If we start with the engines for regional/single aisle aircraft and then climb the thrust scale, we will cover the engines in climbing thrust class.
Bjorn’s Corner; Turbofan engine challenges, Part 7
By Bjorn Fehrm
December 16, 2016, ©. Leeham Co: After the turbine comes the engine’s exhaust system. This is where the thrust characteristics of the engine are formed. It is also the environment that defines the back pressure for the fan and turbines. It’s therefore more high-tech than one thinks.
For the very high bypass airliner engines of tomorrow, the common fixed bypass exhaust of today (Station 18 in Figure 1) will not be acceptable. Variable exhaust areas will have to be introduced.
Figure 1. GasTurb principal representation of a three shaft turbofan like our reference Rolls-Royce Trent XWB. Source: GasTurb.
On engines that function in high supersonic speed, it gets really complex. Not only is the exhaust area variable, it must have a dual variation exhaust, a so-called Con-Di nozzle.
2017: the year ahead
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Introduction
Jan. 3, 2017, © Leeham Co.: The New Year is here and it doesn’t look like a good one for commercial aerospace, if measured against previous outstanding years.
There are some troubling signs ahead, piling on to a slowdown in orders from last year that didn’t even reach a 1:1 book:bill.
This year looks to be worse than last. Airbus and Boeing will give their 2017 guidance on the earnings calls this month and next. Bombardier and Embraer earnings calls are a ways off, when each will provide its guidance.
But LNC believes the Big Two in particular will be hard pressed to hit a 1:1 book:bill this year and may even struggle to match 2016 sales.
Boeing’s year-end order tally comes Thursday. Airbus’ comes on Jan. 11.
Summary
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1 Comment
Posted on January 3, 2017 by Scott Hamilton
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Airbus, Boeing, Bombardier, CFM, Comac, Embraer, GE Aviation, Irkut, Mitsubishi, Pratt & Whitney, Rolls-Royce, Sukhoi