Leeham News and Analysis
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Leeham News and Analysis
- How Boeing’s actions affect Products, Airbus: Analysis (Update) October 11, 2024
- Boeing Announces Preliminary Significant Q3 Loss: Cuts 767 Freighter Program, Delays 777X EIS, Major Layoffs October 11, 2024
- Bjorn’s Corner: New engine development. Part 28. Wrapup. October 11, 2024
- Boeing strike hits suppliers, Airbus steps in October 10, 2024
- Boeing-IAM contract talks fail, no new negotiations scheduled, no end in sight October 9, 2024
Bjorn’s Corner: New engine development. Part 10. Airframe integration
By Bjorn Fehrm
May 24, 2024, ©. Leeham News: We do an article series about engine development. The aim is to understand why engine development now has longer timelines than airframe development and carries larger risks of product maturity problems.
To understand why engine development has become a challenging task, we need to understand engine fundamentals and the technologies used for these fundamentals.
In the last Corner, we looked at the nacelles used for a turbofan engine and for an open-rotor engine. Now, we go one step further and look at the integration of modern engines on an airliner.
Figure 1. Boeing 737NG (left) and MAX (right) nacelles compared. Source: Leeham Graphic from Boeing 737 images.
Bjorn’ s Corner: Engine development. Part 1. Introduction
March 29, 2024, ©. Leeham News: We finished our article series about New Aircraft Technologies last week. It dealt with the different new technologies that a next-generation airliner could use to increase efficiency and by it environmental emissions.
An area that we touched upon but didn’t dig deeper into was engine development. When airframe development historically decided how long a new generation of aircraft took to develop, it gradually changed to engine development being the more calendar-time-consuming and riskier development for the last generations. This article series will discuss why and what can be done about it.
Figure 1. CFM RISE, a new engine development for the next generation of airliners. Source: CFM.
Bjorn’ s Corner: New aircraft technologies. Part 49. Engine Maintenance
By Bjorn Fehrm
March 8, 2024, ©. Leeham News: We are discussing the different phases of a new airliner program. After covering the Design and Production, we now look at the Operational phase of a new airliner family.
For the operational phase, the airplane must pass scrutiny for Continued Airworthiness. The biggest item in a regulator’s Instructions for Continued Airworthiness is the required Maintenance program to keep an airliner airworthy. We discussed airframe maintenance in the last article. Now, we look at engine maintenance.
Figure 1. The CFM56-7 engine for the Boeing 737NG. Source: CFM.
Bjorn’ s Corner: New aircraft technologies. Part 44. Operation and Continued Airworthiness
By Bjorn Fehrm
January 5, 2024, ©. Leeham News: We are discussing the different phases of a new airliner program. After covering the Design and Production, we now look at the Operational phase of a new airliner family.
For the customer, the design and production are exciting and interesting, but it’s the information and services around the operational phase (Fleet Support in Figure 1) of the airliner that are most important to the airline customer.
Figure 1. The development plan for a new airliner. Source: Leeham Co.
Bjorn’s Corner: New aircraft technologies. Part 42. Improving the learning curve
By Bjorn Fehrm
December 15, 2023, ©. Leeham News: We are discussing the different phases of a new airliner program. After covering Conceptual, Preliminary, and Detailed design, the manufacturing of prototypes, and their roles in flight tests, we now look at the production phase.
Last week, we discussed why production costs vary over time and why they can be up to 500% higher for the first units than for units past 400 to 500 aircraft produced. Now we go deeper into the reasons behind this and what can be done to improve the situation.
Figure 1. The program plan for a new airliner. Source: Leeham Co.
The Exception to the Green Propulsion Rule
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By Bjorn Fehrm
November 30, 2023, © Leeham News: The interest in Green alternative propulsion for airliners started in earnest at Farnborough Air Show 2014, where Airbus flew the E-Fan battery-electric aircraft. What followed was a dense stream of alternative propulsion airliner projects.
They all have in common that nothing much has come out of them. We have a Pipistrel two-seat trainer that can fly for 50 minutes on batteries, but not much else. More elaborate projects have wide slips in their plans, and nine years later, we lack real prototypes for all projects.
We have functional models flying for nine-seat hybrids and 19/30-seat hydrogen fuel cell aircraft that swap one engine for a Green alternative. Of the latter, there is one project that stands out from the rest. It has shown real progress over the last years and has realistic plans for a 55-seat hydrogen airliner that can be operational in three to four years.
We will analyze why the Universal Hydrogen ATR fuel cell project is the exception to the “Green Propulsion Rule,” that nothing comes out of all plans, and why it could be the first Green Propulsion airliner, ending a 10-year draught.
Figure 1. The Universal Hydrogen Dash 8-300 functional demonstrator. Source: Universal Hydrogen.
Summary:
- A Green Propulsion project means the airliner does not use hydrocarbon-burning (Kerosene or SAF) gas turbines.
- The project that breaks the rule that nothing seems to reach practical use this side of 2030 is the Universal Hydrogen ATR project.
Further developments of the A321, Part 6
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By Bjorn Fehrm
November 23, 2023, © Leeham News: We do an article series about what can be the subsequent development for Airbus’ most popular aircraft, the A321neo. We looked at different changes to the aircraft in previous articles and the economics in short haul configuration. Now, we compare the capacity and economics of the different variants when configured for long-haul missions.
We use our Airliner Performance and Cost Model (APCM) to look at passenger capacity, seat-mile costs, and range.
Summary:
- A stretched A321 is limited as a long-haul aircraft, as it needs additional fuel and additional takeoff weight to carry the fuel.
- Long-haul variants of a stretched A321 will need the XLR center tank or the new, larger wing of an A32x to extend the range to long-haul values.
Further developments of the A321, Part 4
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By Bjorn Fehrm
October 26, 2023, © Leeham News: We do an article series about what can be the next development for Airbus’ most popular aircraft, the A321neo. We looked at a minimal makeover in Part 3; now, we make a larger change.
We use our Airliner Performance and Cost Model (APCM) to examine what a new wing and revised engines can bring regarding larger passenger capacity, range, and lower seat-mile costs.
Summary:
- To increase the capacity significantly of the A321, a new wing is needed.
- We design a new wing combined with uprated engines and look at the result.
Bjorn’s Corner: New aircraft technologies. Part 35. Prototype manufacturing and Testing
By Bjorn Fehrm
October 20, 2023, ©. Leeham News: We are discussing the different design phases of an airliner development program. The typical phases and their time use and manning are described in the Gant chart in Figure 1.
After covering Conceptual, Preliminary, and Detailed design, we now discuss Prototype manufacturing and Testing.
Figure 1. The development plan for a new airliner. Source: Leeham Co.
Further developments of the A321, Part 2
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By Bjorn Fehrm
October 5, 2023, © Leeham News: We look at what can be the next development for Airbus’ most popular aircraft, the A321neo. We looked at the history of the A320/A321 last week and how the aircraft progressively were updated to take more passengers and fly longer sectors.
The series represents more than 50% of the revenue and margin for Airbus. With the latest development, the A321XLR, soon finished, what is next? We use our Airliner Performance and Cost Model (APCM) to look at base data and what changes are necessary to increase capacity and efficiency further.
A321XLR during cold weather testing in Canada. Source: Airbus.
Summary:
- The A321 is reaching its weight and capacity limits.
- There are ways to lift these limits, but the changes must not break its Airport gate classification.