Leeham News and Analysis
There's more to real news than a news release.
Leeham News and Analysis
- 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: Air Transport’s route to 2050. Part 24. May 30, 2025
- Does an A220-500 need a new wing and engines? Part 3. May 29, 2025
- Boeing’s future depends on FAA approvals May 26, 2025
Bjorn’s Corner: New engine development. Part 22. High Turbine technologies.
By Bjorn Fehrm
August 30, 2024, ©. Leeham News: We do an article series about engine development and why it has longer timelines than airframe development. It also carries larger risks of product maturity problems when it enters service than the airframe of an airliner.
We reached the turbine part on our way through the engine, where we last looked at high-pressure turbine temperatures. It’s the most stressed part of the engine and, in most cases, decides its durability. To understand why, we look closer at turbine technologies.
Figure 1. Our example engine, the LEAP-1A, is in cross-section with booster to compressor bleed valve area marked with a red circle. Source: CFM.
Bjorn’s Corner: New engine development. Part 19. Turbines.
By Bjorn Fehrm
August 9, 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.
We have covered the problem areas of (Figure 1) compression in the compressor and combustion. Now, we look at the power-generating section, the turbines.
Figure 1. The gas turbine cycle and its parts. Source: Rolls-Royce: The Jet Engine.
Bjorn’s Corner: New engine development. Part 18. Combustors.
By Bjorn Fehrm
August 2, 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.
We have covered the problem areas of (Figure 1) compression in the compressor and combustion, with its requirements on low Soot and NOx emissions. Now we look at how combustors are designed to achieve such low emissions.
Figure 1. The gas turbine cycle and its parts. Source: Rolls-Royce: The Jet Engine.
Rolls-Royce aims to shorten hydrogen program pace
By the Leeham News Team
July 25, 2024, © Leeham News, Farnborough Air Show: Rolls-Royce is calling in data specialists Tata Consultancy Services (TCS) to help speed up the development of its hydrogen program, with the help of quantum computing and generative artificial intelligence.
Rolls-Royce hydrogen testing at DLR, Cologne. Credit: Rolls-Royce
The partnership – announced this week at the Farnborough International Airshow – aims to significantly shorten the design time for new hydrogen-powered propulsion systems under development at Rolls-Royce facilities.
The environmental benefits of hydrogen are gaining increased attention and have been front and centre at this year’s airshow. Hydrogen forms a central plank of the Rolls-Royce alternative fuels program.
Anupam Singhal, president of the TCS manufacturing division, told LNA the rationale for the collaboration with the engine manufacturer was bringing proven hydrogen-powered engine designs to market as quickly as possible.
“We have to look at all the tools and technologies available to us to make the entire ecosystem more sustainable,” he said. “Can we cut short the whole engine design time? Can we have this engine on the wing as quickly as possible?”
Under the expanded partnership, TCS will provide engineering skills and support for system design, component design, supply chain support, and program management to Rolls-Royce as it addresses three key challenges related to hydrogen: fuel combustion, fuel delivery, and fuel systems integration with an engine.
TCS has been working with Rolls-Royce for more than a decade, including testing to demonstrate the integration of technologies required for 100% hydrogen fuel operation on a modified Pearl 15 engine. However, this new partnership is not tied to any one product and aims to streamline the Rolls-Royce development program across its various hydrogen research projects. Read more
Bjorn’s Corner: New engine development. Part 16. Compressor air use.
By Bjorn Fehrm
July 19, 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.
We have covered the problem areas of a compressor and how these achieve power-to-air-pressure conversion efficiencies of over 90% by using advanced 3D airflow modeling. Now, we look at the users of the air from the engin’s compressor.
Figure 1. The gas turbine cycle and its parts. Source: Rolls-Royce: The Jet Engine.
To what extent can the A321XLR replace the Boeing 757, Part 3
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By Bjorn Fehrm
July 11, 2024, © Leeham News: We are comparing the Airbus a321XLR to the Boeing 757 to understand to what extent it can replace the 757 on the longer routes it operates for major airlines like United, American, and Delta.
We have looked at the development and operational history of the aircraft, their Apples-to-Apples capacity and range. Now, we use Leeham’s Aircraft Performance and Cost Model (APCM) to compare the operational costs of the aircraft.
Summary:
- The Boeing 757-200 has the same passenger capacity as the A321LR/XLR and a larger cargo capacity.
- Its range can compete with the A321LR but not the XLR. Both beat the 757 on operational economics.
Bjorn’s Corner: New engine development. Part 14. The compressor problems.
By Bjorn Fehrm
July 5, 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.
We covered the basics of how a compressor works last week. Now, we look at the challenges in compressor design (there are plenty).
Figure 1. The gas turbine cycle and its parts. Source: Rolls-Royce: The Jet Engine.
Bjorn’s Corner: New engine development. Part 13. The compressor.
By Bjorn Fehrm
June 28, 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.
We have covered the need for the axial speed of the core air to decrease and increase depending on the needs of the core engine’s sections. Now, we will start to look at the different parts of the core in more detail. We start with the compressor.
Figure 1. The gas turbine cycle and its parts. Source: Rolls-Royce: The Jet Engine.
Trent 7000 reliability under the spotlight
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By the Leeham News Team
June 24, 2024, ©. Leeham News: The Rolls-Royce Trent 7000 is the exclusive engine for the A330neo and the seventh in Rolls Royce’s Trent series.
Having entered into service in early 2019, the engine has already surpassed one million flying hours.
The powerplant – which is the Trent 1000 but with bleed air features vs the electrically-based Trent 1000 – features efficient hollow Titanium fan blades enabling a fuel burn improvement of 14% per seat compared to previous iterations of the A330.
Launched by Airbus in July 2014, the A330-900 Neo is powered exclusively by Trent 7000 engines. Credit: Airbus
However, there have been issues relating to the reliability of the Trent 7000 which have complicated the A330neo’s early years of service.
Industry insiders have told LNA that operators of the A330neo faced lower than expected time-on-wing for the powerplants, as well as a lack of spares that has impacted maintenance and return to service.
Experts say the protective coatings on the engine’s turbine blades have reportedly been a factor.
But RR strongly denies there have been any reliability issues with the engine.
A RR spokeswoman said: “Our fleet of Trent 7000 engines is performing exceptionally well, and has delivered industry-leading levels of reliability to our customers over the last 18 months.” Read more
Bjorn’s Corner: New engine development. Part 11. Core cycle.
By Bjorn Fehrm
June 14, 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.
We have covered the main thrust-generating device, which we can call a propeller, fan, or open rotor, depending on the application. To drive the main thrust device, we need a lot of shaft power, which is provided by the core. We start with how the core, which is a gas turbine, generates power.
Figure 1. The core cycle compared to a piston engine cycle. Source: Rolls-Royce, The Jet Engine.