Leeham News and Analysis
There's more to real news than a news release.
Leeham News and Analysis
- 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
- Boeing 3Q deliveries up despite strike October 8, 2024
- Strike slows Boeing’s march toward improving safety culture October 7, 2024
- Aerospace supply chain still ailing; Sustainable Aviation Fuel isn’t the answer to go green October 4, 2024
Bjorn’s Corner: New engine development. Part 26. New versus old, Trent 1000 vs. XWB
By Bjorn Fehrm
September 27, 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.
In our look at examples of recent developments with problems and these put in a historical perspective, looking at the reliability and durability of its predecessor we compare the Rolls-Royce Trent 1000 for the Boeing 787 to the Trent XWB for the Airbus A350.
Figure 1. The Rolls-Royce Trent 1000 with its wide cord hollow titanium fan. Source: Rolls-Royce.
Bjorn’s Corner: New engine development. Part 25. New versus old, CFM56 vs. LEAP
By Bjorn Fehrm
September 20, 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.
In our look at examples of recent developments with problems and these put in a historical perspective, we compare the CFM56 to the LEAP, comparing their reliability and durability.
Figure 1. The CFM56 with its mid-span shrouded titanium fan. Source: CFM.
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 21. The High Turbine.
August 23, 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. We discuss why.
In our journey through an engine, we have reached the turbine part, where we will dig deeper into the high-pressure turbine. This is the most stressed part of the engine and has a major influence on engine performance and durability.
Figure 1. Our example engine, the LEAP-1A cross-section with the high-pressure turbine marked. Source: CFM.
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.
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.
Bjorn’s Corner: New engine development. Part 10. Propeller, Rotor or Fan?
By Bjorn Fehrm
June 7, 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.
Following the last Corner on airframe integration, several comments were made about the definition of propeller, open rotor, and/or fan. So, we’ll explore this further.
Figure 1. Evolution of Wright Brothers propellers from 1903 to 1905. Source: wright-brothers.org
Bjorn’s Corner: New engine development. Part 8. Open Rotor technology
By Bjorn Fehrm
May 17, 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 why Open-Rotor engines are more efficient. Their propulsive efficiency can be considerably higher than that of a turbofan. We will explore this further this week.
Figure 1. A counterrotating Open Rotor design that SAFRAN ground tested in 2019. Source: SAFRAN.
A350-1000 or 777-8? Part 2
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By Bjorn Fehrm
May 16, 2024, © Leeham News: We are doing an article series comparing the capabilities of the Airbus A350-1000 and the Boeing 777X. We have looked at the A350-1000 versus the 777-9 and started comparing the history and capabilities of the 777-8 versus the A350-1000 last week.
Now, we use our Aircraft Performance and Cost Model (APCM) to fly the aircraft on a typical route and compare their performance.
Summary:
- The A350-1000 and the latest 777-8 definition is a closer payload-range match than the A350-1000 and 777-9.
- Passenger and cargo capabilities are similar. The economic comparison will be determined by maintenance costs for the engines.
Bjorn’s Corner: New engine development. Part 7. Open Rotor Propulsive Efficiency
By Bjorn Fehrm
May 10, 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 started a discussion around Open Rotor engines after looking at geared versus direct-drive Turbofans. We now look deeper at the Open Rotor Propulsive Efficiency.
Figure 1. The CFM RISE Open Fan engine. Source: CFM.