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 13. March 14, 2025
- Rolls-Royce’s remarkable turnaround March 13, 2025
- NASA hit by DOGE layoffs, office closures; Boeing’s X-66A R&D continues for now March 11, 2025
- Boeing faces three labor contracts expiring this year March 10, 2025
- Bjorn’s Corner: Air Transport’s route to 2050. Part 12. March 7, 2025
Bjorn’s Corner: New engine development. Part 20. Temperatures.
By Bjorn Fehrm
August 16, 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 different areas of a gas turbine except the exhaust (Figure 1). Before we go to the exhaust and the different outputs from a gas turbine Core, we look at the temperatures and how to cope with them in the different sections of a gas turbine.
Figure 1. The gas turbine cycle and its parts. Source: Rolls-Royce: The Jet Engine.
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.
Bjorn’s Corner: New engine development. Part 17. Combustion.
By Bjorn Fehrm
July 26, 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 compression in the compressor (Figure 1) and now go on to combustion in the combustor.
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 15. Compressor efficiency.
By Bjorn Fehrm
July 12, 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 problem areas of a compressor last week. Now, we will discuss how modern compressors can have over 90% conversion efficiency from turbine power to air compression.
Figure 1. The gas turbine cycle and its parts. Source: Rolls-Royce: The Jet Engine.
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.
Bjorn’s Corner: New engine development. Part 12. Speed change.
By Bjorn Fehrm
June 21, 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.
After covering the main thrust-generating device, which we can call a propeller, fan, or open rotor, depending on the application, we now look at the core, which provides the power to the thrust device. And there, we look at how we use the properties of the air as a gas to get it into a state that the gas turbine needs for different sections.
Figure 1. The gas turbine cycle. Source: Rolls-Royce: The Jet Engine.
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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.
