Leeham News and Analysis
There's more to real news than a news release.
Leeham News and Analysis
- 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 27. Long developments October 4, 2024
- Longshoreman strike adds to Airbus, Boeing woes October 1, 2024
- Southwest Airlines Slashing Capacity Growth Shakes Up Their Fleet Plan September 30, 2024
- Bjorn’s Corner: New engine development. Part 26. New versus old, Trent 1000 vs. XWB September 27, 2024
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.
Maeve, P&W Canada team for new hybrid propulsion system airplane
By Bjorn Fehrm and Scott Hamilton
July 24, 2024, © Leeham News at Farnborough International Airshow: Start-up airplane company Maeve and Pratt & Whitney Canada (PWC) have teamed for the design of a new eco-airplane driven by a new type of hybrid electric propulsion system with a target service entry date of 2032.
The M80 aircraft is the latest iteration of a design conceived by Maeve of the Netherlands. It is a 76 to 96-seat twin-engine aircraft that is compliant with the restrictive US pilot Scope Clauses, which limit the size, number, and weight of airplanes operated on behalf of US major airlines. Maeve originally designed a four-engine, 44-passenger electric aircraft called the M01.
Figure 1. The Maeve M80 combines an all-new powerplant from Pratt & Whitney Canada and downward wing droops instead of upward winglets. Source: Maeve.
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 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.
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 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: 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.