Leeham News and Analysis
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Bjorn’s Corner: New aircraft technologies. Part 30. Detailed design -2
By Bjorn Fehrm
September 15, 2023, ©. Leeham News: Last week, we described the beginning of the Detailed design phase of an airliner development program. We discussed the importance of a good information set from Preliminary design, ideally as a collection of digital models forming a Preliminary level digital twin.
We now discuss how the work is managed in the Detailed design phase and how to speed up the work and make it more efficient.
Figure 1. The development plan for a new airliner. Source: Leeham Co.
Bjorn’s Corner: New aircraft technologies. Part 26. Preliminary design
By Bjorn Fehrm
August 25, 2023, ©. Leeham News: We described the different phases of an airliner development program last week.
We will look at the Preliminary design phase this week, what work is done, the tools used, and how it can be made more efficient.
Figure 1. A typical new airliner family development plan. Source: Leeham Co..
Bjorn’s Corner: New aircraft technologies. Part 26. Airliner development program
By Bjorn Fehrm
August 18, 2023, ©. Leeham News: We started last week to look at how to make the development of a new airliner family more efficient.
First, we describe how development projects are phased and how many people with what competencies are engaged in each phase. Then we can start the discussion of what changes can be made and what would be the consequences.
Figure 1. The JetZero Blended Wing Body that USAF partially funds to prototype. Source: USAF and JetZero.
Bjorn’s Corner: New aircraft technologies. Part 25. Efficient development
August 11, 2023, ©. Leeham News: We have described a number of technological advances that can be used to make the next-generation airliners more efficient and, thus, more environmentally friendly.
Part of developing more efficient next-generation aircraft is to change the development process to be more efficient. The last Boeing aircraft, the 787, took 7.5 years from launch to entry into service, and Airbus A350 took 8.5 years.
The target is to reduce this by up to 50%, but how?
Figure 1. The Airbus A350 development schedule. Source: Airbus.
Bjorn’s Corner: New aircraft technologies. Part 24. Single or dual aisle fuselage?
By Bjorn Fehrm.
August 4, 2023, ©. Leeham News: This is a summary article to Part 24P. Single or dual aisle fuselage. It summarizes the drag and weight simulations we have done on fuselages for the next generation Heart of the Market airliners. When it comes to drag and weight for a 250-seat airliner that shall replace today’s Single Aisle, is a Single Aisle fuselage lower in drag and weight than a Dual Aisle fuselage?
Figure 1. The drag components of a Single Aisle airliner at 35kft and M0.78. Source; Leeham Co.
Bjorn’s Corner: New aircraft technologies. Part 23. Efficient flight speeds
By Bjorn Fehrm
July 28, 2023, ©. Leeham News: We touched on efficient flight speeds in Part 21, but it was focused on fuel efficiency and how new technologies require the airliner to fly at new altitude-speed combinations to maximise the fuel efficiency gains.
We now look at how to fly the airliner cost-efficiently, which is slightly different from how to fly it fuel efficiently.
Figure 1. The difference between lowest fuel burn speed (Mmr) and long-range cruise speed Mlrc. Source: Airbus.
Bjorn’s Corner: New aircraft technologies. Part 22. Engine characteristics.
By Bjorn Fehrm
July 21, 2023, ©. Leeham News: Developments in engines and airframe technologies require that future airliners are flown differently to maximize the technology benefit.
After looking at the consequences of new developments for the airframe, we now analyze what engine developments mean for how they will be sized and flown.
Figure 1. The RISE engine from CFM. Source: CFM.
Bjorn’s Corner: New aircraft technologies. Part 21. Changed flight profiles
By Bjorn Fehrm
July 14, 2023, ©. Leeham News: Developments in engines and airframe technologies require that the aircraft are flown differently to maximize the benefits.
We start by locking what changes in parasitic and induced drag mean for how airliners fly.
Figure 1. A Truss Braced Wing airliner shall fly higher. Source: Boeing.
Bjorn’s Corner: New aircraft technologies. Part 20. Efficient flying
By Bjorn Fehrm
July 7, 2023, ©. Leeham News: We explore different technologies in the series that can make our next-generation airliners more efficient and, thus, less polluting.
We have discussed developments of engine and airframe technologies, such as Turbofans versus Open Rotors and different airframe configurations to minimize drag and, thus, energy consumption.
When utilizing these developments to increase efficiency we must fly the aircraft in a different way depending on the technology.
And how we fly the aircraft is not only influenced by the factors we have discussed. We must consider factors at the airplane level, at the airliner operational level, and finally, at the airline fleet level.
Figure 1. The NMA concepts included dual aisle airliners. Source: Leeham Co.