Leeham News and Analysis
There's more to real news than a news release.
Leeham News and Analysis
- RTX Q1 2025 Earnings: GTF Talk Takes A Back Seat To Tariffs April 22, 2025
- Tariffs Tumult Takes Over GE Aerospace Q1 2025 Earnings Call April 22, 2025
- Boeing reports mixed results of latest employee survey, but middle management and officers remain key obstacles April 22, 2025
- Hopes for 1Q financial progress turns into bumpy ride for Boeing April 21, 2025
- Bjorn’s Corner: Air Transport’s route to 2050. Part 18. April 18, 2025
Bjorn’s Corner: Sustainable Air Transport. Part 32. Mixed architectures, Part 2.
August 12, 2022, ©. Leeham News: Last week, we looked at two eVTOLs that don’t fit the terminology we use; Multicopters, Vectored thrust, or Lift and Cruise, the Vertical VX4, and the Archer Maker. We look at Airbus’ CityAirbus NG this week, a Lift and Cruise design like no other (Figure 1).
Figure 1. The Airbus CityAirbus NG. Source: Airbus.
Bjorn’s Corner: Sustainable Air Transport. Part 25. High Temperature Fuel Cell-based 70-seat airliner
By Bjorn Fehrm
June 24, 2022, ©. Leeham News: Last week, we discussed how a High Temperature Fuel Cell (HTFC) could improve the installation of a propulsion system in our 70-seat airliner. We now add this variant to the systems we examined for installation effects and efficiencies.
The deeper discussion is in the sister article, Part 25P. High Temperature Fuel Cell-based 70-seat airliner.
Figure 1. The ATR 72-600 70-seater turboprop. Source: ATR.
Bjorn’s Corner: Sustainable Air Transport. Part 25P. High Temperature Fuel Cell-based 70-seat airliner. The deeper discussion.
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June 24, 2022, ©. Leeham News: This is a complementary article to Part 25, High Temperature Fuel Cell-based 70-seat airliner. It adds the masses and efficiencies of a High Temperature Fuel Cell system to our 70-seat airliner fuel cell variants.
Bjorn’s Corner: Sustainable Air Transport. Part 23. Fuel Cell-based 70 seat airliner
June 10, 2022, ©. Leeham News: Last week, we looked at the different fuel cell systems that can go into a 70-seat airliner like the ATR 72. In this week’s Corners, we implement these in the aircraft and look at installation effects and efficiencies.
The deeper discussion is in the sister article, Part 23P. Fuel Cell-based 70-seat airliner.
Figure 1. The ATR 72-600 70-seater turboprop. Source: ATR.
Bjorn’s Corner: Sustainable Air Transport. Part 13. Hydrogen fuel system and APU.
By Bjorn Fehrm
April 1, 2022, ©. Leeham News: Last week, we looked at how to store hydrogen in an aircraft. We could see the gaseous storage of hydrogen is too heavy other than for demo systems and extreme short-haul. For practical airliners, liquid hydrogen is the solution.
Now we look at what this means for the aircraft fuel system and how to configure a suitable Auxiliary Power Unit, APU.
Figure 1. Typical placement of hydrogen tanks. Source: Leeham Co.
Bjorn’s Corner: Sustainable Air Transport. Part 6P. Energy consumption, the deeper discussion.
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By Bjorn Fehrm
February 11, 2022, ©. Leeham News: This is a complementary article to Part 6. Energy consumption. It uses the Aircraft Performance Model from our Consultancy practice to generate energy consumed data when we fly a typical airline mission for the first aircraft we analyze, the battery-based Eviation Alice and Heart Aerospace ES-19.
These represent what to expect for airliners that have chosen this energy storage principle.
Heart Aerospace ES-19. Source: Heart Aerospace.
Bjorn’s Corner: Sustainable Air Transport. Part 5. Fundamentals recap.
By Bjorn Fehrm
February 4, 2021, ©. Leeham News: We did a simple reality check on two high-profile ideas for Sustainable Air Transport last week, the Eviation Alice project and Heart Aerospace’s ES-19.
We now look at energy usage when performing Sustainable Air Transport flights, but it can be timely to recap some fundamentals of such flights before we discuss this.
Figure 1. A simplified aircraft force model. Source: Leeham Co.
Bjorn’s Corner: Sustainable Air Transport. Part 4. Reality checks.
By Bjorn Fehrm
January 28, 2022, ©. Leeham News: Having discussed where investments would be the most efficient in alleviating our Greenhouse gas problems and identified the low-hanging fruit, we now look at new technology airplanes that can improve the situation.
We start with classical airliners, working our way from small types to the largest, then we discuss the impact of new transport forms like VTOLs for short-haul transportation.
As we will use the Leeham Aircraft Performance Model in some of the work, there will be extra articles (for this one, a Part 4P) which are Paywall, where we use the model to generate deeper data and understanding.
Figure 1. The Alice nine-seater drawings from Eviation’s Web. The present drawing (dark blue) differs from the mid-2021 drawing (light blue, on top). Source: Eviation and Leeham Co.
Bjorn’s Corner: Sustainable Air Transport. Part 2. The problem to solve?
By Bjorn Fehrm
January 14, 2021, ©. Leeham News: Before we dig into the different alternatives we have for more Sustainable Air Transport, let’s look at the problem and its sources.
Figure 1 shows the emissions of CO2 per person since 1900 and the rise of the world temperature. The increase in world temperature changes the weather, with increased weather-related emergencies in recent years.
Figure 1. The increase in CO2 emission per capita and the rise of the world temperature from 1900 to 2018. Source: Wikipedia.
Bjorn’s Corner: The challenges of airliner development. Part 19. Test rigs for ground and air use
By Bjorn Fehrm, Henry Tam, and Andrew Telesca
September 3, 2021, ©. Leeham News: Last week, we looked at the Certification Compliance Planning we do concurrently with Detailed Design, Figure 1.
It’s now time for us to work on our Test rigs and systems for ground and flight testing. We need to get these defined before we freeze the aircraft’s configuration and start making our flight test aircraft.
Figure 1. The program plan for our project. Source: Leeham Co.