Leeham News and Analysis
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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 14. Propulsion system requirements.
By Bjorn Fehrm
April 8, 2022, ©. Leeham News: Last week, we discussed the architecture of a liquid hydrogen fuel system. We now start looking at the propulsion system of a hydrogen aircraft.
Before discussing how a propulsion system is done, we must understand what power requirements different airliner types have and the importance of these types in the market.
Figure 1. The World Jet market forecast for the next 20 years. Source: JADC.
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 12. Hydrogen storage.
By Bjorn Fehrm
March 25, 2022, ©. Leeham News: Last week, we looked at the energy density by mass and volume for hydrogen and regular Jet fuel (Kerosene), Figure 1.
With this information, we now look at how these fuels can be stored in an aircraft.
Figure 1. The Volume and Mass densities of fuels. Source: Boeing.
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Bjorn’s Corner: Sustainable Air Transport. Part 11. Hydrogen and SAF.
By Bjorn Fehrm
March 18, 2022, ©. Leeham News: In our series, we have now seen the major limitations batteries as an energy source impose on an airliner and that hybrids work but don’t bring any advantages for an airliner.
The alternatives are to use an energy source with a higher energy density and combine it with an efficient propulsion system. Sustainable Aviation Fuel, SAF, has the same high energy density as today’s Jet fuel and hydrogen’s density is three times higher than Jet fuel.
Figure 1. The Volume and Mass densities of fuels. Source: Boeing.
Bjorn’s Corner: Sustainable Air Transport. Part 10. Where Hybrids work.
By Bjorn Fehrm
March 11, 2022, ©. Leeham News: After our articles about Serial Hybrids and Parallel Hybrids showed they were unsuitable for airliners, where do these make sense?
The obvious answer is for our stop-and-go cars (as we then can recover the brake waste energy). Still, there are aeronautical special cases where hybrids can bring advantages. Let’s look into these.
Figure 1. The variable angle of rotor blades. Source: FAA Helicopter Flying Handbook.
Bjorn’s Corner: Sustainable Air Transport. Part 9P. Parallel Hybrid. The deeper discussion.
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By Bjorn Fehrm
March 4, 2022, ©. Leeham News: This is a complementary article to Part 9. Parallel Hybrid. It uses Leeham Company’s Aircraft Performance Model from our consultancy practice to analyze the design of a Parallel Hybrid aircraft for regional operations.
Our design brief is to make turboprop upgrade packages for De Havilland DH8-200,-300, and-400 aircraft. By using a Parallel Hybrid we could “target a 30% reduction in fuel burn and CO2 emissions, compared to a modern regional turboprop airliner” according to Pratt & Whitney Canada. Time to check if we can reach these levels.
Bjorn’s Corner: Sustainable Air Transport. Part 8. Serial Hybrids.
February 25, 2022, ©. Leeham News: This is a summary of the article Part 8P. Serial Hybrid, the deeper discussion.
We take an ES-19 type of battery aircraft and add a range extender to avoid the inadequate range we found in Part 6 and 6P.
Initially, it seems a good idea. We can use the benefits of the battery and then complement it with energy from the range extender. As you systematically work through the concept, the problems surface.
Figure 1. Serial Hybrid works for cars (Toyota Prius pictured), but not for aircraft. Picture: Toyota.
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 6. Energy consumption.
By Bjorn Fehrm
February 11, 2022, ©. Leeham News: In a sister article, Part 6P. Energy consumption, the deeper discussion we use Leeham’s Aircraft Performance Model from our consulting practice to generate the aeronautical energy consumption for aircraft like Eviation’s Alice and Heart Aerospace’s ES-19.
This is the energy needed to combat the drag of the airframe during flight (Figure 1). We then add the losses in the chosen propulsion system to arrive at the energy drawn from the energy source.
Figure 1. Simplified force model for an aircraft. Source; Leeham Co.
Forecast 2022: Sustainability
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By Bjorn Fehrm
Introduction
February 7, 2022, © Leeham News: The year that passed was when Sustainability broke through the walls of “I’m not convinced we have a problem” and “If so, what shall we do about it.”
The declarations ahead of, at, and after COP26 in Glasgow, United Nations 26’th climate conference, had many major states and organizations commit to targets for the reduction of Greenhouse gases by 2030 and 2050.
With this change in mind and traction, what can we expect to see in 2022 from the Air Transport industry?
Idea for Sustainable Air Transport, a hydrogen regional. Source: Sustainable Aero Lab.
Summary
- The years that passed were run-up years. Now the preparations shall lead to the first results.
- We summarize what we can expect to see during 2022.