Leeham News and Analysis
There's more to real news than a news release.
Leeham News and Analysis
- The BWB has a long way to go before flying passengers, freight May 12, 2025
- Bjorn’s Corner: Air Transport’s route to 2050. Part 21. May 9, 2025
- Does an A220-500 need a new wing and engines? Part 2. May 8, 2025
- Embraer downplays tariff impact on 2025 results May 6, 2025
- JetZero readies effort for private equity fund raising May 5, 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 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 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 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.
Boeing invests $450m in Wisk Aero air taxi venture
By Bjorn Fehrm
January 25, 2022, ©. Leeham News: Boeing and Wisk Aero yesterday had a media briefing on why Boeing is extending its investment in Wisk Aero with a further $450m.
The main technology is not the eVTOL aircraft. Wisk is just one of many upstarts that relies on batteries and multiple electrical propulsors to create a VTOL air taxi. It’s the pilotless operation that’s the key technology in the project. As perhaps the only VTOL company, Wisk goes directly to pilotless flight.
Brian Yutko, VP of Sustainability and Future Mobility at Boeing, explained: “The pilotless flight technology is of great interest to Boeing. It’s challenging technology, but it has a wide field of applications once mastered. We are not targeting our airliners but other civil and military applications. It’s an important driver for us in the continued support for our Wisk joint venture.”
Figure 1. The fifth-generation prototype Cora, with which flight tests are done in New Zeeland. Source: Wisk Aero.
Bjorn’s Corner: Sustainable Air Transport. Part 3. Low hanging fruit.
By Bjorn Fehrm
January 21, 2021, ©. Leeham News: Whatever is done in terms of new Sustainable technology for the aircraft, will have a limited influence on the amount of Greenhouse gases that Air Transport emits before 2050.
We will only get the new aircraft types into operation about 15 years before the deadline and with, on average, 100 to 200 aircraft per year. That’s 1,500 to 3,000 of the total of 25,000 aircraft that operate in our skies daily. It will not reduce our Greenhouse gas emissions significantly.
Sustainable Aviation Fuel, SAF, will help, but only when it’s available in quantity and to a reasonable cost. We can do things that have a much faster effect, and that’s how we manage our flights.
Figure 1. The US flights as seen on Flightradar24 yesterday. Source: Flightradar24.
Reducing one’s carbon footprint through flying choices
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By Vincent Valery
Introduction
Jan. 20, 2022, © Leeham News: Discussions about reducing commercial aviation’s carbon emissions have become more prominent over the last few years.
Many projects claim that electric(-hybrid) and hydrogen aircraft will be available in the not-too-distant future to make net-zero emissions flying a reality. Sustainable Aviation Fuels (SAFs) will also drastically reduce lifecycle carbon emissions with only minor changes to the current aircraft.
The IATA committed to a net-zero carbon emissions target by 2050. While all those long-term aspirations are well, significant challenges remain.
LNA has highlighted that the low energy density of batteries means that electric aircraft can at best work on small planes for short flights. Developing a medium-haul hydrogen-powered aircraft will require numerous innovations that suggest an entry into service before 2035 is not realistic. The challenges in increasing SAFs supply affordably to meaningful levels are monumental.
We have pointed out that all the above are far into the future. To meaningfully reduce emissions over the next decade, the introduction of more fuel-efficient gas turbines and turboprops is the only realistic and impactful lever.
Another lever has not been mentioned so far to reduce one’s carbon emissions. Other than not flying at all, how we fly from A to B can have significantly different carbon footprint levels.
This series will highlight the different levels of carbon emissions depending on how one flies on different routes.
Summary
- Setting the problem out;
- Challenges in defining unit emissions;
- Factors outside one’s control;
- Introducing a few examples.