Leeham News and Analysis
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Leeham News and Analysis
- Boeing CEO: Lessons learned are key to certification of 737-7/10 and 777X June 2, 2025
- Digital twin is a key to JetZero’s hopes for Blended Wing Body entry June 2, 2025
- Bjorn’s Corner: Air Transport’s route to 2050. Part 24. May 30, 2025
- Does an A220-500 need a new wing and engines? Part 3. May 29, 2025
- Boeing’s future depends on FAA approvals May 26, 2025
Bjorn’s Corner: Sustainable Air Transport. Part 18. Advanced Hydrogen Gas Turbines
By Bjorn Fehrm
May 6, 2022, ©. Leeham News: Last week, we looked at how we create the shaft power for the thrust device we discussed before. We described the basics of a hydrogen-burning gas turbine alternative.
When we have liquid hydrogen as fuel, several advanced developments are possible. It’s what we look at now.
Figure 1. Airbus ZEROe hydrogen gas turbine concepts. Source: Airbus.
Bjorn’s Corner: Sustainable Air Transport. Part 17. Gas Turbine Propulsion
By Bjorn Fehrm
April 29, 2022, ©. Leeham News: Last week, we looked at the thrust generating device that aircraft propulsion systems use. We could conclude that independent of how we create the shaft power, we can choose different thrust technologies with desired characteristics. A propeller, open fan, or fan in nacelle covers different speed ranges and efficiency profiles.
Now we look at how we generate the shaft power for these devices. We start with the hydrogen-burning gas turbine alternative.
Figure 1. Airbus ZEROe hydrogen gas turbine turboprop concept. Source: Airbus.
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.