January 6, 2023, ©. Leeham News: Since we started this series about our Air Transports and their pollution, we have covered different schemes of reduction such as improved Air Traffic Control (ATC), change to electric aircraft (battery/hybrids) or hydrogen as fuel, and lastly, eVTOLs.
Of these changes, only ATC can have a short-term effect, but it’s a slow mover for organizational reasons.
Changes to how our aircraft are propelled are, unfortunately, longer-term improvements, as we see in an example below.
But we need fast change. We’ve had the craziest of summer and now winter in Europe, where I live, and it’s not a one-time variation. And this is not confined to Europe; the weather change is faster than we thought, and it’s worldwide.
So what can we do?
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By Bjorn Fehrm
Dec. 22, 2022, © Leeham News: Last week, we wrote about Universal Hydrogen’s (UH2) plans to fly a hydrogen-fueled demonstrator aircraft in early 2023, followed by a certified conversion kit for an ATR72 airliner mid-decade.
The plans for the ATR72 hydrogen conversion are at an advanced state. As the first publication, we can describe the overall design and the technical details. The ATR72 implementation brings improvements in several areas compared with what’s been revealed before.
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By Scott Hamilton and Bjorn Fehrm
Dec. 15, 2022, © Leeham News: Universal Hydrogen (UH2) is perhaps weeks away from its first flight of a demonstrator that equips a De Havilland Canada Dash 8-300 with tanks of hydrogen and a fuel cell electric propulsion unit. The project shall prove the feasibility of hydrogen-fueled airliners.
The first flight’s date hasn’t been firmly set, but officials at UH2 told LNA it should be soon. Taxi tests of the aircraft will begin in the coming weeks. The flight will occur at Moses Lake in Central Washington State.
Universal Hydrogen supplies its hydrogen to the aircraft in prefilled barrel-sized tanks, called capsules, to avoid the lengthy and costly investment in storing and filling infrastructure at airports. The proof of concept is with a Dash 8, followed by a complete hydrogen conversion kit for an ATR-72 turboprop airliner.
By Bjorn Fehrm
November 29, 2022, © Leeham News: MTU and Pratt & Whitney presented an EU Clean Sky project today where they will develop an advanced engine concept based on the Pratt & Whitney GTF. The project is called SWITCH, an acronym for Sustainable Water-Injecting Turbofan Comprising Hybrid-Electrics.
There are participants from 11 countries in the project, among them Pratt & Whitney’s sister company Collins aerospace, GKN’s Swedish part, and Airbus.
The engine, which has a mild parallel hybrid architecture, extracts more energy from the turbofan fuel by driving the core exhaust through a vaporizer, where it recovers more heat from the core exhaust, Figure 1. Water from the exhaust, extracted from the core exhaust in a condenser, is heated to steam by the vaporizer and then drives a steam turbine that co-drives the fan. The steam is finally injected into the combustor to lower emissions.
The WET cycle will gain about 10% efficiency compared to today’s GTF. The concept also has a hybrid part which is primarily used for a low-emission taxi.
November 25, 2022, ©. Leeham News: We have gone through the flight principles for different eVTOLs, the critical systems such as battery systems and flight controls, their energy consumption/performance, and how green they are compared to other ways of getting to an airport.
This is all about the flying vehicle. But it’s only part of the system needed for this transport system to work and be safe. We now discuss the other bits needed.
November 18, 2022, ©. Leeham News: In the comments to last week’s Corner, there were requests for a comparison with a helicopter re. Sustainability (kWh/km). Here you go.
I also threw in a cost of operations discussion, as the helicopter is the present alternative to an eVTOL for city-to-airport air transports.
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October 28, 2022, ©. Leeham News: This is a complementary article to Part 43, eVTOL IFR range. It discusses the typical maximum range we can expect from a certified eVTOL when it faces IFR weather conditions.
Flying in IFR conditions requires flight planning with increased reserves if the eVTOL can’t land at the destination airport and must divert to an alternate airport.
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By BRYAN CORLISS
Oct. 3, 2022, © Leeham News: Aviation is “a key vulnerable economic sector that is only in the early stage of adaptation to climate change,” according to a new report from EASA, the European Union’s Aviation Safety Agency.
To meet the industry’s environmental challenges – and there are several — more must be done to identify the hazards and risks that extreme weather events caused by climate change can bring to the industry, the report says.
The report also recommends that more needs to be done to plan for the impact of extreme weather on aircraft and airline infrastructure. The industry and regulators also need to “identify and apply ‘win-win’ solutions” to reduce carbon dioxide and other emissions from airliners, and to accelerate the deployment of aircraft and air traffic control technology to improve the efficiency of Europe’s airline fleet.
The good news in the report is that researchers believe aviation could cut emissions by 69% by 2050 by adopting a suite of changes, including increased use of sustainable aviation fuel (SAF), improved aircraft technology, better operational practices and by using hydrogen or electric motors to power aircraft where feasible.
September 23, 2022, ©. Leeham News: Last week, we looked into the hardware needed for the Flight Control System (FCS) of the eVTOLs in development.
We could see the redundancy of the FCS had to be extensive as the tricky hover to forward flight transition demanded a full-time Fly By Wire concept with no direct mode backup.
Yet the FCS hardware demands are not the main problem of a safe eVTOL FCS. The pilot interaction is. Not because it’s tricky. Because every project does it their way.
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By BRYAN CORLISS
Sept. 5, 2022, © Leeham News: Saying the climate crisis now is at “Code Red for Humanity,” the UN-sponsored International Civil Aviation Organization is calling on nations and companies to increase their investments toward techniques and technologies that can reduce aviation’s climate impact.
It won’t be easy, ICAO said in its Environmental Report 2022, which was released in July.
The aviation industry will be one of the hardest to ween off carbon-based forms of energy, a recent report concluded.
“Scaling the production of sustainable aviation fuels (SAF) and other energy sources requires substantial investment and financial support from both fuel suppliers and governments on top of what would be needed for associated infrastructural changes,” the report said. “This is particularly important, considering that the drop-in fuels have the largest potential to reduce the overall emission from international aviation by 2050.”
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