October 7, 2022, ©. Leeham News: Last week, we discussed the reality of mass fractions for certified aircraft. There is an abundance of statistics on projects that have gone through the arduous development and certification phase, which always turns out heavier than projected.
Using such statistics, we have a base from which to fly a typical hover and cruise eVTOL design and see what we get in terms of energy consumption and range.
September 9, 2022, ©. Leeham News: Over the last weeks, we have discussed the cells that make up the battery system for an eVTOL.
The battery system has 10,000 cells or more. All these must, on an individual level, be managed to ensure they operate inside their allowed values. The Battery Management System, BMS, has this responsibility. It’s one of the most critical safety systems in an eVTOL.
August 19, 2022, ©. Leeham News: This is a complementary article to Part 33, eVTOL batteries. It discusses the trickiest system on an eVTOL, the battery system.
While Lithium Ion batteries have come a long way since the electric flight ideas took off in 2015, the battery system is still the biggest challenge for eVTOL designers, not only for total energy content but for a range of parameters.
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).
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.
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.
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.
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.
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.
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.