Leeham News and Analysis
There's more to real news than a news release.
Bjorn’s Corner: Sustainable Air Transport. Part 34. eVTOL battery cells
By Bjorn Fehrm
August 26, 2022, ©. Leeham News: This is a summary of the article Part 34P, eVTOL battery cells. It discusses the main component of the battery system, the battery cell.
The Lithium-Ion cells in an eVTOL battery system are the key components of the energy supply system. The cells are of a high power and energy type and must be used and managed correctly to last long and be safe.
Bjorn’s Corner: Sustainable Air Transport. Part 33. eVTOL batteries.
August 19, 2022, ©. Leeham News: This is a summary of article Part 33P, eVTOL batteries. This article discusses the trickiest system on an eVTOL, the battery system.
The battery system supplies the energy to the VTOL, and given today’s and tomorrow’s battery technology; it’s a tight resource that needs a lot of pampering.
Figure 1. We use graphs in the Pipistrel spare parts catalog to show the battery system of the Pipistrel Velis Electro. Source: Pipistrel and Leeham Co.
Bjorn’s Corner: Sustainable Air Transport. Part 31. Mixed architectures.
By Bjorn Fehrm
August 5, 2022, ©. Leeham News: This week, we look at two eVTOLs that don’t fit the terminology we use; Multicopters, Vectored thrust, or Lift and Cruise. The Vertical VX4 and Archer Maker are Lift and Cruise designs, but they use vectored thrusters for the cruise thrust, Figure 1.
Figure 1. The Vertical VX4. Source: Vertical Aerospace.
Bjorn’s Corner: Sustainable Air Transport. Part 30. Lilium Jet VTOL.
By Bjorn Fehrm
July 28, 2022, ©. Leeham News: This week, we analyze the Lilium Jet VTOL.
It’s a vectored thrust design, but it’s different enough in its characteristics from the vectored thrust VTOLs we looked at in Part 28 (Joby S4 ..) to motivate a separate article.
Figure 1. The final Lilium Jet configuration transports six passengers plus a pilot. Note the changed number of wing jets (from 24 to 20). Source: Lilium.
Bjorn’s Corner: Sustainable Air Transport. Part 29. Lift + Cruise VTOLs.
By Bjorn Fehrm
July 22, 2022, ©. Leeham News: We analyzed vectored thrust VTOLs last week, like Joby Aviation’s Joby S4. Now we look at VTOLs that separate vertical and forward flight thrust generation into two different systems. Typical exponents are Wisk Aero Cora, Beta Technologies Alia-250, and Embraer’s EVE.
Figure 1. Wisk Aero Cora. Source: Wisk Aero.
Bjorn’s Corner: Sustainable Air Transport. Part 28. Vectored thrust VTOLs.
By Bjorn Fehrm
July 15, 2022, ©. Leeham News: We started the analysis of the market’s most prominent VTOLs with multicopters last week. Now we continue with vectored thrust VTOLs.
The most known exponent for vectored thrust VTOLs is Joby Aviation’s Joby S4 VTOL, Figure 1.
Figure 1. Joby S4. Source: Joby Aviation.
Bjorn’s Corner: Sustainable Air Transport. Part 27. Multicopters.
July 8, 2022, ©. Leeham News: We will start the analysis of the market’s most prominent VTOL variants by looking at the simplest version, multicopters.
When we analyze the multicopters, we can go through some fundamentals of how VTOL operates and the technology used.
Figure 1. The VoloCity multicopter of the Volocopter company. Source: Volocopter.
Bjorn’s Corner: Sustainable Air Transport. Part 26. VTOLs.
By Bjorn Fehrm
July 1, 2022, ©. Leeham News: Last week, we finished our discussions around Fuel Cell-based airliners using hydrogen as fuel.
We could see the technology has true zero emissions, but the maturity of the many parts needed (hydrogen tank and fuel system, multi-MegaWatt class aeronautical fuel cells, motors, and controls) are not there. We are in the crawling before walk stage with sub-MegaWatt systems to make their first flights over the next years.
Another area claiming Green credentials is the VTOL space. Because these are based on electric technology, VTOLs are claimed as environmentally friendly and a good way to transport people.
We will analyze this industry and its claims of being an efficient, environmentally friendly way of transportation.
Figure 1. Joby S4, the VTOL project that has come the furthest. Source: Joby Aviation.
Bjorn’s Corner: Sustainable Air Transport. Part 25. High Temperature Fuel Cell-based 70-seat airliner
By Bjorn Fehrm
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.
Figure 1. The ATR 72-600 70-seater turboprop. Source: ATR.
Bjorn’s Corner: Sustainable Air Transport. Part 25P. High Temperature Fuel Cell-based 70-seat airliner. The deeper discussion.
Subscription required
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.