Leeham News and Analysis
There's more to real news than a news release.
Leeham News and Analysis
- Bjorn’s Corner: New engine development. Part 4. Propulsive efficiency April 19, 2024
- Boeing unlikely to meet FAA’s 90-day deadline for new safety program April 18, 2024
- Focus on quality not slowing innovation, says GKN April 18, 2024
- Boeing defends 787, 777 against whistleblower charges April 17, 2024
- Dissecting Boeing CEO’s statement next new airplane will cost $50bn April 15, 2024
Bjorn’s Corner: Sustainable Air Transport. Part 41. VTOL mission calculations.
By Bjorn Fehrm.
October 14, 2022, ©. Leeham News: Last week, we defined the phases of an eVTOL mission that shall show us the typical range and endurance of the eVTOLs of a hybrid vectored thrust/lift and cruise eVTOL, similar to a Vertical VX4, Figure 1.
Several parts of the energy consumption calculations are complex, and surprisingly it’s not the vertical parts. We go through why and how we calculate the energy consumed for the mission.
Figure 1. The Vertical Aerospace VX4 in an early rendering with similar looks to the eVTOL we discuss. Source: Vertical Aerospace.
Bjorn’s Corner: Sustainable Air Transport. Part 40. VTOL mission.
By Bjorn Fehrm.
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.
Figure 1. The Vertical Aerospace VX4 in an early rendering with similar looks to the eVTOL we discuss. Source: Vertical Aerospace.
Bjorn’s Corner: Sustainable Air Transport. Part 38. Piloting the VTOL
By Bjorn Fehrm
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.
Figure 1. Pilot flying the Joby S4 simulator. Source: Joby Aviation.
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Bjorn’s Corner: Sustainable Air Transport. Part 37. VTOL Flight Control.
By Bjorn Fehrm.
September 16, 2022, ©. Leeham News: We discussed one of the critical systems for an eVTOL over the last weeks, the battery system, its cells, and its management system.
Another critical system for a VTOL is its Flight Control System (the FCS).
Figure 1. The Honeywell UAM FBW (Fly By Wire) triple channel computer. Source: Honeywell.
Bjorn’s Corner: Sustainable Air Transport. Part 36. Battery Management.
By Bjorn Fehrm
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.
Figure 1. The Battery Management System and battery packs from EP Systems. Source: EP Systems.
Bjorn’s Corner: Sustainable Air Transport. Part 35. Lilium battery cells.
By Bjorn Fehrm
September 2, 2022, ©. Leeham News: This is a summary of the article Part 35P, Lilium battery cells.
It discusses the requirement the Lilium jet principle puts on its battery cells and how this is solved, both with a slightly different cell type and with some operational adaptations.
Figure 1. The final Lilium VTOL configuration with 30 jets. Source: Lilium.
Bjorn’s Corner: Sustainable Air Transport. Part 35P. Lilium battery cells. The deeper discussion.
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September 2, 2022, ©. Leeham News: This is a complementary article to Part 35, Lilium battery cells. It discusses the requirement the Lilium jet principle puts on its battery cells and how this is solved, both with a modified cell type and with some operational adaptations.
Bjorn’s Corner: Sustainable Air Transport. Part 34P. eVTOL battery cells. The deeper discussion.
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August 26, 2022, ©. Leeham News: This is a complementary article to Part 34, eVTOL battery cells. It discusses the trickiest system on an eVTOL, the battery system, and its key component, the battery cells.
The Lithium-Ion cells in an eVTOL battery system are the core 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 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.