Leeham News and Analysis
There's more to real news than a news release.
Bjorn’s Corner: New aircraft technologies. Part 35. Prototype manufacturing and Testing
By Bjorn Fehrm
October 20, 2023, ©. Leeham News: We are discussing the different design phases of an airliner development program. The typical phases and their time use and manning are described in the Gant chart in Figure 1.
After covering Conceptual, Preliminary, and Detailed design, we now discuss Prototype manufacturing and Testing.
Figure 1. The development plan for a new airliner. Source: Leeham Co.
Bjorn’s Corner: New aircraft technologies. Part 34. Design for Certification
October 13, 2023, ©. Leeham News: We are discussing the Detailed design phase of an airliner development program. We have discussed program management methods, development techniques, tools for Detailed design, that improved production methods are as important as improved technology, and that the interaction with the suppliers is key.
But another consideration that affects detail design is the influence of the Certification process. Certification has a major influence on the program work in every step of the aircraft program.
Figure 1. The online version of the FAA 14 CFR Part 25 Airliner Airworthiness regulations. Source: US CFR.
Bjorn’s Corner: New aircraft technologies. Part 33. Supply chain
By Bjorn Fehrm.
October 6, 2023, ©. Leeham News: We are discussing the Detailed design phase of an airliner development program. We have discussed program management methods, development techniques, tools for Detailed design and that the production methods today are as important as technology for achieving aircraft performance.
Another decisive part is how to involve and manage the suppliers to a project. The supply chain contributes about two-thirds of the value of an aircraft. Methods and tools to control this part of the project are therefore critical for the program.
Figure 1. The development plan for a new airliner. Source: Leeham Co.
Bjorn’s Corner: New aircraft technologies. Part 29. Detailed design
By Bjorn Fehrm
September 8, 2023, ©. Leeham News: We described the Preliminary design phase of an airliner development program over the last weeks. Now our project is transitioning into Detailed design.
It’s the most challenging part of the project as we now go from perhaps a thousand people involved at the OEM into tens of thousands and even more people at consultancies and suppliers.
Figure 1. A new airliner family development plan. Source: Leeham Co.
The range of the Airbus A321XLR, Part 2
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By Bjorn Fehrm
September 7, 2023, © Leeham News: The advertised range of 4,700nm for the Airbus A321XLR enables true trans-Atlantic single-aisle routes that can originate further inland, both in the US and Europe. When EASA and FAA demanded that Airbus add extra fire protection around the tank that gives the extended range, rumors told of a substantial range loss.
Last week we could see that whatever the weight increase, the range loss is not substantial. Now we look at what Airbus could do to restore the range of the A321XLR.
Figure 1. The Airbus A321XLR. Source: Airbus.
Summary:
- We could see last week that the range shortfall from the rumored weight increases is less than rumored.
- When we look at the fixes for any range shortfall, they seem straightforward and doable.
Bjorn’s Corner: New aircraft technologies. Part 28. Alternative Preliminary design
By Bjorn Fehrm
September 1, 2023, ©. Leeham News: We described the Preliminary design phase of an airliner development program last week. One could say this was the classical way that aircraft projects conduct Preliminary design.
There is a different way that Conceptual and Preliminary design can be run. It’s more along the lines of pre-development of functions, as a reader commented on two articles back.
Figure 1. An alternative new airliner family development plan. Source: Leeham Co.
The range of Airbus’ A321XLR
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By Bjorn Fehrm
August 31, 2023, © Leeham News: The advertised range of 4,700nm for Airbus’ A321XLR enables true trans-Atlantic single-aisle routes that can originate inland both in the US and in Europe. It was, therefore, worrying when EASA and FAA demanded that Airbus add extra fire protection in the area where the new center tank is placed, the tank that enables the longer range.
Extra fire protection increases the empty weight, which has an impact on range. How much is lost, and what can Airbus do about it? We model the range shortfall and possible fixes with our Aircraft Performance and Cost model.
Figure 1. The Airbus A321XLR. Source: Airbus.
Summary:
- The A321XLR is the first trans-Atlantic single-aisle airliner that can fly further than coast to coast between the US and Europe.
- The range shortfall from the rumored weight increases is less than written about but still troublesome.
The reality behind the eVTOL industry’s hyperbole, Part 6.
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By Bjorn Fehrm
August 17, 2023, © Leeham News: We look at the promises that the VTOL industry has made in their Investor prospects and what the reality is as they come closer to Certification and production.
We used our Aircraft Performance and Cost model to understand the data for the typical missions for the Joby S4 and Archer Midnight VTOLs and how the economics pans out for these missions. We now look at the results and compare them to what’s been projected from the OEMs.
Figure 1. The Joby S4 VTOL. Source: Leeham Co.
Summary:
- We found the VTOL OEM’s economics for the typical 10-minute shuttle flights optimistic.
- When we go back and look at investor deck projections, the cost comparison to helicopter costs were totally off the mark. When we correct this the VTOL is more expensive to operate then an equivalent helicopter.
The reality behind the eVTOL industry’s hyperbole, Part 4.
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By Bjorn Fehrm
August 3, 2023, © Leeham News: We look at the promises that the VTOL industry has made in their Investor prospects and the reality as they come closer to Certification and Production.
After looking at claims of range and utility, we now look at the operating economics. To do that, we need to predict the net sales price of these machines. We use our Aircraft Performance and Cost Model (APCM) to predict the production cost over time and, thus, the needed net sale price of the VTOLs.
Figure 1. The Archer Aviation Midnight VTOL mockup at the Paris Air show. Source: Leeham Co.
Summary:
- The VTOLs are big; the Archer Midnight is the size of a nine-seater commuter aircraft (Figure 1). Aircraft costs are related to size and weight.
- VTOLs use aeronautical production methods and supply chains for parts and systems. The production costs are, therefore, predictable.
The reality behind the eVTOL industry’s hyperbole, Part 3.
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By Bjorn Fehrm
July 27, 2023, © Leeham News: We look at the promises that the VTOL industry has made in their Investor prospects and what the reality is as they come closer to Certification and present their production-level prototypes. We also analyze whether these capabilities will be the final level.
Today we go through the trickiest part of any electric aircraft or eVTOL, the batteries. They are large, very heavy, and the most difficult part to certify on the aircraft, as the battery is dangerous if not designed, produced, and managed correctly.
Figure 1. The Joby Aviation S4 production prototype. Source: Joby Aviation.
Summary:
- The battery system of an eVTOL sets restrictions on the operational usefulness of the category.
- The everyday operational utility of VTOLs is far from the industries’ claims.