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.

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Engine Development. Part 4. Turbofans go mainstream.

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By Bjorn Fehrm

Introduction

September 8, 2022, © Leeham News: Last week, we analyzed the change from turbojets to turbofans for civil air transport. The jet engine was developed for high-speed military fighters and was not ideal for subsonic airliner use.

We also dwelled on why the three major engine OEMs came to different solutions for the first-generation turbofans. Now we look at the engine that made turbofans mainstream, the Pratt & Whitney JT8.

Figure 1. The Boeing 727-100 with Pratt & Whitney JT8 engines. Source: Wikipedia.

Summary

  • The JT8 competed with the more developed Rolls-Royce Spey to engine the first US domestic jet airliner, the Boeing 727.
  • After it captured the Boeing 727, it went on to engine all US short and median haul jets of the 1960s.

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HOTR: Could airport caps lead to 777X success?

Sept. 6, 2022, © Leeham News: Will Europe’s airport passenger caps ultimately save the Boeing 777X?

Sometimes it’s more important to be lucky than it is to be good.

It may be purely speculative, but Boeing may well be on the verge of being lucky.

Amsterdam and London Heathrow imposed daily caps of 67,000 and 100,000 passengers, respectively. Other airports considered following suit. The caps were imposed because airport operations were melting down. Short staffing across several professions, including passport control, was blamed.

The short-staffing no doubt will be rectified eventually. But some industry observers speculate that the European Union may decide to impose flight capacity restrictions as one way to reduce aviation emissions. This, some think, might result in a sales boost for the slow-selling 777X.

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ICAO report outlines steps to reduce aviation’s carbon output

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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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Pontifications: Some customers face 3 month delays in current 737 MAX delivery stream

By Scott Hamilton

Sept. 5, 2022, © Leeham News: Boeing has been delivering 737s from its stored inventory and its new production line more slowly than desired. Some customers face a three-month delay, even as Boeing tries to return to normalcy following the 21-month grounding of the MAX and the impact of the two-year pandemic.

The supply chain is a key culprit. Reconfiguring stored airplanes for lessees or buys after a change from the original operator is another. Engine shortages are still another.

BOC Aviation, a lessor headquartered in Singapore, faces three months delays, Robert Martin, the CEO, said in an interview with LNA.

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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.

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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.

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Engine Development. Part 3. The early turbofans.

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By Bjorn Fehrm

Introduction

September 1, 2022, © Leeham News: Last week, we looked at the motivation to change from propeller engines to jet engines as higher cruising speeds were sought for airliners.

We learned the straight jet engine, while good for military jets, wasn’t well suited for civil airliners. It was noisy and fuel-thirsty. It was why the subsequent engine development, the turbofan, was quickly accepted by the airlines.

Figure 1. A Boeing 707 with Pratt & Whitney JT3D turbofan engines. Source: Wikipedia.

Summary
  • The first turbofans from Rolls-Royce, Pratt & Whitney, and GE had different designs.
  • The advantages of the turbofan over the straight jet were quickly recognized. The turbofan has been the choice for airliners since the late 1950s.

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Retrospective: 2011 pros and cons of composite airplanes as Boeing, Airbus look to next 20 years

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By Scott Hamilton

What will the Future Small Airplane look like? Composites, metal, or a combination? Concept Credit: Leeham News.

Aug. 29, 2022, ©Leeham News: Airbus and Qatar Airways are in a nasty court battle over composite degradation on the A350. Lightning strike protection is a major concern in the Qatar lawsuit. Paint begins to strip off composite materials on the A350 and Boeing 787. Building composite airplanes is expensive.

Composites have been on airplanes since the days of the Boeing 727 when the wing-to-body fairings were made of composites. Airbus put composite vertical fins on the A310 and A300-600R. Private airplanes used composites.

But it was the Boeing 787 that became a ground-breaking airliner with its composite wings and composite fuselage. Boeing’s launch of the 787 in December 2003 was what would later be described as a moonshot. It was the first “all” composite airplane. (About 52% by weight was composite.)

It was the first “all-electric” aircraft, meaning all systems were powered by electric energy. Boeing intended that this would be a “snap-together” airplane. Fuselage sections were to be “stuffed” when delivered to the final assembly line in Everett (WA) and “snapped” together, like a prefabricated house. Outsourcing to industrial partners was taken to unprecedented levels at Boeing. (Airbus already largely practiced this for its aircraft.)

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Pontifications: Signs point to China OK soon for Boeing deliveries, orders

By Scott Hamilton

Aug. 29, 2022, © Leeham News: The Chinese government appears on a path toward authorizing Boeing to resume deliveries to airlines by or early in the fourth quarter, China watchers tell LNA.

China hasn’t placed new orders for Boeing aircraft, with few exceptions, since then-President Donald Trump initiated a trade war with China shortly after taking office in 2017.

Nor has China taken delivery of more than single-digit numbers since 2019, following the grounding of the 737 MAX in March that year. China’s regulator, CAAC, was the first to ground the domestic MAX fleet following the second accident of the type in March 2019, five months after the first accident.

China was the last major regulator to recertify the MAX, in December 2021, following the FAA’s recertification in November 2020. But CAAC has not authorized deliveries. It appeared on the cusp of doing so when last May a China Eastern Airlines 737-800 nose-dived from cruising altitude into the ground, killing all aboard. CAAC ordered China Eastern and its affiliated airlines to ground all 737-800s, a move widely believed to be unwarranted given the circumstances of the crash that tentatively pointed to a cockpit-controlled dive. Later investigation largely confirmed this, though no accident report has been released yet.

Because of the crash, CAAC withheld authorization for Boeing to resume deliveries of the MAX. Geopolitical considerations also are believed to have played a role as tensions between the Washington and Beijing continued over the unresolved trade war, China’s straddling sides in the Russian-Ukraine War, and visits by members of the US Congress visited Taiwan. China regards Taiwan as a renegade province and objects to political visits by other countries.

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