The California-based company said that on its maiden flight, its hydrogen-powered, electric S4 eVTOL air taxi flew 841 kilometers (520 miles) and left only a few trails of smoke behind it. The aircraft still had 10 percent of its fuel remaining in its tank when it landed, but it still beats the 249-kilometer (150-mile) record set by the battery-only Joby in 2021.
The S4 is a six-rotor, five-person aircraft. The full-scale structure first flew in 2017, and current examples are prototypes before mass production. The eVTOL in the name means it’s electric and can take off and land from a location. Behind the record is German technology H2Fly, which was acquired by Joby in 2021. The heart of the system is a fuel cell called the H175, which produces heat, water and electricity from supercooled liquid hydrogen and atmospheric oxygen.
Why hydrogen?
Under the surface of the development of environmentally friendly technology, lithium-ion batteries and hydrogen technology compete with each other, and the battery usually wins. In the competition, costs, safety and other parameters are determined – among these factors, energy density should be highlighted, because it will play an important role later. Energy density is about how much energy we can extract from a given mass of matter. In this area, uranium is the coolest, gasoline and hydrogen are good, batteries are not. To achieve the range that can be obtained from a tank of gasoline, an electric car must be equipped with a battery weighing from half a ton. In addition, the development of batteries is slow, that is, they often promise radical improvements, but rarely come to fruition.
When burned, hydrogen has three times the energy content of gasoline, although by volume it is only a quarter. From the colloquialism of energy density, it would be appropriate to move towards the physically correct terminology here, but we will not: energy content
It doesn't take everything, until it finally takes everything.
Hydrogen production is expensive, storage is difficult, inefficient and unsafe, all of which require entirely new and expensive infrastructure.
According to Elon Musk, hydrogen fuel cells are a dead end. He’s right that the roads are now full of electric cars, and there are no hydrogen cars with a similar range, because there’s nowhere to refuel them – but to charge the battery, all you need is a working plug and a thick puzzle magazine to wait for.
However, on the ground things are a dead end; in aviation, weight is crucial. In addition, aviation was responsible for 2% of global carbon dioxide emissions in 2022, according to data from the International Energy Agency. The use of hydrogen here is not a dead end, but a civilizational shift.
Julia wasn't as strong or stronger than us.
The H175 fuel cell built into the Joby logger is fueled by a tank that stores 40 kilograms of liquid hydrogen at a temperature of -251 degrees Celsius. There are also batteries on board, but much fewer than the pure battery version, which complicates the take-off and landing process, requiring more energy, which is then recharged by the hydrogen system.
H2Fly originally received a €9.2 million grant from the German Ministry of Transport to develop the H175 system with the aim of building megawatt power cells for 80-seat aircraft.
The hydrogen-powered propulsion system is currently an experimental design, and its widespread use requires official technical tests and approvals. Since it has never flown with such a configuration, the first flight would have set a record regardless of the distance. The purpose of the 840-kilometer flight was certainly to demonstrate the technical capabilities. According to Gobi, with a mature system
A range of 1,500 km is realistically achievable.
According to the company’s original plans, battery-powered air taxis were supposed to appear worldwide in 2025, but the new range puts their potential in a completely different light. Aircraft that transport people or goods quickly and without pollution are practically catching up and could compete with other infrastructures – and could even replace classic airlines, buses, trains and trucks.
The puzzle is missing two pieces, both of which reduce costs. The first is that offshore wind farms produce many times more electricity than those on land, but the transmission of electricity is costly. At the level of ideas and plans, it is constantly suggested that it would be an efficient solution to use wind turbine power to produce hydrogen locally. This would obviously provide abundant and cheap hydrogen. The other piece of the puzzle is that for self-driving cars, it is not roads or rules, but people and unpredictable human behavior, that make transportation so complicated—autonomous flight, if not trivial, is exempt from this factor.
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