The Lilium Jet is a proposed eVTOL (electric Vertical Take Off and Landing) aircraft that the German company Lilium GmbH has claimed it will bring to the market ‘soon’, which would made it the first eVTOL aircraft in the world to enter into commercial service. As anyone who has any experience with VTOL knows, it’s a tricky subject to engineer, let alone when you want to do it fully electric. In a deep-dive video on the Lilium Jet and eVTOL in general, [John Lou] goes through the physics behind VTOL take-off, landing and flight, as well as range and general performance.
It is clear that Lilium’s presented aircraft concept has many issues, some of which are due to new and unproven technologies, while others seem to be founded in over-promising and likely under-delivering. With Lilium having signed a number of contracts to deliver the first Pioneer Edition Lilium Jets and commercial service promised by 2025, it’s hard to ignore that the first full prototype of the 7-seater Lilium Jet is supposed to fly this year.
Although as [John] points out in the video, eVTOL is not an impossible concept, it is important to remain realistic about what is physically possible, and not seek to push the boundaries. When the UK introduced its first mass-produced VTOL jet in the form of the Harrier, it too faced an uncomfortable time as bugs got ironed out. As these eVTOL aircraft would be carrying real human passengers, it’s a good place to realize that although you can pick a fight with physics, you will never come out on the winning side.
Hopefully Lilium realizes this too, and these sleek, battery-powered aircraft will truly take to the skies in a few years.
The James Webb Space Telescope has had a long and sometimes painful journey from its earliest conception to its ultimate arrival at Lagrange point L2 and subsequent commissioning. Except for the buttery-smooth launch and deployment sequence, things rarely went well for the telescope, which suffered just about every imaginable bureaucratic, scientific, and engineering indignity during its development. But now it’s time to see what this thing can do — almost. NASA has announced that July 12 will be “Image Release Day,” which will serve as Webb’s public debut. The relative radio silence from NASA on Webb since the mirror alignment was completed — apart from the recent micrometeoroid collision, of course — suggests the space agency has been busy with “first light” projects. So there’s good reason to hope that the first released images from Webb will be pretty spectacular. The images will drop at 10:30 AM EDT, so mark your calendars and prepare to be wowed. Hopefully.
eVTOL (Electric Vertical Take-off and Landing) craft are some of the more exciting air vehicles being developed lately. They aim to combine the maneuverability and landing benefits of helicopters with the environmental benefits of electric drive, and are often touted as the only way air taxis could ever be practical. The aircraft from Joby Aviation are some of the most advanced in this space, and [Peter Ryseck] set about building a radio-controlled model that flies in the same way.
The result is mighty complex, with six tilt rotors controlled via servos for the utmost in maneuverability. These allow the vehicle to take off vertically, while allowing the rotors to tilt horizontally for better efficiency in forward flight, as seen on the Bell-Boeing V-22 Osprey.
The build uses a 3D-printed chassis which made implementing all the tilt rotor mounts and mechanisms as straightforward as possible. A Teensy flight controller is responsible for controlling the craft, running the dRehmFlight VTOL firmware. The assembled craft only weighs 320 grams including battery; an impressive achievement given the extra motors and servos used relative to a regular quadcopter build.
With some tuning, hovering flight proved relatively easy to achieve. The inner four motors are used like a traditional quadcopter in this mode, constantly varying RPM to keep the craft stable. The outer two motors are then pivoted as needed for additional control authority.
In forward flight, pitch is controlled by adjusting the angle of the central four motors. Roll is achieved by tilting the rotors on either side of the plane’s central axis, and yaw control is provided by differential thrust. In the transitional period between modes, simple interpolation is used between both modes until transition is complete.
Outdoor flight testing showed the vehicle is readily capable of graceful forward flight much like a conventional fixed wing plane. In the hover mode, it just looks like any other multirotor. Overall, it’s a great demonstration of what it takes to build a successful tilt rotor craft.
We have to admit that flying cars still sound pretty cool. But if we’re ever going to get this idea off the ground, there’s a truckload of harsh realities that must be faced head-on. The most obvious and pressing issue might seem to be the lack of flying cars, but that’s not really a problem. Air taxis are already in the works from companies like Airbus, Rolls-Royce, and Cadillac, who premiered theirs at CES this year.