China's TCab Tech is pushing forward with the development of its E20 eVTOL aircraft. During the first quarter of the year the Shanghai headquartered company has completed a number of tilt-rotor transition flights with the E20 50% subscale demonstrator.

The E20 50% subscale demonstrator features a six-metre wingspan, two lift rotors and four tilt-rotors. Like the E20, the demonstrator uses six rotors in VTOL and transits to four rotors in cruise. The two lift rotors are switched-off and locked during cruising flight.

The demonstrator serves as a flight-testing platform for the engineering team to collect valuable flight test data for early validation of the E20 configuration and design. Being the first passenger-carrying eVTOL company in China employed with vectored thrust configuration, the 50% subscale demonstrator is one of the largest eVTOL demonstrators currently flying in China.

The 50% subscale demonstrator is the second subscale demonstrator built by TCab Tech. Compared to the previous 25% subscale demonstrator, the latter has the following improvements:

- Aerodynamics: larger in size and exactly the same external layout as the full-scale E20, the flight test results collected can further validate the computational fluid dynamics (CFD) simulations.

- External Layout: includes flaps and variable pitch rotors to improve control laws and aerodynamic validations.

- Systems: Conversion corridor of the tilt-rotor can be fine-tuned, plus every control unit has an independent control channel to facilitate failure hazard analysis (FHA) and the examination of the fail-safe design.

- Flight Controls: Mounted with many data-feedback sensors to collect thorough flight data, which can be used to further improve aircraft control algorithms.

During the testing period, TCab's team strictly followed the preset research and development progress of the 50% scaled down verification machine, including a large number of ground tests, such as power system bench tests, aircraft static tests, flight engine durability tests and semi-physical physical simulation tests.

The E20 eVTOL 50% scaled down verification aircraft completed its maiden flight in December 2021. After several months of continuous and high-density running-in and test flight, the team has established a complete test flight including route planning, logistical maintenance, inspection and release, and safety assurance. It also has a deeper understanding of the aerodynamic performance and tilting characteristics of the aircraft, which provides strong support for the ongoing development of the E20 eVTOL prototype. A certain number of basic flight tests and database construction are the milestones in the development process of E20 eVTOL. TCab Tech will continue to invest in design, R&D and flight test work with a down-to-earth and rigorous attitude, and will work closely with the Civil Aviation Administration of China to complete the determination of the E20 eVTOL certification basis as soon as possible.