Bauhaus Luftfahrt, a Germany-based aerospace think tank, has outlined its vision of an electrically powered, emission-free airliner–relying on batteries–that it believes could be in service by 2035. The most obvious aspect of the design is a C-shaped wing for greater lift. Another major feature is the use of superconductivity for better power transmission and greater motor power density.
The Ce-Liner would seat 190 passengers and have a range of 900 nm. This would cover 79 percent of all flights operated by aircraft of a similar size, according to Bauhaus Luftfahrt. The designers insist they have taken into account the requirements of real commercial operations. For example, some seats would be foldable for boarding flexibility.
The minimum recharge time for the batteries would be two hours, so for fast-turnaround operations the batteries would be exchanged, Kay Ploetner, deputy head of the visionary aircraft concepts group at Bauhaus Luftfahrt, told AIN. In this instance 16 standard LD3 containers of lithium-ion batteries could be replaced within a 30-minute turnaround time. Bauhaus Luftfahrt used a forecast of future battery technology development to assume an energy density of 900 Wh/lb (meaning each pound of battery can supply 900 Watts for an hour) in 2035.
But is it reasonable to assume that elusive superconductivity techniques will be a usable reality in just over two decades? Yes, insists Ploetner: “The third generation of superconduction technology just needs temperatures of 77 [Kelvin], as opposed to very close to 0 K for the first generation [respectively -320-degrees F and -459-degrees F].” Some offshore oil platforms are already testing “high-temperature” superconducting generators. Moreover, third-generation superconducting techniques use liquid nitrogen, which is safer than hydrogen (used in the second generation).
Asked about the wing, Ploetner said the Ce-Liner would be 30 metric tons (66,000 pounds) heavier than an Airbus A320 and would therefore need more lift from airfoils sized to fit within existing infrastructure. Nevertheless, the “C-wing” is a departure from a previous Bauhaus Luftfahrt concept that featured a box wing. “The aerodynamic benefits from a box wing and a C-wing are very close,” according to Ploetner. A benefit of the C-wing is that the top wing is not attached to the fuselage, simplifying and stretching or shortening of the fuselage for different variants.
Ploetner points out that the C-wing is not necessarily more difficult to manufacture than a conventional design: “In an electric aircraft, you have no fuel in the wings so you can change the structural layout.”