A team of engineers led by Airbus Defence and Space advanced project system engineer Marco Prampolini has secured a U.S. patent for an “ultra-rapid air vehicle” design that envisions transport of 20 passengers at up to Mach 4.5 and range of nearly 5,000 nm. The patent is part of an effort begun in 2009 as “pre-studies” to a research project called ZHEST (zero emission hypersonic transportation). The patent application was submitted in 2010, and recent publication reflects the lag in the processing of patents, which began with the French , then the EU and finally the U.S. patent. 

The vehicle features a “gothic” delta wing, so called because of its resemblance to cathedral arches, with a leading edge sweep of 70 to 75 deg. Three engine types power the vehicle. For takeoff, a turbojet and a rocket motor (or multiple versions of each) propel the vehicle first horizontally into the air then into a vertical flight path. The turbojet(s) shut down before reaching Mach 1 then retract into the fuselage. Ramjets help maintain the high-speed cruise at altitudes of 98,000 to 115,000 feet. To slow down and descend, the vehicle’s ramjet/s are shut down, split flaps are deployed and trapezoid-shaped fins on the outer edge of each wing’s trailing edge are repositioned perpendicular to the delta wings after speed drops below Mach 1. The turbojets would then be deployed and started, and landing would involve “insertion into standard air traffic.” The primary fuel load of liquid or slushy hydrogen and liquid oxygen would be contained in large fuselage tanks.

As for Airbus’s plans for the ultra-rapid air vehicle, a spokesman told AIN, “Airbus Group and its divisions apply for hundreds of patents every year in order to protect intellectual property. These patents are often based on R&D concepts and ideas in a very nascent stage of conceptualization, and not every patent progresses to becoming a fully realized technology or product.”