XCOR Aerospace demonstrated two key aspects of its reusable rocket engine technology in two flight tests of its modified Rutan Long-EZ kitplane testbed - one deliberately and one inadvertently. The 11th test flight of the EZ-Rocket on 27 June was cut short by an electrical problem which prevented shutdown of one of its two rocket motors. But XCOR says its "fail operational" design gave pilot Dick Rutan time to turn the engine off manually, jettison liquid oxygen and conduct a dead-stick landing at Mojave Airport, California. The EZ-Rocket is testing technology for a low-cost reusable launch vehicle (RLV). "With our approach, an electrical problem leaves the engine running and the pilot has a redundant manual-valve to shut the engine down," says chief executive Jeff Greason. The aborted flight lasted 2min 24s - the engines burn for around 3min.
On the 10th flight two days earlier, the EZ-Rocket became the first rocket-powered aircraft to conduct a touch-and-go. After shutting down engines in flight, Rutan made a power-off landing, the aircraft touching down and rolling along the runway for some distance before he reignited the engines and took off. The flight lasted 7min 47s. "Performing a touch-and-go demonstrates safe and routine rocket-powered vehicle operation," says Greason. "You need to be able to safely abort a landing." The ability to reignite the engines and change the landing increases RLV safety, he adds.
Source: Flight International
