The U.S. Air Force Research Laboratory is still hopeful of getting a coveted X-plane designation for its Advanced Composite Cargo Aircraft, which flew for the first time at Lockheed Martin's Skunk Works on June 2. The next number available is X-55, says AFRL program manager Barth Shenk, X-54 having been reserved for a NASA low-boom supersonic demonstrator that has yet to materialize.
Photos: Lockheed Martin
Interviewed after the flight, Shenk pointed out that ACCA is the first new aircraft - "the first new mold line" - flown by AFRL in 20 years. Which explains why it's so keen on getting an X-plane designation - and why NASA Dryden is helping with flight test. It's been a while!
Interestingly, Shenk says ACCA qualifies for an X- designation because the technology it demonstrates - advanced composite materials and manufacturing processes - is "pervasive beyond the type to which it is applied". If it was just applicable to cargo aircraft, ACCA would get an XC- designation, he says. The last of those I can remember was the tiltwing XC-142.
And don't worry about ACCA having flown before getting its X-number. NASA's Active Aeroelastic Wing demonstrator didn't get its X-53 designation until after the modified F-18 had finished flight testing!