The third test flight of the Air Force's hypersonic X-51A Waverider aircraft has failed, the Los Angeles Times reports. The X-51A was launched over the Pacific Ocean yesterday, and the Air Force was hoping that it would reach mach 6 and keep flying for five minutes afterward, but unfortunately that never happened. Instead, a problem was discovered with one of the aircraft's control fins only 15 seconds into the flight, causing the Waverider to lose control and crash into the ocean.
This is the second Waverider test flight to end in failure. During the first test of the aircraft in 2010, everything went according to plan, but in another test last year, a flaw caused the engines to shut down prematurely, which in turn sent the aircraft into the ocean. Now there's only one X-51A left, and the LA Times says that the Air Force hasn't decided when this last Waverider will fly.
During this particular test, the Waverider was dropped from 50,000 feet, free-falling for four seconds before the rocket it was attached to engaged. After being propelled by the rocket, the Waverider was supposed to break away and use its own engines to fly, but the control fin failure meant this didn't happen. Instead of flying, the Waverider simply fell into the ocean. "It is unfortunate that a problem with this subsystem caused a termination before we could light the Scramjet engine," said Air Force Research Laboratory program manager Charlie Brink, adding that all of the Air Force's data showed that the team had the right conditions for a successful flight.
Unfortunately, failure is something you have to get used to if you're testing hypersonic aircraft. We've been attempting hypersonic flight for decades now, and the number of failures is far greater than the number of successes. There is a ray of light to be found in that first Waverider test from 2010, however, so here's hoping that the Air Force gets the results it's looking for if it eventually tests this fourth and final Waverider aircraft.