The X-31 is using thrust vectoring to change the rules for aircraft carrier landings

BY WILLIAM COLE

The U.S. Navy has long dreamed of making carrier landings safer, more operationally efficient, and less wearing on the structure and aircraft landing gear.

The answer may lie in the X-31 thrust-vectoring technology demonstrator.

This aircraft, which recently resumed flights at Naval Air Station Patuxent River, Md., under the second phase of the VECTOR technology demonstration program, will be able to land at 150 knots, versus the typical 165 knots, and at a 20-degree angle of attack, versus the normal 12 degrees.

Should the technology from VECTOR be transferred to fleet aircraft, the result would be reduced wear and tear on the aircraft, less need to jettison unused stores and fuel before landing, and less maintenance on carrier arresting gear and catapults. The landing technology also could lead to fewer wind-over-deck requirements for aircraft carriers. All this will greatly increase operational flexibility, life-cycle savings and safety. Boeing Phantom Works is the U.S. prime contractor for the program.

The VECTOR program name stands for Vectoring Extremely Short Takeoff and Landing Control Tailless Operation Research. The X-31’s secret lays in three paddle-like tail vanes that redirect the engine’s exhaust plume in response to pilot input, and provide lift and control at low speeds and high angles of attack. The United States Navy’s ultimate goal for the VECTOR program is to verify that thrust vectoring can be used for extremely short takeoff and landing.

The X-31 originally was flown under the auspices of the Enhanced Fighter Maneuverability program during the early 1990s, and the $53 million VECTOR program is capitalizing on this previous investment. VECTOR is a joint venture that includes the Navy; Germany’s defense procurement agency; Boeing Phantom Works; and European Aeronautic, Defence and Space Co.

The first flight of the second phase of the program, May 17, checked out numerous upgrades and modifications. These included new flight control software, an auto-throttle system, a belly-mounted video camera and components of inertial navigation and global positioning systems. The X-31 also carries EADS’ Flush Air Data System, a nose-mounted sensor package accurate at all angles of attack.

“The airplane flew nicely and as predicted,” said German Naval Reserve Cmdr. Rüdiger “Rudy” Knöpfel, who piloted the first flight of the second phase. “I’m very confident about the future of the program.”

Jennifer Young, U.S. Navy VECTOR Program Manager, said, “It’s great to get back in the air. We learned a lot about the airplane and look forward to getting more data from the ongoing flights.”

Boeing Phantom Works VECTOR program manager Gary Jennings said, “In this phase, we’ll demonstrate this important technology that could eventually lead to significant operational and cost benefits for flight operations aboard aircraft carriers. We have a great airplane, a great program and a great team.”

About 30 more flights are expected before the second phase concludes late this summer. The X-31 will fly extremely short takeoff and landing approaches to a virtual runway at 5,000 feet in the sky, to ensure that the Inertial Navigation System/Global Positioning System accurately guides the aircraft with the centimeter accuracy required for such landings. The program will culminate in extremely short takeoff and landing on a real runway. And that might hold significance for unmanned systems of the future, said the Navy.