Dryden's X-31 VECTOR project manager. "Phase I has gotten off to a great start; the Swedish Gripen fighter RM-12 engine fit-check in the aircraft and the aircraft equipment and parts inventory has gone very well," he said. The goal of the X-31 VECTOR program is to research advanced flight- enabling technologies using the X-31 aircraft. Plans include removing the aircraft's tail for tailless operation research; developing Advanced Airdata System (AADS) and Extremely Short-Takeoff-and-Landing (ESTOL) research for potential high Angle of Attack (A0A) use; and installing an Axisymmetric Vectoring Exhaust Nozzle (AVEN).

VECTOR program Cooperative Test Organization team members pose for a minute during the initial Phase I work which began at Dryden on March 2. NASA Photo EC98 44434-2

The Phase I effort of the VECTOR program includes negotiations of a Memorandum of Agreement between the international partners (the United States, Sweden and Germany), an X-31 equipment and parts inventory, the fit-check of a SAAB JAS-39 Gripen fighter RM-12 engine (GE F-404 engine derivative) into the X-31 aircraft and the painting of the aircraft. Phase I work began at Dryden March 2 and included the successful installation and fit-check of the RM-12 engine into the aircraft and the aircraft equipment and parts inventory by the VECTOR partners.

A proposed Phase II of the VECTOR program, the Technology Development and Demonstration phase, would be the actual VECTOR flight research and could begin as early as September 1998.

As a result of VECTOR program flight research, future applications could include the incorporation of this technology into new fighter/attack and other aircraft designs. Potential modifications to current fighter/attack aircraft designs and aircraft operations also could occur. Commercial subsonic transport aircraft upgrades could possibly benefit from the research, as may High Speed Civil Transport technology.

The ESTOL portion of the VECTOR program is one of the more exciting elements of the Phase II flight research effort. The ESTOL effort could enhance current aircraft operations by greatly reducing approach and landing speeds.

Reduced landing speeds can greatly reduce an aircraft's landing energy, making for less demand on the aircraft. This would greatly reduce the cost associated with safety and operations. Increased low speed control would raise the weight of armament and of fuel that could be carried in the tanks when landing. Greatly reduced takeoff and landing distances could certainly enhance aircraft operations and basing modes.

Benefits from the VECTOR program applied to an existing aircraft would include an increase in Angle of Attack (AOA) and a decrease in speed upon approach to landing. The approach sink rate also would be reduced.

Preliminary simulations show de-rotation from high AOAs to lower AOAs would increase an aircraft's speed only slightly.

An installed autoland system would provide the required precise flight path control and de-rotation commands. The aircraft landing payoff with these flight configuration changes translates into a 38-percent landing energy reduction.

The original X-31 program logged an X-plane record of 580 flights - 559 were research missions and 21 took place in Europe for the 1995 Paris Air Show. Fourteen pilots representing all agencies of the International Test Organization flew the aircraft.

In 1994, during the original X-31 flight research program, software was installed in the X-31 to demonstrate the feasibility of stabilizing a tailless aircraft at supersonic speed using thrust vectoring. Tests also included subsonic flight speeds.

The X-31 was the first international experimental aircraft development program administered by a U.S. government agency and was a key effort of the NATO Cooperative Research and Development Program.

The X-31 VECTOR Cooperative Test Organization participants/partners are the U.S. Navy, Boeing, General Electric and NASA in United States; the Swedish Government, Volvo and SAAB in Sweden; and the German Ministry of Defense and DASA (Daimler-Benz consortium) in Germany.

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Responsible NASA Official: John Childress For questions, contact: Dryden Web Group Page Curator: Marty Curry Modified: March 31, 1998