Technology development phase begins

Submitted by TEAM Public Affairs

NAVAL AIR SYSTEMS COMMAND, Patuxent River, Md. – A joint two-year U.S./German test program using thrust vectoring to develop short takeoff and landing capabilities using the X-31 thrust vectoring technology demonstrator began here recently.

The Vectoring Extremely Short Take-Off and Landing Control Tailless Operation Research program is a low-cost, highly leveraged approach to developing and demonstrating thrust vectoring and supporting technologies to enable complete flight control/engine/thrust vectoring integration for ESTOL and tailless flight.

The Navy is particularly interested in thrust vectoring benefits in its unique take-off and landing environment. Germany is interested in the integrated FCS design and a major supporting technology, an Advanced Air Data System, which provides accurate air data information throughout the AoA range. Current systems develop inaccuracies at high AoA.

VECTOR is a follow-on to the Defense Advanced Research Projects Agency (DARPA)/Navy/German X-31 Enhanced Fighter Maneuverability (EFM) program completed in 1995. The EFM program, flying the only international X-plane at the time, conducted 580 flights, more than any other X-plane program. EFM explored the tactical utility of post-stall maneuvering using thrust vectoring for air combat.

The X-31 demonstrated outstanding controllability and agility over a range of flight conditions with the aircraft flying at very high nose up attitudes - angles of attack (AoA) greater than stall (up to 70 degrees) by using thrust vectoring. The use of thrust vectoring control integrated with the flight control system (FCS) provided safe, departure-free close-in combat maneuvering throughout the conventional and post-stall flight envelopes.

In previous testing, the X-31 provided data for air combat maneuvering. In this program, however, the aircraft will be exploring thrust vectoring technology in the take off and landing environment. In that flight regime, thrust-vectoring technologies have potentially significant pay-off in a number of critical areas, including operational capability, performance, safety, vehicle complexity, maintenance, and total cost of ownership.

Simulated tailless X-31 flight tests conducted for the Joint Strike Fighter program successfully provided an initial demonstration that thrust vectoring could provide yaw control and, thus, reduce or eliminate the need for an aircraft vertical tail.

The capability of thrust vectoring to control and maneuver the X-31 at very slow speeds near the ground was demonstrated during the 1995 Paris Air Show.

The program will be administered through a joint US/German program office located here. In contrast to other program teams located here, the VECTOR Product Team brings together representatives of multiple engineering disciplines, as well as representatives from Boeing, DASA and the German government in one office.

VECTORat a glance:

The VECTOR Program will develop and demonstrate three technology areas

ESTOL using thrust vectoring control
Advanced Air Data System (AADS)
Tailless/reduced vertical tail configurations
Potential pay-offs for such technologies and concepts include:

ESTOL
Reduced takeoff and landing distances/speeds
Basing flexibility for expeditionary fields or damaged runway operations
Reduced carrier catapult/arresting gear demands or reduced wind over deck requirements
Higher payload bring back and asymmetric stores loading capability
Reduced life cycle cost of arresting gear and catapults
Reduced airframe fatigue life expenditure
AADS for tactical aircraft provides improved air data at high angles of attack or low airspeeds and reduced radar cross-section (RCS).
Tailless/reduced vertical tail configurations reduce aircraft weight, drag and radar cross section (RCS), while providing increased range and/or payload.
In February 1998, the participating contractors started Risk Reduction and Requirements Definition. Efforts included defining detailed program and design requirements, identifying technology risks and performance goals, as well as agreeing on work and cost share in the Technology Demonstration Program. An enabling milestone was accomplished in April 1999 with the signature of the Memorandum of Agreement (MoA) between the German and U.S. Governments to conduct the VECTOR program.

VECTOR Program major contractors :

US – The Boeing Company, Inc. (prime contractor)
Germany – DaimlerChrysler Aerospace AG (Dasa)
The Boeing Company is responsible to the Naval Air Systems Command (NAVAIR) for VECTOR program integration and the flight control system hardware effort. DaimlerChrysler Aerospace of Germany is responsible to the German Federal Office for Defense Technology and Procurement (BWB) for the flight control law software, Advanced Air Data System development, simulation build-up, and aircraft wings and thrust vectoring vanes.

In partnership with Dasa, Boeing will lead X-31 aircraft re-activation, modification, maintenance, repair, and flight test technology. Boeing is also responsible for the Extremely Short Take-Off and Landing activities. This effort includes development and integration of highly accurate navigation equipment. Reduced Tail studies are pursued in a joint effort of Boeing and Dasa. Major subcontractors of the VECTOR program include IntegriNautics, Honeywell, RJK Technologies, Moog, and Nord-Micro. Government participants include the Naval Air Systems Command, the German federal test center for military aircraft (WTD 61), and the German aerospace research center (DLR). Flight testing will be led by NAVAIR at the Patuxent River facility.

VECTOR Quotes

"Germany is excited to do a new technology program with the US, especially an aeronautical demonstration program. Recent aeronautical cooperative efforts with the US have been, necessarily, limited to exchanges of study results and smaller cooperative research projects. This major program is a significant, very positive step for both technology and international cooperation."

Michael Hahn, German Program Manager

"VECTOR is a highly efficient program. Not only does it heavily leverage previous work, the integrated flight test team of government and contractor personnel includes a number of Patuxent River and German personnel who were active in the EFM Program. In addition, flying the program at Patuxent River puts it very close to top-notch Navy engineering and the rigorous Navy flight clearance process, which ensure the quality and safety of flight test".

Jennifer Young, US Navy Program Manager