Lateral Asymmetry Envelope Expansion Testing on a Highly Augmented Fighter/Attack Aircraft.
Abstract
Modern fighter aircraft flight control systems are typically highly augmented to tailor flying qualities, increase departure resistance, and help protect the airframe structure throughout the flight envelope. To successfully defeat hardened targets, fighter/attack aircraft need to be capable of employing larger and heavier weapons than were envisioned when the aircraft was designed. The high lateral asymmetries that result from normal employment of these weapons represent a significant off-design condition that may have a severe impact on stability and control. Adequately defining flight envelope limits for these situations requires a flight test program that could result in a departure from controlled flight, loss of the aircraft, and possibly the aircrew. This paper presents the preliminary results of a flight test program conducted to expand the lateral asymmetry limits of the F/A-18. This flight test program addressed the stability and control, structural, and mission suitability issues associated with lateral weight asymmetries up to 28,000 ft-lb. In addition, test data was generated from which estimates of the maximum lateral store carriage asymmetry and its associated flight envelope could be made. Initial results indicate that with certain limitations, flying qualities are acceptable for performing typical mission tasks such as air-to-ground weapons delivery, in-flight refueling, and formation flight at asymmetries up to 28,000 ft-lb. Moreover, the test results indicate that the current flight manual maneuvering limitations could be expanded significantly within the existing 12 deg angle-of-attack limits. This paper will also address the flight test methods and real-time flight test tools proposed by the authors for mitigating the risks associated with this type of flight test.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 21, 1995
- Accession Number
- ADA301149
Entities
People
- C. M. Clark
- G. D. Dungan
Organizations
- Naval Air Warfare Center