Historical Review of Uncommanded Lateral-Directional Motions at Transonic Conditions

• Published in: Journal of aircraft 2004-05, Vol.41 (3), p.436-447
• Main Authors: Chambers, Joseph R, Hall, Robert M
• Format: Article
• Language: English
• Subjects: Aerodynamics; Air transportation and traffic; Applied sciences; Exact sciences and technology; Ground, air and sea transportation, marine construction; Military aircraft
• ISSN: 0021-8669; 1533-3868
• DOI: 10.2514/1.4470

This paper presents the results of a survey of past experiences with uncommanded lateral-directional motions at transonic speeds during specific military aircraft programs. The effort was undertaken to provide qualitative and quantitative information on past airplane programs that might he of use to the participants in the joint NASA/Navy/Air Force Abrupt Wing Stall Program. The Abrupt Wing Stall (AWS) Program was initiated because of the experiences or the F/A-18E/F development program, during which unexpected, severe wing-drop motions were encountered by preproduction aircraft at transonic conditions. These motions were judged to be significantly degrading to the primary mission requirements of the aircraft. Although the problem was subsequently solved for the production version of the F/A-18WF, a high-level review panel emphasized the poor understanding of such phenomena and issued a strong recommendation to "initiate a national research effort to thoroughly and systematically study the wing drop phenomena." A comprehensive, cooperative NASA/Navy/Air Force AWS Program was designed to respond to provide the required technology requirements. A work element was directed at a historical review of wing-drop experiences in past aircraft development programs at high subsonic and transonic speeds. In particular, information was requested regarding: specific aircraft configurations that exhibited uncommanded motions and the nature of the motions; geometric characteristics of the airplanes; flight conditions involved in occurrences; relevant data, including wind-tunnel, computational, and flight sources; figures of merit used for analyses; and approaches used to alleviate the problem. An attempt was also made to summarize some of the more important lessons learned from past experiences and to recommend specific research efforts. [PUBLICATION ABSTRACT]