Presenter Information

Paul Vitt


In supersonic flight, there is a large positive shift in the static margin, which causes extreme positive shifts in longitudinal stability, and is an undesirable characteristic. This paper investigates some of the stability and control aspects of an alternative configuration, that of a variable pivot wing aircraft -- an aircraft with two sets of wings, one set sweeps forward, the other set sweeps rearward. By prescribing a sweep schedule, it is desired to minimize the static margin shift with Mach number. The effects of the two lift elements -- that of mechanical shift of the center of pressure forward with sweep, and aerodynamic coupling with the reduction in aspect ratio which cause a decrease in lift-curve slope due to sweep — on simple longitudinal stability and control parameters will be presented. Two cases are examined. The first case has four equal-area wings with a fuselage / strake; the second case has the area of the front wings twice the area of the rearward wings with a fuselage \ strake.

Document Type


Presentation Date

April 1991