JOINED-WING TILTROTOR AIRCRAFT STUDY

Period of Performance: 01/01/1989 - 12/31/1989

$80K

Phase 1 SBIR

Recipient Firm

Aca Industries, Inc.
28603 Trailriders Drive
Rancho Palos Verde, CA 90274
Principal Investigator

Abstract

THE JOINED-WING AIRPLANE IS A NEW TYPE OF AIRCRAFT CONFIGURATION EMPLOYING TWO SETS OF WINGS RIGIDLY CONNECTED TOGETHER TO FORM A TRIANGULATED SELF-BRACING STRUCTURE. FINITE-ELEMENT STRUCTURAL ANALYSES AND WIND-TUNNEL TESTS HAVE SHOWN THAT, COMPARED TO CANTILEVER-WING AIRCRAFT, JOINED WING AIRCRAFT ARE LIGHTER, STIFFER, AND HAVE HIGHER SPAN-EFFICIENCY FACTORS, GIVING LOWER INDUCED DRAG. THE JOINED WING ALSO PERMITS THINNER AIRFOILS TO BE USED, THUS INCREASING THE MACH NUMBER FOR DRAG DIVERGENCE AND THE MAXIMUM SPEED. THE PROPOSED STUDY INVESTIGATES THE APPLICATION OF THE JOINED WING TO TILTROTORAIRCRAFT. FOR SUCH AIRCRAFT, IN ADDITION TO THE ADVANTAGES CITED ABOVE, THE JOINED WING MAY REDUCE ADVERSE DOWNWASH EFFECTS IN HOVER. THE PROPOSED STUDY WILL DELINEATE JOINED-WING TILTROTOR CONFIGURATIONS THAT GIVE MAXIMUM INCREASES IN PERFORMANCE. THE STUDY WILL COMPARE THE PERFORMANCE AND AERO-ELASTIC CHARACTERISTICS OF SUCH CONFIGURATIONS VERSUS CANTILEVER CONFIGURATIONS. IN ADDITION, THE STUDY WILL OUTLINE DETAILED ANALYSES AND TESTS WHICH WILL PROVIDE A DATA BASE FOR DESIGN OF JOINED-WING TILTROTOR AIRCFAFT.