Structural Problems Associated with Variable Geometry: A review of the problems involved in the structure of variable sweep wings Available to Purchase

This paper presents a broad survey of the structural problems associated with variable geometry for aircraft. Variable sweep allows an aircraft to fly throughout a broad regime of speed and altitude efficiently and without excessive power requirements. Tailored lift drag, improved ride quality, lessening of fatigue damage, and reasonable control sensitivities are advantages. Structural problems fall into two general categories: (1) Because of the number of wing positions, the equivalent of many fixed‐wing aircraft must be investigated, analysed and tested; (2) there are unusual problems which have heretofore not been important considerations in design. Category (1) presents the problem of managing and assimilating large amounts of data. Computer pogrammes and a family of cross‐plots assist greatly. Category (2) presents new fail‐safe criteria, a large lumber of possible flutter‐critical configurations, unavoidable free play in mechanisms which affect flutter speeds, dynamic loads, pivot mechanism bearing life, and requires high reliability in materials. Analyses and wind‐tunnel tests have shown that free play in mechanical joints may or may not cause significant service problems depending upon the mechanical arrangement selected and the actual degree of free play under service conditions.