The application of a parametric method of fatigue load measurement to wings based on flight measurements on a Lightning Mk T5

Abstract

A study is made of the application to wings of fighter-type aircraft of a parametric method of deriving fatigue loads, similar to that developed previously for fins. In this method load is not measured directly but is deduced from a statistical correlation with an appropriate combination of aircraft motion variables and control surface angles~ New problems arise in the application to wings associated with the variation in load levels upon which the manoeuvre loads are superimposed. The combined effect of symmetric and asymmetric loading is considered and the method can be regarded as extending current operational methods based on CG normal acceleration to include asymmetric and pitching effects. The study is again centred on Lightning flight measurements; its scope is limited however by the lack of ground load calibrations for the wing strain gauges which has necessitated the development of parametric formulae for local rather than overall loads.