IFM Applications to Trajectory Predictions–Past, Present and Future 871792
The Influence Function Method (IFM) is an innovative technique for predicting store loads within an aircraft flowfield. The method was originally developed to utilize data obtained for one store traversed parallel to the parent aircraft to predict the forces and moments on any other store in the same aircraft flowfield. It has since been shown to be capable of accurately predicting external aircraft flowfields, as well as using using experimental and theoretical aircraft flowfield data to predict store grid loads, up in and including pylon carriage. Some of the more striking examples of these capabilities are shown in the paper.
The method has been recently shown to be applicable under certain constraints, to high aspect ratio stores. This required the development of a new calibration technique, which is in the process of evaluation. This work, in addition to the extension of the IFM technique to tow targets is also reported.
The accuarte prediction of store grid loads requires a good calibration as well as an accurate prediction of the aircraft flowfield. The recent development of TranAir, a transonic version of the PAN AIR code, opens the possibility of theoretically predicting store grid loads at all Mach numbers everywhere in the aircraft flowfield. These complimentary features of IFM and TranAir are discussed.