Dynamic model of the interface reactions in an aircraft bomb rack due to an external store.

摘要

In today's downsizing environment, more demands than ever are being placed on aircraft flight test programs. To compensate for shrinking budgets and increased requirements, new and more versatile test techniques and data processing systems must be developed. Standard flight test procedures must be reexamined and optimized to maximize the availability of the test asset while processing the collected data more quickly and at a lower cost.; This research demonstrated the ability to predict the reaction loads transmitted to an aircraft bomb rack due to the inertial forces acting on an external store. These load calculations typically require lengthy test programs with strain gage and accelerometer instrumentation placed on the store, suspension equipment and rack interface points. Instrumented testing procedures are cost prohibitive and time consuming, requiring much pre-flight and post-flight work to instrument the test articles and reduce the data, respectively. This research focused on calculating the interface reactions relying only on store mass properties, accelerometer data and geometry, all of which can be collected at minimal effort and cost while allowing real-time data reduction.; Equations were developed from classical theory and the accuracy of the data was proven with actual flight test information. A full-scale static ground test provided data for model improvement and verification. Flight test data for final validation were primarily accumulated during a carrier suitability flight test program conducted at the Naval Air Warfare Center, Patuxent River, Maryland on a fully instrumented F-14, BRU-32/A bomb ejector rack and a GBU-24B/B 2,000-lb. bomb.; In the 300 milliseconds following arrestment, forces and moments up to 15,000 lbs. and 150,000 in-lbs., respectively, were calculated at the store CG. Compared to the measured data, very good agreement was found in form and magnitude for all calculated interface reactions. Critical lug and swaybrace rod reactions averaged less than 7% and 9% absolute error, respectively. Swaybrace rod and vertical lug reactions that were less than 2,000 lbs. and 5,000 lbs., respectively, were considered non-critical and in the noise of the test.