DEVELOPMENT OF SIMULATED METAL WHEELS FOR SUSPENSION OF FULL AIRFRAME STRENGTH TEST SPECIMEN FOR A FIGHTER AIRCRAFT

摘要

Structural test programs form an integral part of an aircrafts design and certification process. The airworthiness clearance of the structure of the fighter aircraft shall be based on the static strength test of the full airframe consisting of fuselage along with the wings, fin and rudder. The challenge was to install the test airframe on the test rig (consisting of a superstructure of steel towers and trusses), as well as loading structures and loading actuators that will be used to apply test loads to the test specimen. The objective of introducing simulated metal wheel concept was to fulfill the following requirements, for conducting the full airframe static test. (a) To demonstrate static strength, a series of load cases representing flight maneuvers, landing, take-off and other in-flight and landing conditions (b) Test airframe was required to be mounted to ensure free-floating, non-restrained, counterbalanced conditions. (c) To achieve the self alignment of the entire airframe during the test load applications Simulated metal wheels were used in the landing gear axle, in place of actual aircraft wheels, for suspending the airframe. These simulated metal wheels have a special feature of spherical ball and socket concept, for self-alignment of the specimen. Also these simulated metal wheels have provision for attaching the instrumented reaction links in all the three directions, to monitor the reactions developed during the test. The same provision can be used for application of loads at wheel axles.