Investigations Into Glider Chassis Load Spectrum

The paper describes investigations on load spectrum of a glider chassis during take-off and landing. The experiments were conducted on different kinds of airfield surfaces, and recorded time-courses of loads acting on the main and front gear were used for analysis. The paper shortly describes the tests carried out on a PW-6 glider (description of the measurement system installed on the glider main and front landing gear). There is included a comparison of different methods used for time-courses analysis and full cycle counting. The following methods were used: local extremes count method, level exceeds count method, full cycles count method, rainflow count method, and a method developed by the first author. The outputs generated by application of the above mentioned methods for different test-time-courses of load, and the real time-courses of load observed during take-off and landing, are described. Paper presents also load spectrum for the main gear for take-off and landing on a grassy runway. This load spectrum were used later on an experimental stand, build by the authors for fatigue tests of special shock-absorbing element, made from GFRP composite for a new glider.