Research on laboratory testing and evaluation methods for aircraft windshield wiper systems

A laboratory test method for aircraft windshield wiper system based on high speed blowing-rain environment simulation and a semi-quantitative subjective evaluation method for rain removal visual performance are proposed for aircraft windshield wiper system testing. Analyzing CCAR25.773 and related standards and advisory circulars, it is concluded that the two key factors for simulating rainy environments are rainfall intensity and wind speed. The range of rainfall intensity values is (10~25) mm/h, and the range of wind speed values is (40~120) m/s. The definition and calculation method of equivalent blowing-rain intensity are provided. A high-speed rain environment simulation device has been built, which can simultaneously simulate the rain intensity received by the windshield during aircraft rainy flight, as well as the relative velocity between the windshield and free flow and raindrops. A subjective evaluation method for the visual performance of windshield rain removal based on visual evaluation reference objects was proposed. A rain blowing test was conducted on the windshield wiper system of a certain aircraft, and the test results showed a statistically significant difference between the rain blowing environmental conditions and the rain removal characteristics at a significance level of 0.05. Engineering practice has shown that this method is feasible.