Flight experimental analysis of largemulti-propeller airtanker dropping capability

Abstract In the absence of a dropping capability experiment of domestic airtankers, it is necessary to know the actual dropping capability of fixed-wing airtankers for data support to wildfire-fighting, improving fire-fighting efficiency, and reducing the loss of forest and grassland resources. According to the design characteristics of large multi-launch propeller airtankers in China, this experiment shall collect retardant samplesof the filled flame retardant with collection equipment on the flat ground after being dropped by the airtanker in the air. Then, the sample coverage was counted and contour maps of the ground patterns were plotted to compare the dropping coefficients, dropping heights, and dropping speeds of the different dropping modes. At the last, according to the comparison result, the best dropping strategy shall be shown in different requirements. The result shows that when the coverage level is required to be GPC-6, the maximum coverage shall be obtained by all compartments released simultaneously, with a maximum coverage coefficient of 0.16. When the coverage level is required to be GPC-1, it is better to release the retardant from the tank independently with a suitable interval for larger coverage, and the maximum coverage coefficient is 4.49.