On 11 August 1940, 4th PG CO Maj. Zheng Shaoyu personally selected a team of five of his top fighter pilots, including ace-fighter pilot Capt. Liu Zhesheng and future-ace Lt. Gao Youxin to deploy a new weapon in an experiment to help with the dispersal of, and attacks against the massive Japanese bomber formations; multiple air burst bombs developed by combat flight instructor Yan Lei of the Central Air Force Academy at the Wujiaba Airbase. At 13:56 hours that day, 90 G3M bombers appeared in two waves, and Maj. Zheng's team, with ample preparations, maneuvered high and above the approaching bomber formation with precision flying while the Japanese aircrews observed the unusual movements of the Chinese fighters, whom soon dropped the air-burst devices that descended under parachutes, and detonating just a few hundred meters in front of the lead bombers, resulting in a breakup of the bomber formation followed by furious attacks from the Chinese fighter pilots the best they could with the handicap of the highly challenged performance and firepower of their Polikarpovs, claiming five shot down (two wrecks confirmed) and damaging many others; eight Chinese fighters suffered various degrees of damage while the wreckages of Japanese bombers were found in Shichuxian and Shuangqing with three of the seven-man crew in one of the bombers found alive and taken prisoner.