Abstract: How to increase initial velocity is an eternal subject matter for tube weapon technology. An operating principle is put forward for three-powder chamber launch device with secondary acceleration function, and the launch test is made. The characteristic of the device is that two accessory powder chambers are added on the barrel, which are at a distance from the primary powder chamber. When a projectile passes through the entrance of accessory powder chambers, the charges in the accessory powder chambers are ignited by high-heat and high-compressed power gas. The gas generated by accessory power burning can slow up the space pressure and keep the projectile base at high pressure, achieving the objective of secondary acceleration . The interior ballistic analysis and launch test result show that the initial velocity is increased by 15% in the case of indistinctively increased chamber pressure.

Key words: ordnance science and technology, secondary acceleration, three-powder chamber, accessory powder chamber, launch device, terminus effect