Small Postponed Mechanism for Delay-Unfolding Based on Pressure Device

A new small postponed mechanism for delay- unfolding based on pressure device is proposed, which is composed of several pistons, chambers, springs, steel balls, valve and other structural parts. The principle and working process of the postponed mechanism are expounded, and a mathematical model is proposed to characterize the performance of the mechanism. The delay time of the mechanism for unfolding is greatly affected by the radius of the vent, initial volume of chamber and initial gas pressure. The unfolding time can be delayed by 0~20 s with this kind of mechanism. The mechanism has advantages of simplicity, high reliability and recycling compared with those mechanism based on electrical system or pyrotechnic device, thus it has a good application prospect in small aircraft.