Nomenclature

This paper presents a derivation of the opening shock factor (Ck) and inflation duration (tfill) that characterize the inflation of slider-reefed parafoils. The results apply to large-mass ratio systems, such as personnel parachutes, that inflate along a downward vertical trajectory and experience maximum drag (Fmax) during slider-descent. The derivation of Ck is based on a formulas derived from the well-validated inflation computer model discussed in another paper presented at this conference (see paper 2007-2501). The formula for tfill is obtained by merging this result with a general expression for Ck, obtained from the Momentum-Impulse theorem in which the inflation time is a crucial input. These derivations are followed by an altitude-scaling study of the maximum deceleration (and force) sustained by the system. The importance of the duration and characteristics of the “slider-up ” phase in determining overall inflation performance is also examined