Notes on a Parachute Opening Force Analysis Applied to a Vertical Toward-the-Earth Trajectory
Final rept. 1986-1987
NAVAL SURFACE WEAPONS CENTER SILVER SPRING MD
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Recovery of payloads from high altitude often requires the deployment of parachutes on trajectories that are essentially vertical and toward the earth. The parachute opening shock force developed by a parachute deployed in this manner exceeds the opening shock force of the same parachute system deployed horizontally at the same altitude and velocity. As the deployment trajectory angle varies from horizontal to vertical, the opening shock force increased to a maximum. Hence, the vertical trajectory has special significance. This report develops an analysis to permit the calculation of opening shock forces in vertical deployment. The validity of the rule of thumb that the vertical deployment opening shock force exceeds the horizontal shock force by one g is tested, and criteria are developed. Examples are used to demonstrate applications of the approach, and a method of calculating the inflation time of Solid Cloth parachutes in vertical fall developed. Keywords Vertical inflation time Limiting ballistic mass ratio.
- Gliders and Parachutes
- Couplers, Fasteners and Joints