Geometric properties of parachutes using 3-D laser scanning

The technology of gliding parafoils is currently being pursued by the U.S. Army for precision airdrop of cargos and personnel. The performance of parafoils (lift and drag) and round parachutes (drag) is closely related to their 3-D geometry. There have been some studies on the geometry of round parachutes, but hardly any on parafoils. The technology of 3-D whole body scanning provides a viable tool to investigate the 3-D geometry of parachutes. In this paper, we present an investigation on the 3-D geometry, surface area and volume of small-scale models of parafoil, round parachute, ring-slot parachute, and cross parachute using a 3-D laser scanning apparatus. Scan data from these model parachutes were obtained in a climatic chamber with a steady air velocity. Surface areas and volumes of these parachutes were calculated from the scan data using specially developed mathematical methods. In addition, cross sections of the parachute canopies were obtained from the scan images. These cross sections provide valuable information on the relationship between model parachutes and full-scale parachutes, fabric properties on canopy geometry, and parachute canopy design and manufacturing.