PART 7: PARACHUTE CONSTRUCTION
The 6 foot cross parachute is constructed of two rectangular
pieces of F-111 ripstop nylon with dimensions of 2 ft by 6 ft. The white
and orange cross arms are sewn together where they overlap at the center.
The seams of the parachute are sewn with 2 rows of straight stitching using
orange type E (no. 69) nylon thread with a tensile strength of 8.5 lb. The
suspension lines are secured to the canopy skirt with 3 inch loops of 200
lb nylon tape. A 1/2 loop of nylon tape extend beyond the canopy skirt for
attaching the suspension lines. The canopy lines are tied off to the nylon
loop reinforcement at the canopy skrt. The suspension lines are made of
6 foot lengths of 80 lb dacron line tied off at each terminal end with a
loop. The 16 line loops are secured to a no. 4 rapide link that connects
the paracute to the dacron bride lines attached to the payload and rocket
booster. A 5 foot length of 400 lb dacron line attached the parachute to
the booster kevlar bridle. Notice the Y-bridle attached to the payload which
reduces wobbling characteristic from a single point attachment. Details
of the completed parachute and its attachment to the rocket are shown below.
Figure 9: Details of cross chute skirt suspension line attachment. A 7 inch
length of 3/8 inch wide 200 lb nylon tape looped over top and bottom parachute
material with a 1/2 inch loop extending beyond the skirt band. Tape is secured
with a 2-point cross stitch. Suspension lines are tied off to each skirt
loop.
Figure 10: Parachute suspension lines attached to no. 4 rapide link
and 3/16 in wide 400 lb flat finger trapped braided dacron line loop.
Figure 11: Parachute bridles attaching booster and payload to cross
parachute with 2-point Y-bridle. Bridle is made of kevlar tape and flat
braided dacron line.
Figure 12 (left): Details of modified Aerotech Astrobee D parachute recovery system.
Note kevlar bridle exiting booster tube with its protective felt sleeve.
A section of flat braided dacron line attaches the kevlar bridle to the
6 foot cross parachutes by way of two no. 4 rapide links. There are two
small u-bolt anchors at payload base attached to a 2-point Y-bridle also
connected to the cross chute. Details of the cross chute and the suspension
line nylon reinforcement tapes can be seen.
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D Rocket Project