US Parachute

U.S. ARMY PARACHUTES
In 1940, the Army Air corps Pilots were using the T-4, which consisted of 28 foot canopy and was opened by a static line. It was designed with the three (3) snap hooks, fastened to the harness, and a large square backpack containing the canopy and suspension lines. The reserve was a large chest pack hooked to the front of the harness with snap hooks. The suspension lines came out of the top of the pack and ran to the D-rings of the main harness where they joined to it; the handle was on the right, note the snap hooks makes it either a T-4 or T-5 Parachute. The T-5 assembly consisted of a 28-foot canopy with as many panels, each panel being made up of four panel sections.
The top/center of canopy that was known as the apex contained an eighteen-inch diameter hole to let the surplus air escape and keep the parachute from oscillating. There were twenty eight suspension lines, each about twenty two feet long that ran from the canopy to the four cotton web risers. There were seven each attached to the risers by metal rings called connector links. The risers were actually the ends of the harness that were constructed in such a way as to loop around the body, pass through the crotch and back up to the shoulders again. The harness also had a belly-band that held the smaller reserve parachute in front of the trooper and the wide part that fitted the seat was called the "saddle." There was a canvas covered rectangular wire frame on the back, in which the canopy, suspension lines and part of the risers were stored that was called the pack tray. A fifteen foot static line, attached from a cover on the back tray to a cable inside the airplane, ripped the pack cover off as the trooper jumped free of the plane, pulling out the contents of the pack tray. The prop blast would blow the parachute open and snap the break cord tied between the static line and the apex of the canopy. The opening time for the parachute was approximately three (3) seconds which permitted low level jumps in mass formation. The T-7 parachute replaced the T-5 parachute, which was also designed to be a static line parachute. The T-7 demonstrated an improved reliability in opening. It had a three-point harness, using snap hooks one for each leg and one that locked the left and right webbing of the harness near the chest. It had a wide canvas waistband to hold the pack close to the back. The canopy was retained in the pack by a canvas lid, which was held fastened to the outer cover by a breakable line running around the flaps. The lid was firmly sewn to the static line and the apex of the canopy was tied to it with a breakable line, known as the break cord. The static line was stowed outside the pack and held in place by canvas retainers. On extension the static line pulled the canopy clear off the pack by breaking the retaining lines around the pack. On a windy drop zone, the T-7 could be difficult to get out of and would drag the trooper unless he could run ahead of the chute and spill the air from the canopy. It did not have the shoulder release of the later T-10 and required three snap hooks to be undone before the jumper was free. This was not easy to do when being dragged at high wind speeds on rough ground. The T-7 was the standard American parachute and was modified to take a single release box. The single release box was a device that released the harness that came from the rear of the harness under the legs and up into three locks on the metal box. A quarter to a half turn, and then hitting the top of the release mechanism would free a jumper from the harness. A safety fork fit under the quick release box that insured your not releasing prematurely. The quick release was preferred if the trooper was liable to drift into a body of water. (Note) Another big difference in the T-7 and the T-10 was, the T-10 was packed in a sleeve, which allowed you to fall below the prop blast before your chute opened. With the T-7 the canopy came out first and the risers last; with the T-10 the risers came out first and the canopy last. Finally, whether it was the T-5, T-7 or T-10, a chute was used it was always a comfort to receive the "opening shock" you were in a chute that opened. The "opening shock" was worth the riser burns.