Forest Service Parachute Development
The first parachute used by smokejumpers was a flat 30 foot hand deployed canopy with lobes of steering; a 27 foot steerable reserve chestpack completed the system. The reserve utilized two split cable pins extending downward from the handle and inserted into a pocket on the top center of the pack for quick deployment. Both parachutes were manufactured by the Eagle Parachute Company of Lancaster, Pennsylvania. In 1941, a static line deployment system was developed and added to the Eagle. This basic method of deployment has continued in use up to the present time.
America's entry into World War II created a shortage of the Eagle manufactured parachutes, and the Forest Service was forced to look elsewhere for a certain supply. Frank Derry, who had operated a parachute loft at old Mines Field (now Lost Angeles International Airport) and was formerly employed by Eagle as the West Coast distributor of their parachutes, began working to improve the canopy design in hopes that he could develop a parachute that would offer more maneuverability and directional control. Having made some of the first experimental jumps for the Forest Service as an Eagle employee, Derry drew on his knowledge and experience, and experimented until he developed two steering slots. Between 1945 and 1954, a 28 foot flat circular canopy with the seven foot "Derry slots" were used by the smokejumpers. These parachutes were manufactured by the Irvin Parachute Company. Don Whitmarsh was the person to jump the Derry slotted parachute when smokejumpers parachuted to the Paloma Mountain Fire in Idaho during the summer of 1942. Jim Waite, one of the original smokejumpers, worked with the new design through 1945, and actually developed prototypes for the FS-5A, a 32 foot parachute with ten foot slots and tails. The FS-2 was utilized by the smokejumpers until 1956 when the FS-5A was finally placed in service.
The FS-10, a 35 foot parabolic canopy was introduced by the Forest Service in 1970. Improved features included a faster forward speed (approximately 10 mph) and increased 360 degree turning speed (6-9 seconds). This parachute had the added feature of some braking capability, but opened somewhat slower than the FS-5A. Anti-inversion netting was added to the canopy in 1977 to prevent full and partial inversions which often resulted in line over malfunctions. Used through the decade of the 1970's, the FS-10 demonstrated considerable merit, but descent rates were determined to be too rapid, particularly in high temperatures and at excessive elevations. In the late 1970's, an attempt was made to modify the FS-10 canopy by Missoula Equipment Development and a private contractor, but after substituting different porosity material in the canopy and making several experimental jumps at Marana, Arizona, the effort was abandoned. Further modifications on the once used FS-5A were initiated. With input from Loft Foremen from various smokejumper bases, Frank Sanders and Jim Cyr devised a new parachute model, and it is presently being tested in the field by smokejumpers in Alaska and the lower forty-eight. Designated the XP-5, the new parachute also has the anti-inversion netting sewn to the canopy skirt, but has 32 gores and extended steering slots. As designed, it provides a faster forward speed (estimated at 13 mph), more maneuverability, a slower descent rate (because of differing porosities of material used in canopy construction), and full braking capabilities.
Chronology of Forest Service Parachutes
FS-1: 30' extended skirt main canopy packed in a T-7 main type container which had elastic cord
instead of break cord to hold the two halves of the container together and a 27' reserve in a squared off chest mounted container with long risers which snapped to high mounted D rings. It had a center pull handle with two cables. The first sixty were manufactured by Eagle. In 1942, "Derry slots" were added; they were 6 feet long and five gores apart. There was an apron over the vent of the main "to increase maneuverability." The container had a rigid plywood frame. Frank Derry filed for a patent on his slots on 17 March 1944. Derry's original Forest Service drawing P-DSIB-RI was made on 4 April 1945 and called for an alteration to the 28 foot canopy with 2 seven foot slots 7 gores apart. Between 1945 and 1954, they switched to a 28' flat circular with seven foot Derry slots, seven gores apart. These were manufactured by Irvin Parachute Company as Eagle could not keep up with demand during the war.
FS-2: Circa 1954. 28' flat circular canopy with "Derrys and Tails;' steering slots and cut out tunnels in the lower portion of the back three gores. The canopies did not have the usual row of zigzag stitching 8" above the skirt.
FS-3: A 24' flat circular reserve canopy of 1.6 oz. nylon twill fabric with quick opening bands and a puckered vent packed in a roll pack type container.
FS-3A: A 28' flat circular reserve canopy of 1.1 oz. rip stop nylon fabric with quick opening bands and a puckered vent packed in a roll pack type container.
FS-4: A 22' flat circular reserve canopy similar to the T-5, made by Irvin Parachute Company. Weight: 11 pounds. Only a few were made, and they were later replaced by a 24' model.
FS-5: A 32' flat circular main canopy of 1.1 oz. rip stop nylon with Derrys and tails. Does not have the usual zigzag stitching 8 inches above the skirt.
FS-5A: Same canopy as the FS-5, but the slots were lengthened to ten feet. Used a deployment bag and a T-10 type container. Saw considerable Forest Service use.
FS-6: A 32' conical canopy with 28 gores and Derrys and tails. Only three were made and the parachute was never placed in actual service.
FS-8: A 24' flat circular twill nylon canopy packed in a four pin container mounted on a three point release nylon harness. It was only used by spotters and cargo droppers.
FS-9: Experimental. The final model was designated the FS-10.
FS-10: A 35' parabolic canopy. The T-10 type canopy (68K147-2) was one with an elliptical TU alteration with steering toggles and a vent cap. Originally came in four colors: orange, white, sand and olive-drab. Anti-inversion netting was added to the canopy in 1978; successively reduced inversions and line over type malfunctions.
FS-10: (R): A 24 gore reserve type canopy with 20' load lines made of type 1 rip stop nylon fabric. Canvas container; chest mounted, two pin release right hand pull. Container utilized elastic pack opening bands.
FS-11: A 35' parabolic canopy (same as the FS-10) with differing porosity material used in the canopy construction. Experimental parachute that was evaluated with live jumps at Marana, Arizona, but determined to be unsatisfactory and abandoned.
XP-5: A 32 foot flat circular canopy with 32 gores, anti-inversion netting sewn to the canopy skirt and two steering orifices on each side. Parachute is modification of the previously used FS-5A incorporating three different porosities of rip-stop nylon (o-5, 20-50 and 80-120 c.f. per m.). Three colors: red, white and blue. Used with T-10 harness and FS-10R reserve. Manufactured by Switlik Parachute Company; field tested, 1980.
FS 12: The production model of the XP-5. The only major difference was in the fabric colors. Latter models were yellow, white and light blue. The H-5 harness replaced T-10 harness for use with the FS-12 & FS-12R system.
FS-12R: Is a center pull activated, manually deployed chest pack with a pilot chute. It has a steerable 26 foot conical canopy with meshed tri-vent steering systems with slit mesh outer vent. It also has soft toggles, 24 suspension lines and 24 block constructed gores with 4 or 5 sections per gore. The system uses a diaper to provide staged deployment.
FS-14: The FS-14 canopy was developed, using state-of-the-art computer aided engineering. The design is a product of Bill Gargano of Quantum Parachutes. It is a 28 gore poly-conical canopy which comes in three sizes: 32 foot, 30 foot and 28 foot. Each size is designed for jumpers of different weights. The H-5 harness & FS-14R reserve are used with the system.