Patent GB-1320223-A (GB)
Title: Parachute dployment system incorporating a rocket
IPC: B64D17/54
Filed: 1970-08-11
Abstract: 1320223 Parachute deployment system K S WARREN (Stencel Aero Eng Corp) 11 Aug 1970 38736/70 Heading B7G [Also in Division F1] A parachute deployment system includes a main parachute canopy 424, a pilot parachute canopy 464 and a rocket 300 connected between the main and pilot parachutes so that when the pilot parachute is deployed into an airstream it orients the rocket in a downstream direction, while a control means prevents aerodynamic drag forces being transmitted from the pilot canopy to the main canopy and thus prevents deployment of the main canopy, and at the same time prevents ignition of the rocket, and a release means 388 operates in response to a predetermined condition to release the control means so as to cause the rocket to be ignited and propelled in a downstream direction, thus deploying the main canopy. The pilot parachute is deployed by its pack 466, which is closed by snaps 496, being connected by a line 486 to, for example, an ejector seat (490), Figs. 4A-4C (not shown), and a second pilot parachute 474 may be provided which is deployed in the case of high-speed ejection. The control means comprises a flexible sleeve 376 connected by lines 382 and 384 to a ball 386 held by the release means, so as to be released, for example after a predetermined time interval or at a predetermined air speed, altitude or barometric pressure; the release means may alternatively comprise a wire cutter. Release of the line 384 causes lanyard 394 to be pulled taut, thereby pulling back firing pin 346 against the action of spring 370; striking member 342 is locked to the firing pin by locking balls 352, but when the pin has been drawn far enough for the balls to slip into groove 394 the striking member is released and propelled by the spring 370 so as to strike cartridge 334 and fire it to ignite propellant 304 which is expelled through nozzles 314 to propel the rocket and withdraw the main canopy 424, whose apex 422 is connected to the lanyard 394, from parachute pack 390. The ignition of the rocket may cause piston 452 to be propelled so that blade 456 severs the lanyard 448 connecting the rocket to the pilot parachute assembly. Pulling of the firing pin may also free locking balls 540, Fig. 8 (not shown) and Fig. 10, and thus free the rocket 300 from housing 532, thus releasing further locking balls 554 and allowing annular disc 546 to slide away (Fig. 9, not shown) from a flange 542 on the housing 532, thereby releasing the pilot parachute, whose suspension lines 558 are connected to pins 544 extending from the flange 542 into holes (556) in the disc 546. The rocket 300 may be located in a sleeve 562, Fig. 10, extending from the apex of pilot canopy 560, and firing lanyard 566 be maintained slack by a tie cord 570; the tie cord withstands the force necessary to pull the firing pin, but breaks on firing of the rocket. The firing pin is held by end cap 514 and the length of the lanyard 566 is such that the main canopy is only extracted from its pack after the rocket is clear of the pilot canopy (Fig. 11, not shown). The main canopy 424 may be spread by a ballistic spreading gun 502 operated by a centre line 504, and a line cutter (not shown) may be provided to sever the rocket from the main canopy. The main canopy may be provided with a deployment sleeve 510, see Fig. 6C, with the centre line 504 connected by means of a shear link 516 to the rocket. On deployment the line 504 pulls taut, shears the link and operates the spreading gun 502. The sleeve ensures that, since the mouth is free to inflate while the apex is confined, the canopy is inflated gradually. Alternatively, Fig. 7 (not shown), instead of lanyard (520) being connected to the apex of the main canopy it is connected to a series of tapes (524) connected to the canopy between the apex and the hem, so that instead of being extracted as an elongated mass the canopy is in a configuration whence it can be readily inflated by the action of the spreading gun 502. An internal drogue parachute 430, Fig. 3, may be used as an alternative to the pilot chute 464 and the rocket, for example in the case of an overside bail-out. The suspension lines of the drogue parachute are connected to the apex of the main canopy by a strip of webbing 416 connected by clamping wires 418 to the body of an override disconnect assembly 400 which comprises two interlocking pins 402 and 404 connected respectively to the lanyard 394 and to the webbing 416. If the drogue parachute is deployed the strip 416 is drawn taut, thus stripping away the body of the assembly 400 to release the rocket and pilot parachute assembly. Alternatively, Fig. 16, the override disconnect assembly may comprise a housing 590 connected to the apex of the main canopy by webbing 616 and having bores 602 each carrying a pair of interlocking pins connected to the rocket and to the drogue parachute by lines 608 and 610 respectively. The pins are also connected together by a spring-loaded pivoted arm 594. Deployment of the drogue parachute will cause a pull on line 610 which will pull the pins connected to the rocket so that their interface is free of the bore and the rocket and attached pilot parachute assembly is released; likewise deployment of the pilot parachute will cause the drogue parachute to be jettisoned. Alternatively, Fig. 17, lines 630 and 632, respectively from the rocket and the drogue chute may be looped around corners of a spring-loaded triangular member 622 in a housing 620 connected by webbing 644 to the apex of the main canopy. As before, deployment of either the pilot or drogue parachute will cause the other to be released. The nozzles 314 may be formed from material which erodes as the propellant burns. It is stated that with such nozzles a longer constant thrust is obtained than with non-eroding nozzles.