Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B64—AIRCRAFT; AVIATION; COSMONAUTICS
  • B64C—AEROPLANES; HELICOPTERS
  • B64C1/00—Fuselages; Constructional features common to fuselages, wings, stabilising surfaces or the like
  • B64C1/14—Windows; Doors; Hatch covers or access panels; Surrounding frame structures; Canopies; Windscreens accessories therefor, e.g. pressure sensors, water deflectors, hinges, seals, handles, latches, windscreen wipers
  • B64C1/1476—Canopies; Windscreens or similar transparent elements
  • B64C1/1492—Structure and mounting of the transparent elements in the window or windscreen
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B64—AIRCRAFT; AVIATION; COSMONAUTICS
  • B64C—AEROPLANES; HELICOPTERS
  • B64C1/00—Fuselages; Constructional features common to fuselages, wings, stabilising surfaces or the like
  • B64C1/32—Severable or jettisonable parts of fuselage facilitating emergency escape
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F42—AMMUNITION; BLASTING
  • F42B—EXPLOSIVE CHARGES, e.g. FOR BLASTING, FIREWORKS, AMMUNITION
  • F42B1/00—Explosive charges characterised by form or shape but not dependent on shape of container
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F42—AMMUNITION; BLASTING
  • F42D—BLASTING
  • F42D3/00—Particular applications of blasting techniques

Definitions

• the present disclosure relates to a pyrotechnic egress system, and more particularly to systems which facilitate emergency egress from an aircraft.
• Pyrotechnic egress systems explosively sever materials such as aircraft canopy transparencies, egress panels, and other structural members. Operation of this type of system may communicate at least some energy inwards toward the crew in the form of a pressure wave. Furthermore, in aircraft which operate in a maritime environment, the pressure wave may be magnified in an underwater egress situation.
• a pyrotechnic egress system includes an air encapsulation member which at least partially surrounds a charge holder which contains an explosive cord.
• An explosively severable structure includes an explosive cord bonded to a structure.
• a charge holder which at least partially surrounds the explosive chord.
• An air encapsulation member which at least partially surrounds the charge holder.
• a method of reducing peak pressure and impulse intensity of a pyrotechnic egress system includes at least partially surrounding an explosive cord with an air encapsulation member.
• Figure 1 is a general perspective view of an exemplary rotary wing aircraft embodiment depicting the location of various emergency egress exits;
• Figure 2 depicts an isolated perspective view of a pyrotechnic egress system
• Figure 3 is a sectional view of the pyrotechnic egress system
• Figure 4 is a graphical representation of a Pressure and Impulse
• Figure 5 is a graphical representation of a Pressure and Impulse Measurements from operation of the pyrotechnic egress system Superimposed on Human Injury PI Curves;
• Figure 6 is a sectional view of another embodiment of a pyrotechnic egress system.
• Figure 7 is a sectional view of another embodiment of a pyrotechnic egress system.
• Figure 1 schematically illustrates an exemplary vertical takeoff and landing
• the aircraft 10 includes an airframe 14 having an extending tail 16 which mounts an anti-torque system 18.
• an airframe 14 having an extending tail 16 which mounts an anti-torque system 18.
• the aircraft 10 includes at least one explosively severable structure 20 which are appropriately sized to facilitate rapid egress of passengers/crewmembers in the event of an emergency situation.
• the explosively severable structure 20, in one non-limiting embodiment, may be a cockpit window 22 adjacent an aircraft cockpit 24 and a cabin window 26 adjacent an aircraft cabin 28.
• the explosively severable structure 20 is illustrated in an isolated perspective from within the aircraft.
• the window 22, 26 generally includes a transparency 30 bordered and supported by a panel frame 32.
• the transparency 30 may be manufactured from, for example, polycarbonate, polycarbonate laminate, acrylic or acrylic/polycarbonate laminates.
• a pyrotechnic egress system 40 is located about the periphery of the transparency 30 to essentially separate the transparency from the panel frame 32. It should be understood that the pyrotechnic egress system 40 need not be limited to only a transparency and may be utilized to sever other structures to thereby provide an egress exit therethrough.
• the pyrotechnic egress system 40 may be activated through an initiator 42 which is activated from outside the aircraft 10 by pulling a handle 44.
• the pyrotechnic egress system 40 may also be activated from within the aircraft 10 by pulling a handle 48.
• the initiator 42 may include boost charges to fire the pyrotechnic egress system 40. It should be understood that although manual activation through pulling of handle 44 or 48 is typical, other activation systems may alternatively or additionally be utilized.
• the pyrotechnic egress system 40 generally includes an explosive cord 50, a charge holder 52 which at least partially surrounds the explosive chord 50 and an air encapsulation member 54 which at least partially surrounds the charge holder 52.
• the explosive cord 50 may include a linear explosive such as, for example, Jetcord®, X-Cord®, Shielded Mild Detonating Cord, TLX®, ITLX® as well as other linear ignition systems.
• the explosive cord 50 may be bonded directly to the transparency 30 to define a desired egress exit.
• the charge holder 52 may include a "U" shaped silicone rubber extrusion that encases the explosive cord 50. The open side of the "U" is directed toward the transparency 30.
• the charge holder 52 encases and is bonded along the length of the explosive cord 50.
• the charge holder 52 may also be bonded directly to the transparency 30.
• the air encapsulation member 54 may include closed-cell foam such as Styrofoam.
• the Styrofoam is blue expanded polystyrene manufactured by The Dow Chemical Company of Midland, MI USA.
• the closed-cell foam contains air which is approximately 10,000 times more compressible and approximately 800 times less dense than water which attenuates the peak pressure wave. Results of the coupon testing indicate that the application of closed-cell foam over the explosive cord 50 significantly reduced peak pressure and impulse intensity levels ( Figure 4).
• the pyrotechnic egress system 40 utilizes the air encapsulation member 54 to reduce peak pressure and impulse intensity to a level which is considered safe for aircrew and passengers when the pyrotechnic egress assembly is activated in a submerged underwater egress situation.
• the pyrotechnic egress system 40 thereby facilitates aircraft operations in a maritime environment.
• FIG. 6 another embodiment of the pyrotechnic egress system
• 4OA uses an air encapsulation member 54A with a rectilinear cross-sectional shape. It should be understood that various cross-sectional shapes may alternatively or additionally be utilized.
• FIG. 7 another embodiment of the pyrotechnic egress system 4OB uses an air encapsulation member 54B which is at least partially surrounded by a shield 60.
• the shield 60 may be mounted to the panel frame 32 through a fastener 62.
• the shield 60 operates primarily to protect the air encapsulation member 54B which may otherwise be exposed to potential damage from within the aircraft cockpit 24 and aircraft cabin 28.
• the shield 60 further operates to retain the air encapsulation member 54B and explosive cord 50 adjacent to the transparency 30 - yet provide a smooth and essentially snag- free boundary about the perimeter thereof.

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• Engineering & Computer Science (AREA)
• General Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Aviation & Aerospace Engineering (AREA)
• Air Bags (AREA)

Applications Claiming Priority (1)

Publications (2)

Family

ID=42073734

Family Applications (1)

Country Status (3)

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• 2008
  • 2008-09-30 WO PCT/US2008/078241 patent/WO2010039119A1/en not_active Ceased
  • 2008-09-30 EP EP08877199.3A patent/EP2340201A4/de not_active Withdrawn
  • 2008-09-30 US US13/063,980 patent/US20110167994A1/en not_active Abandoned

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