Patent Application
20070007021
The present invention relates to ordnance which is dropped by an aircraft over a forest first. The ordnance is comprised of a plurality of individual submunitions; each submunition is designed to detonate at a preset altitude and geographical position over the forest first. The detonation of each submunition acts to snuff out the available oxygen supply to the fire and disperse a volume of fire retardant over the target-zone.
The term “smart bomb” will be used to define a specific type of ordnance which may be equipped with a special inertial guidance system such as a laser, radar, or Global Positioning System (GPS). The inertial guidance system allows the ordnance to select the precise latitudinal and longitudinal coordinates over the target zone The ordnance is comprised of a plurality of submunitions, each of which is comprised of an altimeter actuated fuse which is triggered to detonate based on the elevation of the submunition above ground zero.
The term “retardant” is defined under a broad construction to include a family of chemicals which are used as effective agents in extinguishing a fire. Preferably, the fire retardant is also biodegradable. The United States Department of Agriculture (USDA) Forest Service uses a thermo gel or other polymers that are water enhancers for Class A fires. For example, a product sold under the commercial product name of Mirex is a common product used by the USDA. Mirex is biodegradable which makes it appropriate for a forest fire application. However, the methods and apparatus of the present invention contemplate the use of any fire retardants that may be used as effective fire extinguishing agents for extinguishing a forest fire.
The term “target zone” is defined as the geographical region of the burning forest which is targeted to be extinguished by the ordnance. As mentioned, the ordnance acts to spread a blanket of fire retardant over this target zone upon detonation of the submunitions at a pre-set elevation above the drop-zone.
The term “ground zero” is defined as a reference point relative to the altitude of the submunition. The term “ground zero” will be defined as having a zero elevation relative to the ground level. Typically, the ground zero will change frequently as an aircraft is flown over hilly terrain. The term “altitude” of the submunition is defined as the elevation of the submunition relative to ground zero. The altitude is a key parameter for the detonation of the submunition which is controlled by the fuze of the detonator of the present invention.
Dropping fire retardant from relatively low altitudes by flying aircraft close to the earth, which may be typically less than a few hundred feet, is an extremely dangerous activity. During a forest fire, the aircraft is vulnerable to terrain, strong thermal updrafts and turbulence, and aerodynamic stresses due to diving and climbing. As a result, many aircraft have disintegrated and crashed under these conditions. Clearly, what is required in the Art is a smart bomb which may be released from a safe altitude above a fire zone that is capable of achieving the desired denotation altitude and predetermined spatial positioning above the forest fire.
Prior Art:
The Boeing Company developed the JDAM (Joint Directed Attack Munition) as a relatively low cost, retrofittable guidance mechanism for a bomb. The JDAM's primary advantage over previous methods is the fact that it can be dropped from up to 45,000 feet with little loss of accuracy, even in difficult weather conditions, so the risk to planes and pilots is minimal. The JDAM maybe modified to deliver a quantity of fire retardant.
Delivery Method of Fire Retardant:
The JDAM usually uses an “airburst” method over the target. The airburst creates a random, unpredictable dispersal of retardant over the target. The primary disadvantage of this method is the dispersal of retardant is relatively non-uniform and unpredictable.
Expired U.S. Pat. No. 3,951,068 issued Apr. 20th, 1976 and assigned to the Dow Corning Corporation discloses an incendiary device such as artillery round, rocket warhead, bomb, or grenade in which a high explosive charge within a casing has imbedded therein a plurality of balls of incendiary material. The incendiary material is a mixture of silicone rubber, powdered magnesium, and an oxidizing agent. The balls are ignited by detonation of the high explosive and are designed to continue burning during dispersion caused by the detonation.
The '068 patent discloses the use of a plurality of smaller submunitions or “balls” for delivering a volume of fire retardant to the fire zone. However, the '068 patent is distinguishable from the methods and apparatus of the present invention because the detonation of the balls occurs as a group or cluster and as a result of detonation of the incendiary device, a random and unpredictable distribution of fire retardant occurs over the target zone.
It is respectfully submitted that the methods and apparatus of the '068 patent do not provide the necessary dispersion and control techniques desired for modern day fire fighting. The methods and apparatus of the present invention provide a means for controlling both the volume of fire retardant to the target zone and the location of the fire retardant over the target zone by providing a plurality of submunitions, each of which contains an individual detonation device. The detonation device for each individual submunition may be pre-set to detonate at the same or a different elevation than the sister submunitions of the cluster.
The methods and apparatus of the present invention provide many advantages over the prior art by providing a means for delivering and detonating each individual submunition at the precise elevation and geographical position. As will be apparent to one skilled in the Art, the methods and apparatus of the present invention provide many degrees of freedom of accuracy over prior art methods by delivering and controlling the dispersal of fire retardant over a fire-zone.
In accordance with the present invention, an ordnance is disclosed for extinguishing a forest fire which is comprised of a dispenser for carrying and delivering a plurality of submunitions to a exit position on the dispenser, a door way on the dispenser for providing an exit position for dispersal of a plurality of submunitions from the dispenser, and a plurality of submunitions, each submunition carrying a detonation device, and a volume of retardant; wherein the detonation device in response to a signal from a sensor on the submunition triggers the explosive to detonate the submunition thereby dispersing a volume of fire retardant over the target zone.
In accordance with another aspect of the present invention, a method is disclosed for extinguishing a forest fire which is comprised of the steps of carrying and delivering a plurality of submunitions to an exit position on a dispenser, dispensing a plurality of submunitions from the exit position on the dispenser, each submunition carrying a detonation device, and a volume of retardant; wherein the detonation device in response to a signal from a sensor on the submunition triggers the explosive to detonate the submunition thereby dispersing a volume of fire retardant over the target zone.
In accordance with yet another aspect of the present invention, a specialized submunition is disclosed for extinguishing a forest fire. A plurality of submunitions may be carried and delivered to the target zone by a dispenser, a missile, a rocket, or a projectile and detonated over the target zone by a detonation device which is triggered to detonate by a sensor on each submunition. Detonation of each submunition by the detonation device disperses a volume of fire retardant over the target zone.
a shows an outer view of the submunition 10 with a quadrant of the submunition removed to show the inner housing 15;
b shows an outer view of the submuntion 10 illustrating the outer housing of the submunition;
a-6c illustrates several embodiments of the dropped dispenser, according to a first preferred embodiment of the present invention;
a-7c illustrates several embodiments of the attached dispenser, according to a second preferred embodiment of the present invention;
Referring to
In accordance with the present invention, a submunition 10 is shown. Typically, each submunition 10 is spherical in geometry since each dispenser is comprised of any number of submunitions and the nature of this geometry allows a payload of submunitions to be efficiently packed into the dispenser which is typically rectangular in cross-section.
Alternatively, the dispenser 5 and the submunitions 10 may be one unit. For this case, the dispenser 5 is detonated with the submunition. In the preferred embodiment, the dispenser 5 may release the payload of submunitions 10 and remain attached to the aircraft. Alternatively, the dispenser may be released from the aircraft with the payload of submunitions, and the dispenser may release the payload of submunitions and be retrieved post-detonation of the submunitions.
The preferred embodiment of the present invention reduces the overall capital cost of fire management for a given fire zone and will be described herein.
Submunitions:
Referring to
Each submunition is further comprised of a third containment portion 15 which carries a volume of retardant 54 for dispersal over the fire zone during detonation. The spatial positioning of the falling submunition is coordinated by use of a fin assembly 26. The fin assembly 26 assists the submunition to fall in such a fashion that the third containment portion 15 falls closest to earth as the submunition is dropped through the atmosphere. In this way, detonation of the explosive by the detonation device 28 results in a fragmentation of the outer wall 56 thereby dispersing a volume of fire retardant 54 over the target zone.
Referring to
The scope of the invention contemplates that the submunitions may be spread by dispensers (as described herein), missles, rockets, or projectiles. Each of these delivery systems dispersers its payload of submunitions while still in flight, and the submunitions drop over the target.
Referring to
Dispensers:
Referring to
The doorway 22 maybe located anywhere on the vessel 21. Preferably, the doorway 22 is triggered to be opened by a proximity fusing subsequent to release of the dispenser 10 from the aircraft. The fusing allows the payload to be dispersed at a predetermined height above the target. Proximity fusing is actuated by detecting an acceleration force as the missle approaches towards the earth. Arming of the fuze is usually delayed until the fuze is subjected to a given level of accelerating force for a specified amount of time.
The location of the doorway 22 may be located anywhere on the sidewall 23 of the vessel 21. Preferably, the location of the doorway 22 will be selected to optimize the preferred distribution of the payload of submunitions 10 above the target.
In a first embodiment, the dispenser is a dropped dispenser 20 (see
The invention contemplates that the dropped dispensers may be in one piece or in multiple pieces. The dropped dispensers may use either mechanical time or proximity fusing. Both of these fuses allow the payload to be dispersed at a predetermined height above the target. Multiple-piece dispensers open up and disperse their payload when the fuse is actuated. Single-piece dispensers eject their payload out of ports or holes in the body when the fuse is actuated.
In a second embodiment, the dispenser is an attached dispenser 30 (see
It will be apparent to one skilled in the Art, that the invention contemplates any type of dispenser—attached, dropped, or otherwise. What is important is the ability to carry a plurality of submunitions to a target zone and dispense the payload in a uniform and efficient manner.
Fuse Assembly:
Each submunition 10 is detonated by the action of the fuze 25. The fuse 25 triggers the detonation of an explosive charge 27 at the precise time after certain key parameters are met.
The invention contemplates that the fuze 25 may be a proximity fuze or a contact fuze.
A proximity fuse is intended to detonate each submunition upon approach to the target zone and more specifically, typically along the flight path of the submunition. The scope of the invention contemplates various methods of obtaining a proximity operation against a target zone: electrostatic, acoustic, optical, and radio fuses.
A contact fuze is intended to detonate each submunition based on the force of impact with ground zero. The force of impact closes a firing switch (not shown) within the fuze to complete the firing circuit thereby detonating the warhead.
The acceleration forces which result upon launching the missle from the aircraft arm both types of fuzes.
In accordance with a preferred aspect of the present invention, the fuze 25 is an optical or photoelectric type. The photoelectric method provides a relatively easy approach to providing proximity fuzing. Typically, the photoelectric method is limited to daytime use, unless light sources are available. However, the term “fuze” should be construed under a broad construction to contemplate any type of fuzing which function with the Safety & Arm (S&A) device, and Thyractron to detonate the submuntion.
Optical Doppler-Type Fuze:
Referring to
The interference created between both waves results in a low-frequency input signal 28 which is transferred to a transmitter (not shown). The input signal is used to trigger an electronic switch, which is typically a trigger device on the detonator. Typically, the input signal 28 requires amplification by an amplifier 44. The amplifier 44 creates an output signal 29 which is used to actuate the trigger device 33.
Trigger Device:
Operation of the fuze 22 occurs when the output signal 29 is received from the amplifier. The output signal 29 is received by the trigger device 33. The amplitude of the output signal 29 must exceed a required threshold voltage (TV) to fire the trigger device 33. Preferably, the trigger device 33 contemplated by the invention is commercially available under the brand name Thyractron.
Operation of the Trigger Device:
For a given orientation of the fuze and target, the amplitude of the output signal 29 produced by the amplifier (not shown) is a function of the distance (d) between the target and the fuze. Hence, by the use of proper settings for the gain of the amplifier and the holding bias of the Thyratron, the distance (d) of the operation may be controlled.
It will be apparent to one skilled in the art that the distance (d) that the fuze detonates from the ground may not be the only parameter which may be controlled by the fuzing device. Orientation or the aspect (θ) of the submunition is another aspect that may be controlled since operation should occur at that point on the trajectory of the submunition when the greatest number of fragments will be directed towards the target zone.
Referring to
For example, in the case of the smart bomb assembly, the detonation of the fuse may be triggered by any, all or a combination of these spatial parameters: (x, y, z, θ) of the dispenser or submunition relative to the origin—surface of the earth. Preferably, the aspect (θ) and altitude (z) of the submunition may be used as detonation parameter for controlling the triggering of the fuze.
Referring to
In a preferred aspect of the present invention, the fuze 25 is further comprised of a Safing and Arming (S&A) device 40. The S&A device 40 is a component of the fuze 25 that isolates the detonation device from the explosive 50 during all phases of the submunition logistic and operational chain until the submunition has been released or launched from the dispenser.
To maximize the safety and reliability of the fuze, the S&A device must ensure that the forces it senses will be unique to the submunition, and cannot be intentionally or accidentally duplicated during ground handling or prelaunch operation. Typically, the S&A device are located between the sensor and the triggering device. The S&A device receive the arming signal 29 from the sensor 22 and determine whether key parameters have been met. Once an arming signal 29 has been sent by the S&A device 40 to the Thyractron 33, a detonation signal 31 is sent by the Thyractron to the explosive 54 triggering the explosive to detonate.
The Explosive
Referring to
Preferably, the outer wall 56 of the third containment portion 15 is stabilized towards the target zone such that upon detonation of the submunition, the retardant 54 and bomb fragments explode orthogonally to the surface of the earth thereby maximizing the dispersion of retardant and bomb fragments over the target zone.
