Patent Application
20160325127
The following is a tabulation of some prior art that presently appears relevant:
This invention relates generally to manned and unmanned fixed wing aircraft and rotorcraft systems that can perform multiple tasks using interchangeable modular subsystem equipment. A few of these tasks are (a) wildfire suppression, either by laser backfire setting or the more conventional water-chemical drop or spray (b) fire suppression of high rise buildings or other structures by chemical spraying, (c) agriculture use, including crop fertilizing, disinfecting, or watering, and (d) remote cleaning of power lines and associated equipment, of buildings, of windmills, or other items. This multipurpose capability allows year-long aircraft utility rather than just single use fire suppression.
Certain multiple use manned aircraft and helicopter firefighting capability has been developed in prior art as will be outlined here. (See Refs. 1-3, 11) We also include here the recently developed manned and unmanned autonomous aircraft and helicopters (Refs. 4-6). Additionally, we also add herein the important capability and methodology to use modular insertable laser systems for enabling aircraft for rapid, precise, operator safe setting of backfires for the early containment of a developing wildfire as well as for other opportunistic laser system uses.
Fighting fires using backfire technology has been developed over many years (Refs. 1-2). It was first based upon short-range manual fire-setting means such as use of torches, hot or explosive projectiles, and the dripping of burning chemicals, such as a mix of kerosene and gasoline, from hand-held canisters. Of course these manual methods expose the fire fighters to possible flare-ups of the main conflagration and falling trees. It also is limited to accessible, man-negotiable forest areas. Additionally, this process is very slow both in setup, requiring flying in to drop in operators to the desired backfire region, and then in the “hot-shots” manual fire-setting execution.
To improve on this manual backfire approach, helicopter approaches were developed (Refs. 2-4). In these, the helicopter holds a torch or a dispenser of a flaming chemical on a cable which is maintained slightly above the ground. While this removes the man-on-the-ground safety issue, now the crew is at risk since the helicopter must fly relatively close to the ground in order to minimize the sway of the cable to allow some precision in the setting of the backfire line. This issue is exasperated because of the upwelling winds that are produced by a large fire and its smoke that may obscure vision. In addition, the helicopter is restricted to certain airspace, away from power lines, hills, and other aircraft, and therefore its backfire cannot always be placed in the desired location. And finally, the rate of setting this backfire by the torch or dribbled incandescent chemical means is very slow, thus allowing time for the fire to spread before efficacious backfire suppression.
Herein we will show that a craft equipped with a properly configured laser system can obviate many of these shortcomings. We begin by showing three military airborne laser systems (Refs. 7-9), Airborne Laser Laboratory, Airborne Laser Testbed and Advanced Tactical Laser that have already shown how such an airborne laser system can propagate its beam over large distances to precisely position the beam to deposit its energy on a succession of target aimpoints. But those military systems are not suitable for the needed firefighting service since they use large, heavy, low efficiency chemical lasers which are very difficult to service in the field and also which provide much higher laser beam power than needed.
In the applications discussed herein the range and power requirements are much lower than these prior demonstrated laser systems. This allows the use of much smaller and lower weight, laser systems rather than heavy chemical lasers. Although the lower power lasers provide shorter range backfire starting capability, even with an easily achievable range capability of up to a kilometer the craft will be out of harm's way. It also will have an excellent field of view to see the conflagration and chose the optimal backfire path to quickly set. We estimate that the times to set the foliage afire will be at least ten times faster than by the state of art burning drip means. The will allow both backfire of treetops as well as ground fire to be easily set. David Leigh and Zrika Arni (Ref. 10) have claimed that treetop backfires may be a better method than ground backfires. Herein we provide the laser system design approaches that would allow fulfillment of their speculation. Such capability is only assumed in their referenced work without consideration of the many requirements and design issues required for operational firefighting capable laser airborne systems as we consider herein.
In particular, the state-of-art laser system designs we will consider will be based upon the use of the electrically-driven, lightweight RELI (Robust Electric Laser Initiative)-class lasers (Ref. 13). Other electric-driven laser types, and perhaps others, would also suffice if they provide the desirable characteristics of the RELI class lasers. The lighter RELI weight, higher efficiency, better beam quality, and robustness for reliable operation in a severe environment, like that encountered by a fire-fighting helicopter, offer a more tolerant capability for the variety of helicopter lift capabilities that might be used for the multipurpose applications we desire.
In accordance with one embodiment, an air vehicle (manned or unmanned aircraft, helicopter, or lighter-than-air ship) equipped with a moderately high power laser system module, said module configured to allow quick insertion or replacement into the craft, that has a means of controlled beam pointing and tracking, is equipped with an infrared or other imaging system to allow observation in darkness or even through smoke of the nearby fire or of the laser beam target interaction, will provide a safe range and rapidly implementable means to set backfires to more quickly contain conflagrations. In addition, there are other uses of such laser beams beyond firefighting. These include setting controlled burns and cleaning of dust from high tension equipment. And, because of the designed-in laser module insertion/removal capability, the air vehicle will additionally be capable of other than backfire setting. Replacement of the laser module with a state-of-art water or chemical holding tank would allow the aircraft to perform that conventional mode of firefighting. Of course it would also enable agriculture fertilizing or chemical pest control spraying.
Their modular exchange capability would allow these aircraft to carry out these and many other tasks throughout the year even outside the usually short 3-4 month fire season. This would enhance the modules' financial benefit.
Advantage The details of one or more embodiments of the invention are set forth in certain of the accompanying drawings and their description below. Other features, objects, and advantages of the invention will be apparent from the description and drawings, and from the claims.
In these, closely related figures have the same number but different alphabetic suffixes.
One embodiment of the invention is illustrated in
In the embodiment discussed here, 34 is the typical laser system (LS) module which will be more fully discussed below in
Exiting the BCA, the laser beam encounters 78, the first of three successive Coude′ mirrors 78, 80, and 82. Then it is deflected by the YAW mirror 64 to hit the Half-Angle mirror 66. This series of five mirrors accomplishes an important task, namely to keep the forward moving laser beam aligned with the turret axis, from whence it began, to now as it leaves mirror 66, even as the turret assembly 42 is rotated about its axis using the rotational bearing assembly 70. This turret rotation is the azimuthal angle, indicated as AZ in
Another aspect of the telescope is its ability to expand the beam's diameter and to focus that expanded beam onto the distant target. It is an important design trade to choose as large of a diameter as is consistent with allowed telescope weight and volume in the laser system module since it's diameter size sets the laser beam's smallest focal spot size at the target. Then, as the beam reflects from 66, the half-angle mirror, it strikes the secondary mirror, 62. This convex mirror reflects the beam into an expanding beam that just fills the primary mirror 60. The primary is a concave focusing mirror. As the secondary mirror's axial distance between it and the primary mirror is changed under control of the secondary, the telescope's focal length is adjustable. This allows the real-time controller, either manually or under computer control, to focus the beam for maximum backfire setting effect on the target.
Moving now to
Nominal beam pointing control is provided through the unit 54, the Real-Time Fire Control Assembly. This electronic computer assembly uses pointing techniques that have matured mostly under military technology development. In the ALL and ATL laser aircraft, “joy stick” beam pointing control was developed and successfully used. In the ABL program we perfected the technique for computer controlled autonomous target acquisition and tracking. In the present embodiment, both Joy Stick and pre-planned computer autonomous track setting and GPS-assisted execution will be provided.
The Tracking & Imaging Subassembly 56 provides imaging of the terrain and foliage in which the backfire is being set. Techniques for tracking the hot spot's path are similar to those we have developed for laser weapon systems. Frequently 56 and 32 work together in this regard, for example an infrared image camera in 56 will see through the smoke and provide the Joy Stick operator located in the cockpit 32 with scene information needed to guide the laser “hot spot” backfire setting.
Completing the laser beam odyssey through the system module, the beam leaves the HEL 48 and enters the Beam Transfer Assembly 58. This unit resizes the laser beam and cores it as needed to fit the requirements of the turret assembly. 58 also removes any beam walk and beam jitter that appears in the HEL beam so that these effects are not present as the beam passes through the void region 46 and enters the turret as beam 72. The 46 is a storage space left to withdraw the turret assembly 42 when the laser is not in use in order to protect it from debris during flight. A bird strike protective cover, not shown, might also be used to close the aperture input.
The operational concept for this first embodiment is as follows. Prior to the fire season, the helicopter is assumed to be outfitted at various times with differing modules for its many agriculture, power company, logging, and other tasks as has been done in the past. But when fire season approaches the craft would normally be outfitted with its water/chemical tank for traditional firefighting. Alternatively, the new laser backfire option may be used by a quick and straightforward replacement of the tank with the laser system module. For this helicopter the rate of climb to altitude is 405 m/min, its cruise speed is 169-203 km/hr, and its range is 370 km. Hence it should arrive at the early stages of the fire in order to start setting a backfire downwind of the conflagration so as to remove possible fuel for the fire's spread.
To illustrate that in addition to helicopter designs, there are also fixed wing aircraft laser system module designs, we consider those aircraft here. While those of us in the laser weapon system design field have considered pallet-loaded laser systems that could fit into large cargo aircraft like the Lockheed Martin C130J, the recent development of the previously discussed lightweight, smaller volume, higher efficiency and hence lower electric power and waste heat cooling requirements, RELI-class lasers makes the fixed wing fighter concept discussed here certainly possible. Previously, a fixed wing state-of-art water/chemical firefighter approach had been patented by Edward C. Herlik (U.S. Pat. No. 5,549,259) awarded 27 Aug. 1996. As seen therein, to illustrate this concept he used the fighter aircraft Fairchild/Northrop Grumman A-10 Thunderbolt-II shown in
Herlik de-militarized the A-10, as we will also assume, first modifying it by removing the 30 mm GAU-8/A seven-barrel Gatling gun 122 and its armament storage drum 94, other military armor protection such as the cockpit armor 96, the two wing fuel tanks 92, and miscellaneous other military hardware not needed for firefighting. One or two new fuel cells were placed in the nose, using some space that was previously occupied by the gun. (See also
Note that the U.S. Defense Advanced Project Agency (DARPA) is nearing completion of its program to develop a 100 kW HELLADS laser system with a smaller total volume of 1 m×1 m×3 m=3 m3. And since our baseline RELI laser is being developed to have equivalent, or even lower volume and weight per unit output power, a 60 kW RELI system should find the available volume of 5.7 m3 more than adequate.
This laser system module seen in
This second embodiment has been described with reference to the A-10 aircraft for illustrative purposes. It is apparent to those skilled in the art of fighting fires from the air that different craft may be used without departing from the spirit and scope of this invention or the associated methods as claimed here. These laser module systems may be attached to other craft to realize many of the same benefits.
The purpose of showing the photos in
This laser system module-assisted fixed wing firefighter will operate much as the helicopter. Note that its telescope has a 360 degree (2π radian) azimuthal angle coverage. Although it needs a runway unlike the helicopter, its cruise speed of 360 mph would allow it to quickly get to the region where the backfire is to be set. The laser system module aircraft will fight fires as follows. It will fly to a known fire's coordinates or locate the fire independently using its surveillance capabilities. Of course these capabilities will allow it to identify and avoid flight hazards and to report such information to the fire controlling agency. Approval to begin setting backfires may be given along with the desired paths or a more free-lance approval given. In either case the co-pilot fire manager aboard will enter the instructions into the laser beam pointing and tracking control system. Joy Stick operation or automatic operation will follow. This backfire operation will continue until the desired path is completed. If the craft needs refueling it will return to refueling base and then quickly return to complete the backfire task. Finally, as stated above, at that point the Fire Control Agency may order the craft to return to base to exchange its laser system module for a water/chemical tank to allow it to perform conventional retardant-drop firefighting. Alternatively, the Fire Controller may order the craft to stay aloft in order to use its enhanced surveillance capabilities to look for new flare-ups or to identify flight hazards such as transmission lines, other aircraft, etc.
The prior embodiments related to piloted aircraft. But the emergence of UAVs, Unmanned Aerial Vehicles, or so-called Drones, offers interesting possible use for laser system module equipped UAVs. (More precisely, the International Civil Aviation Organization refers to these craft as Remotely Piloted Aircraft (RPA), i.e. aircraft without a human pilot aboard.) Its flight is controlled either by on board computers with pre-scripted flight plans or by the remote control of a pilot on the ground or in another vehicle. (Ref. 16) discusses UAV many uses, both military and civilian. Among these is remote fire detection: “Another application of UAVs is the prevention and early detection of forest fires. The possibility of constant flight, both day and night, makes the methods used until now (helicopters, watchtowers, etc.) become obsolete. [They may have] cameras and sensors that provide real-time emergency services, including information about the location [coordinates] of the outbreak of fire as well as many factors (wind speed, temperature, humidity, etc.) that are helpful for fire crews to conduct fire suppression.”
While present day laser system modules for backfire use may appear to be too heavy, voluminous, and inefficient to be accommodated in present day unpiloted aircraft, developments in both UAVs and in laser systems and our discoveries reported here should soon change this. Examples of recent developments by a Lockheed Martin-Kaman Aircraft team,
This remarkable helicopter is based upon one designed by the chief engineer of those used by the German army in WW II. As seen in
Despite its small size, 15.8 m (51 ft) length, 4.14 m (13.6 ft) height, 14.7 m (48.25 ft) rotor diameter, its payload capacity is 2,727 kg (6,000 lbs). While this might appear to be too small to support a “conventional” 30-60 kW output power laser that we have discussed in previous embodiments, our further insight, as follows, will prove otherwise.
Foremost, we have no human aboard, and the safety risk tolerance can be markedly higher. As is well known for manned flight design, this dramatically lowers the weights (and costs) of safety features that had to be built into those aircraft we previously discussed. The same is true of the laser system module designs. But equally important, this allowable risk level also allows the remote UAV operator to fly the UAV much closer to the treetops or ground where the backfires are needed. Since the laser power received on target decreases with the square of the range between laser and target, reducing the range from say a “safe” 1 km to 0.1 km would require 102=100 times less laser power to have the same fire-starting effect! In addition, if therefore instead of a 30 kW laser only a 0.3 kW one were required, smaller scale optics and less sophisticated beam control, would result! In brief, the laser system module volume, electric power, waste heat cooling and weight could dramatically decrease when it is used for backfire setting when mounted in a UAV like the LM K-MAX. Even the lower load capacity of 2,727 kg (6,000 lbs) would then easily suffice.
Another simplification is also possible. The K-MAX nominally carries its load 140 on a cable, as seen in
Turning now to the last UAV photograph shown as
But in its present few kg payload capability limit, only very small designator lasers appear as possible laser payload. However even these could play an important role in firefighting by providing close-in directing of the illuminated aim points to be followed by a more powerful and distant laser system. Of course such low power laser target designation is presently used to guide missiles and even bullets on the battlefield.
Another important firefighting role that such a UAV could play is to provide infrared and optical surveillance. Without the risk of life, such a craft could be allowed to fly into harm's way, through smoke and darkness to obtain close-up infrared images. These could identify risks, or their absence, for follow-on manned aircraft. Of course general surveillance for fire flare-ups, need for restarting some backfires that have died, etc. would all be important information for the Fire Control Agency. Vector Hawk data link uses a high-bandwidth, software-defined radio. This would enable the transmission of these images and their GPS coordinates.
UAVs have unique capabilities to provide to firefighting. Not requiring pilots to prepare and come aboard, they are always ready to immediately take off for duty. This is an important issue to minimize a fire before it begins to spread. Once aloft they can immediately use their IR thermal cameras, day or night or veiled in smog or smoke, their images of infrared emitting hot spots can be quickly sent to Fire Control Headquarters. Then, either under programed GPS computer control, or being flown by a remote pilot, like
Finally, the operational use of a mini-UV like the LM Vector Hawk,
Although the description above contains much specificity, these should not be construed as limiting the scope of the embodiments but as merely providing illustrations of some of several embodiments. For example, the laser system module can have many shapes and various subassemblies which may be provided by many vendors, etc. Thus the scope of the embodiments should be determined by the appended claims and their legal equivalents, rather than the examples given.
This application claims the benefit of provisional patent application Ser. No. 62/077,057, filed Nov. 7, 2014 by the present inventor.
| Number | Date | Country | |
|---|---|---|---|
| 62077057 | Nov 2014 | US |
