Aeronautics and astronautics – Aircraft – lighter-than-air – Balloons
Reexamination Certificate
2001-12-28
2003-07-08
Jordan, Charles T. (Department: 3643)
Aeronautics and astronautics
Aircraft, lighter-than-air
Balloons
C244S033000
Reexamination Certificate
active
06588702
ABSTRACT:
FIELD OF INVENTION
The present invention is generally drawn to lighter-than-air (“LTA”) devices and respective uses thereof.
BACKGROUND OF THE INVENTION
Although there are many examples of connections between the ground and LTA devices, the barrage balloon is the only reported example of an LTA device designed primarily to control the space beneath itself. The barrage balloon was designed to damage or destroy an airplane that flew into the cable between the balloon and the ground. Today Federal Aviation Agency regulations require posting a NOTAM (Notice to Airmen) in addition to marking the aerostat or tethered balloon's tether cable whenever flown, to prevent its unintentionally serving as a barrage balloon.
An LTA device remains airborne because it consists primarily of a buoyant gas, such as hot air or some other gas which weighs less than the air that it displaces. For example: Under Standard Sea-level temperature and pressure conditions, one thousand cubic feet of helium displaces one thousand cubic feet of air, thus providing roughly 64 pounds of lifting force.
Non-limiting examples of buoyant gases to be used in LTA devices include hydrogen, helium, methane, and pipeline gas (natural gas). Hydrogen provides the most lift, but is highly flammable. Helium, which is not flammable, provides nearly as much lift as hydrogen, but is much more expensive than hydrogen. Methane is nearly half as effective a lifting gas as helium, but also is flammable. Natural Gas, because of heavy impurities, is slightly less effective than pure methane, but is widely available and very inexpensive compared to hydrogen, helium or methane.
Accordingly, a 10-foot diameter sphere provides a gross lift of approximately 270 pounds if filled with helium. Although a sphere is the most efficient container, enclosing the greatest volume with the least surface area, conventional balloon construction techniques require many panels and consequently many heavy seams. Thus, the fabric in a spherical balloon may weigh as much as a simple cylindrical balloon of equal volume, but with fewer seams.
Nineteenth century aeronauts invested a great deal of effort developing techniques using one or more appendages to provide the pilot some control over his balloon with respect to the prevailing wind and to take advantage of ocean or river currents. They repeatedly demonstrated that sails could be effectively employed to provide directional control if the balloon moved significantly slower than the relative wind. (Example: AIRSHIPS PAST AND PRESENT, Hildebrandt, A., Van Nostrand Co, New York, 1908. The first attempt to reach the North Pole by balloon (Andre's Red Balloon) combined the use of a balloon mounted sail, and a weighted line which dragged in the water or over the ice.)
With the introduction of the internal combustion engine, aeronauts were finally able to move independent of the wind. However, their airship's speed was limited both by propulsive power and by the effect of dynamic air pressure on the envelope and the airship appendages Conventional airships are still limited to roughly 80 miles per hour, with normal “cruising” speeds in the 30 to 40 mph range.
Other problems associated with conventional airships deal with changes in air temperature, pressure, and the effects of condensation and precipitation. Specifically, while traveling through fog, or more generally clouds, condensation accumulates on the surface of the envelope. Such accumulation over the large surface area of the airship adds undesirable weight to the envelope, thereby adversely affecting the airship's efficiency. In extreme cases, large amounts of water accumulation may be detrimental to the flight of the airship. Most airship designs incorporate features to prevent the dripping water from interfering with pilot visibility and to prevent ice thrown from the propeller blades from damaging the envelope. It was common military practice to fly into a summer shower near the end of a mission, primarily to cool the gas in order to bring the airship back to neutral buoyancy, and secondarily to wash the envelope. Since most flights were over-water, pilots found it more effective to use a winch to pick up ballast water when needed, rather than to hunt for rain,
During the first century of manned flight, balloons were normally inflated shortly before launching, and the envelope collapsed by releasing the gas at the end of the flight, in the same manner as the present-day hot-air balloons and airships. Because of the cost and complexity of rigging cold-gas airships, Santos-Dumont developed the hangar and other techniques for maintaining an inflated airship between flights.
Various techniques were developed, using one or more lines for ground handling, recovery, controlling and anchoring balloons and airships. During World War I, British, Italian, and other airship operators developed multi-point high-moors; the airship was commonly tethered thirty feet in the air. Alternatively, airships were “bedded down”; tethered closely to the ground and protected by natural or manmade windbreaks or shelters if they could not be safely returned to a hangar. The Russian's reported that one of their bedded down airships (SSSR V2, on bivouac) tore loose from sixty “corkscrew” ground anchors and was blown away on Sep. 6, 1935.
Since the development of the mooring mast shortly after World War I, nearly all American airships have been designed to operate from a fixed or mobile mooring mast. Typically, the airship is ballasted to near-neutral buoyancy, connected to the mast by a fitting at its nose, and allowed to weathercock around the mast. High winds or unexpected wind shifts and gusting, while the airship is attached to a mooring mast, or while groundhandling crews are moving the airship, continue to be primary causes of airship losses and accidents.
An airship's lines, ropes and/or cables may be manhandled, fastened to powered winches on land or specially modified ships or heavy vehicles or attached to fixed and drifting anchors. Airship and aerostat lines have been used to carry electrical power, water, gas, telegraph, telephone, analog and digital electronic signals and electro-optical signals between the ground and the buoyant device. Airship's winches have been used to tow boats and sonar-bodies, to transfer passengers, and to pick up other loads from the ground and the sea. However, as previously mentioned, except for the barrage balloon, no applications were designed to control or use the space between the balloon and the earth, except to protect and secure the LTA device itself.
What has not been developed is a system and method to control the space between the earth and the LTA device. What is further needed is a means of controlling the height, orientation and disposition of the system as well as rapid retrieval and stowage at the onset of severe weather or whenever the operator needs to deactivate the system for some other reason.
Rather than using a mooring mast, or multiple lines to constrain and control the LTA device, this invention employs a flexible distributed surface, a surface which in addition to restraining and controlling the LTA device also performs, inter alia, one or more of the following useful functions: blocks light; screens, filters, and/or blocks airflow; collects and condenses aerosols; blocks or stops larger airborne particles, bugs and birds.
SUMMARY OF THE INVENTION
It is an object of this invention to provide a working surface to limit and control the movement of air between an LTA element and the earth beneath it.
It is another object of this invention to provide a working surface to limit and control the movement of objects or materials in the air between an LTA element and the earth beneath it.
It is still another object of this invention to provide a method and system to limit or control light and other radiation effects through this working surface.
It is still yet another object of this invention to provide a method and system for rapid erection and relocation of an extremely lightweight,
Collins Timothy D.
Robbins Thomas D.
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