(On the accompanying patent drawing, 100 is the airship, which includes a shell (102), a strake (104), and a tail (106). A strake is an aerodynamic surface mounted on the fuselage of an aircraft to improve airflow and flight characteristics.)
Rather than relying on helium for buoyancy, the Boeing Company (NYSE: BA) envisioned a system in which both a lighter-than-air gas and heated air would be used in concert. Issued US Patent 8,033,497 in October 2011 for “Hybrid thermal airship,” inventors David Kwok and co-inventors designed,
"[a]n airship [that] comprises a shell, a gas storage system, an air storage system, a cargo storage system, a heating system, and a propulsion system. The shell encompasses a volume. The gas storage system is located within the volume, wherein the gas storage system is capable of storing a lighter than air gas. The air storage system is located within the volume, wherein the air storage system is capable of storing heated air. The heating system is capable of heating air. The propulsion system is capable of propelling the shell during flight."
The airship’s design would allow it to operate at an altitude of about 30,000 feet above sea level, and it was intended to provide cargo transportation. The inventors stated that “cargo is placed into the cargo storage system while a negative buoyancy is present [i.e., when the airship is on the ground]. After the cargo has been placed into the cargo storage system, the temperature of the stored air in the gas storage system is changed to create a variable buoyancy.
Further, “[i]t is also a general goal to reduce the drag force of airships so that less fuel is burned. Alternatively, it is desirable to reduce drag so that the airship may fly faster with the same fuel consumption.” The Boeing hybrid thermal airship can be considered clean tech within the Way Better Patents Transportation Index.
The Government Accountability Office (GAO) report, Future Aerostat and Airship Investment Decisions Drive Oversight and Coordination Needs, issued in October 2012 identified 15 key aerostat and airship efforts that were underway or had been initiated since 2007, and the Department of Defense (DOD) had or has primary responsibility for all of these efforts. Most of the aerostat and airship efforts have been fielded or completed, and are intended to provide intelligence, surveillance, and reconnaissance (ISR) support. The estimated total funding of these efforts was almost $7 billion from fiscal years 2007 through 2012. Most of the total estimated airship investment from fiscal years 2007 to 2012—approximately $1.1 billion—consists of research, development, test, and evaluation (RDT&E) costs. A significant investment that should yield many new inventions.
(Airships, which use a lifting gas—most commonly helium, are manned or unmanned, self-propelled vehicles that have directional control. Aerostats are the airship's tethered siblings.)
News reports a little over a month before the patent issued said that Boeing was no longer working on the airship. The US Air Force and other have dramatically reduced spending on airship and aerostat development. Perhaps another company will purchase or license the Boeing patent, and this clean tech will be brought to market.
Blimps, aerostats, and airships are likely to make another appearance in the future not unlike the other clean technology like the windmill that have returned to the fore. In any event, innovative approaches to solving problems incorporating aspects of clean tech continue to be brought forth by the nation’s inventors.
