Abstract: An aircraft capable of carrying at least 400 pounds of payload, has four rotors systems, each of the rotor systems being independently driven by an electric motor or other torque-producing source. Each of the rotor systems provide sufficient thrust such that the aircraft is capable of controlled vertical takeoff and landing, even if one of the variable pitch rotor is inoperable. An electronic control system is configured to control the rotational speed and pitch of at least one of the rotor systems in each of the first and second rotor pairs. The rotors may be arranged in coaxial stacks or may be otherwise configured.

Abstract: In accordance with one embodiment of the present invention, an aircraft comprises a battery pack mounted external to the aircraft structure. The batteries are configured to vent directly to the environment during battery thermal runaway. In one embodiment, an aerodynamic fairing provides an aerodynamically efficient surface and weather protection during nominal flight conditions. During battery thermal runaway however, the aerodynamic fairing is configured to expose the battery to the environment.

Abstract: In an embodiment, proprotor pitch ranges used during nominal cruise flight may be varied. By selecting ideal combinations of proprotor pitch angle and proprotor rpm, instead of the proprotor blade pitch bearing spending most of its time in a first range, multiple ranges may be alternated between. Additionally, in an aircraft with multiple proprotors, the portion of total thrust produced by each individual proprotor may be varied over time in order to allow for proprotor blade pitch angle to be varied without varying proprotor rpm. By properly cycling between different blade pitch ranges, bearing life can be significantly increased.

Abstract: In one aspect, described herein is an aircraft capable of carrying at least 400 pounds of payload. An embodiment has four rotors systems, each of the rotor systems being independently driven by an electric motor or other torque-producing source. Each of the rotor systems provide sufficient thrust such that the aircraft is capable of controlled vertical takeoff and landing, even if one of the variable pitch rotor systems is inoperable. An electronic control system is configured to control the rotational speed and pitch of at least one of the rotor systems.

Abstract: An aircraft capable of carrying at least 400 pounds of payload, has four rotors systems, each of the rotor systems being independently driven by an electric motor or other torque-producing source. Each of the rotor systems provide sufficient thrust such that the aircraft is capable of controlled vertical takeoff and landing, even if one of the variable pitch rotor is inoperable. An electronic control system is configured to control the rotational speed and pitch of at least one of the rotor systems in each of the first and second rotor pairs. The rotors may be arranged in coaxial stacks or maybe otherwise configured.

Abstract: An aircraft capable of carrying at least 400 pounds of payload, has four rotors systems, each of the rotor systems being independently driven by an electric motor or other torque-producing source. Each of the rotor systems provide sufficient thrust such that the aircraft is capable of controlled vertical takeoff and landing, even if one of the variable pitch rotor is inoperable. An electronic control system is configured to control the rotational speed and pitch of at least one of the rotor systems in each of the first and second rotor pairs. The rotors may be arranged in coaxial stacks or maybe otherwise configured.

Abstract: An aircraft capable of carrying at least 400 pounds of payload, has four rotors systems, each of the rotor systems being independently driven by an electric motor or other torque-producing source. Each of the rotor systems provide sufficient thrust such that the aircraft is capable of controlled vertical takeoff and landing, even if one of the variable pitch rotor is inoperable. An electronic control system is configured to control the rotational speed and pitch of at least one of the rotor systems in each of the first and second rotor pairs. The rotors may be arranged in coaxial stacks or maybe otherwise configured.

Abstract: Systems and methods are contemplated for favorably improving flight dynamics of aircraft, including enhanced aerodynamic braking and improved flight maneuverability. Air braking systems selectively position a first set of blades at a negative thrust pitch to product a net negative thrust across first and second sets of blades, while balancing torque of the drive shafts to zero. First and second sets of IBC blades can be driven by the same shaft or torque-linked shafts. Flight maneuver systems operate a powerplant at a high power mode, and dissipate the energy from the high power output by positioning a first set of IBC blades at a low efficiency pitch while maintaining constant thrust. As increased or rapid flight maneuverability is required, the first set of blades is positioned toward a high efficiency pitch to instantly increase thrust to the aircraft without requiring a related increase in energy output from the powerplant.

Abstract: In one aspect, described herein is an aircraft capable of carrying at least 400 pounds of payload. An embodiment has four rotors systems, each of the rotor systems being independently driven by an electric motor or other torque-producing source. Each of the rotor systems provide sufficient thrust such that the aircraft is capable of controlled vertical takeoff and landing, even if one of the variable pitch rotor systems is inoperable. An electronic control system is configured to control the rotational speed and pitch of at least one of the rotor systems.

Abstract: An aircraft capable of carrying at least 400 pounds of payload, has four rotors systems, each of the rotor systems being independently driven by an electric motor or other torque-producing source. Each of the rotor systems provide sufficient thrust such that the aircraft is capable of controlled vertical takeoff and landing, even if one of the variable pitch rotor is inoperable. An electronic control system is configured to control the rotational speed and pitch of at least one of the rotor systems in each of the first and second rotor pairs. The rotors may be arranged in coaxial stacks or maybe otherwise configured.

Abstract: Systems and methods are contemplated for favorably improving flight dynamics of aircraft, including enhanced aerodynamic braking and improved flight maneuverability. Air braking systems selectively position a first set of blades at a negative thrust pitch to product a net negative thrust across first and second sets of blades, while balancing torque of the drive shafts to zero. First and second sets of IBC blades can be driven by the same shaft or torque-linked shafts. Flight maneuver systems operate a powerplant at a high power mode, and dissipate the energy from the high power output by positioning a first set of IBC blades at a low efficiency pitch while maintaining constant thrust. As increased or rapid flight maneuverability is required, the first set of blades is positioned toward a high efficiency pitch to instantly increase thrust to the aircraft without requiring a related increase in energy output from the powerplant.

Abstract: Methods of manufacturing and operating a solar powered aircraft having segmented wings that can be reconfigured during flight to optimize collection of solar energy are described. The aircraft have rigid construction that is resistant to inclement weather and is configured to rely on free flight control at high altitude and under conventional conditions, thereby providing flight duration in excess of 2 months. The aircraft is particularly suitable for use as part of a telecommunications network.

Abstract: An aerial surveillance and reconnaissance system includes a gimbal-stabilized ISR imaging sensor with 0.8-1.2 microradian optical resolution, using pulsed ultraviolet laser (0.330-0.380 micrometer wavelength) radiation to illuminate the observed target, and a narrow-band-pass filter at the focal plane detector to remove light at frequencies other than the illuminating frequency. Preferred sensors can be operated in a snapshot mode using intermittent illuminating pulses, with timing of the pulses selected for minimum detectability based on observations made with a lower-resolution sensor, or in a video-mode with illuminating pulses selected to generate full-motion video at operator-selectable frame rates. Some sensor embodiments may further combine the UV system described above with conventional daylight optical and sensor systems, though alternative arrangements could also include an IR sensor as well (either using a common aperture with the UV system or with a separate set of light-gathering optics).

Abstract: A solar powered aircraft having segmented wings that can be reconfigured during flight to optimize collection of solar energy are described. The aircraft have rigid construction that is resistant to inclement weather and is configured to rely on free flight control at high altitude and under conventional conditions, thereby providing flight duration in excess of 2 months. The aircraft is particularly suitable for use as part of a telecommunications network. A telecommunications network incorporating such aircraft is also discussed.

Abstract: Methods of manufacturing and operating a solar powered aircraft having segmented wings that can be reconfigured during flight to optimize collection of solar energy are described. The aircraft have rigid construction that is resistant to inclement weather and is configured to rely on free flight control at high altitude and under conventional conditions, thereby providing flight duration in excess of 2 months. The aircraft is particularly suitable for use as part of a telecommunications network.

Abstract: A solar powered aircraft having segmented wings that can be reconfigured during flight to optimize collection of solar energy are described. The aircraft have rigid construction that is resistant to inclement weather and is configured to rely on free flight control at high altitude and under conventional conditions, thereby providing flight duration in excess of 2 months. The aircraft is particularly suitable for use as part of a telecommunications network. A telecommunications network incorporating such aircraft is also discussed.

Abstract: An aerial surveillance and reconnaissance system includes a gimbal-stabilized ISR imaging sensor with 0.8-1.2 microradian optical resolution, using pulsed ultraviolet laser (0.330-0.380 micrometer wavelength) radiation to illuminate the observed target, and a narrow-band-pass filter at the focal plane detector to remove light at frequencies other than the illuminating frequency. Preferred sensors can be operated in a snapshot mode using intermittent illuminating pulses, with timing of the pulses selected for minimum detectability based on observations made with a lower-resolution sensor, or in a video-mode with illuminating pulses selected to generate full-motion video at operator-selectable frame rates. Some sensor embodiments may further combine the UV system described above with conventional daylight optical and sensor systems, though alternative arrangements could also include an IR sensor as well (either using a common aperture with the UV system or with a separate set of light-gathering optics).

Abstract: A multiple-tethered kite extracts power from wind. Systems having three or more tethers coupled to a single kite are contemplated, as are systems having multiple kites coupled to a given pair of tethers. Commercially useful tethers would most likely have a length of at least 1000 meters, and would be fixed at least 100 meters apart. During a given cycle the distance between each of the bases and the kite would likely vary by at least 50 meters. Motion of the tethers can be converted to useful energy in any commercially viable manner, for example by driving an electric generator or a water pump.

Abstract: Power generation systems comprising an array of rotary-wing kites are presented. Rotary-wing kites can coupled to ground-based spools via tethers. As tension varies within the tethers, the spools wind and unwind. The rotational motion of the spools can be converted to electrical power via one or more generators.

Abstract: A manned or unmanned aircraft, and equipment aboard the aircraft, are controlled through a cell phone network or other public package switched network. Some of the information downlinked from the aircraft may include video imagery acquired by sensors integrated with the aircraft. In addition, some of the information uplinked to the aircraft may include instructions to control equipment onboard the aircraft, including cameras, spotlights, and public-address systems.