Pressurized Structure Technology for Uavs

There is a critical need to improve the performance and utility of unmanned aerial vehicles (UAVs). Several areas of UAV performance need to be improved for the next generation of UAVS to be used successfully in expanded future combat roles. For example current time aloft is only on the order of an hour or two for electric-powered UAVs. The current generation of UAVs lacks vertical takeoff and landing (VTOL) capability and precision slow-speed maneuverability required for urban navigation and targeting. In addition, the UAVs are not capable of stealth, and are easily spotted and/or heard. These deficiencies are related mostly to the airframe and method of propulsion. Most fielded UAVs are currently based on fixed-wing or rotor-craft airframes and thus are constrained to their flight characteristics. UAV propulsion using ducted fans may also be fielded. In general, these vehicles require the motors, electrical or internal combustion to be running at high speed to keep the UAV aloft. This requires a substantial amount of energy and generates noise at excessive levels. One way to address the deficiencies of the UAVs just listed is to employ lighter-than-air or pressurized structure-based (PSB) technology. Basically, the UAV will be built such that a considerable percentage of its weight is supported by or constructed from inflatable structures containing air or helium. PSB technology will reduce the amount of energy required to keep the UAV aloft thus allowing the use of smaller, slower, and quieter motors. An airframe near neutral buoyancy will allow much slower flight speeds and increased maneuverability while expending little power. PSB airframes used in conjunction with technologies such as solar cells may be able to stay aloft for extended periods of time.