Some unusual new design schemes for UAVs were recently granted US patents.
"Designs for morphing and articulating UAVs are among some of the latestest patents approved by the US Patent and Trademark Office. One is a Boeing patent for a lifting-body UAV with telescoping wing.
Concentric wing sections extend for a low-speed, high-lift configuration and retract flush with the airframe for high speed and low lift. Russian aircraft designer Ivan Makhonine flew the telescoping-wing MAK-10 in 1931, but Boeing's patent goes a step further and envisions extendable foreplanes, vertical tails - and variable-geometry telescoping wings...
Another Boeing patent is for a solar-powered UAV capable of continuous operation at northern latitudes and during winter months, when sunlight is in short supply.
The aircraft has a planar "solar sail", with solar cells on one side, mounted so it can rotate around the aircraft's roll axis to track the elevation of the Sun while the vehicle remains horizontal. The X-tail also has solar cells on one side and rotates to track the Sun while providing pitch and yaw control of the vehicle.
One final patent, awarded to Virginia-based Geoffrey Summer, is for a "skybase" system of forming a high-latitude UAV from multiple smaller aircraft. These "modular flyers" would be air-launched individually and would join up, wingtip to wingtip, to form a larger "articluated-wing"vehicle - the more that join the higher it can fly.
As illustrated above (right), individual flyers could fail and the skybase would reform and keep flying. Additionally, individual flyers could be detached from the formation and despatched to take a closer look at a target before returning to rejoin the skybase."