Dynamic soaring concept UAV from NASA the Albatross PAV

Many small unmanned aircraft systems will try to emulate nature to help with increase fuel consumption or mobility.

This aircraft is based on the Albatross which in habitats the southern oceans by Antarctica. The typical Albatross weighs about 25 lbs. They have an aspect ratio 16 wing with an 11 foot span. They are estimated to have an L/D of 27. Since there are few static soaring opportunities over the ocean, the Albatross uses a technique called Dynamic Soaring (DS) to maintain flight. Dynamic soaring is a figure eight-like flight maneuver that takes advantage of horizontal wind gradients to maintain flight speed and altitude. The albatross can travel over 1000 km per day without ever flapping their wings through the constant use of such maneuvers, while able to tack any direction with independence of wind direction The Albatross is also able to lock their shoulder joint to rest their muscles and even capable of sleeping while performing the DS flight maneuvers.

This UAV Concept has the same weight and size of the Albatross and would be propelled by the wind alone utilizing this same DS technique. Tip turbines on the wing tips extract power from the tip vortex to power the payload and recharge the batteries. When the wind dies the aircraft has the ability to safely land on the surface of the ocean. Solar cells will be used to keep the payload and other electronics running. The tip turbines can also be used as propellers to provide takeoff thrust and at other times to provide auxiliary propulsion to allow the aircraft to maneuver away from an obstacle.

Its a very appealing concept. It better have good detect sense and avoid on board as some ships are pretty tall.