A propulsion unit includes a motor rotor that spins about a central rotational axis, propeller blades each having a proximal base and a distal tip, and pivot mounts each coupling the proximal base of a corresponding one of the propeller blades to the motor rotor. The propeller blades each freely pivot at the proximal base about a corresponding offset pivoting axis that is substantially parallel to but offset from the central rotational axis of the motor rotor.

A vehicle, includes a main body. A fluid generator is coupled to the main body and produces a fluid stream. At least one fore conduit and at least one tail conduit are fluidly coupled to the generator. First and second fore ejectors are fluidly coupled to the fore conduit, coupled to the main body and respectively coupled to a starboard side and port side of the vehicle. The fore ejectors respectively comprise an outlet structure out of which fluid flows. At least one tail ejector is fluidly coupled to the tail conduit. The tail ejector comprises an outlet structure out of which fluid flows. A primary airfoil element is coupled to the tail portion. A surface of the primary airfoil element is located directly downstream of the first and second fore ejectors such that the fluid from the first and second fore ejectors flows over the such surface.

An arena includes a porous surface through which an airflow is output, thereby providing lift for an unmanned aerial vehicle (UAV) to push the UAV away from the porous surface. The airflow may also provide thrust to push the UAV in a direction that is parallel to the porous surface. The UAV may include one or more propellers that can provide lift, thrust, or both to the UAV. The airflow may be modified over a duration of time to modify lift or thrust to the UAV. The airflow may be modified based on regions of the arena to modify lift or thrust in different regions of the arena. The arena may include a scoreboard to display a score that may be modified as a result of actions undertaken by the UAV. Two or more UAVs may be used to play a game via the arena.

Heavier-than-air, aircraft having flapping wings, e.g., ornithopters, where angular orientation control is effected by variable differential sweep angles of deflection of the flappable wings in the course of sweep angles of travel and/or the control of variable wing membrane tension.

A vehicle includes a main body and a gas generator producing a gas stream. At least one fore conduit and tail conduit are fluidly coupled to the generator. First and second fore ejectors are fluidly coupled to the at least one fore conduit. At least one tail ejector is fluidly coupled to the at least one tail conduit. The fore ejectors respectively include an outlet structure out of which gas from the at least one fore conduit flows. The at least one tail ejector includes an outlet structure out of which gas from the at least one tail conduit flows. First and second primary airfoil elements have leading edges respectively located directly downstream of the first and second fore ejectors. At least one secondary airfoil element has a leading edge located directly downstream of the outlet structure of the at least one tail ejector.

A propulsion system coupled to a vehicle. The system includes an ejector having an outlet structure out of which propulsive fluid flows at a predetermined adjustable velocity. A control surface having a leading edge is located directly downstream of the outlet structure such that propulsive fluid from the ejector flows over the control surface.

A vehicle includes a main body and a gas generator producing a gas stream. At least one fore conduit and tail conduit are fluidly coupled to the generator. First and second fore ejectors are fluidly coupled to the at least one fore conduit. At least one tail ejector is fluidly coupled to the at least one tail conduit. The fore ejectors respectively include an outlet structure out of which gas from the at least one fore conduit flows. The at least one tail ejector includes an outlet structure out of which gas from the at least one tail conduit flows. First and second primary airfoil elements have leading edges respectively located directly downstream of the first and second fore ejectors. At least one secondary airfoil element has a leading edge located directly downstream of the outlet structure of the at least one tail ejector.

Heavier-than-air, aircraft having flapping wings, e.g., ornithopters, where angular orientation control is effected by variable differential sweep angles of deflection of the flappable wings in the course of sweep angles of travel and/or the control of variable wing membrane tension.

A vehicle includes a main body and a gas generator producing a gas stream. At least one fore conduit and tail conduit are fluidly coupled to the generator. First and second fore ejectors are fluidly coupled to the at least one fore conduit. At least one tail ejector is fluidly coupled to the at least one tail conduit. The fore ejectors respectively include an outlet structure out of which gas from the at least one fore conduit flows. The at least one tail ejector includes an outlet structure out of which gas from the at least one tail conduit flows. First and second primary airfoil elements have leading edges respectively located directly downstream of the first and second fore ejectors. At least one secondary airfoil element has a leading edge located directly downstream of the outlet structure of the at least one tail ejector.

A propulsion system coupled to a vehicle. The system includes a convex surface, a diffusing structure coupled to the convex surface, and at least one conduit coupled to the convex surface. The conduit is configured to introduce to the convex surface a primary fluid produced by the vehicle. The system further includes an intake structure coupled to the convex surface and configured to introduce to the diffusing structure a secondary fluid accessible to the vehicle. The diffusing structure comprises a terminal end configured to provide egress from the system for the introduced primary fluid and secondary fluid.