A diamond quadcopter is described with tilting propulsion modules attached to a diamond faceted fuselage providing vertical thrust for Vertical Takeoff and Landing (VTOL) and transitioning to horizontal thrust for flight. The diamond faceted fuselage generates lift as a low aspect ratio lifting body. The diamond-like facet geometry enables propulsor placement to minimize interaction between the slipstream and fuselage in all modes of operation. A retractable landing gear with powered wheels allows Vertical/Short Takeoff and Landing (V/STOL) including emergency landings, and maneuverability on the ground. Landed and with gear retracted the bottom fuselage facet is close to ground level allowing an aft facet ramp for walk-on or roll-on access of passengers and payload. With the landing gear extended the vehicle can maneuver over cargo using the wheeled hub motors and then retract for insertion of cargo through a fuselage bottom door.

An aircraft comprising a fuselage and an unducted turbine engine. The fuselage having a divot with an upstream edge and a downstream edge. The divot is defined by a straight reference line having a length (L) and a maximum depth (h) relative to the straight reference line. The unducted turbine engine having an engine core, a nacelle, and a set of blades. A first flow ratio (FR1) is equal to: $\frac{h}{L}.$

An aircraft includes a float which provides buoyancy when the aircraft floats on a surface of water. The aircraft also includes a rotor where the rotor is configured to rotate in a horizontal plane and blow a wake across a side of the float. The rotor and the float are positioned relative to each other such that there is no aerodynamic separation between the wake blown by the rotor and the side of the float.

An intentional fluid manipulation apparatus (IFMA) assembly with a first thrust apparatus that imparts a first induced velocity to a local free stream flow during a nominal operation requirement. The first thrust apparatus creates a streamtube. A second thrust apparatus is located in a downstream portion of the streamtube. The second thrust apparatus imparts a second induced velocity to the local free stream flow. The second induced velocity at the location of the second thrust apparatus has a component in a direction opposite to the direction of the first induced velocity at the location of the second thrust apparatus.

An aircraft operable to transition between thrust-borne lift in a VTOL orientation and wing-borne lift in a biplane orientation. The aircraft includes an airframe having first and second wings with first and second pylons extending therebetween. The first and second wings each having first and second outboard nacelle stations. A two-dimensional distributed thrust array is attached to the airframe. The thrust array including a plurality of outboard propulsion assemblies coupled to the first and second outboard nacelle stations of the first and second wings. A flight control system is coupled to the airframe and is operable to independently control each of the propulsion assemblies. A cargo hook module is coupled to the airframe. The cargo hook module is operable for external load operations.

An aircraft includes an airframe having an empennage, a counter rotating, coaxial main rotor assembly located at the airframe including an upper rotor assembly and a lower rotor assembly, and a translational thrust system positioned at the empennage and providing translational thrust to the airframe. At least two control surfaces located at the empennage are independently operable via commands from one or more flight control computers. A method of operating an aircraft includes transmitting a first signal from one or more flight control computers to a first control surface located at a first lateral side of a translational thrust system, and actuating the first control surface to a first position via the first signal. A second signal is transmitted to a second control surface located at a second lateral side opposite the first lateral side, and the second control surface is actuated to a second position via the second signal.

A low stall or minimum control speed aircraft comprising a fuselage that has vertically flat sides; wings with high a lift airfoil profile of constant chord section set at zero degree planform sweep, twin booms having inner vertically flat surfaces, twin vertical stabilizers, a flying horizontal stabilizer; preferably twin engines having propellers and wherein each engine preferably has a thrust-line that is inclined nose-up to a maximum of +8 degrees, and is parallel to the wing chord underneath wing mounts and landing gear doors that provide surfaces for channeling propeller wash in a rearward direction; all working in concert so that the airplane has an extremely low stall speed and minimum control speed. The engines may be diesel, hydrogen fuel cell, electric fuel cell, diesel-electric, gas turbine or combinations thereof. The propellers may be counter-rotating.

An aircraft includes an airframe having an extending tail, a counter rotating, coaxial main rotor assembly disposed at the airframe including an upper rotor assembly and a lower rotor assembly and a translational thrust system positioned at the extending tail and providing translational thrust to the airframe. A flight control computer is configured to control a main rotor rotational speed of the upper and the lower rotor assemblies of the main rotor assembly as a function of airspeed of the aircraft. A method of operating an aircraft includes retrieving a threshold main rotor rotational speed of the dual coaxial main rotor assembly and calculating an actual main rotor rotational speed according to an environment of the aircraft. The actual main rotor rotational speed is maintained to remain at or below the threshold main rotor speed according to an airspeed of the aircraft.

A blended wing body aircraft having an interior cabin with a usable volume of at most 4500 ft.sup.3 and a cabin aspect ratio of at most 4, wherein a combination of the wings and center body has a wetted aspect ratio of at least 1.7 and at most 2.8. Also, a blended wing body aircraft having an interior cabin with a usable volume of at least 1500 ft.sup.3 and at most 4500 ft.sup.3 and a cabin aspect ratio of at least 2 and at most 4, wherein a combination of the wings and center body has a wetted aspect ratio of at least 1.9 and at most 2.7. Also, a blended wing body aircraft wherein at least each profile section having normalized half-span values from 0 to 0.3 has a leading edge having a normalized height having a nominal value within the range set forth in Table 4.

A blended wing body aircraft wherein at least each profile section corresponding to the normalized half-span values from 0 to 0.2 has a thickness ratio having a nominal value within the range set forth in Table 1. Also, a blended wing body aircraft wherein at least each profile section corresponding to the normalized half-span values from 0.15 to 0.3 has a normalized chord having a nominal value within the range set forth in Table 1, and wherein a ratio between a maximum thickness of the center body and the chord length along the centerline has a nominal value of at least 16%. Also, a blended wing body aircraft wherein a region of the aircraft defined by normalized half-span values from 0.1 to 0.2 has a normalized chord having a dimensionless rate of change from ?3.5 to ?5.1, and a thickness ratio having a rate of change from ?0.27 to ?0.72.