WZ-ZZ Tiltrotor

An aerospace show in May 2021 at an unreported location in China showcased three models of new vertical aviation concepts, including a single-seat tiltrotor with two wing pairs, at least four wing-mounted rotors and a pair of engines mounted interally in the fuselage. Each of the four wings also mounts two further pods of indeterminant function. Possibly these also contain rotors that are retractable, with some deployed rotors for forward flight and and others are folded when not needed to provide vertical lift. The design is a cross between an attack helicopter and a VTOL jet fighter. possibly for shipboard [LHD?] operations. The designation and institutional sources of the design were not reported [the WZ-ZZ designator is an arbitrary placeholder].

This configuraiton is not widely proposed in China, though Chinese military observers are no strangers to tiltrotors. As early as in the Tianjin Expo in 2013, China exhibited a model called "Blue Whale". "The quad-rotor tilt-rotor aircraft model, similar in appearance to the American V-44 tilt-rotor aircraft. And in 2018 the Rainbow-10 unmanned tilt rotor aircraft will be unveiled in Zhuhai! Rainbow-10 Unmanned Tilting Rotor is a new type of unmanned aerial vehicle that integrates helicopter technology and fixed-wing aircraft technology. It takes off and landed vertically in helicopter mode, cruises quickly in fixed-wing aircraft mode, and realizes flight mode through rotor tilting conversion.

Tiltrotor aircraft have a vertical takeoff and landing function and have the advantages of high speed forward flight and long flight compared to general vertical takeoffs such as helicopters. In the case of a general tilt rotor, the rotor has rotors rotated at left and right ends thereof, and the rotor on the left side and the rotor on the right side rotate in different directions (forward rotation and reverse rotation). The angle of the nacelle on which the rotor is mounted can be changed according to the flight mode, and the angle of nacelle can be changed to 90 degrees during take-off and landing, and to be in the direction of flight and horizontal, i.e., 0 degrees, for fixed flight aircraft.

This has the advantages of vertical takeoff and landing and high speed forward flight. Fixed-wing aircraft, such as airplanes, are capable of flight using wings that generate lift responsive to the forward airspeed of the aircraft, which is generated by thrust from one or more jet engines or propellers. The wings generally have an airfoil cross section that deflects air downward as the aircraft moves forward, generating the lift force to support the aircraft in flight. Fixed-wing aircraft, however, typically require a runway that is hundreds or thousands of feet long for takeoff and landing.

Unlike fixed-wing aircraft, vertical takeoff and landing (VTOL) aircraft do not require runways. Instead, VTOL aircraft are capable of taking off, hovering and landing vertically. One example of a VTOL aircraft is a helicopter, which is a rotorcraft having one or more rotors that provide lift and thrust to the aircraft. The rotors not only enable hovering and vertical takeoff and landing, but also enable forward, backward and lateral flight. These attributes make helicopters highly versatile for use in congested, isolated or remote areas. Helicopters, however, typically lack the forward airspeed of fixed-wing aircraft due to the phenomena of retreating blade stall and advancing blade compression.

Tiltrotor aircraft attempt to overcome this drawback by including a set of proprotors that can change their plane of rotation based on the operation being performed. Tiltrotor aircraft generate lift and propulsion using proprotors that are typically coupled to nacelles mounted near the ends of a fixed wing. In fixed nacelle tiltrotor aircraft, the nacelles are fixed relative to the fixed wing and the proprotors are rotatable relative to the fixed wing and nacelle such that the proprotors have a generally horizontal plane of rotation for vertical takeoff, hovering and landing and a generally vertical plane of rotation while cruising in forward flight. In forward flight, the fixed wing provides lift and the proprotors provide forward thrust. In this manner, tiltrotor aircraft combine the vertical lift capability of a helicopter with the speed and range of fixed-wing aircraft.

In China, the development of tilt rotor aircraft also rests on theoretical and engineering research stage, the pertinent data that any model of still not publishing is succeeded in developing.It is reported, domestic certain unit has developed the miniature self-service principle prototype, the work of taking a flight test, but the tiltrotor of its overall plan and European and American countries is similar.Physical resource can be referring to the paper " model investigation of tiltrotor aircraft flight mechanics " of China's aerodynamics journal in June, 2008 publication.

In 2015, NASA Langley researchers completed the Greased Lightning (or GL-10) carbon fiber hybrid-electric Vertical Take-Off and Landing (VTOL) drone prototype which was successfully remotely piloted from a hover to wing-borne flight back to landing, in tests at Fort A.P.Hill, Virginia, USA. The flight tests successfully transitioned from hover to wing-borne flight like a conventional airplane then back to hover again. The initial thought was to develop a 20-foot wingspan (6.1 meters) aircraft powered by hybrid diesel/electric engines, but the team started with smaller versions for testing, built by rapid prototyping. The remotely piloted plane has a 10-foot wingspan (3.05 meters), eight electric motors on the wings, two electric motors on the tail and weighs a maximum of 62 pounds (28.1 kilograms) at take off.

The aircraft depictred in the 2021 Chinese display model seemingly comprises two turboshaft engines that provide shaft power and are capable of providing thrust; at least one of: one or more electrical generators or one or more hydraulic pumps connected to a shaft of the one or more turboshaft engines; and at least two rotatable pairs of wings, each with nacelles housing at least one of: one or more electric motors or one or more hydraulic motors each connected to a proprotor, wherein the electric motor is electrically connected to the electric generator, or the hydraulic motor is connected to the hydraulic pump, respectively, wherein the proprotors provide lift whenever the aircraft is in vertical takeoff and landing and stationary flight, and provide thrust whenever the aircraft is in forward flight.