Boxwing in development - Curt Lewis

Vertical takeoff and landing boxwing planes capable of twice the speed of helicopters

Elytron Aerospace is designing box wing aircraft to provide the vertical take-off and landing capability of helicopters combined with the speed and efficiency advantages of fixed wing aircraft. Elytron's solution provides greater safety, speed, and simplicity of operation over any existing class of vertical take-off aircraft which makes it ideally suited for various uses, such as emergency medical services.

The Elytron design combines three sets of wings: one pair of rotary wings called "proprotors", mounted on a single tilt-wing in central position, and two pairs of fixed wings. The fixed wings are split into a forward pair and an aft pair that are joined by winglets, which make use of the joined-wing concept. By splitting the wings apart, the design eliminates any interference with the thrust of the proprotors. The main wings have a high aspect ratio, are braced and can be built very light which reduces drag. Since the front and rear wings are joined together by winglets, they enclose the proprotors eliminating the risk of rotor strikes. The plane has superior glide ratios and low stall speeds because of this low wing loading design, and also displays excellent Short Take-off and Landing (STOL) capabilities.

Though there have been some aggressive development projects in recent years, such as the Bell V-280, the AugustaWestland Project Zero and AW609, the only operational manned, prop-driven aircraft that manages this sort of hybrid flight is the V-22 Osprey tiltrotor aircraft.

Elytron Aircraft is working with NASA to test a scaled version of its highly unconventional convertiplane concept, which is designed to takeoff and land like a helicopter but cruise at fixed wing speeds. Free flight and captive wind-tunnel tests are expected to take place early in 2017 at NASA's Ames Research Center, California. The anticipated aerodynamic data will be compared with predictive models that will help Elytron refine the design of a planned five-seat, potential air taxi.