Mountain View, CA (07/21/14) - For the past 60 years, engineers have tried to combine the advantages of airplanes and helicopters, but currently the Boeing V-22 Osprey is the sole realization to be in production. The Elytron family of aircraft is designed 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, search and rescue, air taxi, and oil exploration.
The concept for the Elytron design has evolved over a 10-year period during which Elytron Aircraft LLC experimented with several quarter-scale convertiplanes, as well as full-size airframe modeling, extended flight simulations, and CFD simulations. The popular Verticopter flying-wing design with in-wing propulsion was the most successful of these prototypes but still had aerodynamic limitations. In 2012, Elytron Aircraft LLC invented a new and optimized wing configuration that addressed all of the earlier design shortcomings.
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.
Because the proprotors are tilted forward during normal flight, the Elytron design does not suffer the performance penalty that helicopters do with the retreating blade. Therefore, Elytron aircraft will be capable of achieving airspeeds two to three times those of equivalently powered helicopters. The airframe has also been optimized for low drag at the higher airspeeds made possible by its tilt wing. Fixed wings planes are also far more fuel efficient than rotary wing aircraft, reducing operational costs and increasing range. The combination of the speed of a fixed wing plane and the vertical take-off of a helicopter will allow for applications such as air taxi from city center to city center.
The Elytron mechanism for controlling the plane during vertical flight will have far fewer parts than helicopter swash plates. The helicopter's complex rotor hub with the cyclic, collective mechanism is replaced with a single continuous wing that rotates 100 degrees and embeds four control surfaces that are controlled with regular linear actuators. The power train has two 90-degree gear boxes and a reduction drive. Elytron’s design has no complex hub but instead distributes the parts across the tilt wing making them lighter and easier to inspect and maintain. All of the tilt wing actuators have redundant control. In the case of engine failure, the airframe's superior glide ratio will eliminate the need for autorotation, which is a requirement in any helicopter. The plane will also offer a “zero-zero” ballistic parachute as an additional emergency safety feature.
Using a small budget and fast prototyping techniques with carbon composites, Elytron has built a 2-seater demonstrator aircraft which serves as a technology showcase. The next step for Elytron is to start commercial applications which include a 7-seater class of aircraft able to support applications, such as emergency medical services. Elytron's patented designs will incorporate a host of additional safety features, such as run dry gear boxes, full time health and usage monitoring, FADEC engine control, and envelope protection.