A LAMINAR FLOW, PROPULSIVE, JET-FLAPPED CONCEPT FOR ELECTRICALLY POWERED TRANSPORT AIRCRAFT

Friction drag constitutes approximately half of the total drag of subsonic civil transport aircraft at cruise conditions. Several means were examined to control the flow over an aircraft and achieve laminar flow. Here, a new concept for friction drag reduction in the form of an integration of the aerodynamics and propulsion of the aircraft is put forward. Engines buried in the wing and at the rear of the fuselage suck the boundary layer of the entire wing and fuselage surface, and then, they used it as intake air and exhaust through ducts. At the wings, the engines exhaust in the form of a jet flap at the trailing edge providing distributed propulsion. By this laminar flow, propulsive concept laminar flow is established over the entire aircraft, resulting in substantial drag reduction. The analysis showed that out of the four electrically powered aircraft versions considered only the combined lift distribution with tailless fuselage is about to be feasible. It was also found that the example aircraft design is inappropriate. It is expected that a design purposely based on the proposed concept would bring electrically powered transport aircraft within the specific energy levels of present batteries.