Propulsion power plant for aircraft

Claim 1

A propulsion power plant for a supersonic aircraft comprising a first air duct having front and rear ends and located therein, an engine of the ducted-fan gas turbine type located within said first air duct, said engine having a gas-generator portion including a front face and being contained within an outer shell extending rearwardly from the front face and a fan located toward the rear of said gas-generator portion, air speed reducing means located near the front end of said first duct for reducing the air within the duct to subsonic speed, and a second duct leading only to the gas-generator portion of the engine, and being continuous with said outer shell, the mouth of the second duct being within and spaced from the walls of the first duct and positioned forward of the front face of the gas-generator portion and aft of said air speed reducing means, said mouth being of smaller cross-sectional area than that of the front face such that the relatively smooth air flow toward the middle of the first duct is captured by said mouth, said second duct having a diverging configuration such that said air flow therein is further reduced in speed and delivered to the gas-generator over a relatively short distance, with relatively turbulent air flow in the area of the outer edge of said first duct being delivered to said fan at the rear of said gas-generator portion over a relatively longer distance, said second duct aft of the mouth of the second duct, being divergent to approach the walls of said first duct aft of the mouth of the second duct until the plane of the gas-generator front face is reached to increase the speed of the air flow through said first duct until the plane of the gasgenerator front face is reached, said outer shell of the gasgenerator portion subsequently receding from the said walls of said first duct aft of said plane, such that during said relatively longer distance the air flow to the fan is increased in speed until the plane of the front face is reached and is sUbsequently decreased in speed for delivery to the fan, said first duct being of substantially constant circular cross section aft of the plane of the front face of the gas generator portion and just enclosing the fan, the gas-generator portion of the engine being tapered to a minimum transverse dimension at the fan.