Method and apparatus for controlling tip vortices

An aircraft comprising:

• a fuselage;
• a lift wing on each side of said fuselage having a tip end allowing an associated drag-inducing vortex fluid flow therearound from the higher pressure surface toward the lower pressure surface of said wing;
• first engine means on said aircraft for producing a major portion of forward thrust for the aircraft;
• second engine means on said aircraft for producing a minor portion of said forward thrust, and including a power thrust tip engine disposed adjacent each of said tip ends producing an exhaust flow intercepting said associated vortex flow;
• and
• directing means associated with each of said tip engines for directing at least a portion of said exhaust flow therefrom to rotate in opposition to said associated vortex flow to reduce said vortex induced drag, each of said tip engines being a jet engine having fluid inlet and exhaust ducts, said exhaust duct defining an annular exhaust opening of at least partially annular configuration, said directing means extending radially across said annular exhaust opening to direct exhaust flow therefrom, said tip jet engines being secured to said wings whereby said annular exhaust opening are disposed substantially completely forwardly of and in general alignment with the respective wing tip relative to the direction of flight of said aircraft.

In combination with a lift wing of finite length having a tip end allowing a drag-inducing vortex fluid flow therearound from the higher pressure surface toward the lower pressure surface of said wing:

• a jet engine mounted to said wing at said tip end and having a fluid exhaust duct defining an exhaust opening arranged relative to said wing whereby fluid exhausts from said exhaust opening substantially completely forwardly of said tip end in a rearward direction to intercept said vortex in a manner materially reducing the formation and magnitude of said vortex flow to reduce said drag;
• said exhaust opening including an annular exhaust opening of at least partially annular configuration located forwardly of said tip end a distance approximately equal to the maximum diameter of said annular exhaust opening;
• directing means in said exhaust duct for directing fluid exhausting from said annular opening to rotate in opposition to said vortex flow;
• and
• said directing means extending radially across said annular exhaust and being circumferentially inclined relative thereto whereby exhaust flow rotates in a vortex pattern at a spiral angle determined by said inclination of the directing means.

A method of reducing drag induced by vortex fluid flow about a tip end of a lift wing of an aircraft having a jet engine disposed adjacent said tip end, comprising the steps of:

• operating said engine to produce forward thrust for powering said aircraft;
• exhausting fluid flow from said engine in intercepting relationship with said vortex flow;
• rotating at least a portion of said exhausting flow in a vortex pattern at a spiral angle in opposition to said vortex flow to materially reduce said drag during normal in-flight operation of the aircraft;
• varying said spiral angle to materially dissipate said vortex flow during take-off and landing operation of the aircraft;
• and
• maintaining a substantially constant restriction to exhaust flow from said engine while varying said spiral angle.

A jet engine adapted to be secured to an aircraft wing adjacent a tip end thereof whereby exhaust flow from said engine intercepts a drag-induced vortex fluid flow around said tip end from the higher pressure surface to the lower pressure surface of the wing, said engine comprising:

• a housing having fluid inlet and exhaust ducts at opposite ends thereof, said exhaust duct defining an annular exhaust opening of at least partially annular configuration;
• power means in said housing for producing thrust for powering the aircraft;
• and
• a plurality of guide vanes extending radially across said annular exhaust opening and inclined in a circumferential direction relative thereto whereby said exhaust flow tends to rotate in a vortex pattern in opposition to said vortex flow to reduce said vortex induced drag, said vortex pattern having a spiral angle determined by the degree of inclination of said vanes, said vanes being pivotally secured to said housing to permit variation of said degree of inclination and said spiral angle, said vanes being cyclically pivotal to cyclically vary said spiral angle in a manner inducing dissipation of said vortex flow.

A jet engine adapted to be secured to an aircraft wing adjacent a tip end thereof whereby exhaust flow from said engine intercepts a drag-inducing vortex fluid flow around said tip end from the higher pressure surface to the lower pressure surface of the wing, said engine comprising:

• a housing having fluid inlet and exhaust ducts at opposite ends thereof, said exhaust duct defining an annular exhaust opening of at least partially annular configuration;
• power means in said housing for producing thrust for powering the aircraft;
• a plurality of guide vanes extending radially across said annular exhaust opening and pivotally secured to said housing to permit variable inclination of said vanes in a circumferential direction relative to said annular exhaust opening, whereby said exhaust flow tends to rotate in a vortex pattern in opposition to said vortex flow to reduce said vortex induced drag, said vanes operable to variably restrict said exhaust flow in accordance with variation in said inclination of the vanes;
• movable restricting means for variably restricting said exhaust flow through the exhaust duct;
• and
• means for actuating said restricting means in correlation with said variation in inclination of the vanes to present a substantially constant restriction to said exhaust flow.

A jet engine adapted to be secured to an aircraft wing adjacent a tip end thereof whereby exhaust flow from said engine intercepts a drag-inducing vortex fluid flow around said tip end from the higher pressure surface to the lower pressure surface of the wing, said engine comprising:

• a housing having fluid inlet and exhaust ducts at opposite ends thereof, said exhaust duct defining an annular exhaust opening of at least partially annular configuration, said annular exhaust opening including an annular section adapted to extend approximately 180 degrees around said tip end of the wing;
• power means in said housing for producing thrust for powering the aircraft;
• and
• directing means associated with said exhaust duct for directing at least a portion of said exhaust flow to rotate in opposition to said vortex flow to reduce said vortex induced drag.