NESTED CORE GAS TURBINE ENGINE
An aircraft, with the ability to cruise at supersonic speeds, designed to increase cruise lift/drag ratio, reduce sonic boom and have greater downward visibility by having an ‘inverted’ nose profile that has greater inclination of the lower surfaces to the flight direction than the upper surfaces.
This application is a continuation from co-pending application Ser. No. 12/537,045, filed Aug. 6, 2009, which is a continuation from Ser. No. 11/682,077, filed Mar. 5, 2007, which is a continuation from application Ser. No. 11/201,441, filed Aug. 10, 2005 which is a continuation from application Ser. No. 10/635,956 filed Aug. 7, 2003, now issued U.S. Pat. No. 6,988,357, which is a continuation from application Ser. No. 09/947,002, filed Sep. 5, 2001, now issued U.S. Pat. No. 6,647,707, which claims the benefit of U.S. Provisional Application No. 60/230,891, filed Sep. 5, 2000, and of which are incorporated by reference herein in their entireties.
FIELDThe disclosed embodiments relate to supersonic aircraft.
Previous DevelopmentsConventional supersonic aircraft, such as the Concorde, have a sharp, needle-type, quasi-conical nose, that is designed to minimize the strength of the shock waves formed when the aircraft is traveling at supersonic speeds. This nose is generally somewhat angled down, looking forward from the cockpit, to enable downward visibility for the pilots. Examined another way, the tip of the nose, viewed from the side of the profile, is located below the centerline of the fuselage behind the nose.
This conventional design of the nose for conventional supersonic aircraft is not advantageous from the viewpoint of aerodynamic performance. The quasi-conical nose acts as a supersonic ramp that compresses oncoming air. Because the ramp is not axi-symmetric, the ramp has a greater angle to the flight direction on a part of the surface, such as the upper surface in a conventional aircraft, and has a smaller angle to the flight direction on another part of the surface, such as the lower surface in a conventional aircraft. The intensity of the supersonic shock waves thus formed along the angled surfaces of the quasi-conical nose are not symmetric with respect to the flight direction. Parts of the curved surface of the nose that have a greater angle to the flight direction have a greater intensity of shock, and other parts of the curved surface of the nose have a lesser intensity of shock. It is well known that a greater intensity of shock creates a greater increase in static pressure of the flow, that is the pressure normal to the local surface.
The shockwaves on the nose surfaces also create drag for the aircraft, due to a combination of pressure drag and increased skin friction drag.
In conventional aircraft, with the nose angled down from the fuselage, the upper part of the nose has the greater intensity of shock and the greater static pressure, compared to the lower part of the nose. As a result, the nose experiences a net downward force.
The foregoing aspects and other features of the exemplary embodiments are explained in the following description, taken in connection with the accompanying drawings, wherein:
FIGS. 13 and 14-14A respectively are schematic top plan, elevation, and bottom plan views of an unmanned aerial vehicle (UAV) in accordance with yet another embodiment;
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Claims
1. An aircraft for supersonic operation at least some of the time, said aircraft having a nose pointing above the fuselage centerline, such that the tip of the nose is above the fuselage centerline.
2. An aircraft for supersonic operation at least some of the time, said aircraft having a nose region configured to have greater inclination to the flight direction, during supersonic cruising flight, on its lower surfaces as compared to its upper surfaces.
3. An aircraft for supersonic operation at least some of the time, said aircraft having a nose region configured to have greater intensity of inclined shock waves, during supersonic cruising flight, on its lower surfaces as compared to its upper surfaces.
4. An aircraft for supersonic operation at least some of the time, said aircraft having a nose region configured to have greater static pressure, during supersonic cruising flight, on its lower surfaces as compared to its upper surfaces.
5. An aircraft for supersonic operation at least some of the time, said aircraft deriving net positive lift from the nose region during supersonic cruise conditions.
6. An aircraft for supersonic operation at least some of the time, said aircraft having greater cockpit window areas on the lower surface of the nose rather than the upper surface of the nose.
Type: Application
Filed: Aug 26, 2011
Publication Date: Dec 22, 2011
Inventor: Sudarshan Paul Dev (Ashburn, VA)
Application Number: 13/219,314
International Classification: B64C 30/00 (20060101); B64C 23/00 (20060101);