Semi-axisymmetric scramjet flowpath with conformal nozzle
In accordance with a first aspect of the present invention, an aircraft having a scramjet engine is provided. The scramjet engine includes a flowpath which varies in three dimensions. In accordance with a second aspect of the present invention, a method for launching an aircraft having a scramjet engine with a nozzle section and a solid rocket booster positioned within the nozzle section is provided. The method includes the steps of igniting the solid rocket booster to accelerate the aircraft to a speed at which the scramjet engine can operate, clearing the nozzle section by ejecting the solid rocket booster from the nozzle section upon exhaustion of the solid rocket booster; and injecting fuel into a flow of air passing through the scramjet engine and igniting the fuel and the air to provide thrust to the aircraft.
1. An aircraft having an annular body forming an internal volume and a scramjet engine within said internal volume, said scramjet engine including a semiannular flowpath which varies in three dimensions from an inlet portion to a nozzle section, said flowpath being formed by a curved section of an inner wall of the aircraft body, an internal wall spaced from said inner wall, and two side walls within said internal volume extending between said internal wall and said inner wall, and said flowpath having a concave configuration at an inlet to said nozzle section, and said nozzle section having a convex curvature at an intermediate portion downstream of said inlet to said nozzle section.
2. An aircraft according to claim 1 , wherein the inlet portion of said flowpath has a semiannular configuration.
3. An aircraft according to claim 1 , further comprising a conical nose, a semi-conical forebody contiguous with said conical nose, and at least one conical ramp leading to the inlet portion.
4. An aircraft according to claim 1 , further comprising a solid rocket booster positioned within said nozzle section.
5. An aircraft according to claim 4 , wherein said solid rocket booster is ejectable.
6. An aircraft according to claim 4 , further comprising a flange at a rear portion of the solid rocket booster for transmitting thrust loads to the aircraft.
7. An aircraft according to claim 4 , wherein said solid rocket booster has a circular casing along its length for absorbing aerodynamic contouring requirements.
8. An aircraft according to claim 4 , further comprising detachable elastomeric pads attached to a casing of said solid rocket booster for transmitting pressure and vibratory loads from said solid rocket booster to said nozzle section.
9. An aircraft according to claim 1 , wherein said aircraft is a missile.
10. An aircraft having an annular body forming an internal volume and a scramjet engine within said internal volume, said scramjet engine including a semiannular flowpath being formed by a curved section of an inner wall of the aircraft body and an arcuately shaped internal wall spaced from said inner wall, and two side walls within said internal volume extending between said internal wall and said inner wall, and said flowpath varying in three dimensions from an inlet portion to a nozzle section, the inlet portion of said flowpath having a semiannular configuration, the flowpath having a concave configuration at an inlet to said nozzle section, wherein said nozzle section has a convex curvature at an intermediate portion downstream of said inlet to said nozzle section, and an expendable solid rocket booster positioned within said nozzle section.
11. An aircraft according to claim 1 , wherein said scramjet engine has a combustor positioned between said inlet portion and said inlet to said nozzle section.
12. An aircraft according to claim 11 , wherein said scramjet engine further has an isolator positioned between said combustor and said inlet portion.
13. An aircraft according to claim 10 , further comprising said flowpath having a semi-annular means for accommodating back-pressure due to downstream combustion, said semi-annular means being located aft of the inlet portion, and a combustor located aft of the semi-annular means for accommodating said back-pressure.
14. An aircraft according to claim 10 , wherein said internal wall serves as an inner surface of said nozzle section and varies in three dimensions from the semiannular inlet portion to a concave configuration at an exit of a combustor section to a convex configuration at an intermediate point along a length of the nozzle section.
15. An aircraft having a scramjet engine, said scramjet engine including a flowpath which varies in three dimensions from an inlet portion to a nozzle section, the inlet portion of said flowpath having a semiannular configuration, said flowpath having a concave configuration at an inlet to said nozzle section, a solid rocket booster positioned within said nozzle section, and detachable elastomeric pads attached to a casing of said solid rocket booster for transmitting pressure and vibratory loads from said solid rocket booster to said nozzle section, wherein said elastomeric pads are ejectable with said booster.
16. A method for launching an aircraft comprising the steps of:
providing a scramjet engine having a semiannular flowpath configuration within an internal volume of an annular aircraft defined by an arcuately shaped inner wall and an arcuately shaped internal wall spaced from said arcuately shaped inner wall and joined to said inner wall by two side walls and having a nozzle section with an inlet and a convex curvature at an intermediate portion downstream of said inlet to said nozzle section;
positioning an expendable solid rocket booster within said nozzle section;
igniting said solid rocket booster to accelerate the aircraft to a speed at which said scramjet engine can operate;
clearing said nozzle section by ejecting said solid rocket booster from said nozzle section upon exhaustion of said solid rocket booster; and
injecting fuel into a flow of air passing through said scramjet engine and igniting said fuel and said air to provide thrust to said aircraft.
17. The method according to claim 16 , further comprising:
attaching detachable elastomeric pads to a casing of said solid rocket booster for transmitting pressure and vibratory loads from said solid rocket booster to said nozzle section.
18. The method for launching an aircraft comprising the steps of:
providing a scramjet engine having a nozzle section with an inlet and a convex curvature at an intermediate portion downstream of said inlet to said nozzle section;
positioning a solid rocket booster within said nozzle section;
igniting said solid rocket booster to accelerate the aircraft to a speed at which said scramjet engine can operate;
clearing said nozzle section by ejecting said solid rocket booster from said nozzle section upon exhaustion of said solid rocket booster;
injecting fuel into a flow of air passing through said scramjet engine and igniting said fuel and said air to provide thrust to said aircraft;
attaching detachable elastomeric pads to a casing of said solid rocket booster for transmitting pressure and vibratory loads from said solid rocket booster to said nozzle section; and
ejecting said detachable elastomeric pads with said booster.