Projectile structure
View Patent ↗A scramjet has a cowl, a center structure, and a plurality of wide pylons connecting the cowl to the center structure, with scramjet engines positioned between adjacent pylons. Leading surfaces of adjacent pylons converge to one another to provide side wall compression to air entering the engines. The center structure includes a fore body, a center body and an aft body that, with the pylons, define a basic structure either formed entirely from one piece or several securely connected pieces. A method of testing the scramjet projectile comprises using a gun to accelerate the scramjet projectile to the takeover velocity of the engines.
1. A projectile structure, comprising:
an annular member;
a center structure;
a plurality of pylons comprising side surfaces and connecting the annular member to the center structure, the plurality of pylons being spaced circumferentially from one another around the center structure by flow passages therebetween; and
at least one engine comprising one of the flow passages having an inlet and positioned between side surfaces of two adjacent pylons of the plurality of pylons;
wherein at least a portion of each of the side surfaces of the two adjacent pylons is arranged to compress and to turn air entering the inlet of the flow passage, wherein the flow passage of the at least one engine defines a throat at a minimum transverse cross-sectional area thereof, wherein each of the plurality of pylons has a profile width defined as a width of a pylon between adjacent flow passages at throats of the adjacent flow passages, wherein the profile width of each of the plurality of pylons at the throat thereof is from 2 to 5 times a profile width of the at least one engine at the throat thereof, wherein the profile width of the at least one engine is defined as a width of the flow passage between the two adjacent pylons at the throat.
2. The projectile structure of claim 1 , wherein the at least one engine comprises a plurality of engines.
3. The projectile structure of claim 2 , wherein each of the plurality of engines has an output, and the outputs of all of the plurality of engines are controllable together.
4. The projectile structure of claim 2 , wherein each of the plurality of engines has an output, and the output of a first of the plurality of engines is controllable independently from the output of a second of the plurality of engines.
5. The projectile structure of claim 4 , wherein the output of each of the plurality of engines is controllable independently from the output of each of the other engines.
6. The projectile structure of claim 2 , wherein the annular member comprises a cowl having a notched leading edge, the notched leading edge having a plurality of forward points, and a plurality of rearward points, wherein one of the plurality of forward points corresponds to each of the plurality of pylons, and one of the plurality of rearward points is positioned over each of the flow passages.
7. The projectile of claim 6 , wherein the notched leading edge is shaped to cause a leading edge of the cowl to conform to planar shock waves set up by air flow contacting leading portions of the side surfaces of the pylons.
8. The projectile of claim 7 , wherein the notched leading edge is of one of a V-shape, a U-shape, an elliptical shape and a hyperbolic shape.
9. The projectile structure of claim 2 , further comprising a plurality of boosters, wherein each of the boosters is located within an aft portion of a respective one of the plurality of pylons.
10. The projectile of claim 2 , wherein the profile widths are measured in a circumferential direction about a longitudinal axis of the projectile structure.
11. The projectile structure of claim 1 , wherein the at least one engine is a scramjet engine.
12. The projectile structure of claim 1 , wherein the inlet is defined in part by the two adjacent pylons between which the at least one engine is positioned.
13. The projectile structure of claim 12 , wherein the projectile structure has a fore and an aft, and the inlet is defined in part by side surfaces of the adjacent pylons, the side surfaces converging toward one another from fore to aft.
14. The projectile structure of claim 13 , wherein the center structure includes a tapered fore body to compress and to turn air entering the inlet, the inlet being defined in part by the tapered fore body.
15. The projectile of claim 14 , wherein the annular member comprises a cowl and the leading edge of the cowl is arranged to intersect a conical shock wave set up by air flowing over the tapered forebody.
16. The projectile of claim 14 , wherein the tapered forebody has an exterior surface at an angle of about eight degrees to a longitudinal axis of the projectile structure.
17. The projectile structure of claim 1 , wherein the center structure and the plurality of pylons are formed of one piece.
18. The projectile structure of claim 1 , wherein the annular member, the center structure, and the plurality of pylons comprise individually formed parts connected to one another by one of welding and threaded connections to define a basic structure having an engine.
19. The projectile structure of claim 18 , wherein the basic structure comprises titanium.
20. The projectile structure of claim 1 , wherein at least a portion of at least one pylon is hollow.
21. The projectile structure of claim 20 , wherein the hollow portion comprises a fuel storage area.
22. The projectile structure of claim 20 , wherein the hollow portion comprises a munitions storage area.
23. The projectile of claim 1 , wherein a leading portion of each of the side surfaces is configured to compress and to turn the air entering the inlet.
24. The projectile of claim 1 , wherein the profile widths are measured in a circumferential direction about a longitudinal axis of the projectile structure.