Projectile

• US 4,539,911 A
• Filed: 12/28/1981
• Issued: 09/10/1985
• Est. Priority Date: 06/20/1979
• Status: Expired due to Fees

• Current Assignee: The United States Of America As Represented By The Secretary Of The Army
• Original Assignee: The United States Of America As Represented By The Secretary Of The Army
• Inventors: Flatau, Abraham
• Primary Examiner(s): TUDOR, HAROLD JAY
• Assistant Examiner(s): Davis, Tyrone
• Application Number:
  US06/335,306
• Time in Patent Office: 1,352 Days
• Field of Search: 102/374, 102/376, 102/380, 102/381, 102/444, 102/445, 102/498, 102/501, 102/503, 102/513, 102/520, 102/521, 102/522, 102/523, 60/243, 60/245, 60/241
• US Class Current: 102/374
• CPC Class Codes: F02K 7/18 Composite ram-jet/rocket engines
• CPC Class Codes: F42B 10/34 Tubular projectiles

Abstract

A projectile is adapted to be launched from a barrel. The projectile incls a tubular housing and a structural member. The tubular housing has a forward inlet throat and aft nozzle. An annular layer of solid fuel combustible material is mounted within the housing between the inlet throat and nozzle. The structural member is detachably mounted over the nozzle. The structural member is sized to cover the nozzle so that pressurized gas applied to the structural member forwardly thrusts the housing. Thus, the projectile is gun-launchable and can produce a ramjet action.

Claims

1. A ramjet projectile adapted to be launched from a gun barrel, consisting of:

a tubular housing having a forward air inlet with a throat, an aft nozzle, and a generally cylindrical combustion chamber contiguous therebetween

said inlet having a throat with a first predetermined cross-sectional area,

said forward air inlet having a sharp leading edge defining a forward-facing circular discoidal-shaped inlet with a second predetermined cross-sectional area,

said first area being at least 0.6 of said second area,

an annular layer of solid combustible material mounted in said housing between said inlet throat and said nozzle, and

said combustion chamber having a cross-sectional area larger than said first predetermined cross-sectional area.

2. A projectile according to claim 1 wherein said forward air inlet comprises an outer airway having rearwardly converging interior walls adapted to provide compression and heating of air at said airway sufficient to ignite and maintain combustion of said layer of combustible material upon launching of said projectile at supersonic velocity.

3. A projectile according to claim 2 wherein said nozzle is adapted to increase the downstream velocity of combustion gas of said combustible material above its velocity without said nozzle.

4. A projectile according to claim 3 wherein said layer of combustible material is of a composition and thickness adapted to provide a trajectory initially simulating that of a predetermined heavier object.

5. A projectile according to claim 4 wherein said layer of combustible material is adapted to finish combustion within a predetermined interval, whereby the range of said housing is limited.

6. A projectile according to claim 5 wherein said layer of combustible material includes a chemical enhancer to provide an observable trace of the trajectory of said housing.

7. A lightweight ramjet training projectile for ballistically simulating an armor-piercing combat projectile having a ballistic coefficient C_B according to the relationship:

space="preserve" listing-type="equation">C.sub.B =W/C.sub.D A

Wherein;

W=The combat projectile total weight

C_D =The combat projectile drag coefficient and

A=The combat projectile cross-sectioned area,

said lightweight training projectile consisting of;

a hollow cylindrical tubular housing having a forward inlet throat forms a surface of revolution, an aft nozzle, and a cylindrical combustion chamber contiguous therebetween having an inside diameter larger than said forward inlet throat, forming a rearward-facing step,

an annular layer of combustible material mounted in said combustion chamber within said housing between said inlet throat and nozzle, and

a structural member detachably mounted over said nozzle, said structural member being adapted to cover said nozzle, said lightweight training projectile having a total weight less than the weight of said combat projectile, and a substantially constant ramjet thrust less than its aerodynamic drag so that its ballistic coefficient C_B of said training projectile according to above formula is equivalent to the ballistic coefficient C_B of said combat projectile.