A spin-velocity actuated ball valve in a hollow-nose, hollow base projectile is positioned to selectively close or open a projectile. In the closed position normal propellant pressure or projectile carried propellant causes the projectile to achieve operational velocity. In the open position a conduit through the projectile reduces frontal area and tail drag caused by turbulence.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
This invention relates to projectiles. More particularly, this relates to 
high speed ballistic projectiles. By way of further characterization, this 
invention relates to the class of projectiles known as tubular 
projectiles. By way of further characterization, this invention pertains 
to a high speed tubular projectile which may be fired without the use of a 
sabot. 
2. Description of the Prior Art 
Ballistic projectiles comprise a very old segment of the armament arts and 
the study of such weapons has involved a long history of analysis and 
experimentation. The study of the ballistic flight of the projectile, 
known as exterior ballistics, shows that a major limiting factor of the 
projectiles efficiency in transferring the energy of flight is that of 
ballistic drag. The major cause of ballistic drag is the base drag or 
turbulence following the projectile in flight. One promising form of 
projectile which diminishes this ballistic drag is the tubular projectile. 
In this class of projectile a longitudinal bore extending through the 
projectile permits the gas of the atmosphere to pass therethrough and 
diminish the turbulence of the base of the projectile. Additionally, it 
has been shown that the tubular projectile has certain advantages in 
target penetration. 
In order to prevent the propellant which provides the mode of power for the 
projectile from passing through the central aperture, tubular projectiles, 
in the past, have incorporated and encasing sabot to contain this pressure 
until the projectile has cleared the muzzle of the launching mechanism. 
The sabot then falls away and the projectile proceeds on its intended 
ballistic path. Although satisfactory for some purposes, the sabot 
launched projectile suffers from certain disadvantages. The loss of the 
sabot and its mass diminishes the kinetic energy that the projectile 
delivers to the target and the sabot impacts areas other than the target. 
Further, the separation of the sabot and projectile is not uniform and 
therefore adversely affects the ballistic path. Additionally, the 
sabot-fired tubular projectile has difficulties in firing from an aerial 
platform in that the sabot may be ingested by the engine of the launching 
airframe. Because of these, and other, considerations, the sabot launched 
tubular projectile has failed to gain satisfactory exploitation. 
SUMMARY OF THE INVENTION 
The present invention employs a tubular projectile with a valve located in 
the longitudinal passage of the tubular projectile which is closed to 
prevent gas flow therethrough during initial launch or firing and opens 
when the projectile is airborne to permit the gas flow through the central 
aperture. Thus, the mass of the valve remains an integral portion of the 
projectile and no sabot is required to fire and launch the projectile. 
Further, the design lends itself to enclosing a propellant charge to give 
a propulsion boost to the projectile in addition to the propellant in the 
cartridge case. 
Accordingly, it is the object of this invention to provide an improved 
projectile. 
A further object of this invention is to provide a tubular projectile 
having a high velocity. 
Another object of this invention is to provide a high velocity tubular 
projectile which may be launched without a sabot. 
A still further object of this invention is the provision of a tubular 
projectile which may be fired from aircraft. 
Another object of the invention is the provision of a projectile which may 
be safely fired over friendly forces. 
These and other objects and advantages will become apparent and understood 
with reference to the following detailed description, figures, and claims.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
Referring to FIG. 1, a projectile is illustrated generally at 11. As shown, 
projectile 11 has a nose portion 12 having a longitudinal bore 13 
extending therethrough. 
A base portion of projectile 11 is illustrated at 14. Base portion 14 has a 
longitudinal bore 15 extending therethrough. Base portion 14 is shouldered 
to telescopically receive nose portion 12 and has a circumferentially 
extending groove 16 into which nose portion 12 is cold-rolled during 
assembly. This cold-rolling produces an external cannelure 17. A 
rotational band 18 is also carried by base portion 14 and serves the 
conventional function of engaging the rifling lands in the launching 
barrel. Base portion 14 also carries a cannelure 19 on its outer surface 
for engagement by the cartridge case, not shown. Bores 13 and 15 are 
conical with their apexes innermost. A valve seat is machined in nose 
portion 12 and base portion 14. 
A spherical ball valve 20 is carried on the seat within projectile 11 and 
is configured to close the passage formed by bore 13 and 15 when the 
cartridge is at rest, prior to firing. Valve 20 has an internal bore 21 of 
a diameter chosen to mate with bores 13 and 15 in the nose and base 
portions of projectile 11, respectively. The outer surface of valve 20 
carries an indexing indentation 22 which is used in assembling projectile 
11, as will be described. A small amount of cement 23 holds valve 20 in 
the illustrated closed position during handling of the complete projectile 
prior to firing. Cement 23 additionally provides a hermetic seal to 
prevent moisture in the ambient air from entering the propellant space 
within the cartridge case. 
In operation, the projectile is fired in a conventional fashion and, 
because of engaging band 18 cooperatively tracking the lands within the 
rifle barrel, projectile 11 is set into a spinning motion as it exits the 
barrel. Of course, such longitudinal spin is common in the ballistic 
projectile arts and need not be described in greater detail. 
Because valve 20 has the axis of bore 21 slightly displaced by an angle 
.alpha. from the longitudinal axis of projectile 11, the valve is caused 
to move to a centrifugally stable position such that bore 21 is brought 
into alignment with passages 13 and 15. This alignment is made possible 
when the forces of the spherical annulus of valve 20 have exceeded the 
restraining force provided by cement 23. 
If desired, cement 23 may be of a type which is weakened with increase of 
temperature such that the heat generated by the propellant burning during 
launch causes the cement to weaken such that the rotational forces are 
able to overcome its restraining action. 
When passage 21 is aligned with bores 13 and 15, the air entering bore 13 
exits base portion 14 through bore 15 to effectively diminish turbulance 
at the base of the projectile. 
Referring to FIG. 2, a variation of the projectile of FIG. 1 is illustrated 
generally at 25. In this illustration, like numbers denote similar 
components as illustrated in FIG. 1. It will be observed that nose portion 
12 is joined to base portion 14 by either welding or a cement bond, not 
shown, rather than the roll-crimp method illustrated in FIG. 1. Such 
methods of joining nose portion 12 to base portion 14 are conventional in 
the projectile arts and the choice as between various conventional 
techniques depends upon the technological tradeoffs familiar to those 
versed in projectile design. 
A more significant difference in the projectiles of FIG. 1 and FIG. 2 
resides in the use of a propellant booster carried by base portion 14 in 
the design of FIG. 2. As illustrated, the propellant may be placed within 
passage 15 in three separate grains indicated at 26, 27, and 28. These 
propellants may be chosen with different burning rates in order to provide 
optimum propellant assisted trajectories. The use of such propellants is 
well understood in the art and need not be explained in greater detail 
here. However, it should be noted that in such an arrangement, cement bond 
23 may be extended across the entire aft surface of valve 20 such as to be 
in contact with propellant grain 26. 
Referring to FIG. 3, another variation of applicants projectile is 
illustrated at 30. As in FIG. 1, a nose portion 31 has a tapered conical 
bore 32 extending longitudinally therethrough and communicating with a 
cylindrical passage indicated at 33. Valve 34 has a cylindrical passage 35 
of the same diameter as passage 33. An exterior detent 22 serves the same 
purpose as detent 22 in the embodiments of FIGS. 1 and 2 to align valve 34 
at an angular offset indicated at .alpha. from the longitudinal axes of 
projectile 30. A base portion 36 has a conical passage 37 extending from 
the exterior base to a cylindrical passage 38 which is of the same 
diameter as passage 33 and valve passage 35. Base portion 36 is secured to 
nose portion 31 by means of mated threads 39, as is conventional in the 
projectile fabrication arts. As previously described, valve 34 as held 
against accidental rotation prior to firing by means of a cement bond 40 
which may be placed on both the forward and aft ends of valve 34. As 
previously noted, this cement provides both means for positioning valve 34 
and hermetic protection for propellant which is in the cartridge fixed to 
the aft end of projectile 30. 
Referring to FIG. 4, another embodiment of the projectile shown in FIG. 3 
houses a propellant charge 41 and 42 in a fashion similar to that 
illustrated in FIG. 2. It will be observed that in the species of FIG. 4 
only two grains of propellant 41 and 42 are used as compared to the three 
grains used in FIG. 2. Thus, the amount and type of propellant may be 
varied with the conventional tradeoffs expected of different propellants 
and burning rates thereof. 
Aside from the different velocity boost provided by the propellant charges 
in the species of the invention employing projectile carried propellants, 
the propellant grains provide additional valve positioning means and 
hermetic seal for protection of the propellant confined within the 
supporting cartridge case, not shown. 
The projectiles of all of the figures may be fabricated from conventional 
material such as steel, for example. Likewise, although illustrated as 
having uniform composition through both the nose portion, base portion, 
and valve, the projectile may be made by using a core metal with plating 
or cladding covering the outer surfaces. Such fabrication techniques are 
common in the projectile arts. Additional projectile weight may be 
obtained by using conventional techniques and heavier materials such as 
derived from spent reactor cores. The machined parts are assembled by 
conventional techniques with the exception that the valve is fitted in the 
obturation position by an alignment fixture, not shown cooperating with 
detent 22 and the nose portion of the projectile. Of course, if desired, 
other positioning arrangements might be employed. 
The nose portion is then joined to the base portion by conventional 
techniques such as rolling, FIG. 1, welding, FIG. 2, or threading, FIG. 3, 
with the ball held in place by the alignment fixture, a cement bond 23 or 
40 is applied to stabilized at the valve in the closed position. 
The angle .alpha. is chosen to provide sufficient eccentric mass to insure 
that the valve will overcome the adhesive bond and move to the open 
position after a short distance of flight. 
The precise reaction of the ball valve to pressures during the internal 
ballistics portion is uncertain. That is, it is not clear by what 
mechanism the valve overcomes the inertial or cement restraint to move to 
the open position. It is hypothesized that either sufficient rotational 
force is derived because of the angular offset .alpha., which may be 
between 95.degree. and 105.degree., or that the rotation of the projectile 
nose and base portion caused by engagement of the rifling by band 18 
sufficiently breaks any cement seal such that the projectile actually 
rotates longitudinally about the ball and transfers momentum thereto by 
frictional engagement. However, experience has shown that regardless of 
which of these forces are in play, valve actuation may be uniformly 
established by constructional variations. 
The shape of the projectile of FIGS. 1-4 is exemplary of many external 
configurations that might be used in the practice of the invention. That 
shown provides a good weight-to-length ratio. 
In use, the projectile is dimensioned to be loaded in conventional fixed 
ammunition cases and handled in a conventional firearms system. The 
projectile of the invention improves this systems operation by providing 
shorter projectile flight times and increased velocities such as to make 
marked improvements in the overall performance of the weapons system. 
The foregoing description taken together with the appended claims 
constitute a disclosure such as to enable the person skilled in the 
ammunition and firearms arts and having the benefit of the teachings 
contained therein to make and use the invention. Further, the structure 
herein described meets the objects of invention, and generally constitutes 
a meritorious advance in the art unobvious to such a worker not having the 
benefit of these teachings.