US2402718A - Projectile - Google Patents

Description

June 25, 1946. Q N, ALBREE A 2,402,718

PROJ ECTILE Filed Feb. 19 1942 l D l @au Q6' Y \n\/enor.' George Norman Albree Patented June 25, 1946 UNITED STATES PATENT 'OFFICE' 7 Claims.

This invention relates to projectiles for nrearms and particularly to that type of projectile that has a stabilizing element rotatably mounted thereon for the purpose of giving the projectile stability during its flight.

O-ne of the objects of the invention is to provide a projectile of this type in which the rotary stabilizing element is provided with wings that project therefrom and are situated to be acted on by the air during the flight of the projectile, thereby to impart rotary movement to said stabilizing element.

A further object of the invention is to provide a projectile of this type with an axial passage through which air flows at high velocity during the flight of the projectile and to provide the stabilizing element with wings or blades that project into the passage so that rotary motion is imparted to the stabilizing element by the stream of air owing through said axial passage.

Another object of the invention is to provide pneumatic means operative independently of the projectile propelling force to give the stabilizing element an initial rotary movement before the element is loaded into the gun.

Other objects of the invention are to improve projectiles of this type in various ways as will be more fully hereinafter set forth.

In order to give an understanding of the invention, I have illustrated in the drawing some embodiments thereof which will now be described after which the novel features will be pointed out in the appended claims.

In the drawing:

Fig. 1 is a longitudinal, sectional View through the projectile embodying my invention.

Figs. 2 and 3 are sections on the lines 2-2 and 3 3, Fig. 1, showing one means for imparting an initial rotary movement to the stabilizing element before the projectile is loaded into the gun.

Fig. 4 is a longitudinal section through a projectile showing a different embodiment of the invention.

Fig. 5 is a longitudinal section through a projectile showing another embodiment of the invention.

Figs. 6 and '7 are sections on the line 1 .'1, Fig. 5, Fig. 6 illustrating the vp-rojectile as having a sleeve thereon for retaining the wings in their retracted position.

Fig. 8 is a longitudinal section through a portion of a ri-led gun barrel.

The present improvements may be embodied in .projectiles of either the ball type or the shell type.

In Fig. 1, the invention is-illustrated as embodied able to place them in the -front portion of the' projectile.

The projectile body may conveniently be made in two sections, the rear section 6 which contains the chamber 2 for receiving the explosive charge, and the iront or nose section 1, said two sections being screw-threaded together as shown at 8. The stabilizing element or elements will preferably be mounted in the nose section lof the projectile, said section being provided with `a chamber 9 to receive said elements.

These stabilizing elements are rotatably mounted in ball bearings so as to provide for free rotation thereof. In the construction herein shown, each stabilizing element is mounted in two ballbearing assemblies, one on each side thereof,those for the stabilizing Velement 4 being indicated generally at lil and Il and those for Vthe stabilizing element 5 being indicated generally at l2 and I3. The two ball-bearings yI-l and l2 are mounted in a disk or plate M which is located fbetween the two stabilizing elementsv and 5. The ball-bearing l Sis partially supported in a similar disk l5 at the outer end of the chamber 9, and the ytwo disks it and l5 are shown as being provided on -their periphery with screw threads adapted lto have screw-threaded engagement with Vscrew threads I6 formed on -the interior of the chamber vil. In this way, the disks i4 and l5 can be properly positioned and adjusted so as to load the ball-bearings -toethe proper extent.

As stated above, the present vinvention involves novel means by which rotary motion is imparted to the stabilizing element or elements by the forward traveling movement of the projectile through the air.

One way of accomplishing this is to make the projectile l with an axial passage Il extending therethrough, which passage also extends axially through the stabilizing elements, and to provide said elements with wings or blades thatproject into this Vpassage so that the :air which vows through the passage at high velocity during the traveling movement of the projectile will act on these wings or blades and will thus impart rotary motion to the stabilizing element or elements.

In Fig. 1, the axial passage through the projectile is indicated at Il, this passage extending axially through the stabilizing elements 4 and 5 as shown at I8, and the wings or blades with which the stabilizing elements are provided are indicated at I9, said wings or blades projecting into the portions I8 of the passage I7. These wings or blades I9 may have any desired` shape or configuration but preferably will be in the form of miniature aerofoils which have a high aspect ratio and an eicient lift-drift ratio, and are so disposed that the current of air flowing through the passage l1 and indica-ted by the arrows a will, by its action on the wings or blades, impart the desired rotary movement to the stabilizing element.

Where two stabilizing elements are used, they may be arranged in closely adjacent tandem relation as shown in Fig. 1, and it is desirable to so construct the wings or blades on each stabilizing element that the ow of air through the passage I1 will cause the stabilizing elements to rotate in opposite directions. This is shown in Fig. l wherein the blades I9 carried by the stabilizing element 4 are designed to give said element a counterclockwise rotary motion looking from the left, while the blades I9 carried by the stabilizing element are designed to give said element a clockwise rotary motion also locking from the left, Fig. 1. Because of the opposite directions of rotation of the two tandem arranged stabilizing elements, the tendency of the projectile to drift laterally during flight due to the rotation of one stabilizing element is counterbalanced by the tendency of said projectile to drift laterally in the opposite direction due t0 the rotation of the other stabilizing element. This will give a high degree of inherent stability to the projectile, thus making it possible to lire the projectile from a smooth bore gun as accurately as a projectile can be fired from a ried gun. It is well understood that for the same powder charge a smooth bore gun will develop a higher muzzle velocity of the projectile than a gun having a riiied barrel because in the case of a riled gun, some of the force of the exploding charge is converted into the spinning motion of the projectile.

The speed at which each stabilizing element is rotated will depend somewhat upon the characteristics, Such as the aspect ratio, lift-drift ratio, angle of incidence, etc., of the wings carried thereby and by employing wings on the two stabilizing elements having certain predetermined characteristics, the said elements may be given a rotary motion of substantially the same speed or may be so driven that the speed of one element will have any desired relation to that of the other element.

While the action on the wings I9 of the stream of air indicated by the arrows a, Fig. 4, will irnpart rotary movement to the stabilizing element, yet in the case of a large projectile, it may be desirable to impart to the stabilizing elements an initial rotative movement before loading the projectile into the gun, so that when the projectile is discharged from the gun the stabilizing elements will be already in rotation thus giving stability to the projectile the instant it leaves the muzzle of the gun. After the projectile has been discharged, the rotative movement of the stabilizing elements will be maintained during ight and may even be increased by the action of the stream of air nowing through the passage I1 and acting on the wings I9.

Various ways of imparting an initial rotative movement to the stabilizing elements before the projectile is loaded into the gun may be employed without in any way departing from the invention, but I prefer to accomplish this by delivering jets of gas under pressure against the peripheral portion of each stabilizing element. One simple construction by which this may .be done is shown in Figs. 2 and 3. Each stabilizing element is formed on its periphery with a series of pockets 2E) and the projectile is provided with two opposed transverse openings 2| and 22 that communicate with the chamber 9 at one side thereof. 23 indicates a nozzle connected to a source of compressed air and by which air under high pressure may be discharged into the inlet opening 2l. The impact of this jet of air under high pressure against the rear walls of the pockets 20 will give the stabilizing element a rapid rotary movement, the air after having done its work being discharged from the outlet passages 22.

In the case of large projectiles that are brought to the breech end of the ordnance on a carriage, the air jet nozzles 23 may be used to impart rotary motion to the stabilizing elements while the projectile is on the loading carriage and just before it is entered into the gun. Where two stabilizing elements are employed, as shown in Fig. 1, which rotate in opposite directions, the pockets 2U in the two elements will be oppositely disposed, as shown in Figs. 2 and 3. For giving initial rotation to the stabilizing element 5, the nozzle 23 will be entered into the opening on the opposite side of the projectile from that just used in giving initial rotative movement to the stabilizing element 4.

The above-described means for giving initial rotary motion to the stabilizing elements is in the nature of pneumatic means operative independently of the projectile propelling force. While I have referred to air as the compressed gas to be used, yet the invention contemplates the use of any suitable gas for this purpose.

Since the projectile shown in Fig. 1 has an axial passage therethrough, it is necessary to provide means for closing this passage at the base of the projectile until the latter has been discharged from the barrel of the gun. For this purpose, a sealing member 24, shown in dotted lines in Fig. 1 is employed, which seals the rear end of the passage I1. This sealing member 24 may be temporarily retained in place by any appropriate means, as by means of some suitable cement or adhesive. As soon as the projectile has been discharged from the gun, the suction condition which tends to form in the vortex immediately in the rear of the projectile together with the pressure of the air in the passage I'I will dislodge the sealing member 24 thus leaving the passage I1 entirely open for the free 110W of air therethrough. The stream 0f air flowing through this passage I1 not only serves to impart rotary motion to the stabilizing elements, but it also reduces very materially the vortex drag on the projectile and relieves the compressibility effect at the nose of the projectile, thus giving the latter an increased sustained velocity.

The projectile shown in Fig. 1 which has two stabilizing elements and is intended to be shot from a smooth bore gun is illustrated as having bands on which it rides as it moves through `the barrel, said bands alsoserving `as gas checks.

In Fig. 4, I have shown adiiferent embodiment of the invention wherein the projectile has a single stabilizing element. This embodiment of the invention is Well suited for use with projectiles that are to be shot from a gun having a rifled barrel such as that illustrated in Fig. 8. The body of the projectile, shown in Fig. 4 is made with the rear section `6u, and lthenosesection 1a which are screw-threaded together as shown at 8a. The nose portion of the projectile lis provided with a chamber 97a .in which is received a single stabilizing element 4a similar to the stabilizing element 4, said `element being ro- .tatively mounted in ball bearings Illa and I la. The projectile shown in Fig. 4 is provided `'with the axial passage lla which extends through the stabilizing element 4a and said element 4a is provided With the Wings or blades 18a that project into the passage 11a so that the air flowing through the passage Ila will be its action onlthe wings lila, impart a rotary movement to the stabilizing element. The projectile la is shown as having a driving band 26 thereon adjacent to its base, said driving band cooperating with the riing 4l! in the barrel 4l of the gun to give the projectile a spinning or rotating motion about its axis. The wings 19a of .the stabilizing element 4a may be so shaped and disposed and have such y characteristics as to give said element a rotation in a direction either opposite to or the same as that imparted to the projectile itself by the -rling in the gun. In Figs. 4 and 8 the Wings I9 and the rifling 48 in the gun lbarrel have such a re'lation that the stabilizing element 4a will be rotated in a direction opposite to that in which the projectile will be spun as it travels through the barrel 4l. The spinning projectile, itself constitutes a stabilizing member during its flight, and by embodying in the projectile a stabilizing element such as shown at 4a `in Fig. 4 andby proyiding for rotating said element in a direction opposite to that in which the projectile is spinning, the effect will be that of a projectile having two stabilizing elements rotating in opposite directions. This will have a counteracting effect on the torque of the projectile, that is, the tendency of the projectile to drift laterally during flight, a tendency 'which is inherent in all projectiles which are shot from a gun having a rifled barrel.

In the devices shown in Figs. 1 and 4, a rotary motion is imparted to the stabilizing element by means of an air current which passes through the projectile. In Fig. 5, there is shown another embodiment of the invention wherein the flow of air around the projectile is utilized to impart a rotary motion to the stabilizing element. In said Fig. 5, the projectile is provided with two stabilizing elements 21 and 28, so mounted that their peripheral surfaces are iiush with the peripheral surface of the projectile body, and each stabilizing element has one or more wings or blades 29 extending outwardly from its peripheral surface and adapted to be acted upon by the air flowing over the surface of the projectile body, thereby to impart rotary movement to the stabilizer. The projectile 30 is formed with a body 3l having a reduced portion 32 on which the two stabilizing elements 21 and 28 are mounted, ball bearings 33 being provided to permit free rotation of said elements. The nose portion 34 of the projectile is separate from the body portion 3| and is screw-threaded onto the end of the rei6 duced portion 32, .the .latter having iexteriorscrew lthreads for this purpose. 'The ftwo stabilizing Aelements 5.21 'and 28 are thus mounted-on the :reduced portion A32 andare confined betweentl'ie :nose `234-and'thebody3l of the projectile. Each stabilizing element lis provided Vwith a plurality of `Wings lor blades 29 adapted .to extend out- `wardly beyond its periphery. Each wing -or blade is shown as carried'by a 'block 35 having flat sides that lis mounted in a radial recess 36 with which the lstabilizing element is :provided and ywhich receives a :spring 31 tending to force the wings 29 outwardly into their operative position. The wings 29 on the two stabilizing -elements are so disposed that the air 110W overfthe surface of the projectile during `flight'will -cause one stabilizing element to rotate in one direction and the other to rotate in the opposite direction. The at'sides of the blocks 35 yprevent the blocks from turning in the recesses and ensures ythat the wings 29 will be held at the proper angles.

In order to protect the wings `2 9` While the `:projectile is being Vhandled preparatory to loading .it into the gun,'a band 38 may -be placed around the stabilizing .elements as shown 'fin 6, kthis band vserving :to hold :the wings 2S -`in their retracted positions. The yielding movement of the springs 31 permit `the wings to be Vthus retracted. When the projectile -is loaded into xthe gun, the band 38 will be removed and the wings will then kbe retained in their Vretracted .position by engagement by lthe interiorf'vwall of the gun barrel.

As .soon as the projectile has been discharged from the gun, .the springs '31 will move the wings 29 outwardly into :their `operative position,y vin which they are acted upon'by the air flow varound fthe projectile, :thereby imparting the desired rotary motion to the stabilizing elements.

In the above discussion in which reference lis 1made to rotary motion being imparted to the stabilizing element, vit has been assumed that the relation between the translational speed of the vprojectile and the rotational speed of the stabilizing element was such that fthe action -of vthe .air on the wings was `effective to give -rotary motion to the stabilizing element. It will be evident, however, that if :the 'translational speed :of the projectile is sufficiently reduced relative tothe rotational speed ofthe stabilizing element, or the initial rotational speed of the stabilizing element is sufficiently increased relative to the translational speed of the projectile as it is discharged from the gun, then the relation between such rotational and translational speeds may be such that the action of the air on the wings of the stabilizing element will have a retarding effect on the rotational speed thereof. In other words, the action of the air on the wings of such stabilizing element may serve either to augment or to retard the rotational motion thereof depending on the relation existing at any moment between the rotational speed of the stabilizing element and the translational speed of the projectile. A

Hence in the case of a projectile which is discharged with a relatively high trajectory the translational speed of the projectile may be reduced to such an extent during its flight toward the vertex of its trajectory that the action of the air on the wings will retard the rotation of the stabilizing element, thereby reducing the stabilizing effect thereof, while the projectile is approaching and traveling through the vertex portion of its trajectory, thereby preservingthe proper balance in the relation between the air resistance on the projectile and the stabilizing eiect to insure that the projectile will maintain its axis in line with its trajectory and will thus nose over properly as'it reaches its vertex and begins its descent. During the descending movement of the projectile it will naturally gather speed and such increased translational speed will then result in giving increased rotational movement to the stabilizing element.

The construction herein illustrated therefore provides means for varying the rotational speed of the stabilizing element as the translational speed of the projectile Varies.

I claim:

1. A projectile for firearms comprising a projectile body provided with an axial passage open at both ends for the iiow of air therethrough during the flight of the projectile, and a stabilizing element rotatably carried by said body and situated co-axially thereof, said stabilizing element having an axial opening which registers with the axial passage of the projectile body and also having an impelling blade projecting into said opening whereby the air flowing through said passage and opening during such ight acts on the blade and imparts rotary motion to the stabilizing element.

2. A projectile comprising a projectile body provided with an open-ended axial passage through which air flows during the ight of the projectile after it has been launched, two stabilizing elements rotatably carried by said body in tandem relation, each stabilizing element having an axial opening which registers with the axial passage of the projectile body, and means actuated by the flow of air through said passage and opening during such flight to impart rotary motion in one direction to one stabilizing element and in the other direction to the other stabilizing element.

3. A projectile comprising a projectile body provided with a through axial passage open at both ends and through which air flows during the night of the projectile, and two stabilizing elements rotatably carried by said body in tandem relation, each stabilizing element having an axial opening therethrough which registers with the axial passage of the projectile body, and also having rigid therewith a blade that extends into said opening, whereby the air flowing through said passage and opening during the flight of the projectile acts on the blades of the two stabilizing elements successively and imparts rotary motion to both stabilizing elements, the blade on one stabilizing element being shaped to cause it to rotate in one direction and the blade on the other stabilizing element being shaped to cause it to rotate in the opposite direction.

4. A projectile for rearms having a stabilizing element rotatively carried thereby, pneumatic means operative independently of the projectilepropelling force for giving the stabilizing element the initial rotary motion, and means actuated by the air through which the projectile travels during its iiight to impart additional rotary motion to the stabilizing element.

5. A projectile comprising a projectile body provided with a through axial passage, a stabilizing element rotatively carried by said body, pneumatic means operative independently of the projectile-propelling-force to give the stabilizing elevment an initial rotary motion, and means actuated by the ow of air through said passage during the ight of the projectile to impart additional rotary movement to said stabilizing element.

6. A projectile for firearms comprising a body portion, a stabilizing element rotatively mounted therein, means independent of the projectile-propelling force for giving said stabilizing element an initial rotary movement about its axis, and wings mounted directly on the stabilizing element which are exposed to the air flow past the projectile during its flight and which thereby vary the rotative movement of the stabilizing element as given to it by said means.

7. A projectile comprising a projectile body provided with a through axial passage open at its ends for the flow of air therethrough during the ight of the projectile, a stabilizing element rotatively carried by said body and having an axial opening which registers with the axial passage of the projectile body, means independent of the projectile-propelling force to give the stabilizing element an initial rotative movement about its axis, and wings carried by the stabilizing element and projecting into said opening whereby during the flight of the projectile the air flowing through said passage acts on the wings and thus exercises an influence over the rotative movement of the stabilizing element.

GEORGE NORMAN ALBREE.

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