US1407532A - hadfield - Google Patents

Description

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R. IIADFIELD, A. G. NICK. JACK, AND A. B. H. CIERRE.

CAPPED ARMOR PIERCING PROJECTILE,

APPLICATION FILED NOV. 29,19I9.

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Specification of Letters Patent. latented Fab. 2l,

I Application lec November 2,8, 1919. Serial No. 341,024.V

To all whom t may concern Be it known that we, Sir ROBERT ABBOTT HAnFmLD, ALEXANDER GEORGE MoKnNZIE JACK, and AUGUSTUS BAsIL Hor/r CLERKE, subjects of the King of Great Britain andA Ireland, residing, respectively, at Westminster. England, and Sheffield, in the county ot, York, England, have invented mprovements in or Relating to Gapped Armor- Piercing Projectiles, of which lthe following is a specification.

This invention has for its' object to provide a. capped .armor piercing projectile having a hollow fore-cap which shall combine a percentage weight and distribution of cap material suitable for the attack of thick armor at considerable angles'of Obliquity with-such external contour as is required to `Qbtain a ballistic flight equivalent to that obtained by the use of an ogival forni of seven calibres or greater and without exceeding `the limits of length of the whole projectilev imposed by the consideration ot' easy stowage and handling.

In forming the outline dimensions ot the caps of such armor piercing projectiles it' has hitherto been the custom to construct such acap, in the main, of portions of two arcs of the desired radius struck from centres lying in the transverse plane of the bourelet or within a short distance seldom exceeding say one sixth of the calibre, in rear of the same. At the same time, in order to limit the overall length or" the projectile to that convenient foreasy handling and stowage, it has been customary to employ a shorter radius than that which would be required to form a true ogive; that is to say, the arcs with which the outline is mainly constructed would cut the plane of the bourelet within the wall ofthe projectile itself.

While thus producing an outline of a capped projectile of suitable length as mentioned above, this form of-construction has the etfect of limiting the weight of the cap and imposing a distribution of cap material unsuitable 'for the' successful penetration of thick armor at considerable angles of obliquity. The'maximum diameter of a cap so constructed is further considerably less than the calibre of the projectile itself, seldom exceeding three-fourths of the calibre and in no case reaching to 98 per cent of thel calibre of the projectile so that the weight of the cap forms about 7 or 8% of the total yweight of the cap and projectile.y

Now thejpresent invention has Jfor its object to produce-a capped armor piercing projectile capable of being' fired with the vaid of existing `range tables' and of successfully penetrating modern hard faced armor. of calibre thickness when striking the armor at a considerable Obliquity, say of 200 or more to the nonnahcorresponding "to long lrange and comparatively low velocity. f

To attain thisobject we have fou-nd that it is necessary that the Weight of the cap used should be equall to about 12% of the total weight of the combined cap and projectile, whilst the external contour of the cap should, as heretofore, be of seven calibres or more in radius, in order to obtain the required ballistic flight characteristics.

To produce a capped armor piercing` proj ectile having the required weight of cap and external contour necessary for successful. use as set forth, the armor piercing projectile is provided with an ogival shaped head of from one point tive to one point seven calibre radiufpreferably of about one point six calibre radius, the cap being arranged to nal distance from the centres of these arcs: to the transverse plane passlng through the hourelet maybe defined as being not less` than three fourths of the calibre. u

The I construction above described '-per'mlts of a cap being obtained of much greaterY weight, for a given overall length7 than that which has heretofore been adopted with caps having an external contour of seven or more calibre radius, and of the diameter of the rearend of the cap being made ofnearly the'- same diameter as the calibre of the projectile, say 98 per cent of the calbre,-so that the Weight of the cap may constitute 12% of the weight of the combined cap and projectile.

tei-nal contour of the combined solid cap and hollow fore-cap terminating 'at the blunt forward end of the fore-cap.

In the accompanying illustrative drawings, Fig. l shows in central longitudinal section, a portion of a fourteen inch armor piercing projectile provided with a solid cap and hollow forecap embodying the invention, ,the head of the projectile having a radius of curvature of about one point six times the diameter of the body of the projectile. Fig.

2 is a sectional detail view showing a modification. Fig. 3 is a View in elevation illustrating a fourteen inch armor piercing projectile having incorporated therewith a' cap embodying the features of my present invention and wherein the centres of the respective arcs are indicated diagrammatically.

As shown, the base end of the solid cap a vextends back near to the bourelet b of the "projectile and the front end el of the hollow1 vforecap e is made of truncated shape, the outline dimensions of the combined solid cap and hollow forecap being constituted by the two arcs f each of about seven calibres in radius. Each arc is struck from a centre considerably in rear of a transverse plane passing through the bourelet and so placed that the arc if extended rearwardly, would pass near to but outside the extremeifmward end of the cylindrical surface of the body f/ of the projectile. the centres of the arcs* being situated at a distance behind the said transverse plane not less than about three-fourths of the calibre of the projectile, as set forth.

By the construct-ion described the maximuin diameter of the cap will be seen'. practically equal to the calibre of the projectile and the weight of the cap will be equal to about 1Q?? of the total weight of thc cap and projectile.

The truncated bluntfront end c1 of the hollow forecap r; in the example, has a diameter of about one sixth or one seventh of the calibre of the projectile and may advantageously be made at its front surface of conical shape, advantageously of the obtuse angular shape shown, though it may` if desired, be made of rounded shape, shown for example in Fig. 2, the front end of each case being therefore blunt- The front end of the cap a is shown in the example as of rounded shape and having a radius of about eight inches from the screw threaded-junction a" of the forecap c with the cap a, t wards the front end or tip al of the cap where it may have a much snialler'ra dius, say of about one point two four or two five inches.

In the exemplication of my invention as illustrated in Eig. 3 indicates the radius line defining the contour of the cap portion composed of the cap a and forecap e. In the fourteen inch projectile as illustrated this radius line is of a length equal to seven calibres 'of the projectile and the centre of this arc defining the curvature of the combined main and fore-cap, as indicated diagrammatically at in, is located in the plane i A. rlhis plane A as noted occurs at a distance of 10.85. (.775 calibre),4

behind the plane B B of the bourelet of the projectile. ln similar diugran'imatic inanner the radius line defining the arc of curvature of the, head of 'the projectile is shown at n, said radius having a length as indicated of twenty-three inches and equal to 1.541 cali.- bres' of the vprojectile and the centre of the arc .being indicated at o as occurring in the plane C C, the latter as illustrated being located a short distance behind the plane l B of the. bourelet.

An armor piercing projectile fitted with a combined solid Vcap and a hollow forecap constructed as described, whilst of standard overall dimensions and having standard ballistic and range characteristics, has a heaviercap and is better adapted for successfully penetrating thick hard faced armor plate at lower velocity and more ol'iliquely than the standard capped armor piercing projectile withhollow forecaps heretofore used.

lVhat we claim 1. An armor piercing projectile having an ogival head of fron 1.5 to 1.7 calibres radius and a solid cap extending nearly over the whole of the head/of the projectile and having an external contour formed mainly of Ytwo arcs of about seven calibres or more in radius struck from centresAso situated that the arcs if produced rearward would pass near to but outside the forward. end of the body of theY projectile for the purpose set forth.

2. An armor piercinfr projectile provided with a combined solid cap and hollow fore cap, the projectile having an ogival shaped head of from 3 .5 to 1.7 calibre radius and the combined solid cap and fore-cap having an external cont-our formed mainly of two arcs of about seven calibres or more in radius struck from centers so situatedv that the arcs. if produced rearward, would pass near to but outside the forward. end of the body of the projectile. the solid cap extending' backward over a large extent of the head of the projectile.

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