US1531624A - Projectile - Google Patents

Description

I 7 March 31, 125. 1,531,624

w. K. RacHARDsoN PROJECTILE Film! Au 21, 1924 letented Mar. 31, 1%25.

PROJEGTILE.

Application filed August 21, 1924. Serial No. 733,390.

To all w/zom it may concern.

Be it known that I, WILLIAM K. RiounnnsoN, a citizen of the United States. residing at Washington, in the District of Columbia, have invented certain new and useful Improvements in Projectiles, of which the followin is afspccification.

The oliject of this invention is to provide improved means to iinpart rotary mo tion to a tired projectile by means of vanes or grooves tonnedupon the ogival head of the projectile, or upon the windshield. or both.

This means may be employed either inde pendent of or inconjunction with the present mode of imparting-rotation to the pro .pectile, namely, the rotating hand and the .l m. I

in the accompanying drawings, Fig. 1 is a side elevation of a shell. constrnctedaocording to the invention. Fig. 2 is an end view thereof. F ig. 3 an enlarged crossscction on the line of Fig. 1. Fig. 4 is a siniiiar view of a modification.

Referring to the drawings, 1 indicates the ogiva'l head upon which his .nounted.

the windshield 3 indicates the cylinder of the shell having atits forward extremity the honrrelct 4. 5 indicates the rotating hand and 6 the tapered iiase at the rear of the rotating hand of which there are twenty-five in, the shell shown, spaced equidistant and inclined forward from the hourrelet to the windshield 5, with a right hand twist having an angle normal to the plane of flight of ahout it)" 44". This angle has the effect of displacing the air tangentially at the same velocity of displacement as the radially displaced air from the ogival head of the projectile. the ogival head hcing struck on 7 calihre radius. 8 indicates the lace or front of the vane F which is pcrpcmlicular or at a 90 angle from the base or bottom 9 of the grooves forming the vane.

In the scale of construction shown for a- 14 shell. the faces 8 (ifthe vanes urei deep. and the bottoms 9, at. the horrelet have a width oi about 1 and at their forward extremity. back ot' the windshield 2. a width of about 1.

The manner in which the vanes 7 impart rotation to the projectile is as follows;

7 indicates the vanes.

Assuming the projectile. to he a 14 shell.

designed as in the drawings. having factors.

asfollows: W'eight loaded, 1210 lbs; muzzle velocity 2700 ft. per second; angle of elevation 15; coefficient of reduction of velocity 2% per second of time. Such a projectile fired from present guns, having a twist of'one turn in 25 calibres' and a muzzle velocity of 2700 ftipseo, would have impressed upon it 1068368 ft. lbs. of rotary energy, and a. peripheral velocity of 339.27 it. see.

Instead of: using sucha gummy invention permits and I propose to fire my projectile from a rifled gun having one turn in 100 Calibers. Therefore the peripheral rotary velocity ivill be 84.82 ft. sec., and ,the rotarycncrgy impressed upon thelired shell will he ($6773 ft. lbs. when the shell loaves the gun. There are on the projectile selected for this description, 25 vanes, each 25" long, deep, angle of vanes 10 44", which give a velocity of displacement of .186'7, oi the translatory velocity of the shell. The total area of the face of the vanes equal T8125".

To determine the air pressure upon the vancsF-With a muzzle velocity. of 2700 it. see; coefiicionl. of reduction 2%; the average velocity equalsfitl 3 ft.; angle of elevation 15; sine oi angle equals .2589; altitude 67G i't.: average density of air, .075875 lbs. per cu. it. With such factors the pressure equals the weight of the air (1175875) multiplied hy'thc square of the average velocity, or 7144929, divided by twice the acceleration (@LBQ) due to gravity, multiplied .by .186'vel0city of displace ment, divided by 14.4, the number of inches in a square foot, equals 10.886 lbs. ressure per square inch. The area. of vanes, 8.125". tirncS 1. .886,

nmximum,

p ssure pe in hequa s lOO 850.46875. ft. lbs. er foot rotary travel of the vanes. There ore for one foot of travel,

- relet will be 115/14 of 850.4687 or 698.6 ft.

m lb

. minus 103.6373

' 136063 ft. lbsstrue final energy;

'be im velocities. 84.82

acceleration 36.263 ft.

second of flight: Take the To determine thg acceleration :As the shell leaves the gun at a muzzle velocity of 2700 it. see. the rifling of the gun having a twist or one turn in 100 calibres, there Will ressed upon the shell a rotary energy of 66 73 ft. lbs. and a rotary velocity of 84.82 ft. sec. at the bourrelet. As shown above, thepe will be 698.6 ft. lbs. generated and impressed upon the shell in one foot of mum ,travel. 698.6 divided by 66773, the rotary energy impressed upon the shell due to the rifling ,of the gun,.equals .01004623 times 84.82 equals .887412 divided by 2 equals .4437 times 84.82 equals 37.634 ft, the acceleration for the first second of flight, plus 84.82 initial velocity equals 122.4546 ft. see. the rotary velocity. The rotary travel will be 103.6373 ft.; energy due to velocity of 122.4546 ft. sec. equals 139174 ft. lbs.

Proof: Energies are as the square of the 66773 31224542? 139174. Further proof: 698.6 energy per ft. of travel, times 103.6373 the travel, equals 72401 ft. lbs. 1plus 66773, initial energy, equals 13917 4 Correction must be made for. the eiiiciency of th vanes. While it is not material for the first second of flight, this efficiency gradually diminishes until there is no' rotary energy derived from that portion of the vanes which have a velocit reater than 186% of the translatory ve ocity of the shell, because the air cannot'impinge upon the vanes, for they are at an angle of 10. 44". The average velocity of the shell for the first second o flight equals 2673 times .186, sine of the angle, equals 500. 500 equals 250000, (rotary travel 1 sec.) 10740 239260 equals gm of 72401 ft. lbs. equals69290.

Correcting developed first second of flight plus 66773 ft. lbs., initial energy, equals which equals ft. sec. True -Travel 102.9515 ft.

to a rotary velocity of 121.083

sec. e To determine ,the energy developed for average ran e, the maximum ordinate, and average altitu e and from these factors determine the weight and pressure of the air and proceed to determine theenergy developed, final rotary velocity, etc.

.It is determined'inthe second second of flight there will be developed and impressed 306.05 ft. sec.

-When we reduce the twist upon the shell a rotary energy of 89524.53 ft. lbs. and-theshell will have a final rotary velocity 155.911 it. see. p

I The peak of efficiency of the vanes occurs in'the 6th second of flight, when there will be developed 93590 'ft. lbs. and. the total energy will be 595589 ft. lbs. and 'a rotary velocity 263.3255 ft. sec.

From this point in the "flight oi the shell the energy developed per each second lessens, due to reduced velocity of the shell, the density of the atmosphere, and the cflicieney of the vanes.

For the 8th second of flight developed equals 73428 ft. lbs.

For the 10th second of flight it will be 56661 ft. lbs. and a total energy impressed upon the shell for the ten seconds of flight will be 938689 ft. lbs.

the energy The advantages derived from a shell of the form stated are an increased muzzle velocity for the same propellant charge; re

duced maximum pressure in the gun; less erosion to the gun and therefore longer life; reduced longitudinal stress upon the' gun; greater accuracy of fire; increawd range; and the only means by which we may n1aterially increase the muzzle velocity of oiir highly developed guns. Y

We will now proceed to'analyze the advantages claimed by use of this invention. First a greater muzzle velocity: It. it evident that if that portion of energy of the propellant charge required to impart rotation to the shell is utilized to assist in producing acceleration of the shell in its travel thru the gun, there will be increased muzzle velocity in proportion to the square root of the energy eX1: ended, Which is of three distinct characters :,1st. quired to produce rotation; friction of the load upon the rifles of the gun; friction of the rotating base of the s ll upon the dense gases, and stripping of the rotating band by the lands of the gun, which represent the energy required for the flow of the copper band under pressure. 2nd. Reduced maximum pressure. As the resistance to the generated gases on detonation are reduced so isthe pressure, and a higher initial velocity is obtained and maintained thru out the gun, with but without a higher terminal pressure, for the reduced load governs both the pressure and the velocity. 3rd. Erosion, is directly. as the density of the/gases confined at that point, which'is determined by the pressure andthe temperatu v Therefore, when We reduce the maximum pres sure We at the same time perature,'and by so doing of the gun. 4th. Greater increase the life accuracy cf fire. or the gun one turn in calibies ta one in 100 and a rotary velocity Energy remore uniform pressure,

of the gun reduce the iZBllldue to ritiing of the guns.

as the range, due to the shell rolling upon the denser air on its lower sidedue to the acceleration of fall.

upon the vanes on the lower side counteracts the drift. As the great-est. rotary velocity will he attained after the shell has passed the crown of the trajectory or maximum ordinate, the gyroscopic influence offers resistance to the resultant of, forces,

1. e., motion of translation of the shell and the fall, due to gravity, the air pressure of each controlling the angle of tall. By slower obeying the pressure due to acceleration of fall the. range is materially increased, due to two causes, first, the area of crosssection of the longitudinal axis of the shell when at right angles to the plane of gravity offer the greatest resistance to the force of gravity, thru displacement of the air. Therefore acceleration of fall is reducedand the increased time of flight will represent that increase in range.

lt may appear on superficial consideration ht the subject matter presented in relation to this invention that: While the vanes of the ogival head will produce rotation of invention, displaces airat the same velocity,

but that portion of the air Which impinges upon the vanes is displaced tangentially and not radially and thru re. ction performs a useful function-i1nparts' rotation to the shell.

The art has arrived at the limit of muz zle velocity in our present constructed guns \Vith reduced twist (one turn in 100 calibers) the rotating band may he reduced in both Width and thickness, and the ritles shallower, for but of the energy is impressed upon the shell to produce rotation, compared to one turn in caliber-s, the prevailing custom. The vaw is reduced and the intensity of vibration is reduced as the square of the toler- With this turbine head shell, the greater reaction of the air mice. The great pressure in the first few feet of movement of an old or known shell, required to force the hand against the lands of the gun to produce flow of the dopper band, retards movement of the shell inthc first few feet of its travel and high maxi:

mum. pressure results, producing high tem-\ peralure and loss of energy. t is a Wellknoun principle of physics that Work performed of Whatever kind by a given source of energy reduces that initial energy directly as the resistance overcome; therefore, the energy which is employed to form the rotating hand to the lands and riding of the gun can perform no other function dynamically.

Une ot' the important principles to be deduced from the foregoing disclosure, and observed in making a most ellicient shell, is that the curvature of the spiral of the vanes equals the curvature of the ogival head, or, stated in another way, their projected area or face should he the same angle to the plane of the flight of the shell as'the angle of the ogival head. Thereby they produce the same velocity of displacement of the air as the ogival'head and produce the'desired turning.etlect Without changing the ballistic coellicient of the shell. By the projected area is meant that surface of the vanes which extends radially to the surface of the ogival head and at a right angle to the plane of flight. Thus, the projected area in the 14 shell herein illustrated equals the product of the vanes multiplied by their length 25", multiplied by A their depth, multiplied by .186 the sine of the angle, amounting to 14.53125, the projected area of the vanes.

The projected area. of the vanes in turbine head shells for all calibers should I equal .0053 of the cube of their calibre in inches. comparatively, their projected area should be approximately as their weights.

I would suggest as a scheme of design for any calibre shell, the ogival head of which is struck on from 6 to 7 calibre radius, that" the number of vanes be 1.8 timestho calibre of the shell, 1.8 times the calibre for.

for each inch of.-

their length, and .00 calihrc tor the depth of the vane. Thus for a 6" 'hll the number of vanes .would be 11, their mgth ll, and their depth (.008 times 6) .048. sine of angle .186 equals 1.0788" projected area. The correct projected area for a 6 shell, Weight 100 lbs. is 1.1488. Thus 6 equals 216 times .0053 equals 1.1448, the required projected area to impart a rotary velocity equal to rifled guns having one twist in 25 Calibers, by the time the fired shell has reached the crown of its trajectory or maximum ord1- natc. gun having at least 5 of elevation.

It not to be understood that the angle formed by surfaces 8 and 9 cannot be an liO - tional densit obtuse angle, that is, an angle greater than pFme of flig t must necessaril be increased shell is changed because the-air will be disan clearance for the deflects air from the surfaces is thus provided for. But in such construction, the ballistic coefiiecient of the placgd ata greater velocity than by a simia'fogi al head ungrooved. A greater an 'le than tllhtshown in Fig. 4, 7", is obtained by further spacing of the groove and a greater depth to the vane may be employed. The greater depth compensating for less vanes and not changing the total projected area required.

The depth of the vanes is a matter of design; likewise their number; but their combined projected area is a definite quantity, sufiicient to produce the desired result, depending on the weight, the calibre, the muzzle velocity, and the desired rotary velocity of the shell." Also, the vanes should be upon the ogival head, instead of elsewhere, because when so located they do not absorb otential energy of the shell and are most e oienti Grooves on a cylindrical sur face absorb potential energy-of the shell, hence the grooves should not extend rear+ ward of the bourrelet, and the best result is attained with grooves (or vanes) as above described, located on the ogival head of a stream line shell having a long struck on a radius of from 6 to 10' cahbers, a relatively short cylinder length, and a tapered base, such as-that disclosed in my U. S. PatentNo. 1145115. Y

I claim:

1. A projectile having an ogival head, and a plurality of vaneson the head curved andinclined at substantially the same angle to the longitudinal axis of the projectile as that of the ogive of the head.

2. A projectile having an o'gival head, and a plurality of spiral vanes on said head having substantially the same angle to the longitudinal axis of the projectile as that of -thc ogival head.

3. A projectile having in combination an ogival head, and vanes thereon consisting of two surfaces forming at leasta rightangle, lhe'numher of said vanes, their length, and angle with respect to the longitudinal axis, and depth, being such as to produce a total projected area on all shots and shells approximately proportional "to their weight,

at. A projectile as stated in claim 3, the curvature of the grooves w :.tl1 respect to the o'int longitudinal, axis of the projectile being;-

and vanes thereon todisplace t e air tan-- gentially in the flight of the projectile, said vanes being at an angle to displace the air at substantially the same velocity as that dis placed radially by the head.

7. A projectile as stated in claim 2, the pro ected area of the vanes bein substantially equal to .0053 of the cu e of the calibre. 8. A projectile having an ogival head and spiral vanes thereon, the rojected area of the vvanes being substantially equal .to .0053 of the cube of the calibre.

9. A projectile having an ogival head, and curved vanes thereon the projected area of which is approximately proportional to the weight, calibre, muzzle velocity and desired rotary velocity of the projectile.

10. A projectile having an ogival head,

and vanes on the head, one surface of said vanes being radial to'the central axis ofthe shell and having an angle to the-plane of flight equal to that of the ogival head.

11. A shell having an ogival head, and vanes on the head, one surface of said vanes being radial to the'central axis of the shell and theprojccted area. of said surface being approximately equal to 1.2 inches for 'cach lbs. weight of the shell.

12. A shell havihg an ogival head, and vanes on the head having two surfaces,-the projected area of said surfaces aggregating in inches proximatcly .0053 of the cali' I, of the shell in inches.

of the cube- 13. A pidjectile having in combination an ogival head and vanes thereon consisting of two surfaces forming at least a right angle,

the numherot said vanes, their length and depth being such as to produce a total projectcd area in all calibre shells approximately proportional to the cube of their calihres.

. In testimony whereof, I aflix my signature in the presence of two witnesses.

WILLIAM K. RICHARDSON. \Vitnesses:

'C. "W; FOWLER, Y

J. VINCENT MARTIN.

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