US3742854A

US3742854A - Fuze

Info

Publication number: US3742854A
Application number: US00459132A
Authority: US
Inventors: W Donahue; T Cammack
Original assignee: US Department of Navy
Current assignee: US Department of Navy
Priority date: 1965-05-26
Filing date: 1965-05-26
Publication date: 1973-07-03
Anticipated expiration: 1990-07-03

Abstract

1. A shaped charge bomb comprising, AN ELONGATED HOLLOW BOMB CASING HAVING A NOSE PORTION AT ONE END AND A TAIL PORTION AT ITS OTHER END, A SHAPED EXPLOSIVE CHARGE HAVING A CONICAL METAL-LINED RECESS FORMED THEREIN, SAID SHAPED CHARGE BEING POSITIONED WITHIN SAID BOMB CASING SO THAT SAID RECESS IS ADJACENT TO THE NOSE OF THE BOMB, A CYLINDRICAL STRIKER TUBE MOUNTED UPON THE NOSE OF THE BOMB CASING FOR LONGITUDINAL SLIDING MOVEMENT RELATIVE TO THE BOMB CASING, SAID STRIKER TUBE BEING COAXIALLY ALIGNED WITH SAID CONICAL RECESS AND POSITIONED FOREWARDLY THEREOF, AND A MECHANICAL DETONATING MEANS MOUNTED UPON SAID CASING FOR DETONATING SAID SHAPED CHARGE IN RESPONSE TO MOVEMENT OF SAID STRIKER TUBE, SAID DETONATING MEANS INCLUDING AN EXPLOSIVE BOOSTER CHARGE POSITIONED IN THE TAIL PORTION OF SAID BOMB CASING IN OPERATIVE ASSOCIATION WITH SAID SHAPED CHARGE, A STAB DETONATOR TYPE FUZE POSITIONED FOR ACUTATION IN RESPONSE TO MOVEMENT OF SAID STRIKER TUBE, AND A DETONATING CORD LEADING FROM SAID STAB DETONATOR TO SAID BOOSTER CHARGE AND BEING POSITIONED EXTERIORALLY OF THE BOMB CASING, A STRIKER PIN MOUNTED UPON SAID CASING AND POSITIONED FOR MOVEMENT BY SAID STRIKER TUBE TO DETONATE SAID STAB DETONATOR, A FUZE ARMING MECHANISM MOUNTED UPON THE NOSE OF THE BOMB CASING INCLUDING A CYLINDRICAL BEARING TUBE MOUNTED UPON THE NOSE OF SAID BOMB CASING AND BEING CONCENTRICALLY DISPOSED ABOUT THE PERIPHERY PORTION OF SAID STRIKER TUBE, AN ANNULAR ARMING ROTOR ROTABLY MOUNTED UPON SAID BEARING TUBE, SAID STAB DETONATOR BEING MOUNTED UPON SAID ARMING ROTOR FOR ROTATION THEREWITH FROM AN UNARMED POSITION WHEREIN SAID STAB DETONATOR IS OUT OF LINE WITH SAID STRIKER PIN AND WITH SAID DETONATING CORD TO AN ARMED POSITION WHEREIN SAID STAB DETONATOR IS ALIGNED WITH THE STRIKER PIN AND DETONATING CORD, AND MEANS FOR DRIVING THE ROTOR FROM ITS UNARMED POSITION TO ITS ARMED POSITION, WHEREBY THE DESTRUCTIVE JET PRODUCED BY THE SHAPED CHARGE MAY IMPINGE DIRECTLY UPON THE TARGET WITHOUT INTERFERENCE.

Description

United States Patent 1191 Donahue et al.

[ July 3,1973

[ FUZE [75] Inventors: William J. Donahue, Takoma Park; Thomas A. Cammack, Beltsville, both of Md.

[73] Assignee: The United States of America as represented by the Secretary of the Navy, Washington, DC.

[22] Filed: May 26, 1965 [21] Appl. No.: 459,132

Primary Examiner-Samuel W. Eng-1e Attorney-J. P. Dunlavey and J. O. Tresansky EXEMPLARY CLAIM 1. A shaped charge bomb comprising,

an elongated hollow bomb casing having a nose portion at one end and a tail portion at its other end,

a shaped explosive charge having a conical metal-lined recess formed therein,

said shaped charge being positioned within said bomb casing so that said recess is adjacent to the nose of the bomb,

a cylindrical striker tube mounted upon the nose of the bomb casing for longitudinal sliding movement relative to the bomb casing,

said striker tube being coaxially aligned with said conical recess and positioned forewardly thereof, and

a mechanical detonating means mounted upon said casing for detonating said shaped charge in response to movement of said striker tube,

said detonating means including an explosive booster charge positioned in the tail portion of said bomb casing in operative association with said shaped charge,

a stab detonator type fuze positioned for acutation in response to movement of said striker tube, and

a detonating cord leading from said stab detonator to said booster charge and being positioned exteriorally of the bomb casing,

a striker pin mounted upon said casing and positioned for movement by said striker tube to detonate said stab detonator,

a fuze arming mechanism mounted upon the nose of the bomb casing including a cylindrical bearing tube mounted upon the nose of said bomb casing and being concentrically disposed about the periphery portion of said striker tube,

an annular arming rotor rotably mounted upon said bearing tube,

said stab detonator being mounted upon said arming rotor for ,rotation therewith from an unarmed position wherein said stab detonator is out of line with said striker pin and with said detonating cord to an armed position wherein said stab detonator is aligned with the striker pin and detonating cord. and

means for driving the rotor from its unarmed position to its armed position,

whereby the destructive jet produced by the shaped charge may impinge directly upon the target without interference 9 Claims, 4 Drawing Figures PATENTEUJUL3 I975 SHEEIIBFS INVENTORS W////0m J Donahue BY Thomas A. Cammack a? ATTORNEYS PATENTEDJULS 1975 3,742,854

SNEU 2 0F 3 INVENTORS WIN/22m J. Donahue BY Thomas A. Cammac/r ATTORNEYS PATENTEDJUL3 I973 Fig. 3

INVENTORS W/l/fam J. Donahue Thomas A. Gammack ATTORNEYS FUZE The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

The present invention relates to shaped charge bombs and more particularly to a shaped charge bomb having a nose fuze and triggering device which does not impair the penetration capabilities of the bomb. In the construction of shaped charge bombs, it is desirable to have an impact sensing trigger located in the nose of the bomb to insure the rapidity of action necessary for effective firing of weapons at high velocity impacts and which is not obtainable with the slower acting base located inertial triggers, and it is also considered desirable to position the safety and arming system for the bomb fuze near the forward portion of the bomb so that the center of gravity is located near the nose of the bomb to improve its stability in flight. Heretofore it has been inefficient to position the fuze arming device forwardly of the shaped charge because previously known safety and arming devices would obstruct the target penetrating jet produced by the shaped charge. Similarly, the positioning of a piezoelectric impact sensing trigger in the nose of a shaped charge bomb for actuation of a base located fuze also impairs the destructive capability of the jet produced by the shaped charge but to a lesser extent. The present invention provides a fuzing system for a shaped charge bomb which overcomes the aforementioned shortcomings of the earlier arrangements.

Previously known fuzes for bombs of this type have not been entirely satisfactory due to the absence of discriminating intelligence whereby environments peculiar to aircraft landing and take-off operations is distinguishable from that over the target. The conventional practice is to employ an out of line explosive train in a bomb fuze and to drive the explosive train to its armed position by means of a direct connection to an air driven impeller. The arming time required to align the fuze train of conventional bombs is a function of the distance traversed by the bomb after release from the aircraft and it therefore becomes apparent that, when such bombs are launched at very high speeds, the entire arming operation occurs while the bomb is still in the substantially horizontal portion of its trajectory and in close proximity to the aircraft. The present invention overcomes this problem by providing a bomb with a fuze arming device having a built-in timing system to prevent arming of the fuze prior to the expiration of a predetermined constant time interval subsequent to release by the aircraft, thus permitting the aircraft to reach a safe distance from the weapon before the weapon is armed. The present invention additionally provides a shaped charge bomb having an air speed discriminating means which is of simpler construction than previously known means and is more reliable in its operation, thus insuring the safety of the deck crew or ground crew by preventing arming of the bomb until the bomb is exposed to air speeds in excess of the takeoff and landing speeds of the aircraft.

The present invention provides a shaped charge bomb having the fuze and trigger positioned in the nose of the bomb while avoiding interference with the jet produced by the shaped charge. The bomb fuze utilizes an out of line explosive train which is locked in its unarmed position by means of a centrifugal weight type of air speed discriminating means. Upon exposure to a predetermined minimum air speed, the air speed discriminating means releases the arming rotor which is then rotatably driven a first incremental distance towards its armed position which movement requires a predetermined constant time interval and the arming rotor is subsequently driven a second incremental distance to its fully armed position by means of an air driven impeller. Upon impact with a target when the fuze train is aligned, a cylindrical steel tube in the nose of the bomb drives a firing pin into a stab detonator in the explosive train to explode a booster charge in the base of the shaped charge by means of an interconnecting detonating cord positioned exteriorally of the bomb casing.

An object of the present invention is to provide a shaped charge bomb having a trigger and fuze positioned in the nose of the bomb forwardly on the shaped charge.

Another object of the invention is to provide an all mechanical shaped charge bomb which does not impair the penetrating power of the jet produced by the shaped charge.

Another object of the invention is to provide a shaped charge bomb having a nose located trigger and fuze which will prevent arming of the bomb until a bomb has been exposed to an air velocity in the excess of the landing and take-off velocities of the launching aircraft.

Still another object is to provide a shaped charge bomb having a nose located trigger and fuze which wili prevent arming of the bomb prior to the expiration of a predetermined time interval after release of the bomb by the aircraft.

A further object of the invention is to provide a shaped charge bomb having an all mechanical trigger and fuze located in the nose of the bomb and which incorporates a target discriminating means.

Other objects in many of the attendant advantages of this invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings in which like reference numerals designate like parts throughout the figures thereof and wherein;

FIG. 1 is an elevational view partially in section showing a shaped charge bomb constructed in accordance with a preferred embodiment of the present invention;

FIG. 2 is an enlarged sectional view of the fuze arming device and nose trigger taken along line 2--2 of FIG. I, the fuze being shown in its unarmed position;

FIG. 3 is an enlarged sectional view of the fuze shown in its armed position; and

FIG. 4 is an enlarged perspective view showing the details of the arming rotor.

Referring now to the drawings and more particularly to FIG. 1 thereof, the numeral 10 generally designates a shaped charge bomb constructed according to a preferred embodiment of the present invention. The bomb is shown as having a casing 11 within which is positioned a mechanical metallic partition 12, the space between the mechanical partition 12 and the casing 11 being filled with explosive material 13 to form the shaped charge. Upon the nose of the bomb is mounted the fuze arming device 14 which is controlled and driven by an impeller 15 which is rotatably mounted upon the fuze housing. The bomb is further provided with a mechanical nose trigger for detonating a stab detonator within the fuze arming device 14 upon impact with the target, said nose trigger comprising a short thin metallic tube 16 fixedly secured to the bomb to form a bearing for an annular arming rotor and to function as bearing or guide for a longer thin metalic striker tube 17 concentrically disposed within the first tube 16 and positioned for telescopic sliding movement therein upon impact with the target for actuation of the stab detonator. The striker tube 17 is of such length as to provide the proper stand-off distance of the shaped charge from the target. Upon detonation of the stab detonator by the striker tube 17, the detonation is transmitted from the nose of the bomb to a booster charge 19 positioned in the base of the shaped charge by means of a detonating cord 18 positioned exteriorally of the bomb casing. The bombs position during free-fall flight upon being released by the aircraft is controlled by a tail fin assembly 21 secured to the bomb housing by any conventional means.

Referring now to FIG. 2 which shows an enlarged sectional view of the fuze arming device shown in its unarmed position, a fuze housing 22 is secured to the forward portion of the bomb casing 11 by any convenient means. Positioned within the fuze housing is an annular support plate 23 which is mounted upon one end of the bearing tube 16 and against a portion of the bomb casing 11. An annular fuze arming rotor 24 is rotatably mounted upon the bearing tube 16 for rotation about the common axis of the bearing tube and the conical shaped charge for movement from an unarmed position to an armed position. The arming rotor has an explosive stab detonator 25 positioned therein which is rotatable from its unarmed position shown in FIG. 2, to its armed position shown in FIG. 3. In the armed position, the stab detonator 25 is positioned in alignment with and adjacent to a pair of

striker pins

26 and 27 secured respectively to a pair of annular support blocks 28 and 29. In the unarmed position shown in FIG. 2, movement of the

striker pins

26 and 27 is prevented by their contact with the solid metallic portion of the arming rotor. The arming rotor is held in its unarmed position by means of a lock pin 31 which engages a recess 32 in the rotor, the locking pin being resiliently biased by means of a helical compression spring 33 into contact with a pair of

centrifugal weights

34 and 35 which are pivotally mounted upon

posts

36 and 37 respectively, said weights being resiliently biased toward one another for mutually abutting contact to prevent axial movement of the lock pin 31. The support posts for the centrifugal weights are mounted upon a spur gear 38 which is rotatably journalled in a recess 39 formed in a bearing block 41. The bearing block 41 not only serves as a pivotal support for the centrifugal weight assembly but additionally serves as the outer race for the ball bearings 42 upon which an annular ring gear 43 is rotatably mounted for the engagement with the spur gear 38. The ring gear 43 is driven by impeller 15 which is secured thereto for reaction with the air stream about the bomb. The ball bearings 42 may be made of conventional bearing materials but are preferably made of plastic to withstand the high frequency vibrations to which the bomb is subjected when mounted upon the aircraft. In weapons of this type, lubricants cannot be used on the bearings because low temperatures increase the viscosity of the lubricant and increase the bearing drag while high temperatures lower the viscosity to an extent that the lubricant may flow into contact with the explosive and contaminate the explosive. In the absence of lubricants, metal bearings are subject to fretting when exposed to normal aircraft vibrations, and such bearing deterioration presents a potential source of high friction losses and possible binding of the rotating assembly. The resiliency of the plastic bearings enables the bearings to absorb the vibrations and therefore prevent fretting, thus offering a low friction rotating coupling which is extremely reliable, even when subjected to high frequency vibrations.

When the bomb has been released from the aircraft and the impeller is subjected to the air stream around the bomb, the reaction of the impeller with the air stream rotates the impeller and the ring gear 43 to thereby rotate the centrifugal weight assembly. The resilient force of the springs which bias the

centrifugal weights

34 and 35 into mutual abutting contact is predetermined so that when the impeller 15 is exposed to an air velocity in excess of the landing and take-off velocity of the aircraft, the centrifugal force of the

weights

34 and 35 overcomes the bias force of their respective springs, thus causing the weights to rotate about their respective pivot posts 36 and 37 in opposite directions to create a void therebetween into which the lock pin 31 may be forced by the helical compression spring 33. Upon movement of the lock pin 31 into the void formed between the centrifugal weights, the opposite end of the lock pin is withdrawn from recess 32 in the arming rotor and the rotor is then released for movement by' a stored energy spring 44 acting through a gear train 46.

The arming rotor is connected to the stored energy spring by means of a sector gear 45 which is mounted upon the arming rotor for engagement with a spur gear in a runaway clutter gear assembly 46 which functions as a clock mechanism and is driven by the stored energy spring 44. The runaway clutter gear assembly is similar to that gear train disclosed in FIG. 5 of my copending application Ser. No. 428,264 filed Jan. 26, 1965, now U.S. Pat. No. 3,670,656, wherein an oscillating balance bar is employed to regulate the speed of the gear train. In the present invention, the stored energy spring drives the gear train at a fixed rotational velocity to rotate the arming rotor 24 a predetermined angular distance before the sector gear 45 is disengaged from the spur gear in the gear train 46. The incorporation of an oscillating balance bar in the runaway clutter gear assembly regulates the speed of the gear train and therefore enables the gear train 46 to perform the dual functions of a time delay means and a rotor driving means. When the sector gear 45 is released by the gear train 46, the rotor 24 has been driven by the stored energy spring 44 an angular distance which is only an incremental portion of the total distance required for the rotor to move from its unarmed position to its armed position.

' The manner by which the rotor is driven the remaining distance to its fully armed position is by means of the impeller and a friction clutch. The centrifugal weight assembly, which is rotatably driven by the impeller 15 in the manner hereintofore described, is provided with a cylindrical hub portion which houses the rotor locking pin and its bias spring, said hub portion having an annular knurled drive wheel 49 formeci thereon. An arcuate friction pad 47 is fixedly secured to a circumferential portion of the arming rotor and is circumferentially positioned upon the arming rotor in such a manner that the pad does not normally contact the driving wheel 49 but will be brought into contact with the driving wheel only after the stored energy spring 44 has rotated the arming rotor and just prior to the release of the sector gear 45 from the spur gear in the gear train 46. Upon release of the rotor by the locking pin and just prior to completion of the time delay measured by the gear train 46, the friction pad is moved into the contact with the knurled driving wheel so that the arming rotor may be rotated by the impeller to its fully armed position. The device is provided with any conventional stop means to prevent movement of the rotor beyond its fully armed position and to iock the rotor in that position.

Prior to reaching the fully armed position, the stab detonator is out of line with the detonating cord and the striker pins 26 and 27 to thereby prevent inadvertent actuation of the bomb. Moreover, movement of the striker tube 17 for actuation of the striker firing pin 26 is prevented when the rotor is in its unarmed position by virtue of the contact of a stop pin 51 with the solid portion of the arming rotor. The annular arming rotor is provided with an axial slot 52 formed in the inner peripheral wall thereof which, when the rotor is in its fully armed position, is brought into alignment with the stop pin 51 to permit movement of the striker tube 17 and stop pin 51 upon impact with a target.

The present invention has been provided with a target discriminating means to prevent actuation of the bomb as it encounters objects other than the target such as tree branches, leaves and or other foilage or camouflage. To perform the target discriminating function, a shear wire 52' is fixedly secured to the arming rotor and extends transversely across the axial groove 52 to prevent movement of the striker tube and pin 51 unless the bomb makes contact with a very rigid object such as a tank or other hard targets. The shear wire is designed to be of such a strength as to resist movement of the striker tube and actuation of the bomb by forces applied to the tube of a magnitude such as encountered when the bomb falls through the leaves and branches of a tree or other target sheltering means, but the wire will break when the striker tube makes impact with a solid object or target. Since the bomb of this type is intended for-use in a cluster weapon wherein a large number of similar bombs are released from the cluster to be scattered about a target area, it is foreseeable that some of the bombs will miss their targets and land on the ground adjacent to enemy personnel or infantry. In such cases, the bombing may not be sufficient to shear the wire 52 and therefore the bomb is further provided with a secondary firing system comprising a tubular metallic inertial weight 53, mounted for sliding movement within the bearing tube 16. The inertial weight hs an axial slot formed in one wall thereof to receive the striker pin 27 so that, when the bomb is subjected to a large deceleration force, the inertial weight will slide to the left as viewed in FIGS. 2 and 3 to force the striker pin 27 down into the stab detonator to detonate the bomb. The inertial weight is provided with a stop pin 54 similar to pin 51 for preventing movement of the inertial weight before the bomb has been armed.

In operation, a plurality of shaped charge bombs are released from a cluster bomb which is dropped by an aircraft over the target. Upon exposure to the air stream around the bomb, the impeller 15 rotates upon reaction with the air stream, thus rotating ring gear 43, spur gear 38, the centrifugal weight assembly and the driving wheel 49. When the impeller reaches a predetermined rpm, the centrifugal force of the centrifugal weights causes the weights to separate and thereby creates a void between the centrifugal weights into which the locking pin is biased by spring 33, thus releasing the locking pin from the detent to free the rotor for movement by the stored energy spring 44. The stored energy spring drives the time delay gear train 46 to move the arming rotor a first incremental distance toward its armed position. Upon movement through the first incrementaldistance, the sector gear 45 disengages from the gear train 46 to free the rotor from control by the stored energy spring and the friction pad 47 is brought into contact with the rotating drive wheel 49, which then moves the rotor a second incremental distance into its fully armed position. In its fully armed position, the stab detonator is aligned with the striker pins and is adjacent to the detonating cord and the axial slot 52 is aligned with pin 51 on the striker tube so that the nose fuze is ready for actuation upon impact with the target.

From the foregoing description, it will be apparent that a new and improved shaped charge bomb has been disclosed wherein the bomb is characterized by a nose fuze and nose trigger which do not impede nor obstruct the jet produced by the shaped charge upon impact of the bomb with the target. The positioning of the trigger and the fuze in the nose of the bomb provides a bomb having its center of gravity in the nose rather than in the tail, as characterized by conventional shaped charge bombs. The shaped charge bomb of the present invention is additionally characterized by an ability to discriminate between air velocities and to permit the bomb to be armed only when exposed to air speeds in excess of the landing and takeoff speed of the launching aircraft. The time delay function provided by the stored energy spring driven gear train prevents arming of the bomb prior to the expiration of a predetermined time interval subsequent to exposure of the bomb to an air stream in excess of the take-off velocity of the launching aircraft, thus insuring that the aircraft reaches safety before the bomb is permitted to arm. Having been armed, the shear wire prevents destructive of the bomb if it should pass through any branches of target trees and upon impact with the target, the trigger tube 17 forces the striker pin 26 into the stab detonator 25 to fire the bomb. In the event that the bomb misses the target and strikes the ground or some other object which will not shear the wire 52', the inertial weight 53 will drive the striker pin 27 into the stab detonator to fire the bomb.

Obviously many modifications and variations of the present invention are possible in the light of the above teachings. It is therefore to be understood, that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described.

What is claimed is:

l. A shaped charge bomb comprising,

a shaped explosive charge having a conical metallined recess formed therein,

a cylindrical striker tube mounted upon the nose of the bomb casing for longitudinal sliding movement relative to the bomb casing, said striker tube being coaxially aligned with said conical recess and positioned forwardly thereof, and

a mechanical detonating means mounted upon said casing for detonating said shaped charge in re sponse to movement of said striker tube,

a stab detonator type fuze positioned for actuation in response in movement of said striker tube, and

an annular arming rotor rotatably mounted upon said bearing tube,

said stab detonator being mounted upon said arming rotor for rotation therewith from an unarmed position wherein said stab detonator is out of line with said striker pin and with said detonating cord to an armed position wherein said stab detonator is aligned with the striker pin and detonating cord, and

means for driving the rotor from its unarmed position to its armed position,

whereby the destrictive jet produced by the shaped charge may impinge directly upon the targe without interference.

2. The bomb of claim 1 wherein the inner diameter of the striker tube is at least one-fourth the diameter of the shaped charge.

3. The bomb of claim 1 further comprising an inertial weight positioned in the nose portion of said casing for actuation of said stab detonator when the bomb is subjected to a large deceleration force.

4. The bomb of claim 1 wherein said fuze arming means includes rotor locking means responsive to the air speed of the means comprises an impeller mounted upon saidbomb casing to be driven by the air flow around' the bomb,

a rotor locking pin having one end extending into a recess formed in said rotor and being resiliently biased in a direction away from said rotor, and

a rotatably mounted centrifugal weight assembly connected to said impeller for rotation thereby,

said centrifugal weight assembly being in contact with said rotor locking pin to hold the pin in locking engagement with the rotor until the impeller rotates the centrifugal weight assembly at a predetermined minimum rpm,

whereby the fuze arming mechanism is capable of discriminating between environments peculiar to aircraft landing and take-off operations from environments encountered under normal bomb release conditions.

6. The bomb of claim 4 wherein said rotor drawing means includes a time delay means for preventing arming of the bomb prior to the expiration of a predetermined time interval subsequent to release of the arming rotor by the rotor locking means.

7. The bomb of claim 6 wherein said time delay means'comprises a stored energy spring driven clock mechanism mounted upon said rotor and releasably engaging said clock mechanism,

said sector gear being of such dimensions that the sector gear is released from engagement with the clock mechanism when the rotor has been driven only an incremental portion of the distance toward its armed positions.

8. The bomb of claim 7 wherein said rotor driving means further includes an environmentally powered drive mechanism for moving the rotor to its fully armed position upon release of the sector gear from said clock mechanism.

9. The bomb of claim 8 wherein said environmentally powered drive means includes a drive wheel pivotally mounted upon said casing and rotatably coupled to said impeller for rotation thereby,

a friction pad secured to a portion of said rotor and being positioned for operative engagement with said drive wheel just prior .to release of the sector gear from the clock mechanism.

t I i t i

Claims

1. A shaped charge bomb comprising, an elongated hollow bomb casing having a nose portion at one end and a tail portion at its other end, a shaped explosive charge having a conical metal-lined recess formed therein, said shaped charge being positioned within said bomb casing so that said recess is adjacent to the nose of the bomb, a cylindrical striker tube mounted upon the nose of the bomb casing for longitudinal sliding movement relative to the bomb casing, said striker tube being coaxially aligNed with said conical recess and positioned forwardly thereof, and a mechanical detonating means mounted upon said casing for detonating said shaped charge in response to movement of said striker tube, said detonating means including an explosive booster charge positioned in the tail portion of said bomb casing in operative association with said shaped charge, a stab detonator type fuze positioned for actuation in response to movement of said striker tube, and a detonating cord leading from said stab detonator to said booster charge and being positioned exteriorally of the bomb casing, a striker pin mounted upon said casing and positioned for movement by said striker tube to detonate said stab detonator, a fuze arming mechanism mounted upon the nose of the bomb casing including a cylindrical bearing tube mounted upon the nose of said bomb casing and being concentrically disposed about the periphery portion of said striker tube, an annular arming rotor rotatably mounted upon said bearing tube, said stab detonator being mounted upon said arming rotor for rotation therewith from an unarmed position wherein said stab detonator is out of line with said striker pin and with said detonating cord to an armed position wherein said stab detonator is aligned with the striker pin and detonating cord, and means for driving the rotor from its unarmed position to its armed position, whereby the destructive jet produced by the shaped charge may impinge directly upon the target without interference.

4. The bomb of claim 1 wherein said fuze arming means includes rotor locking means responsive to the air speed of the bomb for locking the rotor in its unarmed position until the bomb is exposed to a predetermined minimum air speed which is in excess of the take-off and landing speeds of the launching aircraft.

5. The bomb of claim 4 wherein said rotor locking means comprises an impeller mounted upon said bomb casing to be driven by the air flow around the bomb, a rotor locking pin having one end extending into a recess formed in said rotor and being resiliently biased in a direction away from said rotor, and a rotatably mounted centrifugal weight assembly connected to said impeller for rotation thereby, said centrifugal weight assembly being in contact with said rotor locking pin to hold the pin in locking engagement with the rotor until the impeller rotates the centrifugal weight assembly at a predetermined minimum rpm, whereby the fuze arming mechanism is capable of discriminating between environments peculiar to aircraft landing and take-off operations from environments encountered under normal bomb release conditions.

7. The bomb of claim 6 wherein said time delay means comprises a stored energy spring driven clock mechanism mounted upon said rotor and releasably engaging said clock mechanism, said sector gear being of such dimensions that the sector gear is released from engagement with the clock mechanism when the rotor has been driven only an incremental portion of the distance toward its armed positions.

9. The bomb of claim 8 wherein said environmentally powered drive meaNs includes a drive wheel pivotally mounted upon said casing and rotatably coupled to said impeller for rotation thereby, a friction pad secured to a portion of said rotor and being positioned for operative engagement with said drive wheel just prior to release of the sector gear from the clock mechanism.