US Government As Represented by the Secretary of the Army

Bradford S Davis

Thomas E Harkins

David J Hepner

William P D'Amico

Gary S Borgen

James M Garner

Michael S L Hollis

James F Newill

Jerry Lee Watson

Peter C Muller

Lawrence W Burke

John L Thompson

Edward F Bukowski

A fin disengagement device for limiting the range of a projectile uses an electronic safe and arm circuit to sense launch and spin levels. Once armed, the stored energy from the electronic safe and arm circuit is dumped into an initiator or directly to explosive bolts. The initiator ignites an energetic material to separate the fin from the projectile in-flight at a predetermined time. Alternatively, the explosive bolts separate the fin from the projectile in-flight at a predetermined time. In the embodiments using an initiator and energetic material, an opening or cavity in the rear portion of the projectile body or rod adapter acts as a pressure chamber. When enough pressure has built up from the burning of the energetic material, the front hub of the fin section expands enough to disengage the threads and separates the fin section from the projectile body.

Fin disengagement device for limiting projectile range

A system which derives the attitude of a body as it rotates and travels through the earth's magnetic field. At least one magnetometer is placed in the body and provides an output signal during flight of the body. The zero crossings of the output signal are used to formulate a time discriminant. This time discriminant is compared with a roll angle discriminant for which a value of attitude has been previously determined. From the comparison, the attitude during flight may be determined. A time discriminant can also be formulated using two magnetometers.

Method and system for determining magnetic attitude

An electronic safe and arm apparatus disposed in a projectile having a spin axis and a spin rate includes a battery; a power supply board connected to the battery, the power supply board including a mechanical G-switch that closes permanently at a predetermined acceleration, and a time-delay circuit connected to the G-switch; a firing board connected to the power supply board, the firing board including: an accelerometer that is oriented perpendicular to and disposed a fixed distance from the spin axis, an output of the accelerometer varying according to the fixed distance from the spin axis and the spin rate of the projectile; a comparator connected to the output of the accelerometer wherein the comparator compares the output of the accelerometer to a threshold voltage and an output of the comparator is low when the output of the accelerometer is less than the threshold voltage and the output of the comparator is high when the output of the accelerometer exceeds the threshold voltage; a rectifier connected to the output of the comparator; a firing capacitor, the rectifier being connected between the battery and the firing capacitor whereby when the output of the comparator is high the comparator saturates a gate of the rectifier thereby allowing the firing capacitor to charge; and an initiator connected to an output of the firing capacitor; and a timing board connected to the power supply board and the firing board, the timing board for setting and controlling a predetermined time delay for discharge of the firing capacitor into the initiator.

Electronic safe and arm apparatus for initiating a pyrotechnic

A system which is packaged within a projectile fuze body and obtains data relative to the projectile during a launch. Sensors are provided which obtain in-bore data as well as in-flight data. The in-bore data is recorded at a fast rate during in-bore travel of the projectile and is read out, continuously, at a slower rate during in-flight travel. Both in-bore data and in-flight data are encoded and transmitted to a ground station for analysis.

Aeroballistic diagnostic system

In a projectile launched by a gun, the projectile including a fuze with a longitudinal axis of symmetry and a braking device, an apparatus disposed in the fuze for determining a time of deployment of the braking device, the apparatus including a first accelerometer having a sense axis and mounted with its sense axis coincident with the longitudinal axis of symmetry of the fuze; a second accelerometer having a sense axis and mounted a known axial distance from the first accelerometer and with its sense axis coincident with the longitudinal axis of symmetry of the fuze; a magnetometer having a sense axis and mounted with its sense axis orthogonal to the longitudinal axis of symmetry of the fuze; a field-programmable memory unit loaded with aiming data of the gun, magnetic field direction at the gun, a nominal path length table, and a braking device maneuver authority table; and a microprocessor connected to the first and second accelerometers, the magnetometer, the field-programmable memory unit and the braking device.

Drag-brake deployment method and apparatus for range error correction of spinning, gun-launched artillery projectiles

A receiver, modeled after the spade-like lug attachment of a M198 howitzer spade, inserts into the recess on the bottom rear end of the left trail of the howitzer. On this end surface is a square hole for inserting the spade key which secures the receiver to the trail. Attached to the receiver is an interface plate that acts as the union between the receiver and a pair of caster wheels. The interface plate has a keyway, in which the receiver bottom inserts, and also has two built-in handles. Two bolts affix the receiver to the interface plate and thread directly into the receiver body. The interface plate is bolted to dual-pneumatic caster wheels. This combination allows the left trail of the howitzer to be mobile and facilitates the increased mobility of the M198 howitzer.

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Jarrettsville, MD, United States of America

Bradford S Davis