# US 9,040,885 B2 · Trajectory modification of a spinning projectile > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,040,885 B2 - Document ID: US9040885B2 - Status: Granted - Kind: B2 - Application number: 12/617,634 - Filed: 2009-11-12 - Published: 2012-08-23 - Granted: 2015-05-26 - Earliest claimed: 2008-11-12 - Assignees: General Dynamics Ordnance and Tactical Systems, Inc. - Applicants: Joseph P. Morris; Douglas L. Smith - Inventors: Joseph P. Morris; Douglas L. Smith - Web page: https://patentgrep.com/patent/US9040885B2 ## CPC - F42B 10/54: Spin braking means - F42B 10/62: Steering by movement of flight surfaces - F42B: EXPLOSIVE CHARGES, e.g. FOR BLASTING, FIREWORKS, AMMUNITION (explosive compositions C06B; fuzes F42C; blasting F42D) ## Abstract The invention is a projectile, device and system having a roll control device which may be fixed or deployable, for providing torque counter to the spin of the projectile and providing drag on the projectile. The roll control device includes a guidance collar rotatably attached to the projectile located near a front end of the projectile wherein the guidance collar includes one or more guidance collar aero-surfaces shaped to provide torque counter to the spin on the projectile. The guidance collar aero-surfaces may be controlled by a brake and guidance electronics on the projectile. The invention also includes a body collar fixedly attached to the projectile aft of the guidance collar, wherein the body collar includes one or more body collar aero-surfaces and fixed or deployable drag devices. Another embodiment use only a guidance collar aero-surfaces to orient a fixed drag device relative to an Earth inertial reference frame to create asymmetrical drag on the projectile and thereby altering its trajectory. ## Claims ### Claim 1 A projectile having a roll control device on the projectile while the projectile is spinning, comprising: a guidance collar rotatably attached to the projectile, guidance electronics attached to the projectile, wherein the entire guidance collar is rotatable relative to the spin of the projectile, wherein the guidance collar includes one or more guidance collar aero-surfaces shaped to provide a torque counter to the spin of the projectile and wherein the guidance collar further comprises one guidance collar drag device fixed upon the guidance collar making an asymmetrical drag surface on the guidance collar, and wherein the guidance collar rotation is controllable by the guidance electronics. ### Claim 2 (depends on 1) The projectile of claim 1, wherein the guidance collar is located near a front end of the projectile. ### Claim 3 (depends on 1) The projectile of claim 1, wherein the guidance collar is located near an aft end of the projectile. ### Claim 4 (depends on 1) The projectile of claim 1, wherein the guidance collar aero-surfaces are strakes. ### Claim 5 (depends on 1) The projectile of claim 1, wherein the one guidance collar drag device comprises a single, fixed drag device fixedly attached to an outer surface of the guidance collar. ### Claim 6 (depends on 1) The projectile of claim 1, wherein one guidance collar drag device is deployable. ### Claim 7 (depends on 1) The projectile of claim 1, wherein the one guidance collar drag device is controlled by a brake. ### Claim 8 (depends on 1) The projectile of claim 1, wherein the one guidance collar drag device comprises an element that changes the pressure profile around the projectile. ### Claim 9 (depends on 1) The projectile of claim 1, wherein the one or more guidance collar aero-surfaces and the guidance collar drag device are controllable by a braking element located within the roll control device. ### Claim 10 (depends on 1) The projectile of claim 1, wherein the guidance collar drag device comprises an asymmetric shape of the guidance collar. ### Claim 11 (depends on 1) The projectile of claim 1, wherein the guidance collar drag device comprises one or more of the following: a contour on the surface of the guidance collar providing asymmetrical drag and a tube on the surface of the guidance collar that diverts air flow to an interior portion of the tube. ### Claim 12 (depends on 1) The projectile of claim 1, further comprising a body collar fixedly attached to the projectile aft of the guidance collar, wherein the body collar includes one or more body collar aero-surfaces. ### Claim 13 (depends on 12) The projectile of claim 12, wherein the body collar aero-surfaces are strakes. ### Claim 14 (depends on 12) The projectile of claim 12, wherein the body collar further includes one or more body collar drag devices. ### Claim 15 (depends on 14) The projectile of claim 14, wherein one or more of the body collar drag devices are deployable. ### Claim 16 (depends on 14) The projectile of claim 14, wherein all of the body collar drag devices are deployable. ### Claim 17 (depends on 15) The projectile of claim 15, further comprising guidance electronics located in the interior of the roll control device, wherein the body collar drag devices are in electronic communication with the guidance electronics. ### Claim 18 A trajectory modification system for a projectile, comprising: a roll control device for providing torque counter to a projectile while the projectile is spinning, including: a guidance collar rotatably attached to the projectile, guidance electronics attached to the projectile, wherein the guidance collar includes one or more guidance collar aero-surfaces shaped for providing torque counter to a projectile while spinning, wherein the entire guidance collar is rotatable relative to the spin of the projectile, and wherein the guidance collar further comprises one guidance collar drag device fixed upon the guidance collar making an asymmetrical drag surface on the guidance collar, and wherein the guidance collar rotation is controllable by the guidance electronics. ### Claim 19 (depends on 18) The trajectory modification system of claim 18, wherein the guidance collar further located near a front end of the projectile. ### Claim 20 (depends on 18) The trajectory modification system of claim 18, wherein the guidance collar further located near an aft end of the projectile. ### Claim 21 (depends on 18) The trajectory modification system of claim 18, wherein the one guidance collar drag device comprises a single, fixed drag device. ### Claim 22 (depends on 18) The trajectory modification system of claim 18, wherein one more of the guidance collar drag device is deployable. ### Claim 23 (depends on 18) The trajectory modification system of claim 18, wherein the drag device comprises one or more elements that change the boundary layer around at least a portion of the projectile from laminar to turbulent or turbulent to laminar. ### Claim 24 (depends on 18) The trajectory modification system of claim 18, further comprising a body collar fixedly attached to the projectile aft of the guidance collar, wherein the body collar includes one or more body collar aero-surfaces. ### Claim 25 (depends on 24) The trajectory modification system of claim 24, wherein the body collar further includes one or more body collar drag devices. ### Claim 26 (depends on 25) The trajectory modification system of claim 25, wherein one or more of the body collar drag devices are deployable. ### Claim 27 (depends on 25) The trajectory modification system of claim 25, wherein all of the body collar drag devices are deployable. ### Claim 28 (depends on 18) The trajectory modification system of claim 18, wherein the guidance collar drag device comprises an asymmetric shape of the guidance collar. ### Claim 29 (depends on 18) The trajectory modification system of claim 18, wherein the guidance collar drag device comprises one or more of the following: a contour on the surface of the guidance collar providing asymmetrical drag and a tube on the surface of the guidance collar that diverts air flow.