# US 4,399,967 A · Staggered coil and nose-torquer electromagnetic pulse deicing systems > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 4,399,967 A - Document ID: US4399967A - Status: Granted - Kind: A - Application number: 06/214,541 - Filed: 1980-12-09 - Granted: 1983-08-23 - Earliest claimed: 1980-12-09 - Assignees: Lockheed Corporation - Inventors: Paul E. Sandorff - Web page: https://patentgrep.com/patent/US4399967A ## CPC - B64D 15/163: {using electro-impulsive devices} - B64D: EQUIPMENT FOR FITTING IN OR TO AIRCRAFT; FLIGHT SUITS; PARACHUTES; ARRANGEMENT OR MOUNTING OF POWER PLANTS OR PROPULSION TRANSMISSIONS IN AIRCRAFT ## Abstract The invention is a staggered-coil and nose-torquer electromagnetic pulse deicing system and process for deicing airfoil surfaces. A plurality of upper and lower electromagnetic impulse coils (18) and (20) are arranged in a staggered geometrical array spanwise of an airfoil or wing (22). The upper coils (18) are arranged adjacent to and spaced from the upper wing skin surface (24) while the lower coils (20) are arranged adjacent to and spaced from the lower wing skin surface (26) so that when the coils are activated a torsional wave mode deformation of the skin (14) occurs. In another embodiment, a deflection wave mode deformation is generated in the skin (14) by activation of two electro-magnetic coils (42). In yet another embodiment, torsional movement of a blade mass balance element (64) in a helicopter blade brings about a twisting of the upper and lower skin surfaces (24) and (26) of the blade (60) to produce a torsional travelling deformation wave in the skin. ## Claims ### Claim 1 An electromagnetic pulse deicing system for deicing the surface skin of an airfoil, said airfoil including a leading edge portion formed by upper and lower surfaces terminating at a leading edge, said system comprising a plurality of electromagnetic pulse generating devices positioned adjacent to and spaced from said skin and means for electrically activating said plurality of pulse generating devices to produce a resultant deformation of said skin, wherein said plurality of pulse generating devices are arranged in a staggered geometrical array spanwise of said airfoil, whereby upon electric activation of said devices a torsional wave mode deformation of said skin occurs. ### Claim 2 (depends on 1) The electromagnetic pulse deicing system according to claim 1 wherein said staggered geometrical array comprise at least one set of said pulse generating devices, each of said at least one set including a first one of said devices located in proximity to said upper surface, and a second one of said pulse generating devices located in proximity to said lower surface, each of said first and second devices being located at different spanwise locations of said airfoil. ### Claim 3 (depends on 1) The electromagnetic pulse deicing system according to claim 1 wherein said staggered geometrical array comprises at least one set of said pulse generating devices, each of said at least one set including a first and second one of said devices located in proximity to said upper surface, and a third one of said devices located in proximity to said lower surface, said first and second ones of said devices being located at some distance from each other spanwise on said airfoil, and said third device being located at an intermediate spanwise location of said airfoil. ### Claim 4 (depends on 1) The electromgnetic pulse deicing system according to claim 1 wherein said staggered geometrical array comprises at least one set of said pulse generating devices, each of said at least one set including a first and second one of said devices located in proximity to said lower surface, and a third one of said devices located in proximity to said upper surface, said first and second ones of said devices being located at some distance from each other spanwise of said airfoil, and said third device being located at an intermediate spanwise location of said airfoil. ### Claim 5 (depends on 1) The electromagnetic pulse deicing system according to claim 1 wherein said staggered pulse generating devices are spaced one-half wave length spanwise with respect to each other. ### Claim 6 A process for removing ice from the surface skin of an airfoil, comprising the steps of: providing an electromagnetic pulse system within said airfoil, said system including a plurality of electromagnetic pulse generating elements and means for electrically activating said system; positioning said elements adjacent to and spaced from said skin in a predetermined staggered geometrical array spanwise of said airfoil, whereby upon activation of said electromagnetic pulse system, said elements are activated and a torsional wave mode deformation of said skin takes place; generating said torsional wave mode deformation of said skin by activating said electromagnetic pulse system; and repeating said torsional wave generating step by intermittently activating said electromagnetic pulse system until said ice is removed from said skin. ### Claim 7 A process for removing ice from the surface skin of an airfoil having a nose portion separating an upper skin portion from a lower skin portion, said process comprising the steps of: providing an electromagnetic pulse system within said airfoil, said system including at least two electromagnetic pulse generating elements and means for electrically activating said elements; positioning respective upper and lower ones of said elements adjacent to and spaced from said upper skin portion and said lower skin portion respectively with a predetermined spacing from one another spanwise of said airfoil whereby upon the respective activation of said upper and lower elements, respective upper and lower spanwise propagating travelling waves are initiated in the respective said upper and lower skin portions; adjusting the timing of the activation of the upper one of said elements relative to that of the lower one such that the spanwise travelling wave in said upper skin portion causes an outwards bulge in said upper skin portion at a given spanwise location at the same time the spanwise travelling wave in said lower skin portion causes an inwards bulge in said lower skin portion at said given spanwise location; and maintaining the same said relative timing between elements while intermittently activating said at least two elements as required for the efficient removal of ice buildup from said skin. ### Claim 8 (depends on 7) The process of claim 7 wherein said activation of each particular one of said elements results in an outward bulging of the skin portion adjacent said particular element. ### Claim 9 (depends on 8) The process of claim 8 wherein said relative timing is essentially simultaneous and said spanwise spacing is staggered. ### Claim 10 (depends on 9) The process of claim 9 wherein said staggered spacing is approximately equal to one half the wavelength of said travelling waves.