US3906308A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Aircraft lightning protection system
Assignee: McDonnell Douglas Corp
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Filing: 1973-09-27
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Granted: 1975-09-16
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Expires: 1993-09-27
Abstract
Abstract Basic design criteria are established for the Zones 1, 2 and 3 aircraft regions defined in the zonal lightning protection design concept. In fulfilling the Zone 2 criteria, a lightning protection system utilizing dielectric materials in the form of coatings and/or films applied to critical components including boron or graphite epoxy composite skin panels, metallic or composite fuel tank access doors and other metal components located at the external surface of the aircraft, is used. This provides a complete dielectric surface shield of appropriate dielectric strength and thickness which electrically isolates the protected component from the swept-stroke and restrike lightning current channel. For large span skin panel protection, properly oriented and spaced foil or solid metal strips of appropriate dimensions are suitably affixed to the dielectric material surface and grounded to provide dwell points for the lightning current channel.
Inventors
- 👤 Myron P Amason
- 👤 Joseph T Kung
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 16:25
CPC Classifications
B; B64; B64D; B64D45/00; B64D45/02; Y; Y10; Y10T; Y10T428/00; Y10T428/24; Y10T428/24149
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
104 words
In a zonal lightning protection system for aircraft and other vehicles, lightning protection means comprising: at least one layer of dielectric material applied over an ordinarily lightning-accessible surface of an aircraft component to be protected from lightning damage, said at least one layer being of a predetermined thickness and said dielectric material of said at least one layer being of a predetermined dielectric strength, and overall dielectric material layer thickness and dielectric strength including said predetermined thickness and dielectric strength of said at least one layer being of such character that attachment of a lightning channel to said surface of said component is prevented.
Claim 2
Dependent Claim
104 words
In a zonal lightning protection system for aircraft and other vehicles, lightning protection means comprising: at least one layer of dielectric material applied over an ordinarily lightning-accessible surface of an aircraft component to be protected from lightning damage, said at least one layer being of a predetermined thickness and said dielectric material of said at least one layer being of a predetermined dielectric strength, and overall dielectric material layer thickness and dielectric strength including said predetermined thickness and dielectric strength of said at least one layer being of such character that attachment of a lightning channel to said surface of said component is prevented.
Claim 3
Dependent Claim
29 words
The invention as defined in claim 1 wherein said at least one layer of dielectric material includes a coating of dielectric material applied over said surface of said component.
Claim 4
Dependent Claim
29 words
The invention as defined in claim 1 wherein said at least one layer of dielectric material includes a film of dielectric material applied over said surface of said component.
Claim 5
Dependent Claim
67 words
The invention as defined in claim 1 further comprising at least one strip of conductive material positioned generally within the area of said at least one layer of dielectric material and lightning-accessible to provide dwell points for said lightning channel, said at least one strip of conductive material being connected directly to a selected part of a common metallic structure of zero reference potential for said aircraft.
Claim 6
Dependent Claim
24 words
The invention as defined in claim 2 wherein said coating of dielectric material applied over said surface of said component comprises an elastomeric coating.
Claim 7
Dependent Claim
24 words
The invention as defined in claim 3 wherein said film of dielectric material applied over said surface of said component comprises a polyimide film.
Claim 8
Dependent Claim
33 words
The invention as defined in claim 4 wherein said at least one strip of conductive material includes a foil strip of conductive material affixed over said at least one layer of dielectric material.
Claim 9
Dependent Claim
33 words
The invention as defined in claim 4 wherein said at least one strip of conductive material includes a bar strip of conductive material affixed over said at least one layer of dielectric material.
Claim 10
Dependent Claim
95 words
The invention as defined in claim 4 wherein said at least one strip of conductive material is oriented to extend angularly with respect to the direction of normal air flow over said at least one layer of dielectric material due to motion of said aircraft, said at least one strip of conductive material being so constructed and arranged that said lightning channel is able to contact said at least one strip of conductive material when said lightning channel sweeps in said direction of normal air flow over said at least one layer of dielectric material.
Claim 11
Dependent Claim
39 words
The invention as defined in claim 9 wherein said at least one strip of conductive material is oriented to extend perpendicularly with respect to said direction of normal air flow over said at least one layer of dielectric material.
Claim 12
Dependent Claim
164 words
In a zonal lightning protection system for aircraft and other vehicles, lightning protection means comprising: at least one layer of dielectric material applied over an ordinarily lightning-accessible and at least semiconductive surface of an aircraft component to be protected from lightning damage, said at least one layer being of a predetermined thickness and said dielectric material of said at least one layer being of a predetermined dielectric strength, and overall dielectric material layer thickness and dielectric strength including said predetermiNed thickness and dielectric strength of said at least one layer being of such character that attachment of a lightning channel to said surface of said component is prevented; and a plurality of conductive material strips positioned and spaced generally within the area of said at least one layer of dielectric material and lightning-accessible to provide dwell points for said lightning channel, said conductive material strips being all connected directly to selected parts of a common metallic structure of zero reference potential for said aircraft.
Claim 13
Dependent Claim
164 words
In a zonal lightning protection system for aircraft and other vehicles, lightning protection means comprising: at least one layer of dielectric material applied over an ordinarily lightning-accessible and at least semiconductive surface of an aircraft component to be protected from lightning damage, said at least one layer being of a predetermined thickness and said dielectric material of said at least one layer being of a predetermined dielectric strength, and overall dielectric material layer thickness and dielectric strength including said predetermiNed thickness and dielectric strength of said at least one layer being of such character that attachment of a lightning channel to said surface of said component is prevented; and a plurality of conductive material strips positioned and spaced generally within the area of said at least one layer of dielectric material and lightning-accessible to provide dwell points for said lightning channel, said conductive material strips being all connected directly to selected parts of a common metallic structure of zero reference potential for said aircraft.
Claim 14
Dependent Claim
114 words
The invention as defined in claim 11 wherein said conductive material strips are oriented to extend angularly with respect to the direction of normal air flow over said at least one layer of dielectric material due to motion of said aircraft, and the spacing between two adjacent ones of said conductive material strips is predetermined as a function of said overall dielectric material layer thickness and dielectric strength, said conductive material strips being so constructed and arranged that said lightning channel is able to contact at least one of said conductive material strips when said lightning channel sweeps in said direction of normal air flow over said at least one layer of dielectric material.
Claim 15
Dependent Claim
104 words
In an aircraft or other vehicle, the combination with an aircraft component including a normally forward conductive surface and a normally aft partially conductive surface, of: at least one layer of dielectric material applied over said partially conductive surface, said at least one layer being of a predetermined thickness and said dielectric material of said at least one layer being of a predetermined dielectric strength, and overall dielectric material layer thickness and dielectric strength including said predetermined thickness and dielectric strength of said at least one layer being of such character that attachment of a lightning channel to said partially conductive surface is prevented.
Claim 16
Dependent Claim
104 words
In an aircraft or other vehicle, the combination with an aircraft component including a normally forward conductive surface and a normally aft partially conductive surface, of: at least one layer of dielectric material applied over said partially conductive surface, said at least one layer being of a predetermined thickness and said dielectric material of said at least one layer being of a predetermined dielectric strength, and overall dielectric material layer thickness and dielectric strength including said predetermined thickness and dielectric strength of said at least one layer being of such character that attachment of a lightning channel to said partially conductive surface is prevented.
Claim 17
Dependent Claim
67 words
The invention as defined in claim 13 further comprising at least one strip of conductive material positioned generally within the area of said at least one layer of dielectric material and lightning-accessible to provide dwell points for said lightning channel, said at least one strip of conductive material being connected directly to a selected part of a common metallic structure of zero reference potential for said aircraft.
Claim 18
Dependent Claim
95 words
The invention as defined in claim 14 wherein said at least one strip of conductive material is oriented to extend angularly with respect to the direction of normal air flow over said at least one layer of dielectric material due to motion of said aircraft, said at least one strip of conductive material being so constructed and arranged that said lightning channel is able to contact said at least one strip of conductive material when said lightning channel sweeps in said direction of normal air flow over said at least one layer of dielectric material.
Claim 19
Dependent Claim
43 words
The invention as defined in claim 1 wherein said at least one layer of dielectric material applied over said surface of said component is progressively increased in total thickness in the direction of normal air flow thereover due to motion of said aircraft.
Claim 20
Dependent Claim
27 words
The invention as defined in claim 4 wherein said at least one positioned strip of conductive material includes an environmental protection coating provided on exposed surfaces thereof.
Claim 21
Dependent Claim
23 words
The invention as defined in claim 11 wherein said positioned conductive material strips include respective environmental protection coatings provided on exposed surfaces thereof.
Claim 22
Dependent Claim
35 words
The invention as defined in claim 12 wherein said conductive material strips are oriented to extend perpendicularly with respect to said direction of normal air flow over said at least one layer of dielectric material.
Claim 23
Dependent Claim
27 words
The invention as defined in claim 14 wherein said at least one positioned strip of conductive material includes an environmental protection coating prOvided on exposed surfaces thereof.
Claim 24
Dependent Claim
112 words
The invention as defined in claim 15 wherein said common metallic structure on said aircraft includes airframe structure thereof and said at least one strip of conductive material is oriented to extend angularly with respect to said direction of normal air flow over said at least one layer of dielectric material so that at least one end of said at least one strip of conductive material can be connected directlly to a selected part of said airframe structure, said at least one strip of conductive material being so constructed and arranged that it is relatively short length to reduce its impedance when connected to said airframe structure part at a chosen location.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-09-15 | 1979-03-17 | 1979-09-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-09-15 | 1983-03-17 | 1983-09-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-09-15 | 1987-03-17 | 1987-09-16 | $7700.00 | Window Closed / Lapsed |