AIRCRAFT WITH ISOLATED GROUND

• US 20090322147A1
• Filed: 05/01/2008
• Published: 12/31/2009
• Est. Priority Date: 05/01/2008
• Status: Abandoned Application

• Current Assignee: Soectrum Aeronautical, LLC, Spectrum Aeronautical, LLC
• Original Assignee: Spectrum Aeronautical, LLC
• Inventors: Cooney, Daniel E.
• Application Number:
  US12/113,761
• Publication Number:
  US 20090322147A1
• Time in Patent Office: Days
• US Class Current: 307/9.1
• CPC Class Codes: H01Q 1/283 Blade, stub antennas
• CPC Class Codes: H01Q 1/48 Earthing means; Earth screens; Counterpoises

Abstract

An aircraft having an airframe made of a composite material is provided with an isolated ground in order to reduce the threat of electrical fires. The aircraft includes a voltage source and at least one electronic device mounted on the airframe. Further, a power wire isolated from the airframe interconnects the voltage source and the electronic device. Also, a ground wire isolated from the airframe interconnects the voltage source and the electronic device. As a result, the onboard electric circuits are isolated from the airframe. In order to reduce electromagnetic interference in the circuit, the aircraft may be provided with a powerside capacitor, to interconnect the power wire and the airframe, and a groundside capacitor, to interconnect the ground wire and the airframe.

Claims

1. An aircraft with isolated ground which comprises:

an airframe made of a composite material;

a voltage source mounted on the airframe;

at least one electronic device mounted on the airframe;

a power wire isolated from the airframe and connecting the electronic device to the voltage source;

a circuit breaker interconnected to the power wire; and

a ground wire isolated from the airframe and grounding the electronic device to the voltage source.

2. An aircraft as recited in claim 1 further comprising:

a powerside capacitor interconnecting the power wire and the airframe; and

a groundside capacitor interconnecting the ground wire and the airframe, wherein the capacitors reduce electromagnetic interference.

3. An aircraft as recited in claim 2 wherein the voltage source has a positive bus bar and a negative bus bar, wherein the powerside capacitor connects the positive bus bar of the voltage source to the airframe;

and wherein the groundside capacitor connects the negative bus bar of the voltage source to the airframe.

4. An aircraft as recited in claim 1 further comprising:

an antenna defining an antenna axis;

a mounting means for affixing the antenna to the airframe with the antenna electrically isolated therefrom; and

a ground plane electrically connected to the antenna, with said ground plane being perpendicular to the antenna axis.

5. An aircraft as recited in claim 4 wherein the ground plane is formed from a wire mesh.

6. An aircraft as recited in claim 4 further comprising a conductor means for electrically connecting the antenna to the electrical device for trafficking signals with the antenna.

7. An aircraft as recited in claim 6 wherein the airframe has an external surface and an internal surface and the airframe is formed with an aperture extending between the external and internal surfaces, and further wherein the mounting means comprises:

a first insulating gasket positioned outside of the external surface to surround the aperture;

a second insulating gasket positioned inside of the internal surface to surround the aperture; and

a backing plate positioned against the second insulating gasket to surround the aperture and to position the second insulating gasket between the backing plate and the airframe for connection of the conducting means with the antenna through the aperture.

8. An aircraft as recited in claim 7 wherein the ground plane is mounted between the second gasket and the internal surface of the airframe.

9. An aircraft as recited in claim 1 wherein the composite material is a graphite/epoxy composite.

10. An isolated ground electrical system for use in an aircraft having an airframe made of a composite material which comprises:

a voltage source mounted on the airframe, the voltage source having a positive bus bar and a negative bus bar;

at least one electronic device mounted on the airframe, the electronic device having a positive terminal and a negative terminal;

a power wire isolated from the airframe and connecting the positive terminal of the electronic device to the positive bus bar of the voltage source;

a circuit breaker interconnected to the power wire; and

a ground wire isolated from the airframe and connecting the negative terminal of the electronic device to the negative bus bar of the voltage source.

11. A system as recited in claim 10 further comprising:

a powerside capacitor interconnecting the power wire and the airframe; and

a groundside capacitor interconnecting the ground wire and the airframe, wherein the capacitors reduce electromagnetic interference.

12. A system as recited in claim 10 further comprising:

an antenna defining an antenna axis;

a mounting means for affixing the antenna to the airframe with the antenna electrically isolated therefrom; and

a ground plane electrically connected to the antenna, with said ground plane being perpendicular to the antenna axis.

13. A system as recited in claim 12 further comprising a conductor means for electrically connecting the antenna to the electrical device for trafficking signals with the antenna.

14. A system as recited in claim 13 wherein the airframe has an external surface and an internal surface and the airframe is formed with an aperture extending between the external and internal surfaces, and further wherein the mounting means comprises:

a first insulating gasket positioned outside of the external surface to surround the aperture;

a second insulating gasket positioned inside of the internal surface to surround the aperture; and

a backing plate positioned against the second insulating gasket to surround the aperture and to position the second insulating gasket between the backing plate and the airframe for connection of the conducting means with the antenna through the aperture.

15. A system as recited in claim 14 wherein the ground plane is embedded in the airframe.

16. A method of grounding electronic devices in an aircraft having an airframe made of a composite material which comprises the steps of:

mounting a voltage source on the airframe;

positioning at least one electronic device in the airframe;

electrically connecting the electronic device to the voltage source with a power wire isolated from the airframe;

interconnecting a circuit breaker to the power wire; and

electrically connecting the electronic device to the voltage source with a ground wire isolated from the airframe.

17. A method as recited in claim 16 further comprising the steps of:

interconnecting the power wire and the airframe with a powerside capacitor; and

interconnecting the ground wire and the airframe with a groundside capacitor to reduce electromagnetic interference.

18. A method as recited in claim 17 further comprising the steps of:

affixing an antenna to the airframe, with the antenna electrically isolated from the airframe, and with the antenna defining an antenna axis;

grounding the antenna to a ground plane perpendicular to the antenna axis; and

electrically connecting the antenna to the electrical device for trafficking signals with the antenna.

19. A method as recited in claim 18 wherein the airframe has an external surface and an internal surface, wherein the airframe is formed with an aperture extending between the external and internal surfaces, and wherein the affixing step comprises:

positioning a first insulating gasket outside of the external surface to surround the aperture;

positioning a second insulating gasket inside of the internal surface to surround the aperture; and

positioning a backing plate against the second insulating gasket to surround the aperture and to position the second insulating plate between the backing plate and the airframe for electrical connection of the antenna through the aperture.

20. A system as recited in claim 19 wherein the affixing step further includes the step of mounting the ground plane between the second gasket and the internal surface of the airframe.