RU2395434C2 - Aircraft lightning protection device - Google Patents

Abstract

FIELD: transport.

SUBSTANCE: invention relates to aircraft engineering, particularly to aircraft lightning protection devices. Proposed device comprises lightning-arrester representing a target, a lightning receiver or receivers, arranged in appropriate aircraft zone, built in airframe and electrically isolated from airframe. There is electric resonance LC-filter with its input connected to lightning receiver output of common output of lightning receivers set, and its output earthed to aircraft airframe. Aforesaid LC-filter consists of capacitor and throttle. Said low-impedance-winding throttle has its winding output terminal connected in parallel with diode bridge. High-capacity capacitor, lightning charge power accumulator, is connected in diode bridge diagonal.

EFFECT: higher flight safety and aircraft operating performances.

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Description

The invention relates to aeronautical engineering, in particular to means for protecting an aircraft (A / C) from damage due to the intense impact of lightning discharges of lightning on an aircraft body, and can be applied to other objects.

The aim of the invention is to increase flight safety, improve operational characteristics by preventing the passage of a lightning discharge on the aircraft body.

State of the art

Known means of trapping electric charges of lightning, for example, to protect the aircraft from lightning, include metallized shielding of the entire aircraft, shielding of the most important electrically conductive systems and equipment compartments, filtering signals that can be input to highly sensitive equipment, or removing these signals through other channels, replacing electrical fiber optic wiring (see Aviation Week and Space Technology, 1983, v119, 12 / 1x, No. 11).

The first Falcon-50 transport aircraft are known, on which large components from composite materials (KM) are used. Anti-lightning protection of these elements is carried out using a metal edging of titanium. The folding hoods of the Falcon - 900 aircraft engines are made of phenolic carbon fiber, they have tin metallization to protect equipment and engine systems from induced currents.

However, the voltage and current levels induced in the wires can reach values significantly higher than permissible.

Used KM from lightning strikes burn out, are destroyed by electrodynamic forces. When exposed to lightning, electrical wiring is the main collector of parasitic energy that occurs at the entrance to electrical equipment (see. "Protection of modern aircraft from atmospheric electricity and electromagnetic pulses." Technical Information, 1987, No. 9, TsAGI, pp. 1-12).

Known lightning conductor, which relates to a device for protecting aircraft from lightning strikes in stratified clouds, containing n pointed arresters, each of which is made in the form of a conductor mounted on an insulator, one end of which is connected to the aircraft skin, a constant or connected source is connected to both ends of the conductor alternating current (see US Pat. RU No. 2007344, 1991.10.29).

However, lightning charges, partially accumulated in n pointed arresters, conductors and on the aircraft body, reduce the reliability of the on-board electronic equipment.

Known lightning protection means for a fairing of an aircraft’s onboard antenna, containing lightning conductors made in the form of dielectric longitudinal plates, with metal conductive segments fixed to their outer part with a gap, interconnected by a resistive layer. The base of the longitudinal plate is made of 0.1-inch fiberglass, and the resistive layer is made of R-14 type material. A bunch of longitudinal plates is installed on the surface of the fairing, the ends of the plates are grounded using electrically conductive means to the mass of the aircraft. Such a lightning protection device provides radome transparency to the fairing, see US Pat. US 3.416.027, NCI 315-36.

However, with repeated lightning strikes, lightning resistance decreases, coatings are destroyed due to the high current density in the spot of a pulsed electric arc between the metal segments of the plates from lightning strikes, and the accumulated charge flows off over the entire surface of the aircraft and through the antenna into the surrounding atmosphere.

A device is known for protecting an aircraft from lightning damage, comprising charge strippers, a lightning rod made in the form of a target integrated into the aircraft body and electrically isolated from the case, connected to the corresponding charge removal zones by a current collector from sequentially branching conductors, the inputs of which are through an electrically conductive target and a choke connected to the aircraft’s hull, and the outputs to the charge removal zones, see AC No. 1409104.

However, the complex design of the device, branching conductors reduce the strength of the aircraft and does not ensure the reliability of the onboard equipment.

Thus, the known lightning protection means do not provide sufficient lightning protection and the reliability of the onboard equipment, as well as the protection of the aircraft body under icing conditions when flying in layered clouds.

The technical result, which is achieved by the claimed device for protecting the aircraft from being struck by lightning, is to increase the efficiency of lightning protection of onboard equipment.

To obtain the specified technical result in the proposed device for protecting the aircraft from being struck by lightning, containing a lightning rod, made in the form, for example, of a target - a lightning rod, located in the corresponding area of the aircraft, built into the aircraft body and electrically isolated from the body, connected to it by a down conductor with grounding on the aircraft housing, according to the invention, the collector is made in the form of an electric resonant LC filter containing a capacitor and a choke with one low-resistance winding, to the output of which a diode bridge is connected in parallel, in the diagonal of which a large-capacity capacitor is included - a storage of energy of lightning charges.

In addition, in the device for protecting the aircraft from being struck by lightning in order to protect the aircraft antenna fairing, a group of lightning rods is connected to the common input of the resonant LC filter.

The throttle is made with two windings, a second diode bridge is connected to the second additional winding of the throttle, the diagonal of which includes resistance, a zener diode and a capacitor C3 in parallel with it, a signal llama placed on the pilot's instrument panel for signaling to the pilot.

This embodiment of the inventive lightning rod will improve flight safety, reliability of aircraft protection, and prevent the passage of electric lightning discharge current to the aircraft body through the use of the proposed device, which absorbs almost all lightning energy, which improves the operational characteristics of the equipment. The device provides more reliable protection against a lightning charge getting on the skin of an aircraft’s hull from lightning damage, in particular, under icing or flying in layered clouds, when full protection is not provided in all the analogs considered, therefore the lightning charge passes through the body to the pointed gangways.

List of drawings

The invention is illustrated by drawings, in which:

figure 1 is a circuit diagram of a device for protecting an aircraft from being struck by lightning, made in accordance with the invention;

figure 2 is a circuit diagram of a device with a signaling circuit to a pilot;

3 represents a transient in the electrical resonance circuit of an LC filter.

A device for protecting an aircraft from being struck by lightning comprises a lightning rod made, for example, in the form of a target - an air terminal 1, located in the corresponding area of the aircraft, built into the aircraft body and electrically isolated from the body, an electric resonant LC filter 3, the input of which is connected to the output air terminal 1, and the output is grounded on the aircraft LA 2. The electric resonant LC filter 3 is made of capacitor C1 and an inductor. The inductor is made with one low-resistance winding, a diode bridge is connected to its output in parallel, a large capacitor C2 is included in the diagonal of it - an energy storage device for lightning charges (see Fig. 1).

In the presence of a group of lightning rods located in a certain area of the aircraft, in the proposed device, the input of the resonant LC filter 3 is connected to the general output of the group of lightning rods.

A possible embodiment of a choke with two windings (see figure 2).

In this case, the device for protecting the aircraft from being struck by lightning contains a lightning rod, made in the form, for example, of a target - an air receiver 1, located in the corresponding area of the aircraft, built into the aircraft body and electrically isolated from the body, an electric resonant LC filter 3, the input of which connected to the output of the air terminal 1, and the output to ground on the aircraft LA 2. The electric resonant LC filter 3 is made of capacitor C1 and a choke with two windings, the first winding of which is made of low resistance, to its output a diode bridge is connected in parallel, the diagonal of which includes a large-capacity capacitor C2 - an energy storage device for lightning charges.

A second diode bridge is connected to the output of the second inductor winding, the diagonal of which includes resistance, a zener diode and parallel to it capacitance C3, a signal lamp located on the instrument panel of the pilot for signaling to the pilot.

The operation of the device to protect the aircraft from lightning

The proposed device operates as follows. When a lightning strike is close to an aircraft, for example, on a target - lightning rod 1, charges are concentrated that flow into an electric resonant LC filter 3, consisting of inductance in the form of a choke and capacitance C1, the values of which are chosen so that resonance arises in this circuit voltage with the maximum possible amplitude. Under this condition, as is known from the course of physics, the current at the output of such a circuit is practically zero, therefore, although the output of the resonant circuit is connected to the aircraft’s body, the lightning current charge practically does not pass through it. However, as a result of the resonance in the circuit LС, the voltage amplitude can reach significant values, which will require the use of a choke and capacitors such that they are designed for voltages that differ by an order of magnitude from the input signal of the lightning discharge. Therefore, in the proposed device, at the output of the resonant LC filter, a diode bridge is installed, in the diagonal of which a lightning discharge energy storage device is connected. Thereby, a sharp decrease in the amplitude of voltage 6 is achieved (see FIG. 3), where the voltage axis 4 and the time axis are shown 5. The power (energy) of the lightning discharge accumulates on the storage capacitor C2 for a long time compared to the duration of the input lightning discharge lasting from 0.01 sec. To 0.1 sec. This is the main difference from all previously proposed devices.

To protect against lightning strikes in such areas as the aircraft antenna fairing, a group of lightning rods is installed, connecting their output to the common input of the resonant LC filter of the proposed device.

For signaling by means of a signal light to the pilot about lightning strikes (see Fig. 2), a throttle with two windings is used in the proposed device, a second diode bridge is connected to the output of the second additional winding, in the diagonal of which resistance, a zener diode and a capacitor C3 are connected in parallel with which provide energy storage, for example, to power a signal lamp.

Thus, the proposed device allows you to protect the hull of the aircraft 2 from lightning. According to the results of experiments, it was determined that the main lightning discharge and a significant part of the power are captured by the filter.

Claims (1)

A device for protecting an aircraft (A / C) from lightning, containing a lightning rod made in the form of a target - a lightning rod or lightning rods, located in the corresponding protection zone of the aircraft, built into the aircraft body and electrically isolated from the body, with an output connected to the input of the down conductor, output which is connected to ground to the aircraft housing, characterized in that the down conductor includes an electric resonant LC filter, configured to represent the input signal as a pulse, causing a long track atelnogo process with excess initial amplitude oscillatory process voltage compared to the input signal, wherein the input and output to the collector connected to a diode bridge, a second diagonal which included large-capacitance capacitor - lightning energy storage charges.

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