A universal aircraft air-to-ground status sensor

Abstract

The present invention discloses a universal aircraft air-ground state sensor, which is applicable to air-ground state measurement systems of aircraft transmitter controllers, flight timing and other general aviation control systems, and includes a micro switch and a windward blade fixed to the end of the micro switch operating rod; in at least one working state, the micro switch is fixed to the inner side of an opening in the aircraft skin through a bracket assembly; the windward blade extends out of the opening and has a windward surface substantially perpendicular to the aircraft heading, so that the windward blade pushes the operating rod to trigger the micro switch by the wind pressure on its windward surface. The technical solution of the present invention only increases a small amount of cost and weight while ensuring that no major changes are made to the structure and circuit of the aircraft, and meets the technical requirements of various general aviation system designs.

Description

Technical Field

[0001] The invention belongs to the field of aviation electronics, and in particular relates to a sensor for providing an air-ground state identification signal. Background Art

[0002] In the field of general aircraft, in order to improve the flight performance of the aircraft, when the aircraft's piston engine is converted into a turboprop engine, most turboprop engines need to provide an air state identification signal to distinguish whether the aircraft is on the ground or in the air. However, the piston engine aircraft used as the basis for the modification generally do not have the ability to identify the air-ground state. On the one hand, in some general aviation markets, it is difficult to add a micro switch on the landing gear of an aircraft with a fixed landing gear to distinguish the air-ground state. At the same time, the identification form of adding a micro switch on the landing gear can only distinguish whether the aircraft is grounded, and cannot meet the criterion for air-ground state identification - 15m above the ground is the air state requirement. On the other hand, if the air-ground state identification problem is solved by data extraction based on the airspeed acquisition system, it is necessary to add an atmospheric data computer with digital output capability to achieve it. In general, the atmospheric data computers on aircraft are imported equipment, and the imported atmospheric data computers do not develop interfaces for other equipment. If modified in this way, it is necessary to add an atmospheric data computer separately, which greatly increases the modification cost and the weight of the whole aircraft, and has a great impact on the economy of general aircraft. Summary of the invention

[0003] The purpose of the present invention is to provide a universal aircraft air-ground status sensor, which only adds a small amount of cost and weight without making major changes to the aircraft structure and circuit, meets the air-ground status identification needs after the piston engine is converted into a turboprop engine, and meets the technical requirements of the technical transformation project.

[0004] The technical solution provided by the present invention is a universal aircraft air-to-ground state sensor, which comprises a micro switch and a windward blade fixed to the end of the micro switch operating rod; in at least one working state,

[0005] The micro switch is fixed to the inner side of an opening in the aircraft skin through a bracket assembly; the windward blade extends outward from the opening and has a windward surface that is substantially perpendicular to the heading of the aircraft, so that the windward blade pushes the operating rod to trigger the micro switch by the wind pressure on its windward surface.

[0006] It is easy to understand that the principle of the present invention is to design the windward surface of the windward blade by the aircraft speed parameter. When the aircraft speed is greater than or equal to a design speed, the thrust formed by the wind pressure on the windward surface is greater than or equal to the operating force (OF) designed by the micro switch, so that the operating rod presses down the action reed of the micro switch, changes the contact state of the internal moving contact and the static contact, and outputs the contact state through the signal output terminal of the micro switch. Therefore, in the present invention, the micro switch at least outputs the first state when the aircraft speed is less than the design speed, and the second state when the aircraft speed is greater than or equal to the design speed. When the design speed is selected as the standard speed when the aircraft is 15m above the ground, the first state shows the ground state in the air-to-ground state, and the second state shows the flight state in the air-to-ground state.

[0007] Preferably, the signal output terminal of the micro switch includes a common terminal, a normally open terminal and a normally closed terminal.

[0008] Preferably, the universal aircraft air-to-ground status sensor comprises a multi-core silver-plated shielded wire connected to the signal output terminal of the micro switch; the multi-core silver-plated shielded wire is provided with a wave-proof sleeve.

[0009] In some embodiments, the multi-core silver-plated shielded wire connects an aircraft engine signal processing unit and the micro switch. The aircraft engine signal processing unit converts the output signal of the micro switch into a digital quantity and applies it to the operation of the engine.

[0010] In some other embodiments, the multi-core silver-plated shielded wire connects the engine timer and the micro switch. The engine timer converts the signal carrying the second state information into a timing enable signal, and the timing stops when the micro switch is in the first state, and the timing continues when the micro switch is in the second state, thereby realizing flight timing.

[0011] Preferably, the bracket assembly includes an L-shaped bracket installed inside the aircraft skin and a pad installed outside the aircraft skin.

[0012] In some embodiments, the pad includes a first pad in contact with the aircraft skin and an outermost second pad; the first pad has the same hardness as the aircraft skin, and the second pad is less hard than the first pad. In a further improved embodiment, the micro switch is fixed to the inner side of the aircraft skin by two L-shaped brackets on both sides thereof.

[0013] Preferably, the windward area of ​​the windward surface is designed according to the speed of the aircraft 15 m above the ground and the operating force of the micro switch.

[0014] Preferably, the windward surface is a rectangular plane.

[0015] The technical solution of the present invention can be applied to at least one new type of air-to-ground state measurement system, which triggers the micro switch by measuring the windward pressure of the aircraft during flight. The micro switch transmits the air-to-ground state switch value to the engine signal processing unit through a cable, thereby ensuring that the engine accurately determines the physical position of the aircraft. In the new air-to-ground state measurement system, on the one hand, because the sensor provided by the present invention is small in size and is not limited by physical space, it only needs to be installed on the windward side of the aircraft; on the other hand, the micro switch involved in the invention can be selected from existing mature products, and can be produced and sold through self-designed circuits and systems, without being subject to technical restrictions of atmospheric data computer suppliers. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of the assembly state structure of a universal aircraft air-to-ground state sensor in one embodiment of the present invention;

[0017] Figure 2 for Figure 1 Schematic diagram of the structure in the A-direction assembly state;

[0018] Among them, the drawings show: a micro switch 1, an operating lever 11, a windward blade 2, a windward surface 20, a cable 4, a transmitter signal processing unit 5, an aircraft skin 31, a first pad 32, a second pad 33, L-shaped brackets 34, 35, and a DB15 plug 6. DETAILED DESCRIPTION

[0019] refer to Figure 1 , 2 This embodiment is an air-ground state measurement system, which uses the universal aircraft air-ground state sensor provided by the technical solution of the present invention, and the sensor includes a micro switch 1, a windward blade 2, a bracket assembly, and a cable 4. The sensor is plugged into the engine signal processing unit 5 through the DB15 plug at one end of the cable 4. The engine signal processing unit 5 in the air-ground state measurement system collects the switch quantity output by the sensor of this embodiment and outputs the data required by the engine. It can collect and process the switch quantity of the air-ground state, thereby ensuring that the engine accurately determines the physical position of the aircraft.

[0020] Specifically, the micro switch 1 of this embodiment is a push-type trigger switch, model BZ2RW855511T, which has three signal output terminals and two mounting holes. The L-shaped brackets 34 and 35 are clamped with the micro switch 1 on both sides by bolts passing through the mounting holes. When the aircraft is on the ground, the common end is connected to the normally open end, and an open circuit signal is provided to the engine signal processing unit 5 through the cable 4; when the aircraft is in flight and the airspeed reaches 67 knots (34.4 meters per second), the common end is connected to the normally closed end, and a ground signal is provided to the engine signal processing unit through the cable 4. The bottom of the L-shaped brackets 34 and 35 are fixed to the aircraft skin 31 by bolts with the first pad 32 and the second pad 33 outside the aircraft skin 31. The operating rod 11 of the micro switch 1 basically passes vertically through the opening of the aircraft skin 31, and is connected and fixed to the windward blade 2 outside the aircraft skin 31.

[0021] In this embodiment, the windward blade 2 is a steel structure, which is welded to the end of the operating rod 11 of the micro switch 1. The operating rod of BZ2RW855511T is 63.5mm (2.5in) long, with an operating force of 0.7N. The welding length h2 between the operating rod and the micro switch 1 is 12.5mm. The windward surface 20 of the windward blade 2 is designed as a rectangle, with a height h1 of 19mm and a width w1 of 25.5mm. Therefore, the surface area of ​​the windward surface is approximately 484.5mm. 2 (19mm×25.5mm). In this embodiment, the standard speed of the aircraft is 67 knots when it is 15m above the ground. Referring to the Bernoulli equation, the thrust generated by the air weight converted to wind pressure on the operating lever under standard conditions is about 0.74N, which is greater than the standard operating force of the operating lever of 0.7N. Therefore, when the aircraft is parked on the ground, the operating force of the operating lever 11 acting on the action reed of the microswitch 1 is less than 0.7N, the common end of the microswitch 1 is connected to the normally closed end, and a ground signal is output to the 1st hole of the DB15 plug 6 of the engine signal processing unit 5, that is, the first state is output; when the pressure generated after the aircraft airspeed reaches 67 knots acts on the windward blade, the operating force of the operating lever 11 acting on the action reed of the microswitch 1 is greater than 0.7N, the microswitch 1 is triggered and quickly acts, its common end is disconnected from the normally closed end, and the second state is switched to be output, and it is connected to the normally open end, and a ground signal is output to the 2nd hole of the DB15 plug 6 of the engine signal processing unit 5. The DB15 interface of the engine signal processing unit 5 receives the switch signal provided by the micro switch, converts it into a digital signal through the analog-to-digital conversion function, distinguishes whether the aircraft is on the ground or in the air, and then guides the operation of the engine. In an improvement of this embodiment, for the same type of technically modified aircraft, in order to consider the aerodynamic shape error of the windward surface 20, the welding length between the windward blade 2 and the micro switch 1 is designed to be 7.5mm. The surface area of ​​the windward blade is 500mm 2 (25mm×20mm). 500mm2 The windward area can better ensure that the micro switch 1 is actuated when the aircraft airspeed reaches 67 knots. It can be seen that the operating distance of the micro switch 1 operating rod 11 is relatively short. Whether in the first state or the second state, the windward surface of the windward blade at the end of the operating rod 11 is basically maintained perpendicular to the aircraft heading. It is easy to understand that the positional relationship between the operating rod 11 and the windward blade 2 in this embodiment is only a calculation demonstration of the operating force. Those skilled in the art can improve and implement it according to the technical inspiration provided by the invention and in combination with the wind pressure optimization scheme in fluid mechanics in the prior art and the trigger structure of the micro switch in the prior art, such as: in some embodiments, the windward surface can actually be an equivalent projection of the plane where the windward surface of the windward blade in this embodiment is located, such as a circular plane, a fan-shaped plane or even the total windward area of ​​a projection surface of a streamlined body; in this embodiment, the average direction of the wind pressure acting on the operating rod is the standard trigger direction of the operating rod. In some embodiments, the thrust of pushing the operating rod in the standard trigger direction can also be a component of the force of the wind pressure acting on the windward blade; in some embodiments, the bracket assembly can have a dynamic mechanical structure, so that the windward blade can be integrated into the opening of the aircraft skin with the micro switch when not working; these improved implementations should also be included in the technical solution of the present invention as embodiments of the present invention; in some embodiments, the micro switch does not need to be provided with a specific housing, and the micro-node gap quick-acting mechanism driven by the operating rod in the existing micro switch can be regarded as an implementation of the micro switch in the present invention.

[0022] In this embodiment, the bracket assembly includes 3, which is composed of a first pad 32, a second pad 33, and L-shaped brackets 34 and 35. The first pad 32 and the L-shaped brackets 34 and 35 are all made of aluminum, and their hardness is equivalent to that of the aircraft skin 31; the second pad 33 is made of rubber material, and its hardness is less than that of the aircraft skin 31 and the bolts used to assemble the bracket assembly. It can be seen that in the present invention, the bracket assembly is used to ensure that the windward surface 20 of the windward blade 2 is perpendicular to the heading of the aircraft, and the micro switch is fixed to the opening position of the aircraft skin 31 by bolts. In some embodiments, the bracket assembly can adopt any fixed structure in the prior art to achieve an equivalent replacement of the bracket assembly in this embodiment to achieve the same effect.

[0023] In this embodiment, the cable 4 is a three-core silver-plated shielded wire, one end of which is connected to the three signal output terminals of the micro switch 1, namely, the common terminal, the normally open terminal, and the normally closed terminal, through the HB6-91-14 terminal block, and the other end is connected to the engine signal processing unit 5 through the DB15 plug 6. The cable 4 has a temperature tolerance of 200°C and is provided with a wave-proof sleeve to effectively prevent external electromagnetic interference and improve the accuracy of data transmission.

[0024] In this embodiment, during the installation of the sensor, only the mounting bracket and the micro switch need to be installed and fixed on the modified aircraft. The opening at the installation position uses the φ110mm lightening hole of the upper left wing of the original aircraft. No changes are required to the remaining structural parts, and the modification is easy. The cable 4 is the cable used by the original aircraft, and there is no new material, which reduces the production and use costs of the technical modification. The engine signal acquisition unit 5 is an original device on the aircraft, and only the cable needs to be connected without any other changes.

[0025] During use, the engine signal acquisition unit 5 can determine the air-to-ground state of the aircraft by reading the switch signal of the micro switch. When the signal read by the engine signal acquisition unit 5 is a suspended signal, it indicates that the aircraft is in the ground state. When the signal read by the engine signal acquisition unit 5 is a ground signal, it indicates that the aircraft is in the air.

[0026] The air-to-ground state measurement system of this embodiment has been applied to a small general-purpose aircraft in China and has achieved good results.

[0027] It is worth noting that those skilled in the art know that, according to the needs, the system of the above embodiment can be adjusted on different turboprop aircraft, and the area of ​​the windward surface on the windward blade can be changed according to the speed of the aircraft when it is 15m off the ground to adapt to different turboprop aircraft models. The installation form of the micro switch can be perpendicular to the horizontal structural surface of the aircraft, or perpendicular to the horizontal structural line of the aircraft, which expands its installation form and increases its applicability; the size and shape of the bracket can be improved to match the original opening of the aircraft skin.

[0028] Another embodiment of the present invention provides an engine timing system, which is different from the above embodiment in that the application scope of this embodiment includes piston engines and turboprop engines, and the cable 4 is connected to the engine timer of the aircraft. The engine timer converts the signal carrying the second state information into a timing enable signal, and the timing stops when the micro switch is in the first state, and the timing continues when the micro switch is in the second state, thereby realizing flight timing, that is, measuring the flight time of the aircraft.

[0029] It is easy to understand that the principle of the present invention is to design the windward surface of the windward blade by the aircraft speed parameter. When the aircraft speed is greater than or equal to a design speed, the thrust formed by the wind pressure on the windward surface is greater than or equal to the operating force (OF) designed by the micro switch, so that the operating lever presses down the action reed of the micro switch, changes the contact state of the internal moving contact and the static contact, and outputs the contact state through the signal output terminal of the micro switch. Therefore, in the present invention, the micro switch at least outputs the first state in which the aircraft speed is less than the design speed, and the second state in which the aircraft speed is greater than or equal to the design speed. When the design speed is selected as the standard speed when the aircraft is 15m away from the ground, the first state shows the ground state in the air-to-ground state, and the second state shows the flight state in the air-to-ground state. In the embodiment of the present invention, the micro switch model is a preferred demonstration. Those skilled in the art can select the existing BZ / BA / WA / YZ series of straight rod large-stroke micro switches as the micro switches in the technical solution of the present invention according to design needs.

Claims

1. A universal aircraft air-to-ground status sensor, comprising a micro switch and a windward blade fixed to the end of the micro switch operating rod; in at least one working state, The micro switch is fixed to the inner side of an opening in the aircraft skin through a bracket assembly; the windward blade extends out of the opening and has a windward surface substantially perpendicular to the heading of the aircraft, so that the windward blade pushes the operating rod to trigger the micro switch by the wind pressure on its windward surface; The micro switch at least outputs a ground state where the aircraft speed is less than the design speed, and a flight state where the aircraft speed is greater than or equal to the design speed.

2. The universal aircraft air-to-ground status sensor according to claim 1, characterized in that: The signal output terminal of the micro switch includes a common terminal, a normally open terminal and a normally closed terminal.

3. The universal aircraft air-to-ground status sensor according to claim 1, characterized in that: It comprises a multi-core silver-plated shielded wire connected to the signal output terminal of the micro switch; the multi-core silver-plated shielded wire is provided with a wave-proof sleeve outside.

4. The universal aircraft air-to-ground status sensor according to claim 3, characterized in that: The multi-core silver-plated shielded wire connects the aircraft engine signal processing unit and the micro switch.

5. The universal aircraft air-to-ground status sensor according to claim 3, characterized in that: The multi-core silver-plated shielded wire connects the engine timer and the micro switch.

6. The universal aircraft air-to-ground status sensor according to claim 1, characterized in that: The bracket assembly comprises an L-shaped bracket installed inside the aircraft skin and a pad installed outside the aircraft skin.

7. The universal aircraft air-to-ground status sensor according to claim 6, characterized in that: The pads include a first pad in contact with the aircraft skin and an outermost second pad; the first pad has the same hardness as the aircraft skin, and the second pad has a lower hardness than the first pad.

8. The universal aircraft air-ground status sensor according to claim 3, characterized in that: The micro switch is fixed to the inner side of the aircraft skin by two L-shaped brackets on both sides thereof.

9. The universal aircraft air-ground status sensor according to claim 1, characterized in that: The windward area of ​​the windward surface is designed according to the speed of the aircraft 15 m above the ground and the operating force of the micro switch.

10. The universal aircraft air-ground status sensor according to claim 1, characterized in that: The windward surface is a rectangular plane.

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