Exterior helicopter light

Abstract

An exterior helicopter light is configured to be mounted to a helicopter, in particular to an underside of the helicopter, the helicopter having a longitudinal axis (A). The exterior helicopter light comprises: a first set of light sources configured for emitting, in operation, light of a first color into a at least one rear sector of a ground below the helicopter, the at least one rear sector spatially extending around a projection of a rear portion of the helicopter onto the ground; and second set of light sources configured for emitting, in operation, light of a second color, which differs from the first color, into at least two forward sectors of the ground below the helicopter.

Claims

1. Exterior helicopter light configured to be mounted to a helicopter, in particular to an underside of the helicopter, the helicopter having a longitudinal axis, the exterior helicopter light comprising: a first set of light sources configured for emitting, in operation, light of a first color into at least one rear sector of a ground below the helicopter, the at least one rear sector spatially extending around a projection of a rear portion of the helicopter onto the ground; and a second set of light sources configured for emitting, in operation, light of a second color, which differs from the first color, into at least two forward sectors of the ground below the helicopter, wherein the light, which is emitted into at least two forward sectors, has the same color; wherein the at least two forward sectors are located on opposite lateral sides of the helicopter; and wherein each of the at least two forward sectors extends over at least a portion of an area extending between a forward direction and a lateral direction of the helicopter.

2. An exterior helicopter light according to claim 1, wherein the at least two forward sectors are mirror-symmetric to each other with respect to the longitudinal axis of the helicopter; or wherein the at least one rear sector is mirror-symmetric with respect to the longitudinal axis of the helicopter.

3. An exterior helicopter light according to claim 1, wherein the first color is red and/or wherein the second color is green or blue.

4. An exterior helicopter light according to claim 1, wherein the exterior helicopter light further comprises: a third set of light sources configured for emitting, in operation, light of a third color, which differs from the first and second colors, into at least two lateral sectors of the ground below the helicopter, wherein each of the at least the two lateral sectors is located between the at least one rear sector and one of the at least two forward sectors, wherein the third color is yellow, orange or white.

5. An exterior helicopter light according to claim 4, wherein the exterior helicopter light further comprises: a fourth set of light sources configured for emitting, in operation, light of a fourth color, which differs from the first and second colors, into an intermediate sector of the ground below the helicopter, the intermediate sector being located between two of the forward sectors, wherein the intermediate sector is mirror-symmetric with respect to the longitudinal axis of the helicopter, and wherein the fourth color is identical with the third color.

6. An exterior helicopter light according to claim 1, wherein the exterior helicopter light further comprises: a fourth set of light sources configured for emitting, in operation, light of a fourth color, which differs from the first and second colors, into an intermediate sector of the ground below the helicopter, the intermediate sector being located between two of the forward sectors, wherein the intermediate sector is mirror-symmetric with respect to the longitudinal axis of the helicopter.

7. An exterior helicopter light according to claim 6, wherein the fourth color is yellow, orange or white.

8. An exterior helicopter light according to claim 1, wherein the at least one rear sector has an opening angle (γ) of 120° to 180° around the longitudinal axis of the helicopter and wherein each forward sector has an opening angle (δ) between 30° and 90.

9. An exterior helicopter light according to claim 1, configured for not illuminating a border sector, having an opening angle of up to 5° , between two adjacent sectors.

10. An exterior helicopter light according to claim 1, comprising a light source support, in particular a circuit board, wherein the first set of light sources or the second set of light sources are arranged on the outer periphery of the light source support.

11. An exterior helicopter light according to claim 10, further comprising at least one optical element configured for modifying the light emitted by the first set of light sources and/or the second set of light sources; wherein the at least one optical element includes a refractive annular optical element surrounding the light source support.

12. An exterior helicopter light according to claim 1, wherein the first set of light sources and/or the second set of light sources are arranged with angular distances between 3° and 20° with respect to each other.

13. An exterior helicopter light according to claim 1, further comprising shutter elements arranged between adjacent light sources.

14. An exterior helicopter light according to claim 1, further comprising at least one optical element configured for modifying the light emitted by the first set of light sources and/or the second set of light sources; wherein the at least one optical element in particular includes a refractive annular optical element surrounding the light source support.

15. An exterior helicopter light according to claim 1, wherein the first and second sets of light sources are configured for emitting red light flashes in an airborne operation.

16. A helicopter comprising: an exterior helicopter light according to claim 1, wherein the exterior helicopter light is mounted to an underside of a fuselage or to an undercarriage of the helicopter.

17. A method of illuminating a portion of a ground below a helicopter, having a longitudinal axis (A), with an exterior helicopter light comprising a plurality of light sources on an underside of the helicopter, wherein the method includes: emitting light of a first color into at least one rear sector of a ground below the helicopter, the at least one rear sector spatially extending around a projection of a rear portion of the helicopter onto the ground; and emitting light of a second color, which differs from the first color, into at least two forward sectors of the ground below the helicopter, wherein the light, which is emitted into at least two forward sectors, has the same color; wherein the at least two forward sectors are located on opposite lateral sides of the helicopter; and wherein each of the at least two forward sectors extends over at least a portion of an area extending between a forward direction and a lateral direction of the helicopter.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Further exemplary embodiments are described with respect to the accompanying drawings, wherein:

(2) FIG. 1 shows a schematic side view of a helicopter which is equipped with two exterior helicopter lights according to exemplary embodiments of the invention;

(3) FIG. 2 shows a vertical cross-sectional view of an exterior helicopter light according to an exemplary embodiment of the invention;

(4) FIG. 3 shows a perspective view of the exterior helicopter light depicted in FIG. 2, in which the outer cover, the optical element and the shutter elements have been removed;

(5) FIG. 4 shows a perspective view of the exterior helicopter light depicted in FIGS. 2 and 3, in which the outer cover and the optical element have been removed;

(6) FIG. 5 shows a perspective view of the exterior helicopter light depicted in FIGS. 2 to 4, in which only the outer cover has been removed;

(7) FIG. 6 shows a horizontal cross-sectional view of the exterior helicopter light depicted in FIGS. 2 to 5;

(8) FIG. 7 is a diagram illustrating the relative intensity of the light emitted by a single light beam as a function of the angle in a vertical plane;

(9) FIG. 8 shows a schematic plan view of a light pattern emitted by an exterior helicopter light according to an exemplary embodiment of the invention;

(10) FIG. 9 shows a schematic plan view of a further light pattern emitted by an exterior helicopter light according to an exemplary embodiment of the invention, including overlaps between light beams emitted into adjacent sectors; and

(11) FIG. 10 shows a schematic plan view of a further light pattern emitted by an exterior helicopter light according to an exemplary embodiment of the invention, comprising dark zones between light beams emitted into adjacent sectors.

DETAILED DESCRIPTION

(12) FIG. 1 shows a schematic side view of a helicopter 2, which is equipped with two exterior helicopter lights 12 according to exemplary embodiments of the invention.

(13) The helicopter 2 comprises a fuselage 4 having a front portion or nose 5, including a cockpit 15, and a rear portion or tail 6. An undercarriage 8, mounted to an underside of the fuselage 4, supports the helicopter 2 on a ground 3. In the embodiment depicted in FIG. 1, the undercarriage 8 comprises two skids 9 extending parallel to each other in a longitudinal direction. In FIG. 1, the longitudinal direction extends horizontally, parallel to the ground 3, from left to right. Only one of the skids 9 is visible in the side view depicted in FIG. 1. Alternatively or additionally to the skids 9, rollers 13 may by mounted to the undercarriage 8 for allowing the helicopter 2 to move on a solid ground 3.

(14) The helicopter 2 comprises a main rotor 10 on top of the fuselage 4 and a tail rotor 11 provided in or at the tail 6 of the fuselage 4. In an alternative embodiment, which is not depicted on the figures, the helicopter 2 may comprises two main rotors 10 arranged in a co-extensive manner on top of the fuselage 4.

(15) A first exterior helicopter light 12 according to an exemplary embodiment of the invention is mounted to an underside of the fuselage 4. In the embodiment depicted in FIG. 1, the exterior helicopter light 12 is mounted to a central portion of the fuselage 4. The exterior helicopter light 12 also may be mounted below the front portion 5 and/or below the tail 6 of the fuselage 4.

(16) In the embodiment depicted in FIG. 1, a second exterior helicopter light 12 is mounted to the undercarriage 8 of the helicopter 2.

(17) The helicopter 2 shown in FIG. 1 is equipped with two exterior helicopter lights 12 for illustrative purposes. The helicopter 2 may also be equipped with only one or with more than two exterior helicopter lights 12.

(18) FIG. 2 depicts a vertical cross-sectional view of an exterior helicopter light 12 according to an exemplary embodiment of the invention. FIGS. 3 to 5 depict perspective views of the exterior helicopter light 12 in different states of assembly. FIG. 6 depicts a horizontal cross-sectional view of the exterior helicopter light 12.

(19) The exterior helicopter light 12 comprises a base plate 14, which may be mounted to the fuselage 4 or to the undercarriage 8 of the helicopter 2, as it is depicted in FIG. 1.

(20) The base plate 14 supports a light source support 16, e.g. a circuit board, in particular a printed circuit board, supporting a plurality of light sources 18, in particular light emitting diodes (LEDs). As best seen from FIG. 3, the light source support 16 may have a round periphery, in particular a circular or elliptical periphery, and the light sources 18 may be mounted to said outer periphery for emitting light radially outwards from the light source support 16.

(21) The exterior helicopter light 12 further comprises a plurality of shutter elements 20 (see also FIG. 4) forming a ring around the light source support 16. The shutter elements 20 extend radially with respect to a center C of the light source support 16. As a result, a radially extending light channel is formed between each pair of adjacent shutter elements 20, respectively.

(22) A refractive optical element 22 surrounds the ring of shutter elements 20 (see also FIG. 5). The refractive optical element 22 may be made of glass or an appropriate plastics material, such as Polymethylmethacrylate (PMMA), Polycarbonate (PC), or silicone. The refractive optical element 22 is configured for modifying the light, which is emitted by the plurality of light sources 18 and passes through the light channels formed between the shutter elements 20.

(23) The refractive optical element 22 may in particular be configured to form a plurality of light beams 24 emitted from the plurality of light channels, each light beam 24 having a predefined opening angle α, e.g. an opening angle α of 3° to 20°, in particular an opening angle α of 5° to 10°, more particular an opening angle α of 5°, when projected onto a horizontal plane P, which is arranged parallel to the plane of the light source support 16 (cf. FIG. 6). Each of the light beams 24 may be oriented downwards towards the ground 3 at an angle β with respect to the horizontal plane P (cf. FIG. 2). The angle β may be in the range of 2° to 10°; the angle β may in particular be in the range of 4° to 6°, β more particularly may be 5°.

(24) The opening angle α of each light beam 24 may be set as a function of the number of light channels and light sources 18 arranged on the outer periphery of the light source support 16. The opening angle α of the light beams 24 in particular is set so that all light beams 24, in combination, cover a full circle of 360° around the center C of the light source support 16. In other words, an opening angle α of approximately 5°, as it is exemplarily depicted in FIG. 6, corresponds to at least 72 light sources 18 being arranged along the outer periphery of the light source support 16.

(25) Generally, the opening angle α may be increased, when the number of light sources 18 is reduced; and the opening angle α may be reduced, if the number of light sources 18 is increased, in order to ensure that the combination of all light beams 24 covers the complete circle of 360°.

(26) Light sources 18 emitting light of different colors may be employed in different angular portions along the outer periphery of the light source support 16. This allows generating a desired light pattern 30 on the ground 3 below and in the vicinity of the helicopter 2. In particular, a plurality of sets of adjacent light sources 18 may be formed. All light sources 18 of the same set may emit light having the same color, and the different sets may emit light having different colors or the same color.

(27) The light sources 18, the shutter elements 20 and the refractive optical element 22 are covered by a refractive housing or cover lens 26, which is attached to the base plate 14 by a circular lens retainer 28 (cf. FIG. 2). The refractive housing or cover lens 26 protects the light sources 18, the shutter elements 20 and the refractive optical element 22 from adverse environmental influences, such as dirt, water, moisture and/or mechanical influences.

(28) The exterior helicopter light 12 may have a diameter D of 100 mm to 150 mm in the horizontal plane P, in particular a diameter D between 110 mm and 130 mm, more particularly a diameter of 120 mm. The height H of the exterior helicopter light 12 may be in the range of 20 mm to 50 mm. The exterior helicopter light 12 in particular may have a height H of 30 mm.

(29) FIG. 7 depicts a diagram illustrating the relative intensity I of the light emitted by a single light beam 24 as a function of the angle Θ in a vertical plane.

(30) The maximum intensity (100%) at approximately 5°, e.g. at the angle β, may be at least 2500 cd, in order to achieve an illumination of at least 100 lx in a distance of 5 m at the ground 3 all around the helicopter 2.

(31) FIG. 8 shows a schematic plan view of a light pattern 30 generated by an exterior helicopter light 12 according to an exemplary embodiment of the invention, as viewed from a position above the helicopter 2.

(32) The plurality of light sources 18 include a first set of light sources which are configured for emitting, in operation, light of a first color into a rear sector 32 of the ground 3 below the helicopter 2. The rear sector 32 spatially extends around a projection of the rear portion 6 of the helicopter 2 onto the ground 3. Again, the term in operation refers to the operation of the exterior helicopter light, when the helicopter is on the ground or close to the ground.

(33) The rear sector 32 in particular has an opening angle of γ=120° (+/−60°) to 180° (+/−90°), centered at the longitudinal axis A of the helicopter 2.

(34) Due to the vicinity of the tail rotor 11 and as it is out of sight of a pilot sitting in the cockpit 15, the rear area around the rear portion (tail) 6 of the helicopter 2 is a very dangerous area, which should be avoided by any persons approaching the helicopter 2. Thus, light sources emitting red light may be used for illuminating the rear sector 32, in order to indicate that people should not enter said area.

(35) On the other hand, forward areas in front of the helicopter 2, with the exception of an area directly in front of the helicopter 2, which are in the field of view of the pilot of the helicopter, are relatively safe areas and preferable for approaching the helicopter 2.

(36) The plurality light sources 18 include a second set of light sources which are configured for emitting, in operation, light of a second color, which differs from the first color, into two forward sectors 34a, 34b of the ground 3 below and in front of the helicopter 2.

(37) The two forward sectors 34a, 34b are located on opposite lateral sides of the longitudinal axis A of the helicopter 2, and each of the forward sectors 34a, 34b covers at least a portion of an area extending between the longitudinal axis A of the helicopter and a lateral direction La, Lb oriented orthogonally to said longitudinal axis A.

(38) I.e., each of the two forward sectors 34a, 34b at maximum covers an angular area of 90° extending between the longitudinal axis A and a lateral direction La, Lb, respectively. The two forward sectors 34a, 34b may also be referred to as left and right forward sectors.

(39) Each forward sector 34a, 34b, however, may have an opening angle δ of less than 90°, for example an opening angle δ in the range of 30° to 90°, in particular an opening angle δ between 40° and 80°, more particularly an opening angle δ between 50° and 70°.

(40) The two forward sectors 34a, 34b may be mirror-symmetric to each other with respect to the longitudinal axis A of the helicopter 2.

(41) As the areas covered by the forward sectors 34a, 34b are the safest areas for approaching the helicopter 2, light sources emitting green or blue light may be used for illuminating the forward sectors 34a, 34b.

(42) Areas extending laterally from the helicopter 2 are not as dangerous as the rear portion of the helicopter 2. However, since they are outside the pilot's field of view, they are not as preferable as the previously mentioned forward areas for approaching the helicopter 2. These areas may by marked by employing a third set of light sources emitting light into two lateral sectors 36a, 36b located on opposing lateral sides of the helicopter 2. The light sources of the third set are configured for emitting, in operation, light of a third color, which differs from the first and second colors. Each lateral sector 36a, 36b is located between the rear sector 32 and one of the forward sectors 34a, 34b, respectively.

(43) As approaching the helicopter 2 in the areas covered by the lateral sectors 36a, 36b is not as dangerous as approaching the helicopter 2 via the rear area covered by the rear sector 32, but not as safe and preferable as approaching the helicopter via the forward areas covered by the forward sectors 34a, 34b, the third color, which is used for illuminating the lateral sectors 36a, 36b, may be yellow, orange or white.

(44) It is pointed out that the provision of lateral sectors 36a, 36b, into which light of a third color is emitted, is optional. The rear sector 32 and the forward sectors 34a, 34b may directly border each other.

(45) An area located directly in front of the helicopter 2 is not preferable for approaching the helicopter 2, either. However, as this area is directly in the line of sight of the pilot, approaching the helicopter 2 via this front area is not as dangerous as approaching the helicopter 2 from behind.

(46) Thus, the exterior helicopter light 12 may comprise a fourth set of light sources configured for emitting, in operation, light of a fourth color, which differs from the first and second colors, into an intermediate sector 38 of the ground below and in front of the helicopter 2. The intermediate sector 38 extends between the two forward sectors 34a, 34b along the longitudinal axis A. The intermediate sector 38 in particular may be mirror-symmetric with respect to the longitudinal axis A of the helicopter 2.

(47) The fourth color may be yellow, orange or white. The fourth color may be identical with or different from the third color.

(48) It is pointed out that the provision of the intermediate sector 38, into which light of a fourth color is emitted, is optional. The two forward sectors 34a, 34b may directly border each other. While such a set-up may be perceived by an observer as having a continuous forward sector that extends to both sides of the longitudinal axis A, such a set-up is considered herein as having two forward sectors that directly border each other. In other words, it is understood that the two forward sectors 34a, 34b may both extend to the longitudinal axis A and may blend into each other and that such a configuration is encompassed by the wording of at least two forward sectors located on opposite lateral sides of the helicopter.

(49) The first, second, third and fourth sets of light sources may, in combination, generate a light pattern 30 as it is depicted in FIG. 8, comprising a rear sector 32 indicating the very dangerous area around the rear portion (tail) 6 of the helicopter 2, two forward sectors 34a, 34b indicating safe areas, which are preferable to be used for approaching the helicopter 2, and lateral and intermediate sectors 36a, 36b, 38, indicating areas which are not as dangerous as the rear area, but not as safe and preferable as the forward areas.

(50) The opening angles of the sectors 32, 34a, 34b, 36a, 36b, 38 may depend on the design of the helicopter 2 and may be set individually for each type of helicopter 2.

(51) Optionally, at least some of the light sources 18 may be color-switchable light sources 18, which allow selectively emitting light of different colors. In such a configuration, all light sources 18 may be controlled to emit red light during takeoff, landing and/or hovering of the helicopter 2, in order to indicate that it is not safe to approach the helicopter 2. Also, all light sources 18 may be controlled to emit red light flashes in an airborne operation, thus providing beacon light functionality. When the helicopter 2 has landed, the pilot may switch the lights sources 18 to emit a multi-color light pattern similar to the light pattern depicted in FIG. 8, in order to signal that the helicopter 2 is ready for boarding and may be approached, preferably via the safe areas which are illuminated by the forward sectors 34a, 34b of light emitted by light sources of the first set of light sources.

(52) Color-switchable light sources 18, which allow selectively emitting light of different colors, further allow for adapting the exterior helicopter light 12 to different types of helicopters 2 by selectively switching the color of the light emitted by each of the light sources 18, in order to generate the desired light distribution. In consequence, the same exterior helicopter light 12 may be used in combination with different types of helicopters 2, without modifying the physical configuration of the exterior helicopter light 12.

(53) The light sources 18 of at least one set of light sources, in particular of the set of light sources emitting red light, may be operated in a flashing mode, in order to enhance the warning effect of the emitted light.

(54) FIG. 9 depicts a schematic top view of a light pattern 30 generated by an exterior helicopter light 12 according to an exemplary embodiment of the invention without the helicopter 2.

(55) In this light pattern 30, the opening angle α of the individual light channels is somewhat larger than 5°. As a consequence, there is a slight overlap between adjacent light beams 24. At the interfaces between adjacent sectors 34a, 34b, 36a, 36b, 38 of light having different colors, the overlap of adjacent light beams 24 results in a mixture of the different colors. This may be beneficial for generating the lateral sectors 36a, 36b by mixing light from the rear sector 32 and the forward sectors 34a, 34b.

(56) However, the accidental overlap of light beams 24 of different sectors 32, 34a, 34b may also result in undesired effects, which may irritate and confuse persons approaching the helicopter 2. The mixing may be reduced by reducing the opening angle α of the light beams 24, thereby minimizing the overlap between adjacent light beams 24.

(57) Another option for avoiding an undesired mixing of the colors at the interfaces between adjacent sectors 32, 34a, 34b, 38 is generating dark border sectors 40 at the interfaces by switching off at least one of the light sources at the borders between adjacent sectors 32, 34a, 34b, 38. Such a configuration, in which dark border sectors 40 are formed between adjacent sectors 32, 34a, 34b, 38, is depicted in FIG. 10. The dark border sectors 40 formed between adjacent sectors 32, 34a, 34b, 38 result in a clearly defined separation of adjacent sectors 32, 34a, 34b, 38 having different colors.

(58) While the invention has been described with reference to exemplary embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed, but that the invention will include all embodiments falling within the scope of the appended claims.