DOUBLE-BLADE TANDEM HELICOPTER

Abstract

A double-blade tandem helicopter comprising a fuselage (10), a power system, a control system, and two rotor assemblies (30, 50). The rotor assemblies are longitudinally disposed relative to the fuselage. Each rotor assembly comprises a rotor shaft (31, 51), a rotor head (33, 53), and two blades (35, 37, 55, 57). The rotor shaft is connected to the power system, the rotor head is fixed to the rotor shaft, and the blades are attached to the rotor head. The double-blade tandem helicopter has a larger rotor disk area than that of a single-rotor helicopter while has a fuselage weight approaching that of the single-rotor helicopter, and thus has a take off weight approximately twice or more times of the single-rotor helicopter, and meanwhile has characteristics such as small volume, simple structure and high aerodynamic efficiency.

Claims

1. A double-blade tandem helicopter, comprising: a fuselage; a power system; a control system; and a lift system comprising two rotor assemblies arranged along a longitudinal direction of the fuselage, each rotor assembly comprising: a rotor shaft pivotally coupled to the power system; a rotor head fixedly coupled to an upper end of the rotor shaft; and two blades arranged around the rotor head in linear configuration.

2. The double-blade tandem helicopter according to claim 1, wherein blades of the two rotor assemblies form the same rotor disk diameter and rotate synchronously in opposite directions.

3. The double-blade tandem helicopter according to claim 1, wherein an overlap rate of rotor discs formed by the blades of the two of rotor assemblies is between 30% and 45%.

4. The double-blade tandem helicopter according to claim 2, wherein an overlap rate of rotor discs formed by the blades of the two rotor assemblies is between 30% and 45%.

5. The double-blade tandem helicopter according to claim 1, wherein the rotor heads are located at the same level relative to the fuselage.

6. The double-blade tandem helicopter according to claim 1, wherein the rotor head arranged at the rear of the fuselage is located at a higher level than the rotor head arranged at the front of the fuselage relative to the fuselage

7. The double-blade tandem helicopter according to claim 1, wherein the rotor head is a rigid rotor head, a hingeless rotor head, a see-saw type rotor head or a fully-flapping type rotor head.

8. The double-blade tandem helicopter according to claim 1, wherein axes of the rotor shafts are located in a longitudinal vertical plane of the fuselage, and are parallel to each other and perpendicular to the fuselage.

9. The double-blade tandem helicopter according to claim 1, wherein axes of the rotor shafts are located in a longitudinal vertical plane of the fuselage, and are not parallel to each other and intersect below the fuselage.

10. The double-blade tandem helicopter according to claim 1, wherein a material of an inner layer of the blade is glass fiber and a material of an outer layer of the blade is carbon fiber.

11. The double-blade tandem helicopter according to claim 1, wherein a material of the blade is one of glass fiber and carbon fiber.

12. The double-blade tandem helicopter according to claim 1, wherein the blade has a symmetrical airfoil or an asymmetrical airfoil.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0020] FIG. 1 is a side view of a double-blade tandem helicopter according to a preferred embodiment of the present disclosure.

[0021] FIG. 2 is a top view of the double-blade tandem helicopter shown in FIG. 1.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[0022] Hereinafter, a novel helicopter of the present disclosure will be described in detail with reference to the figures. What are presented are merely preferred embodiments according to concepts of the present disclosure. Those skilled in the art can envisage other embodiment for implementing the present disclosure. Directional terms such as “front”, “rear”, “left” and “right” employed herein are relative to the aircraft fuselage.

[0023] FIG. 1 is a side view of a double-blade tandem helicopter according to a preferred embodiment of the present disclosure, and FIG. 2 is a top view of the double-blade tandem helicopter shown in FIG. 1. As shown in FIGS. 1 and 2, the double-blade tandem helicopter 1 according to a preferred embodiment of the present disclosure comprises: a fuselage 10; a power system (not shown); a control system (not shown); and a lift system 20. The lift system 20 according to the present disclosure includes a first rotor assembly 30 and a second rotor assembly 50. The first rotor assembly 30 and the second rotor assembly 50 are arranged with a distance ds therebetween along a longitudinal direction of the fuselage 10, the first rotor assembly 30 is arranged at the front of the fuselage 10, and the second rotor assembly is arranged at the rear of the fuselage 10.

[0024] As shown in FIG. 1, the first rotor assembly 30 includes: a rotor shaft 31 pivotally coupled to the power system at the front of the fuselage 10, a rotor head 33 fixedly coupled to an upper end of the rotor shaft 31, and a first blade 35 and a second blade 37 arranged around the rotor head 33 in linear configuration. Similarly, the second rotor assembly 50 includes: a rotor shaft 51 pivotally coupled to the power system at the rear of the fuselage 10, a rotor head 53 fixedly coupled to an upper end of the rotor shaft 51, and a third blade 55 and a fourth blade 57 arranged around the rotor head 53 in linear configuration. When driven by the power system, the rotor shafts 31 and 51 drive the rotor heads and blades to rotate.

[0025] In an embodiment, a diameter d of the disk formed by the first blade 35 and the second blade 37 of the first rotor assembly 30 is the same as a diameter d of the disk formed by the third blade 55 and the fourth blade 57 of the second rotor assembly 50. Furthermore, the first rotor assembly 30 rotates in a first direction R1 and the second rotor assembly 50 rotates in a second direction R2 opposite to the first direction R1 (as shown in FIG. 2). According to the configuration of the present disclosure, the distance ds between the two rotor shafts 31 and 51 may be between 55% and 70% of the diameter d of the rotor disc. The rotor disk overlap rate may be between 30% and 45%.

[0026] Preferably, the rotor heads 33, 53 may be fully-flapping rotor heads, i.e., the blades can perform pitching, yawing and rolling motion relative to the rotor heads to a certain degree. In other preferred embodiments, the rotor heads 33 and 53 may be replaced with rigid rotor heads or hingeless rotor heads in which blades cannot move relative to the rotor heads, or see-saw type rotor heads in which blades can perform pitch or yaw motion relative to the rotor heads to a certain degree.

[0027] In a preferred embodiment, the rotor head 53 of the second rotor assembly 50 is located at a higher level than the rotor head 33 of the first rotor assembly 30 relative to the fuselage 10.

[0028] In another preferred embodiment, the rotor head 33 of the first rotor assembly 30 and the rotor head 53 of the second rotor assembly 50 are located at the same level relative to the fuselage 10.

[0029] In a preferred embodiment, axes of the rotor shafts 31 and 51 are located in a longitudinal vertical plane of the fuselage 10, and are parallel to each other and perpendicular to the fuselage 10.

[0030] In a further preferred embodiment, axes of the rotor shafts 31 and 51 are located in a longitudinal vertical plane of the fuselage 10, and are not parallel to each other and intersect below the fuselage 10.

[0031] In a preferred embodiment, a material of an inner layer of the blade is glass fiber and a material of an outer layer is carbon fiber.

[0032] In other preferred embodiments, the material of the blade is one of glass fiber and carbon fiber.

[0033] In a preferred embodiment, the blade is symmetrical airfoils, and upper and lower surfaces of the blade are symmetrical.

[0034] In other preferred embodiments, the blade is asymmetrical airfoil, and upper surface of the blade is convex and lower surface is flat.

[0035] The double-blade tandem helicopter according to the present disclosure has a weight of the helicopter body approximate to that of a single-rotor helicopter, a larger disk area, and a lift weight approximately twice or more times of the single-rotor helicopter. Meanwhile, the double-blade tandem helicopter has characteristics such as a small conveying volume, a simple structure and a high aerodynamic efficiency.

[0036] From the above contents, those skilled in the art will readily appreciate that alternative structures of the disclosed structures may be considered as possible alternative embodiments, and that embodiments disclosed by the present disclosure may be combined to produce new embodiments without departing from the scope of the appended claims.