Airfoil shaped tail boom
A system and method to control fuselage torque of an aircraft. The system includes a tail boom having a first surface that creates a high-pressure region in a downward rotorwash and a second surface that creates a low-pressure region in the downward rotorwash. The difference in pressure regions creates a lateral force that opposes the fuselage torque.
1. A rotary aircraft, comprising:
a fuselage;
an engine carried by the fuselage;
a main rotor rotatably attached to the engine; and
a tail boom attached to and extending from the fuselage, the tail boom having:
a body having a first side surface and an opposing second side surface, the first side surface being contoured to act as a pressure surface of an airfoil and the second side surface being contoured to act as a suction surface of an airfoil;
a leading edge; and
a trailing edge, having:
a rounded corner; and
a sharp edge;
wherein both the first surface and the second surface extend from the leading edge to the trailing edge;
wherein the rounded corner joins the second surface to the trailing edge;
wherein the sharp edge joins the first surface to the trailing edge; and
wherein the sharp edge reduces drag of the tail boom during a sideward flight motion of the aircraft;
wherein the engine rotates the main rotor, thereby creating rotorwash and a fuselage torque;
wherein the rotorwash flows around the first side surface and the second side surface of the tail boom, resulting in a high-pressure region forming near the first side surface and resulting in a low-pressure region forming near the second side surface;
wherein the pressure difference between the high-pressure region and the low-pressure region causes the tail boom to move towards the low-pressure region, resulting in a lateral force opposing the fuselage torque; and
wherein the tail boom is rotatably attached to the fuselage.
2. The rotary aircraft according to claim 1 , wherein an angle of attack of the tail boom with respect to the rotorwash is approximately six degrees.
3. The rotary aircraft according to claim 1 , the sharp edge comprising:
a first linear surface; and
a second linear surface;
wherein the first linear surface is oriented at an angle relative to the second linear surface.
4. The rotary aircraft according to claim 3 , wherein the angle is about 90 degrees.
5. The rotary aircraft according to claim 1 , further comprising:
an anti-torque system attached to the tail boom.
6. The rotary aircraft according to claim 5 , wherein the anti-torque system is a tail rotor.
7. A method to control fuselage torque of a rotary aircraft, comprising:
providing a tail boom attached to a fuselage of the rotary aircraft in accordance with the features of claim 1 ;
creating a high-pressure region in a downward rotorwash along a first surface of the tail boom; and
creating a low-pressure region in the downward rotorwash along a second surface of the tail boom;
wherein the differences in low-pressure and high-pressure regions causes the tail boom to move in a lateral direction opposing the fuselage torque.
8. The method of claim 7 , further comprising:
supplementing the lateral directional movement of the tail boom with an anti-torque system.
9. A rotary aircraft, comprising:
a fuselage;
a main rotor;
a tail boom attached to and extending from the fuselage, the tail boom having:
a first surface and a second surface;
a leading edge;
a trailing edge, having:
a rounded corner; and
a sharp edge; and
a pressure surface and a suction surface, both extending from the leading edge to the trailing edge;
wherein both the first surface and the second surface extend from the leading edge to the trailing edge;
wherein the rounded corner joins the second surface to the trailing edge;
wherein the sharp edge joins the first surface to the trailing edge;
wherein the sharp edge reduces drag of the tail boom during a sideward flight motion of the aircraft; and
a tail rotor attached to the tail boom;
wherein the tail boom creates a high-pressure region and a low-pressure region in the rotorwash flowing therearound, which in turn creates a lateral force in a direction opposing a fuselage torque during flight; and
wherein the tail boom is rotatably attached to the fuselage.
10. The rotary aircraft of claim 9 , further comprising:
a flow control device attached to the tail boom.
11. The rotary aircraft of claim 9 , the sharp edge comprising:
a first linear surface; and
a second linear surface;
wherein the first linear surface is oriented at an angle relative to the second linear surface.
12. The rotary aircraft of claim 11 , wherein the angle is about 90 degrees.