FAST HYBRID HELICOPTER WITH LONG RANGE WITH LONGITUDINAL TRIM CONTROL

• US 20100224720A1
• Filed: 03/31/2008
• Published: 09/09/2010
• Est. Priority Date: 05/22/2007
• Status: Active Grant

• Current Assignee: Airbus Helicopters
• Original Assignee: Eurocopter
• Inventors: Roesch, Philippe
• Granted Patent: US 8,052,094 B2
• Time in Patent Office: Days
• US Class Current: 244/12.300
• CPC Class Codes: B64C 2027/8281 comprising horizontal tail planes
• CPC Class Codes: B64C 27/26 characterised by provision of fixed wings

Abstract

A hybrid helicopter includes an airframe provided with a fuselage and a lift-producing surface together with stabilizer surfaces and a drive system including:

• • a mechanical interconnection system between a rotor of radius (R) with collective pitch and cyclic pitch control of the blades of the rotor and at least one propeller with collective pitch control of the blades of the propeller; and
  • at least one turbine engine driving the mechanical interconnection system. The hybrid helicopter includes first members for controlling the angle at which the at least one pitch control surface is set as a function of the bending moment exerted on the rotor mast relative to the pitch axis of the hybrid helicopter, and second members for controlling the cyclic pitch of the blades of the rotor in order to control the longitudinal trim of the hybrid helicopter as a function of flight conditions.

Claims

1. A hybrid helicopter (1) having a long range and a high forward speed, the helicopter comprising:

an airframe made up of;

a fuselage (2);

a lift-producing surface (3) secured to the fuselage (2); and

stabilizing and maneuvering surfaces, namely for pitch;

a horizontal stabilizer (30) with at least one pitch control surface (35) that is movable relative to the front portion (34); and

for steering;

at least one suitable stabilizer (40); and

an integrated drive system (4) constituted by;

a mechanical interconnection system (15) between firstly a rotor (10) of radius (R) with collective pitch and cyclic pitch control of the blades (11) of said rotor (10), and secondly at least one propeller (6) with collective pitch control of the blades of said propeller (6); and

at least one turbine engine (5) driving the mechanical interconnection system (15);

the helicopter comprising first means (60, 70, 71) for controlling the angle at which said at least one pitch control surface (35) is set as a function of the bending moment exerted on the rotor mast (12) relative to the pitch axis of said hybrid helicopter, and second means (13, 14, 16, 17) for controlling the cyclic pitch of the blades (11) of said rotor (10) in order to control the longitudinal trim of the hybrid helicopter (1) as a function of flight conditions.

2. A hybrid helicopter (1) according to claim 1, wherein said first means (60, 70, 71) automatically control the angle at which said at least one pitch control surface (35) is set as a function of the bending moment exerted on the rotor mast (12) relative to the pitch axis of said hybrid helicopter (1).

3. A hybrid helicopter (1) according to claim 1, wherein said first means (60, 70, 71) are independent of said second means (13, 14, 16, 17).

4. A hybrid helicopter (1) according to claim 2, wherein, by automatically controlling the angle at which said at least one pitch control surface (35) is set, said first means (60, 70, 71) adjust the tilting moment of said hybrid helicopter (1) to a first setpoint value.

5. A hybrid helicopter (1) according to claim 4, wherein said first setpoint value for the tilting moment of said hybrid helicopter (1) is equal to zero.

6. A hybrid helicopter (1) according to claim 2, wherein said first means comprise a computer (60) that controls an electric actuator (70) turning said at least one pitch control surface (35) about an axis (AX) through an angle that adapts the tilting moment of said hybrid helicopter (1) to said first setpoint value.

7. A hybrid helicopter (1) according to claim 4, wherein the computer (60) determines the bending moment exerted on the rotor mast (12), as deduced from information delivered by sensors (71), said computer (60) ceasing to move said at least one pitch control surface (35) when the bending moment exerted on the rotor mast lies in a predetermined range corresponding substantially to the first setpoint value for the tilting moment of said hybrid helicopter (1).

8. A hybrid helicopter (1) according to claim 7, wherein the sensors (71) are strain gauges placed on the rotor mast (12).

9. A hybrid helicopter (1) according to claim 1, wherein the second means (13, 14, 16, 17) adapt the longitudinal pitch of said hybrid helicopter (1) to a second setpoint value.

10. A hybrid helicopter (1) according to claim 9, wherein said second setpoint value for the longitudinal trim is equal to the value of the slope of the flight path of said hybrid helicopter (1).

11. A hybrid helicopter (1) according to claim 9, wherein said second setpoint value for the longitudinal trim of said hybrid helicopter (1) is equal to zero.

12. A hybrid helicopter (1) according to claim 1, wherein said second means comprise a cyclic pitch stick (13) that controls servo-controls (14) for imposing the cyclic pitch of the blades (11) of the rotor (10) via a swashplate (16) and pitch levers.

13. A hybrid helicopter (1) according to claim 1, wherein said second means are associated with a device (80) for automatically servo-controlling the longitudinal pitch of the hybrid helicopter (1) to the slope of the flight path of said hybrid helicopter (1), said automatic servo-control device (80) being integrated in an autopilot (81) specifically including a GPS (82) for determining said flightpath slope and an AHRS system (83) for defining the trim of the hybrid helicopter (1) so as to deduce therefrom the angle of incidence of the fuselage of said hybrid helicopter (1) relative to the air and reduce it to zero, together with an anemometer installation (84) for correcting errors associated with disturbances due to wind.

14. A hybrid helicopter (1) according to claim 1, wherein said first means (60, 70, 71) automatically control the angle at which two pitch control surfaces (35) are set as a function of the moment of the rotor mast (12) relative to the tilting axis of said hybrid helicopter (1).