Compliant helicopter rotor pitch link

1. A helicopter rotor blade control system comprising:

a swashplate assembly operatively connected to each of a rotor shaft and a rotor having a plurality of rotor blades with respective rotor pitch horns, the swashplate assembly including:

a stationary swashplate mounted on the rotor shaft; and

a rotating swashplate rotatably mounted to the stationary swashplate via a swashplate bearing; and

a plurality of pitch links configured to transmit movement of the rotating swashplate to the rotor pitch horns for controlling a pitch of each rotor blade;

wherein each pitch link includes a spring module having a plurality of Belleville springs configured to generate link compliance when a force is transferred through the respective pitch link from the rotating swashplate to a corresponding rotor blade pitch horn; and

wherein at least some of the plurality of Belleville springs are arranged in parallel.

2. The helicopter rotor blade control system of claim 1 , wherein each pitch link additionally includes:

a casing arranged along a longitudinal axis and configured to house the spring module; and

two opposing tie rods, including a first tie rod operatively connected to the spring module and a second tie rod operatively connected to the casing.

3. The helicopter rotor blade control system of claim 2 , wherein each pitch link additionally includes a plunger arranged inside the casing on the longitudinal axis, connected to one of the first and second opposing tie rods, and configured to compress the spring module when the respective pitch link transmits the force to control the pitch of a corresponding rotor blade.

4. The helicopter rotor blade control system of claim 3 , wherein each pitch link additionally includes a cap configured to interlock with the casing and thereby enclose the spring module and retain the plunger inside the casing.

5. The helicopter rotor blade control system of claim 4 , wherein each pitch link additionally includes an adjustment mechanism configured to select a preload of the corresponding pitch link.

6. The helicopter rotor blade control system of claim 5 , wherein the adjustment mechanism includes a threaded connection between the casing and the cap.

7. The helicopter rotor blade control system of claim 1 , wherein the plurality of Belleville springs are arranged in parallel.

8. The helicopter rotor blade control system of claim 1 , wherein the spring module additionally includes a compressible damping element configured to generate vibration damping.

9. The helicopter rotor blade control system of claim 8 , wherein the compressible damping element includes one of a polymer block having internal hysteresis and a viscous fluid bladder.

10. A helicopter rotor blade control pitch link for transmitting movement of a rotating swashplate to a rotor blade pitch horn, the helicopter rotor blade control pitch link comprising:

a spring module having at least one elastic member configured to generate link compliance when a force is transferred through the pitch link from the rotating swashplate to the rotor blade pitch horn;

a casing arranged along a longitudinal axis and configured to house the spring module;

a first tie rod operatively connected to the spring module;

a second tie rod operatively connected to the casing;

a plunger arranged inside the casing on the longitudinal axis, connected to one of the first and second tie rods, and configured to compress the spring module when the respective pitch link transmits the force to control a pitch of a rotor blade; and

a cap configured to interlock with the casing and thereby enclose the spring module and retain the plunger inside the casing.

11. The helicopter rotor blade control pitch link of claim 10 , wherein each pitch link additionally includes an adjustment mechanism configured to select a preload of the corresponding pitch link.

12. The helicopter rotor blade control pitch link of claim 11 , wherein the adjustment mechanism includes a threaded connection between the casing and the cap.

13. The helicopter rotor blade control pitch link of claim 10 , wherein the at least one elastic member is at least one Belleville spring.

14. The helicopter rotor blade control pitch link of claim 13 , wherein the at least one Belleville spring is a plurality of Belleville springs.

15. The helicopter rotor blade control pitch link of claim 14 , wherein at least some of the plurality of Belleville springs are arranged in series.

16. The helicopter rotor blade control pitch link of claim 14 , wherein at least some of the plurality of Belleville springs are arranged in parallel.

17. The helicopter rotor blade control pitch link of claim 10 , wherein the spring module additionally includes a compressible damping element configured to generate vibration damping.

18. The helicopter rotor blade control pitch link of claim 17 , wherein the compressible damping element includes one of a polymer block having internal hysteresis and a viscous fluid bladder.

19. A helicopter rotor blade control pitch link for transmitting movement of a rotating swashplate to a rotor blade pitch horn, the helicopter rotor blade control pitch link comprising:

a spring module having at least one Belleville spring configured to generate link compliance when a force is transferred through the pitch link from the rotating swashplate to the rotor blade pitch horn;

a casing arranged along a longitudinal axis and configured to house the spring module;

a first tie rod operatively connected to the spring module;

a second tie rod operatively connected to the casing;

a plunger arranged inside the casing on the longitudinal axis, connected to one of the first and second tie rods, and configured to compress the spring module when the respective pitch link transmits the force to control a pitch of a rotor blade; and

a cap configured to interlock with the casing and thereby enclose the spring module and retain the plunger inside the casing.