1) Title of the invention
Design of optimized kinematic linkages for Main rotor control system for Helicopter to have simplified mechanism.

2) Field of invention
To invent/design kinematics of Main rotor controls for installation of Flight control Main Rotor Actuators, in order to transfer pilot inputs to the Main Rotor of helicopter.

3) Use of invention
This invention finds application in the flight control system of helicopter.

4) Prior art
During development of Light Utility Helicopter (LUH), it was proposed to integrate flight
actuators in the flight control system of the helicopter. This could be achieved by installing Main Rotor Control Actuators (Fwd Pitch, Rear Pitch & Roll) direct in contact with Non Rotating Swash Plate (NRSP) with bracketry supports attached individually to Main Gear Box (MGB) and by individually connecting hydraulic hoses to the three main rotor actuators (MRA) from twin hydraulic system.
5) Draw backs of prior art
This method of installation of Main Rotor Actuators is complicated due to longer length of actuator body and actuator stroke hence more weight of actuator and has complicated NRSP design (with higher lug length and more tilt angle) and weight penalty of about 6.0 Kgs. In view of this it was decided to design kinematics for Main rotor controls for installation of Flight control Main Rotor Actuators.
6) Comparison between prior art and present invention
> Installation of Main rotor Actuators was complicated earlier, now it is simplified.
> Length of the actuator and stroke is reduced which leads in simpler actuator design.
> Weight of the actuator is reduced.
> NRSP design was complicated (with higher lug length and more tilt angle), now it.is simplified (with shorter lug length and less tilt angle).
> Simplified lower control design with respect to earlier.

7) Aim of the invention
The prime objective of the invention is to have a simplified kinematics, simplified main rotor actuators and simplified non rotating swash plate for main rotor control system.

8) Summary of the present invention
Installation of Main rotor actuators around the Main Gear Box at 45 deg apart with introduction of a lever between actuator and non rotating swash plate has simplified design of kinematics, actuators and non rotating swash plate which in turns gives weight advantage of around 6.0 Kg.

9) Brief description of drawings
The Figurel explains the Installation of Main rotor actuators around the Main Gear Box at 45 deg apart.
The Figure 2 illustrates dimensions of input lever of main rotor actuator (to reduce loads on lower flight control system).
The Figure 3 depicts the dimensions and position of output lever connected between actuator and non rotating swash plate.

10) Statement of invention
The present invention of introduction of a lever in kinematics of control system provides ease of design of lower flight control system, main rotor actuator and non rotating swash plate. In addition to that a weight advantage of around 6.0 Kg is also envisaged.

11) Detailed description of invention
This invention is primarily to have a simplified kinematics, simplified main rotor actuators and simplified non rotating swash plate for main rotor control system and to design optimized kinematic linkages for Main rotor control system for Helicopter to have simplified mechanism with introduction of a lever in between MRA and NRSP in order to reduce the lower flight control loads, out stroke and weight of Main Rotor Actuator and Simplifies the NRSP design.
Old method of installation of Main Rotor Actuators was complicated due to longer length of actuator body and actuator stroke hence more weight of actuator and has complicated NRSP design (with higher lug length and more tilt angle) and weight penalty of about 6.0 Kgs

The input lever of Main rotor Actuator which is connected to lower flight controls link rod assembly is 150 mm in length with hinge at a distance of 90 mm from the eye end centre of link rod assembly,-which divides the lever in to a ratio of 1.5:1 which reduces the lower flight control loads.

Further output end of the actuator is connected to a lever having 160 mm of length with a hinge point at a distance of 64 mm from the actuator output end (hinged at lever mounting bracket assembly on conical housing of MGB), which divides the lever in to a ratio of 1:1.5 which is reverse ratio of earlier input leverage and neutralizes the total input to output control ratio.

This leads in use shorter output stroke of Main Rotor Actuators hence less weight of the .. actuators and .shorter Jength of .non„roiati.ng...contj[p^ Swash Plate to assist the movement of main rotor blades. Another advantage is reduced loads on lower flight control components hence simplifies design of control system. Installation of Main rotor actuators around the Main Gear Box at 45 deg apart with introduction of a lever between actuator and non rotating swash plate has simplified design of kinematics, actuators and non rotating swash plate which in turns gives weight advantage of around 6.0 Kg.


Claims:
1. Design of optimized kinematic linkages for Main rotor control system for Helicopter to have simplified mechanism with introduction of a lever in between MRA (Main Rotor Actuator) and NRSP (Non Rotating Swash Plate) in order to reduce the lower flight control loads, out stroke and weight of Main Rotor Actuator and Simplifies the NRSP design.
Patent is claimed for Design of optimized kinematic linkages for Main rotor control system for Helicopter by introduction of a lever in between MRA and NRSP considering ease of installation of main rotor actuators, reduction of out stroke and weight of Main Rotor Actuators, simplify the lower flight control design and simplifies the NRSP design, improving reliability & flight safety of the helicopter and weight reduction of about 6.0 kgs.