What is the coning angle?
The angle formed between the plane of rotation of a helicopter rotor blade when it is producing lift and a line perpendicular to the rotor shaft. The degree of the coning angle is determined by the relationship between the centrifugal force acting on the blades and the aerodynamic lift produced by the blades.
What causes the rotor to tilt 90 degrees?
Precession is the tilting or turning of the rotor axis as a result of external forces. However, when the same force is applied to the rim of a spinning rotor, the force causes the rotor to move as though the force had been applied to a point 90 degrees around the rim in the direction of rotation.
What is Blade coning in helicopter?
Blade coning. An upward sweep of rotor blades as a result of lift and centrifugal force.
How is dissymmetry of lift correct?
The tail rotor experiences dissymmetry of lift during forward flight, because it also has advancing and retreating blades. Dissymmetry is corrected for by a flapping hinge action. It is designed so that flapping automatically introduces cyclic feathering which corrects for dissymmetry of lift.
What affects the coning angle?
The coning angle increases when more lift is generated as compared to centrifugal force. Conversely, the coning angle decreases when the centrifugal force increases as compared to the lift generated. When a helicopter transitions from the ground to a hover, the increase in coning angle is easy to see.
What is blade flapping?
Flapping is the vertical movement of a blade up or down to increase or decrease lift in order to compensate for dissymmetry of lift. With a lower angle of attack and the same rotational speed, the advancing blade produces less lift than without flapping. The opposite is true for the retreating blade.
Is gyroscopic precession always 90 degrees?
It refers to a principle of gyroscopes that states when a force is applied to a spinning object, the maximum reaction occurs approximately 90 degrees later in the direction of rotation. …
Why does helicopter have huge rotors?
Unlike the small diameter fans used in turbofan jet engines, the main rotor on a helicopter has a large diameter that lets it accelerate a large volume of air. This permits a lower downwash velocity for a given amount of thrust.
What is flapping to equality?
During the movement of a helicopter rotating blade, the speed of airflow over the advancing blade is higher than the retreating blade, resulting in production of an unequal amount of lift. See also dissymmetry of lift. …
How could you reduce the coning angle?
The coning angle increases when more lift is generated as compared to centrifugal force. Conversely, the coning angle decreases when the centrifugal force increases as compared to the lift generated.
Why is blade flapping?
The upward flapping of the advancing blade reduces the angle between the blade chord line and the relative wind. This decreases the angle of attack, which reduces the amount of lift produced by the blade.
When does the coning angle of a rotor increase?
The lift generated by a rotor blade increases from the root to the tip. The coning angle increases when more lift is generated as compared to centrifugal force. Conversely, the coning angle decreases when the centrifugal force increases as compared to the lift generated.
What does Coning mean on a helicopter rotor?
Coning is an upward sweeping angle of the rotor blades as a result of lift and centrifugal force.
What causes the coning of the rotor blades?
What is coning? Coning is an upward sweeping angle of the rotor blades as a result of lift and centrifugal force. Centrifugal force is caused by blade rotation. This force pulls the rotor blades horizontally and provides rigidity to the blades.
What causes an increase in the coning angle?
There are several flight conditions that effect the coning angle. Lower rotor RPM reduces the centrifugal force, which results in an increase in coning angle if the lift requirement remains the same. If the centrifugal force remains the same, the coning angle will increase with an increase in lift.