What is induced flow in helicopter?

What is induced flow in helicopter?

Induced Flow is the airflow which is forced through a rotor disk perpendicular to the disc. It is caused by the defllection of air by the passage of a rotor blade. In the hover a column of air is deflected through the disc. Induced flow is what is felt if you stand near a hovering helicopter, induced flow is DOWNWASH.

What is Coriolis effect in helicopter?

The Coriolis effect is when the rotor blades speed up or slow down as the center of gravity moves closer or further away from the axis of rotation. As the rotor disc diameter becomes smaller, all the blades increase speed. This can be felt as an increase in rotor RPM, without corrective action by the pilot or governor.

How is a helicopter aerodynamic?

Helicopters are able to fly due to aerodynamic forces produced when air passes around the airfoil. An airfoil is any surface producing more lift than drag when passing through the air at a suitable angle. Airfoils are most often associated with production of lift.

Why do helicopters fly nose down?

To move the helicopter in any direction, the rotor disk must tilt and begin pushing air in a lateral direction. This is known as thrust. To accelerate the helicopter forward and gain airspeed the pilot must push forward on the cyclic control which tilts the disk forward. This is why a helicopter takes off nose down.

Why does a helicopter hover left side low?

Helicopters usually hover left side low due to the tail rotor thrust being counteracted by the main rotor tilt. A nose low or high condition is generally caused by loading. Once stabilized, check the engine instruments and note the power required to hover.

What is settling with power in a helicopter?

Settling with Power is a condition of powered flight where the helicopter settles into its own downwash. The condition may also be referred to as the vortex ring state. Conditions conducive to settling with power are a vertical or nearly vertical descent of at least 300 feet per minute and low forward airspeed.

What is ETL in aviation?

Improved rotor efficiency resulting from directional flight in a helicopter is called translational lift. While transitioning to forward flight at about 16 to 24 knots, the helicopter goes through effective translational lift (ETL). The rotor blades of the helicopter become more efficient as forward airspeed increases.

What is Coriolis force in aviation?

The Coriolis effect is caused by the rotation of the Earth. An object, such as an aircraft, travels in a straight line through space. Thus wind travels clockwise around a area of high pressure in the northern hemisphere and anticlockwise around an area of low pressure.

Does the Coriolis effect affect air travel?

It affects weather patterns, it affects ocean currents, and it even affects air travel. In simple terms, the Coriolis Effect makes things (like planes or currents of air) traveling long distances around the Earth appear to move at a curve as opposed to a straight line.

How do helicopters fly forward?

This kind of directional flight is achieved by tilting the swash plate assembly with the cyclic, which alters the pitch of each blade as it rotates. As a result, every blade produces maximum lift at a particular point. The unbalanced lift causes the helicopter to tip forward and move in that direction.

How do helicopters accelerate?

When the pilot moves the cyclic forward to pitch the nose down and accelerate forward, the helicopter responds by decreasing collective pitch on the front rotor and increases collective pitch on the rear rotor proportionally, pivoting the two ends around their common center of mass.

What is induced flow on a helicopter?

What is induced flow? Induced flow is the downward vertical movement of air through the rotor system due to the production of lift, often referred to as downwash. At a hover in calm, no-wind conditions, the induced flow is at its greatest because there is no horizontal air flow affecting the rotor disc.

What is the transverse flow effect in a helicopter?

Transverse Flow Effect As the helicopter accelerates in forward flight, induced flow drops to near zero at the forward disc area and increases at the aft disc area. This increases the angle of attack at the front disc area causing the rotor blade to flap up, and reduces angle of attack at the aft disc area causing the rotor blade to flap down.

What happens to induced flow when there is no wind?

At a hover in calm, no-wind conditions, the induced flow is at its greatest because there is no horizontal air flow affecting the rotor disc. Induced flow increases as the angle of attack of the rotor blades increases. What is relative wind? What is the lift formula or equation?

What is helicopter aerodynamics?

Helicopter aerodynamics is the branch of physics dealing with the forces and pressures exerted by air in motion. The atmosphere, the mass of air, which completely envelops the earth, is composed of varying and nonvarying constituents. The nonvarying constituents include