Helicopter Aerodynamics - retreating blade stall

Helicopter Aerodynamics - retreating blade stall

There are a number of dangerous situations for helicopters and other aircraft that use rotors. This situation is known as blade stall withdrawn. Here, the rotor blades on the road away from the direction of flight will be stalled.

This is caused by a combination of relatively low speed and / or the angle is too large. Retreating blade stall is what limits the speed to fly helicopters are capable of even the fastest helicopters can flyabout 200 knots.

Blades travel in a circular motion, and so some of them are in the running direction (forward) and some are moving (retreating blade) on the road.

Most of the designers of helicopters have this problem somewhat by a certain amount of flexibility to overcome the tabs.

The blades flex during the advance of the blades, which means that the angle of attack is much lower. The blades flex as if the retraction of the blade, increases theLift and the angle of attack.

The cyclic pitch control can also be used to increase the pitch of the retreating blades, and also decrease the slope of the advancing blades. This way you can generate more lift and balance the impact of developments and retreating blades.

Failure

The compensation may be in the modern helicopter, built only reduce the effects, not eradicate it completely. And 'possible for helicopters to move quickly to say, which suggests that theRetreating blades are not enough lift. This leads to retraction of the blade stall.

Performance

As a helicopter has reached the speed of flight, where the retreating blade stall occurs, the helicopter is shaking and the noise becomes louder. If you pulled the nose of the State is correct, as the helicopter begins to slow. If this condition is not corrected in time, the helicopter would roll over.

Causes

It can return the end of the shed leaves mucheasier if one or more of the following conditions are met. The conditions that are present, the more likely that the retreating blade stall will be a problem.

Things, retreating blade stall more than one problem can be turbulent air, the rotor turns at low speeds, turning sharply, or escape at high speed.

Some of these factors have to be pilot error. It 'very important that all helicopter pilots know how to solve this problem should never occur.

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