What causes loss of tail rotor effectiveness?
Loss of tail-rotor effectiveness (LTE) occurs when the tail rotor of a helicopter is exposed to wind forces that prevent it from carrying out its function—that of cancelling the torque of the engine and transmission. Any low-airspeed high-power environment provides an opportunity for it to occur.
What causes tail rotor drift?
The front component of the torque couple and tail rotor thrust (two forces) cause the helicopter to drift to the right. This view is from the rear of the helicopter. A couple is produced by the horizontal component of total rotor thrust and tail rotor thrust causing a rolling tendency to the left.
What is the function of tail rotor?
The tail rotor’s main function is to pull against the torque of the main rotor and hold the helicopter straight. But, by varying the pitch (angle of attack) of the tail rotor blades, a pilot can use it as a rudder for steering.
What happens if tail rotor fails?
If the tail rotor fails in flight, engine torque can no longer be countered by the tail rotor, and uncontrolled spinning of the aircraft is a possibility. Most manufacturers call for an immediate autorotation. Some call for a running landing, instead.
What causes a helicopter tail spin?
A helicopter may spin out of control when the anti-torque system is unable to counteract the torque being created by the engine. When the torque of the engine is greater than the thrust being produced by the anti-torque system, the helicopter will begin to spin.
Why do helicopters hang left skid 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. For example, if the helicopter drifts to one side while hovering, the pilot naturally moves the cyclic in the opposite direction.
Can the tail rotor produce thrust to the left?
The capability for tail rotors to produce thrust to the left (negative pitch angle) is necessary, because during autorotation the drag of the transmission causes the nose to yaw to the left, or in the same direction the main rotor is turning.
What happens when helicopter loses tail rotor?
What is the main function of tail rotor system and how is it controlled by pilot?
The tail rotor is used to control the heading of the helicopter while hovering or when making hovering turns, as well as counteracting the torque of the main rotor. Hovering turns are commonly referred to as “pedal turns.”
What is tail rotor system?
The tail rotor system rotates airfoils, small wings called blades, that vary in pitch in order to vary the amount of thrust they produce. The tail rotor is powered by the helicopter’s main power plant, and rotates at a speed proportional to that of the main rotor.
Can you land a helicopter without a tail rotor?
Yes, it is possible to make an emergency landing in a helicopter should a tail rotor failure occur. The procedure is that same as that of a engine failure and it’s called an autorotative landing. Essentially a powerless helicopter becomes an autogyro (gyrocopter) in flight and can be flown as such.
What causes a reduction in tail rotor thrust?
The reduction in tail rotor thrust comes from the air flow changes experienced at the tail rotor as the main rotor disc vortex moves across the tail rotor disc. The effect of this main rotor disc vortex is to increase the angle of attack of the tail rotor blades (increase thrust).
How does a tail rotor work on a helicopter?
A variable pitch fan is enclosed in the aft fuselage section immediately forward of the tail boom and driven by the main rotor transmission. This fan forces low pressure air through two slots on the right side of the tailboom, causing the downwash from the main rotor to hug the tail boom, producing lift, and thus a measure of directional control.
What are the benefits of a NOTAR tail rotor?
This is augmented by a direct jet thruster and vertical stabilizers. Benefits of the NOTAR system include increased safety (the tail rotor being vulnerable), and greatly reduced external noise. NOTAR-equipped helicopters are among the quietest certified helicopters.
What’s the difference between tail rotors and conventional rotors?
While conventional tail rotors typically have two or four blades, Fenestrons have between eight and 18 blades. These may have variable angular spacing so that the noise is distributed over different frequencies and thus sounds quieter. The housing allows a higher rotational speed than a conventional rotor, allowing it to have smaller blades.