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 is loss of tail rotor effectiveness?
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.
What causes tail rotor thrust to decrease?
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).
Does the tail rotor stall?
Analysis of flight test data verifies that the tail rotor does not stall. The helicopter will exhibit a tendency to make a sudden, uncommanded yaw that will develop into a high turn rate if not corrected.
Why do planes yaw in the tail rotor?
The winds passing on both sides of the tail rotor make it teeter between being effective (providing thrust) and ineffective (not providing thrust). This creates a lot of pedal work for the pilot to eliminate unintended yaw.
How can you prevent loss of tail rotor effectiveness?
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What happens if the 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 helicopter to spin out of control?
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.
What is tail rotor roll usually the result of?
Tail rotor thrust is the result of the application of anti-torque pedal by the pilot. If the tail rotor generates more thrust than is required to counter the main rotor torque, the helicopter will yaw or turn to the left about the vertical axis.
Can you auto rotate without a tail rotor?
The most common reason for autorotation is an engine malfunction or failure, but autorotation can also be performed in the event of a complete tail rotor failure, or following loss of tail-rotor effectiveness, since there is virtually no torque produced in an autorotation.
Can a helicopter fly without a tail rotor?
Without the tail rotor or other anti-torque mechanisms (e.g. NOTAR), the helicopter would be constantly spinning in the opposite direction of the main rotor when flying.
Can helicopters stop in mid air?
A helicopter that is flying forward can stop in midair and begin hovering very quickly.
What are the odds of surviving a helicopter crash?
Fatality rate, amount of warning time prior to the crash, and final position of the helicopter were identified. Results: There were 133 helicopters that crashed into water with 456 crew and passengers. Of these, 119 occupants (26%) did not survive; of those who did survive, 38% were injured.
Do helicopters explode when they crash?
Generally, aircraft do not explode when they crash but the fuel that escapes from the fuel tanks rupturing turns into a fireball. As the aircraft begins to disintegrate upon impact the fuel vapors ignite which then causes the remaining fuel to rapidly vaporize and ignite causing the large fireball.
What is 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.
Why is ground effect good for a helicopter?
In Ground Effect (IGE) is a condition where the downwash of air from the main rotor is able to react with a hard surface (the ground), and give a useful reaction to the helicopter in the form of more lift force available with less engine power required.
What is tail rotor roll?
The vertical lever between the rotor hub and tail rotor is reduced by placing the tail rotor on a pylon. Offset mast as viewed from the rear.