What is the smaller propeller at the back of a helicopter used for?

Question

What is the smaller propeller at the back of a helicopter used for?

Answer 1

The small propeller is used to prevent the helicopter from turning out of control.  If a helicopter only had a main rotor, based on Newton's laws, the cockpit would have to spin in the opposite direction.  The tail rotor puts a counter rotation on the main body.  Though some of the previous answers are somewhat correct, the pitch on that tail rotor does control turns.

Answer 2

Stabilization.

Answer 3

to counteract the tq reaction of the mrh

Answer 4

The small tail rotor is used to keep the helicopter stabalized or going in a straight line.  If that prop ever snapped or stopped working the helicopter would spin out of control.  It would rotate on it's own axis.  Very nasty thing to happen to a pilot.

Answer 5

Keeps the Helicopter from turning in the opposite direction of the main rotors.

Answer 6

to turn the helicopter turn left or right.The big one in the middle is to lift it into the air.

Answer 7

To turn. And to not turn when you don't want to, of course. Some very recent helicopter designs don't have one.

Answer 8

To turn.

Answer 9

To turn and to keep balanced.

Answer 10

Anti torque - the tendency of the body to the helicopter to rotate in the opposite direction to the main rotors. The small roter counters this.

Answer 11

its the most important one, it keeps the helicopter controlable.

Answer 12

Did you know there's a little propellor on aeroplanes too?  It's tiny, and appears at the bottom of the plane if all engines fail. It's so that the wind will propel it to create enough energy to run very basic computer systems, so the pilots can try and fly the gliding plane.

Answer 13

It acts in the same way as a rudder on a boat, to change direction.

Hope this helps and have a good day ;-)

Answer 14

if it wasnt there, then the torque from the main rotor would make the heli spin uncontrollably ( like in black hawk down when the rocket hits the tail rotor) and then you will crash. the tail rotor pulls the tail the other way to counteract this and hold the tail steady. also it is used for turning on the horizontal.

Answer 15

The tail rotor is used for stability.

The torque from the top rotor would spin the helicopter - the tail rotor keeps it stable.

There have been many different designs over the years based on removing the tail rotor, for example helicopters with counter-rotating dual rotors and no tail as well as NOTARS which have a blower in the tail.

NOTAR, an acronym for NO TAil Rotor.

These NOTAR designs were said to be quieter and more stable than the tail rotor versions.

Answer 16

Newtons third law of motion

'for every action there is an equal and opposite reaction'

So if you spin a main rotor using an engine in the fuselage of a helicopter, you are just as likely to get the fuselage to spin as you are to get the main rotor to spin.

The small rotor at the back is angled at 90 degrees to the main rotor and exerts a horizontal force to stop the fuselage from spinning, changing the pitch of this small rotor gives the pilot control and the ability to move the fuselage in the axis of the main rotor.

Basically it gives the pilot control of the helicopter, especially at low and hovering speeds.

Answer 17

for chopping up the fools who stand behind helicopters. originally used in the military for takoff in hostile territory. no lie. it is also great for mixing really big salsa smoothies.

Answer 18

It stops the torque created by the main rotor spinning the helicopter body around with it - it effectively blows the helicopter back into a straight line and by varying the amount of 'blowing' this small rotor does depends on where the helicopter points.

Modern designs use the engine exhaust to do this job.

Answer 19

Its It is called the "tail rotor"

The tail rotor of a helicopter is mounted on the tail of a traditional single-rotor helicopter, close to perpendicular to the main rotor. It is primarily used in order to counteract the yaw motion and the torque that a rapidly turning disk naturally produces. The tail rotor in simple terms is a propeller that pushes the body of the helicopter in the opposite direction of the main rotor, preventing loss of control.

The tail rotor, stabilising the helicopter as it does, is an extremely crucial element of the helicopter, and loss or serious damage often means immediate loss of flight control, often resulting in serious and fatal crashes.

However, the loss does not necessarily mean all control has to be lost - if the aircraft can be kept moving in a forward direction, it can sometimes still be flown. In one case, a New Zealand helicopter pilot with extensive flight experience managed to lose his Robinson R44 helicopter's tail rotor at 4500 ft due to object strike (likely from something that had fallen from the open cabin), and then nursed the aircraft for over 25 minutes to an agricultural airstrip in Fiordland, because no other landing sites were available in the mountaineous terrain. He was forced to land at a speed of 80 knots and skidded for 45 m before coming to a rest, unharmed and with the helicopter in a repairable state.[

Design variations

There are two major variations to traditional tail rotor design concerning the placement of the tail rotor and the surrounding structure. Some companies such as Eurocopter enclose the rotor within a fantail assembly. Such design - called fenestron - protects the tail rotor from foreign object damage better than the traditional outer mounted design but complicates the design of the tailcone to account for the enclosed mechanisms.

New developments

In some more recent helicopter designs, the tail rotor has been mounted tangential to the furthest back point of the top rotor. That is to say that it looks much like an old propeller plane, only at the back of the helicopter instead of the front of a wing. In these new designs the rotor spins in a direction opposite to the top rotor (i.e. counter-clockwise if the rotor spins clockwise and vise-versa). This in effect, cancels the spin and has the added benefit of producing forward thrust.[citation needed]

Most, if not all, dual-rotary helicopters do not use tail rotors, instead, the design of the two main rotors is such that they spin in the opposite directions of each other, thus each cancels out the torque and yaw produced by the other. This has been researched in the past and has been incorporated into some European designs.

Sikorsky Aircraft, a UTC subsidiary is currently researching the merger of these two concepts with a dual rotor helicopter with a rear rotor to provide additional forward thrust and a respective increase in speed and operating range. First flight of a prototype aircraft, the Sikorsky X2 Demonstrator is expected to be accomplished by the end of 2006

Answer 20

The purpose of the tail rotor is to counter the torque of the main rotor. Without the tail rotor, the fuselage will turn OPPOSITE the direction of the main rotor due to Newton's third law.

While in normal cruise flight, the tail rotor is typically NOT used for turning, but instead for yaw control. Turning is accomplished with main rotor cyclic pitch changes.

The tail rotor IS used for turns while hovering, or to assist with turning during certain maneuvers.

Answer 21

to compensate the torque from the main rotor. and to control the helicopter's motion about the veertical axis. it also helps to stabiliye sidewards flight.