Aerodyn Design Forum

Vincent,

 Good Question, the answer is:

Helicopters need a tail boom for anti-torque.  The main rotor produces a torque that must be counteracted by some other force.  This is accomplished by placing a small rotor at some distance from the center of mass, and pushing the air oppisite the direction of the main rotors rotation.

 A good explaination of this can be found here:

http://science.howstuffworks.com/helicopter.htm

Till i need more information technically

The main purpose of tail boom in Helicopters only for the anti-torque tail rotor. am i correct?

is there any other purpose?

It can also be used for producing some vertical lift if it is canted up; however, it would not exist if they didn't need anti-torque.  So yes, its primary reason for having a tail rotor is anti-torque.  It also provides yaw control in hover.  But again this is a fall out of needing anti-torque.

Mike