We know that helicopter should have a tail rotor to counteract the torque created due to the main rotor blades rotation.
There is a special thing about tail rotor too. For example see the picture, there are two sets of blades (2x2=4). One set has two blades in a line.
why two sets? why can't they put just a 4 blade rotor just like a fan in our room?
The tail rotor rotates with a very high speed. Obviously causes noise. To reduce this they will put two sets of blades which will cut off the noise created by the other set
Dude, did u get this from a reliable source? Because, I thought it was to counter balance the torque created by the rotating blades. This can be inferred if u observe that the blade sets rotate in opposite directions.
ReplyDeleteThe sound funda u told doesn't have any scientific explanation!
The main function is to counteract the torque (which is the reaction force). But if they just put the rotor it causes noise too. So this idea is used to reduce the noice.
ReplyDeleteBy rotating blades I mean the tail rotor blades.
ReplyDeleteevery blade produces torque
the main blade torque is counteracted by tail rotor
the tail rotor also creates a torque of its own parallel to its axis.
so to counteract it we need a second rotor that will rotate in opposite direction.
as far as sound is concerned, I think the second rotor would increase the sound rather than decreasing it.