Just passed a helicopter on my way to work. We have read in some detail how an airplane gets forward thrust and lift by deflecting air. How does a helicopter with horizontal fans achieve that ?
In general, the forward thruswt is achieved by tilting the entire helicopter forward. This converts some of the lift produced by the main rotor into a forward component of force. The same is true for turns.
Yes, the swashplate may be used to create a thrust imbalance; but this imbalance does not provide any horizontal forces. It merely creates a force imbalance which tips the helo slightly, so that a component of the upward force of the main rotor gets converted into a lateral force.
Take a look at any helo moving with any kind of rapid forward velocity and you will see that the entire craft is tipped noticably forward. Same with sharp turns: the helo tilts noticably in the direction of the turn.
The fans are not fixed to be always horizontal. The pilot is able to control the deflection angle of each fan, and this deflection angle causes air to be pushed in one preferential horizontal direction which gives thrust.
protected by Qmechanic♦ Apr 23 '14 at 10:06
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