The Art of the Helicopter John Watkinson - Karatunov.net

Fig. 7.19 The turn indicator is spring centred. In a turn, the rigidity of the gyroscope attempts to oppose the
turn but it is overcome by a force from the spring. The tighter the turn, the greater the spring extends and the
higher the reading. A conventional slip indicator is a curved tube containing a weight and damping liquid.
Fig. 7.20 In an aeroplane making a properly co-ordinated turn, the weight in the slip indicator remains central.
aircraft in a properly co-ordinated turn, the acceleration into the centre of the turn and
the acceleration due to gravity combine to give an apparent gravity in the cockpit that
is straight down through the floor. Thus it is possible to use a damped pendulum as a
slip indicator.
As was seen in section 5.2, the conventional helicopter cannot balance main rotor
torque with the tail rotor alone. There has to be another force in conjunction with the
tail rotor in order to create a couple. In forward flight this may come from a slight rotor
tilt or from side slipping the hull or from some combination of both. The least drag is
obtained with zero slip, but in many helicopters the zero slip condition results in a hull
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