It is also known as Slip indicator/balance indicator/inclinometer.
It has a hollow glass tube, which has a steel ball.
Forces on the ball-
- Gravity takes ball into the turn.
- Centrifugal takes ball out of the turn.
In a Coordinated Turn- ball is in the centre
Gravity= Centrifugal
It utilizes a Rate Gyro, which is a Horizontal Axis Gyro.
The gyro rotates at approximately 9000 rpm.
It has a Turn Co-ordinator, which gives Rate of Turn as well Rate of Roll.
When the bank is changing it indicates the Rate of Roll and when the bank is steady it indicates the Rate of Turn.
It gives the rate of change about the vertical axis, i.e. Rate of Turn and also about the longitudinal axis, i.e. Rate of Roll.
T.S.I. Rate gyro Horizontal Axis gyro
If above rotors rotates above 9000 rpm turn shown is more, If rotor rotates below 9000 rpm turn shown is less.
Centrifugal force at difference banks will be difference but still ball can be kept in the centre at (300,600,900) because as bank increases, load factor on the Aircraft also increases, therefore G force on the ball also increases.
Rate of turn- No. of degrees A/c turns in one second.
Rate 1 turn- 30/Sec 3600 in 2 min
Rate 2 turn – 60/Sec 3600 in 1 min
Rate 3 turn- 90°/Sec 3600 in 40 seconds
Rate 4 turn – 120°/Sec 3600 in 30 seconds
Rate of turn varies inversely with airspeed and varies directly with bank angle.
Radius of turn varies directly with airspeed and varies inversely with bank angle.
It shows Rate of Roll when bank is changing.
It shows Rate of turn when bank is steady.
Turn Coordinator is only electrically driven.
Whereas T.S.I. can be electrically as well as air driven.
T.S.I.
It utilizes a Rate Gyro, which is a Horizontal Axis gyro.
T.S.I. indicates rate of turn and utilizes the principle of gyro precession to do so.
The rotor is mounted in a horizontal ring in the athwart ship axis.
The gyro has freedom of movement about one plane only, which is about the fore and aft axis.
Rotor spins at approx 9000 rpm.
In some models rpm is only 4000-5000 rpm.
The speed is considerably lower than D.G.I. or A.H. speed for the reasons that the T.S.I. utilizes the principle of precession for its operation and that the instrument incorporates two springs which hold the gyro axis horizontal in level flight.
The rotor top spins away from the pilot, as viewed from the Cockpit.