turn indicator

Question 1

turn indicator

Answer 1

1 gimbal, gyro and degree of freedom
only able to rotate about longitudinal axis
restrained by springs either side- provide restoring force
as aircraft turns longitudinal axis moves (yaws) along horizontal axis
precession acts 90° to yaw and acts at top or bottom of gyro causing it to tilt

Question 2

turn indicator display

Answer 2

needle shows rate 1,2,3 turns 
and balance ball
rate 1- 3°/sec,360°=2min
rate 2- 6°/sec, 360° = 1min
rate 3- 9°/sec, 360° = 40sec

Question 3

turn indicator operation

Answer 3

needle connected to gimbal

gimbal deflection related to turn rate

Question 4

turn indicator errors

Answer 4

indicator relies on: TAS, gyro rotor RPM, absence of accelerations in pitch
only accurate for one TAS but fairly accurate for wide range of speeds
not at correct RPM precession incorrect:
RPM high- over read
RPM low- under read

affected by pitching:
pitch up- over read
pitch down- under read

Question 5

is there an unusable or toppled position for a turn indicator?

Answer 5

no

provided it is powered

Question 6

turn coordinator

Answer 6

axis for gimbal tilted at 30°- makes it more sensitive to roll
small amounts of roll quickly detected
turn coordinator easier to use than turn indicator

shows wings level or rate 1 turn- display has no pitch info wrote on

Question 7

turn coordinator errors

Answer 7

same as indicator

only strictly accurate at one TAS and one rotor RPM and zero pitch rate

Question 8

TI & TC behaviour during a spin

Answer 8

TI not sensitive to roll- always correctly indicate yaw and thus direction of spin
TC is sensitive to roll- in unstable or inverted spin may indicate incorrectly

Question 9

balance indicator

Answer 9

rear flow tube- allow free movement of fluid when ball moves
shows if turn in balance or not
fluid provides dampening
curved tube acts as pendulum

Question 10

correcting imbalance

Answer 10

step on ball
ball opposite to turn - skid
ball same as turn - slip

Question 11

effect of imbalance on turn radius

Answer 11

skid- radius decrease

slip- radius increase

Question 12

AOB for rate 1 =

Answer 12

(TAS/10) + 7