I am a flight instructor in florida. I was recently teaching a student who asked me if the Turn Coordinator is tied to a specific airspeed in a given aircraft in order to make a standard rate turn. The POH does not specify a given speed. I know the formula for figuring out the given bank angle for a standard rate turn but I read that the Turn Coordinator compensates for the variation in speed and will always give a standard rate turn. There was no further explanation and that still doesn't clear things up for me. How do I explain to this student the mechanics of how the turn coordinator compensates for varying speeds in a constant rate turn??
Turn Coordinator and Airspeed
- Thread starter mtnchica
- Start date
BoeingBoy
Veteran
- Nov 9, 2003
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- #2
It's based on gyroscopic precession......no compensation for speed required.
When the airplane is turning at a constant bank, gyroscopic precession is what causes the turn coordinator to indicate the turn. The higher the rate of turn, the greater the gyroscopic precession and thus the greater the deflection of the turn coordinator. While the bank angle necessary to achieve a standard rate turn changes with airspeed, the rate of turn doesn't - it's always 3 degrees/second. That rate of turn will cause the same gyroscopic precession regardless of speed, thus causing the same indication on the turn coordinator regardless of speed.
The turn coordinator has no clue what the speed or bank angle is - it's only measuring rate of turn, assuming a constant bank angle since the turn coordinator is a roll indicator when bank angle is changing. So those "standard rate turn" marks are located where a 3 degree rate of turn will put the little "airplane" symbol's wings regardless of speed or bank angle.
Jim
When the airplane is turning at a constant bank, gyroscopic precession is what causes the turn coordinator to indicate the turn. The higher the rate of turn, the greater the gyroscopic precession and thus the greater the deflection of the turn coordinator. While the bank angle necessary to achieve a standard rate turn changes with airspeed, the rate of turn doesn't - it's always 3 degrees/second. That rate of turn will cause the same gyroscopic precession regardless of speed, thus causing the same indication on the turn coordinator regardless of speed.
The turn coordinator has no clue what the speed or bank angle is - it's only measuring rate of turn, assuming a constant bank angle since the turn coordinator is a roll indicator when bank angle is changing. So those "standard rate turn" marks are located where a 3 degree rate of turn will put the little "airplane" symbol's wings regardless of speed or bank angle.
Jim
