Gyro Errors
 

Real Wander, Apparent wander and transport wander. I have read them all several times and don't quite understand it. I am not quite understanding the "direction of the gyroscopes spin axis actually moves from its alignment in space." anyone?

Some video clips here for you to build the mental picture of rigidity and precession, http://www.gyroscopes.org/1974lecture.asp

If you're absolutely stuck after this, PM me.

Wander is the loss of relational reference - to the horizon (for example in the ADI) - where the gyros spinning axis does not maintain a perfect 90 degree angle to the horizon.

Real Wander is caused by mechanical imperfections which can cause the axis to 'wander' from true vertical. Most modern mechanical gyros exhibit a very small amount of this error.

Transport Wander comes about due to the earths converging meridian lines.
In a N or S latitude, when your course carries you anything but directly N or S, the DGs output relative to the actual heading will change. The instrument to display an inaccurate reference - the magnitude of which varies according to direction and distance traveled and the degree of latitude you are in.

Apparent Wander is due to the rotation of the earth. The gyro maintains its spatial position - however due to the earths rotation - it will appear that the gyros indication is inaccurate.

While a laser gyro exhibits no appreciable real wander as does its mechanical counterpart, without compensation, both transport and apparent wander do occur within all gyro systems.

There are formulas for both transport and apparent wander compensation. Anyone recall them - I don't have this data on me ?

Mmmm.....sad to see Eric in his gyro-manic mode. Did him a lot of harm did that.

Dplus$, check PM.

App. topple is 15 · cos(lat) per hour.
App. drift is 15 · sin(lat) per hour.
Transport wander is (E/W GS · tan(lat))/60 per hour.
(GS being groundspeed)

Simple table I was taught is:

NH SH
RW ±° ±° [as given]
ER - + [15 · sin(mean lat)]
LN + - [15 · sin(lat as set)]
TWE - + [E GS/60 · tan(mean lat)]
TWW + - [W GS/60 · tan(mean lat)]

PER HOUR.

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LR, for all his shortcomings Eric was a brilliant teacher and a very inspiring fellow. Article he wrote in '74 here, http://www.gyroscopes.org/papers/The...0umbrellas.pdf