did you know that we have

[NachtPiloten]

A directional_gryo_needle? Hmm all these years I have used compass_dial. Just need to see how this works. Knock me down with the feather.

[Frosty]

A directional_gryo_needle? ...

Yes, it is in the SDK. I came across it when trying to find stuff for the P-47.

I did an AN-5735-1 for the P-47 cockpit by having a textured ring rotate behind a stationary 'pointer' (lubber line). So modeling a directional gyro is no different than doing an instrument panel compass (eg. a B-16 model - look it up on the web). The only thing to remember, is to set the pivot point for the rotating ring correctly: Eg. when flying north, the 'north' indication on the compass or gyro ring should be pointing towards the lubber line/pilot ('south').

It doesn't seem to function differently from the magnetic compass in CFS3, so you might as well use the same naming convention (like you said). I think I read somewhere that these gyros are prone to drifting but this doesn't seem to be the case in CFS3, though I haven't tested that extensively: I justed checked that the gyro indicated the same direction as the magnetic compass. You can't set the gyro anyway, just like it is impossible to adjust the gyro horizon indicator.
There may be more aircraft in ETO that have them (perhaps even in one of the aircraft that came with the SDK). If you want, I can sent you mine.