I understand the thread moved past this particular item, but perhaps someone may still find little info on the horizon interesting. The part number is LUN 1202, electrically powered through voltage changer. Best picture I could find is here:
http://pwdt.virtualskies.net/images/lun1202.jpg
Used on 70's design eastern trainers (Zlins), simple design now obsolete. I completed my initial instrument and night training with these.
The mechanical principles are:
Aircraft symbol is fixed in bank. The left knob serves for adjustments in pitch designed to fine tune the vertical position of the aircraft symbol so that in level flight with different speeds pilot could "zero" the indicated pitch and maintain precise reference. I was told not to use it, nor felt it would be required.
The coloured ball inside (not the side-slip indicator) maintains position in 3D with the vertical divider aligned to true horizon.
How to read:
The picture shows a slight nose down attitude, for basic recognition the upper part over which the aircraft symbol is now portrayed is painted brown with a label "descends". Suppose you would like to return to neutral pitch: look at the ball's vertical divider and "pick" it up to align with (fixed) aircraft symbol. The ball's divider needs to go up - pull back on the stick.
Bank is read by comparing the top-down line on the ball to the scales at bottom. The gyro-ball is again stabilised and the whole instrument (and aeroplane) revolves around it. For a right 15 deg bank situation, the scales would turn clockwise over the stabilised background gyro ball. I.e. you need to pull the top-down line drawn on the gyro-ball out from the neutral position behind the scales to the first mark on the right side. As you apply right rudder to keep the sideslip indicator centred you will see the turn coordinator located right in between these to sway to right, all conveniently located at one spot. So once we had banked to the right you would see the top-down line on the reference ball aligned behind the right side of the (fixed) scales on the bottom of the instrument. To return wings level, you push the top-down line back to centre with a left input on the stick. Or, as I was told on the first day of the training "kick" the gyro back to neutral position - with your knee kick the stick.
Maybe different teaching would be required with yoke equipped aircraft, but for Zlins this worked seamlessly.
Yours,
FD (the un-real)