TowerTalkTowerTalkThe full-size navigation computer, both sides. Turn the dials yourself and read the answer as you would on the real one, or type the figures you have: it works the answer out, sets the dials to it in front of you, and lists the steps.
A circular slide rule. The outer scale is fixed and the inner disc turns. With the 60 index set against a speed, every time on the inner scale has its distance above it on the outer scale; the same setting works for fuel flow, fuel used and endurance. The airspeed window sets pressure altitude against air temperature to give true airspeed over calibrated airspeed, and the pointer beside it reads density altitude. The marks around the edge convert nautical, statute and kilometre distances, feet and metres, kilograms and pounds, and litres and gallons.
The scales carry figures only, so 12.5 can mean 1.25, 125 or 1,250. Place the decimal point from a rough estimate first, exactly as you would in the exam.
A compass disc over a card of speed arcs and drift lines. To find a heading: put the wind direction at the true index, mark the wind speed up from the centre, turn the track to the index, slide the card until the dot sits on your true airspeed, then read groundspeed under the centre and the wind correction on the drift line through the dot. It also finds the wind from heading and track, and the headwind and crosswind on a runway.
A typed answer and the dial position it animates to come from the same formulas, so the picture and the figure always agree. The computer is a training aid: for a real flight, use the figures from your own aircraft's flight manual.