Convergence means coming together. Fixed guns on combat aircraft are aimed slightly inwards, so that the bullets meet at a point in front of the aircraft. This is to concentrate as much firepower as possible in the smallest space on the enemy aircraft. In WarBirds, the convergence range is set in the Select screen, or by the .conv XXX command (see The Dot Commands).

In the next example (below), the pilot has got it right. This aircraft with wing-mounted guns has its convergence set to 300 yards. The aircraft that it is firing at, is only 300 yards away. The two banks of guns are hitting the same place on the enemy aircraft. This is the best way of doing it. He is packing a good punch on the enemy, and can expect maximum effect.

This is probably the worst scenario. In the example below, an aircraft with wing-mounted guns has its convergence set to 300 yards. It is firing at an aircraft that is 600 yards away. The two banks of guns are hitting wildly different places on the enemy aircraft. If the enemy was any further away, the two streams of fire, might actually pass either side of the enemy without touching. If you have to fire at distances of double (or more) of your set convergence, try to aim slightly to one side of the enemy. That way, one bank of guns might hit the enemy aircraft.

The last example shows how little effect convergence has on an aircraft with nose-mounted guns. This aircraft has its convergence set to 300 yards. It is firing at an aircraft that is 600 yards away and still manages to achieve a fairly concentrated stream of fire on the enemy aircraft.