Fighter Combat - Tactics and Maneuvering

16 FIGHTER WEAPONS
required firing time. Available firing time commences when the guns are
properly aimed between maximum and minimum ranges, and it ends
whenever range or aiming constraints cease to be satisfied. It is sensitive to
the range at which proper aim is first achieved, closure, firing geometry,
and relative aircraft performance capabilities.
There are two broad categories of air-to-air gun-firing situations: "tracking"
shots and "snapshots/' The tracking shot occurs when the pipper
remains steady on the computed aim point for longer than the settling
time of the sight. A snapshot, sometimes called "raking guns," refers to a
situation when the pipper merely passes through the proper aim point,
never stopping.
Tracking Shots. Steady tracking is usually necessary for a predictor
gunsight to calculate an accurate lead angle, and therefore tracking greatly
improves the chances of achieving a hit with this type of sight. Tracking
also enhances the effectiveness of a fixed sight, since a relatively long firing
time generally is required to find the proper aim point. Since the historical
sight usually requires only that bullets be in the air at least one TOP in
order to display their impact point accurately, tracking is not generally a
requirement with this sight, but it may provide greater chances of a kill by
increasing the firing time.
Aerial gunnery is 90 percent instinct and 10 percent aim.
Captain Frederick C. Libby, RFC
First American to Shoot Down 5 Enemy Aircraft, WW-I
2,4 Victories (10 as Observer, 14 as Pilot)
The best firing technique depends on many factors and tradeoffs. The
improved lethality of tracking must be assessed relative to the shooter's
sight design and gun-system lethality. This assessment then must be
weighed against the tactical situation. Tracking requires the shooter to
concentrate on the target and fly a predictable flight path for a longer time.
If the situation is such that other hostile aircraft may achieve a threatening
position during this time, tracking may not be advisable. Closure is one of
the major factors in available tracking time, and since the shooter's speed
contributes to closure, decreased speed usually increases tracking time.
Performance and maneuverability are also affected by speed, however, so
such a speed reduction may not be desirable because of its effect on the
shooter's offensive or defensive maneuvering potential following the shot.
One other factor is the time required to achieve a position from which a
tracking shot is practical. Because of the resulting presented target size,
reduced closure, and required lead, the optimum firing position for tracking
a maneuvering target is generally in the rear quarter (about 30° to 60° off
the tail with a LCOS, 0° to 30° for fixed sights), near the target's vertical
plane of symmetry. Achieving such a position on an evasive target can take
a considerable amount of time, possibly more than is prudent in a hostile
environment. Target defensive fire is also a consideration. Multi-crew
aircraft, such as many bombers, may be well defended in the area where
tracking is best.