Fighter Combat - Tactics and Maneuvering

FIGHTER WEAPONS 5
gun as the fighter's primary armament. The feeling was that the high
speeds of jet fighters and the heavy armament of new bombers made the
gun obsolete, particularly for night and all-weather missions. During this
period many fighters were not equipped with guns at all; their air-to-air
weapons package consisted entirely of unguided rockets, and then of
guided missiles (which are discussed later in this chapter). This trend was
reversed in the 1970s, after further combat experience had once again
demonstrated the value of the gun and the limitations of some of the more
exotic weapons.
Table 1-1 is a collection of statistics on many of the guns which have
been important in American combat aircraft, and it is fairly representative
of the armaments of other nations, as well. A good indication of the
technological development of a gun is the weight of the projectiles that it
can fire in one minute (assuming barrel limitations and ammunition
supply allows). In this table weight of fire is measured by the factor WF.
Tremendous progress can easily be seen here by comparing the post-World
War I Browning .30-cal M2 machine gun with the 20-mm M61 Catling gun
of the 1950s. Improvement in this area has been one of the leading factors
in the lethality increase of airborne gun systems.
The lethality of a gun can be measured by multiplying the destructive
power of its projectile and the number of hits. For nonexplosive bullets,
destructive qualities are generally proportional to kinetic energy: half the
mass of the projectile times the square of its velocity. To be more technically
correct, the velocity used should be the relative impact velocity,
but for comparison purposes, muzzle velocity will do. The factor FL in
Table 1-1, a measure of the lethality of the gun, is proportional to the
kinetic energy of each projectile and the rate of fire.
FL should be roughly indicative of the lethality of a nonexplosive bullet
fired at the specified rate from a given gun. Cannon are a somewhat
different case, since much of the lethality of these weapons is derived from
their explosive shells. Therefore FL is a fairly accurate relative assessment
of the destructiveness of machine guns, but it underrates the cannon in
comparison. Likewise, it can be used to compare cannon of the same
projectile size, but it would slight larger guns in comparison with smaller
ones.
Even with its limitations, FL can give a qualitative feel for the incredible
increase in fighter gun-system lethality over the years. For example, the
combined FL of the two .30-cal-class synchronized machine guns typical of
fighters at the end of World War I would be on the order of FL = 2, while the
six wing-mounted .50-cal guns of the World War II P-51D fighter would
rate about FL = 38. In addition, a much better gunsight on the P-51 and
many other fighters of its day greatly increased the probability that hits
would be scored. A further lethality increase can be seen in the gun
systems of some present-day fighters, such as the F-14, F-15, F-16, and F-18,
which mount a single M61 Catling gun. Ignoring the increased lethality of
the explosive shell and even better gunsights, these aircraft would rate
about FL = 145. Such technological advances, combined with inherent