Fighter Combat - Tactics and Maneuvering

FIGHTER WEAPONS 59
For forward- or rear-quarter threats, the effectiveness of a missile break
depends on the target's G. Because of the usual large speed advantage of the
missile over the target, a good rule of thumb is that the missile will require
about five times the G capability of the target to complete a successful
intercept. Although the LOS rate increase is primarily a function of target
G, the time required to produce a beam aspect is dependent on target turn
rate. Since the optimum instantaneous-turn-rate performance and maximum
G of an aircraft are obtained near its corner velocity, it behooves the
fighter aircrew to maintain at least this speed when in hostile airspace. (A
discussion of turn performance can be found in the Appendix.) Faster
speeds are usually not as injurious to turn performance as slower speeds,
since deceleration is generally much quicker than acceleration in breakturn
situations. Turn rate and radial G may also be enhanced by breaking
downward, altitude permitting, to exploit the added G of gravity. Nosedown
breaks have the additional advantages associated with lower altitudes
and increased missile look-down. If a heat seeker is suspected,
however, a break toward the sun or into a cloud might be the best move.
Other defensive measures (i.e., chaff, flares, etc.) should be continued
during the break turn as long as the threat may still exist, or until additional
threat information is received.
The direction of the defensive break turn depends on the aspect of the
threat, and usually should be in the closest direction to achieve a beam
aspect. For rear-hemisphere missiles this generally means breaking toward
the threat, and turning away from forward-hemisphere threats. For nearly
head-on or tail-on threats, the break direction is the pilot's choice, with
vertically nose-down usually preferable if that option is available. Particularly
for forward-hemisphere threats, the optimum maneuver plane may
have to be altered somewhat if the defender is to maintain sight of the
missile.
If a threat is detected near a beam aspect, or if a break turn succeeds in
producing a beam aspect before intercept, continuation of the break turn in
the same plane is usually not advantageous, as this would tend to rotate
the missile out of the beam region. In addition to the other possible
problems already mentioned, the beam aspect presents the greatest LOS
rate to the missile. One exception to this rule pertains if the threat is
suspected of being a rear-hemisphere-limited heat-seeking weapon, in
which case a continued turn toward the missile rotates it into the forward
hemisphere, further degrading its chances of guidance.
Otherwise an out-of-plane break turn, similar to the maneuver described
for guns defense (Figure 1-5), usually should be initiated against a
missile in the beam region. This could mean an immediate upward or
downward break on missile launch warning, or an approximate 90° change
in the plane of a turn already commenced. For example, if the reaction to a
rear-quarter threat had been a nose-low vertical turn (split-S) of about 90°,
and indications were that the missile was then near the beam, an approximate
90° roll should be made, followed by a pull-up. This out-of-plane
maneuver should be continued, while turning toward the missile (i.e.,