MIL-HDBK-244A 6 apr 90.pdf

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MIL-HDBK-244A
5.1.7.1.2 Store carriage and se~arationaerodynamics. The aerodynamic
effects of the stores on the aircraft’s flying qualities during carriage and
separationsmust be carefully analyzedfor all possible store combinations
during the initial aircraft design phases. Some of the more general aerodynamic
characteristicsaffected by stores carriage which should be investigated,
but not limited to, are the following:
(a) Stability with external store carriage.
(b) Stability with internal store carriage.
(c) Engine ingestionof missile’exhaustgases.
(d) Store release transients.
5.1.7.1.2.1 Stabilitv with external carriage. Location of external
stores relative to the wing leading edge and horizontal tail can have a
marked effect on longitudinal stability and buffet characteristics. In addition,
increasing wing sweep decreases the longitudinal stability with wing
mounted external stores. Generally, airplanes with wing sweep greater than
30 degrees showthe greatest stability loss with external stores---
5.1.7.1.2.2 Stabilitv with internal carriage. For aircraft designed for
internal store carriage, opening of the bomb”baydoors, similar panels or
trapeze extensions should not excessivelydegrade the airplane flying
qualities. Flying qualities effects such as buffet characteristics,directional
stability, and longitudinal stability should be investigatedwith the
bomb bay doors open (both full and to intermediatepositions) and operating.
,
5.1.7.1.2.3 Enaine ingestion of missile exhaust. Aircraft engineingestion
of missile exhaust plumes from rocket motors can cause engine flame-out
or degraded performance. Often to minimize adverse aircraft engine.characteristics
due to missile exhaust gas ingestion, engine thrust levels are
momentarily reduced during the missile or rocket firing sequence and airplane
trim changes may ensue.
5.1.7.2 Optimizing carriage aerodynamics. When designing an aircraft,
the effect of store carriage on aircraft performance mustbe minimized.
A great variety of stores is available in many different carriage combinations.
For example, certain store combinations can produce an incremental
drag equal to or even greater than the basic drag of the clean aircraft, and
therefore, it is crucial to consider their effects on aircraft . performance.
5.1.7.2.1 Choosinq carriage class. The two major classes of store
carriage are “internal” and “external”. There are important effects of each
to be considered in aircraft design, the choice of either or both types depending
on mission requirements. An analytical approach backed up by substantial
experimental proof will lead to the best store arrangement for a
given mission.
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