MIL-HDBK-244A 6 apr 90.pdf

MIL-HDBK-244A
condition in the carriage envelope. A capability for emergency jettison of all
external storesin cases wherea rapid decrease in aircraft weight or drag is
desired (particularly during take-off and landing operations) must be provided.
Emergency jettison is required to be accomplished at least between normalload
factors of +1.003.5g’s absolute and bank angles and roll rates between ~10° and
tlOe per second, respectively,and pitch attitudes between~lOO.
Selective jettison, where required, for the purpose of intentional
separation of stores or suspension equipment no longer required for the
performance of the’missionin which the aircraft is engaged, must be capable
of being accomplished at least within the load factor, attitude, and angular
rate noted above.
(i) Airframe cavities - The airflow within and around
airframe cavities such as those generated for semi-submerged stores or bays
used for internal carriage should be of such basic character or controlled
such that the separation of stores therefrom shall be safe and shall result
in minimum dispersion due to separationperturbations. The provisions of (e)
should apply equally to stores carried in such cavities.
(j)” Aircraft response - Response of the aircraft to store
‘separationisalso avital considerationto the overall weaponssy-stem design.
The aircraft response will create additional store response, thus, an “
amplification of the total separation transient can result. Aircraft response
is derived from the effects of the ejection sequence, the change to
the aerodynamic characteristicsof the airplane after store release, and the
effect of store induced aerodynamic loads on the aircraft during separation.
The latter effect is pronounced when stores of relatively large size are
utilized or when stores reach large displacements in attitude during supersonic
separation thus producing strong shock waves that impinge on the aircraft.
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(k) Arming wires and clips - A detailed analysis should be
*- made of the effect on the aircraft of store arming wires, lanyards, clips,
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pins, and other debris. There are several ways to install arming wires or
lanyards to stores to effect arming of the weapon. The installationmethod
depends on the fuze selected, the position of the bomb rack arming solenoid,
whether there is -somepilot-operatedinflightfuzing option, and whether the
wire or lanyard is intended to be dropped with the bomb. In any case, arming
wire retaining clips, and pins become debris during store separation. Such
debris may become entangled with aircraft control surfaces or imbedded in
other structure, or it may be ingested into the aircraft engines causing
serious failures. Arming wires routing and securing should be the subject of.
,. detailed analysis,since the wires, if broken, can cause a dud bomb or damage
the aircraft or suspension equipment by flailing around. Arming wires which
become unsecured can cause bombs to become armed while still attached to the
aircraft.
(1) Nake effects - The location of stores on the aircraft
can result in adverse effects on other aircraft structure. Clusters of
stores, store fin wake, and store angle of attack during carriage can affect
the wing or tail boundary layer in such a manner as to cause local flow
separation; Fin extension during employment”candamage adjoining structure.
Vibratory loads, such as those resulting from gun fire, can affect local
structure.
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