MIL-STD-2088-SUP-2 Bomb Rack Unit BRU, Single Store, AircraftThis standard establishes the general guidelines and criteria for the design and development of a single store bomb rack unit BRU for carriage and release of airborne stores excluding air-to-air missiles from fixed wing and rotary wing aircraft using a single suspension point or suspension points spaced at 14 or 30 inches. This standard addresses detailed requirements for gravity non-ejected, pyrotechnic, hydraulic, and pneumatic powered BRUs. Mechanical aircraft armament interoperable interfaces are incorporated to enhance cross utilization and servicing capabilities between military aircraft and aircraft stores see 3.1 of all services of the Department of Defense DoD and North Atlantic Treaty Organization NATO nations.

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MIL-STD-2088B

5.2.6 Electrical fuzing. As required by the procuring activity, this aircraft signal, when present upon store release shall be transmitted directly to the store. After both vertical supports open, connection shall be made to arm the store. The devices used to transfer these voltages

(+ 195 VDC, + 300 VDC) shall be capable of closing and carrying a momentary current of one ampere.

5.2.7 Primary release command. This electrical signal, 28 VDC, to the BRU shall be the primary initiator of the release of the store. Energy sources for opening the BRU vertical supports may include pyrotechnic, pneumatic, hydraulic, or solenoid.

5.2.7.1 Impulse cartridge. When impulse cartridges, as specified in 5.1.7.2.1 b, are used as the release and ejection energy source, this signal shall cause initiation of the primary store release cartridge in the BRU, resulting in the opening of the vertical supports, and extension of the ejector pistons. This command shall operate from a nominal 28 VDC open discrete, shall not require more than 12 amperes (at 15 °C) for more than 50 milliseconds and shall meet the requirements of MIL-STD-704, emergency operation voltage range.

5.2.7.2 Solenoid release. When solenoids are used as the release energy source, this signal shall energize the primary store release solenoid in the BRU, resulting in the opening of the vertical supports. This command shall operate from a nominal 28 VDC open discrete, shall not require more than five amperes (at 15 °C) for more than 75 milliseconds, and shall meet the requirements of MIL-STD-704, emergency operation voltage range.

5.2.8 Secondary release command. This signal to the BRU is the secondary store release initiator should a failure occur in the primary release command circuit. This signal may be applied simultaneously with the primary release command. The characteristics of the secondary release devices shall be identical to those of the primary release devices.

5.2.9 Auxiliary release command. As required by the procuring activity, this signal to the BRU shall initiate a gravity release from the BRU by release of the vertical supports. This operation shall be not greater than the requirements of a primary activation.

5.2.10 Safety interlock electrical requirements. This section describes the electrical power requirements for the control, status and power lines of the BRU safety interlock and interlock override systems.

5.2.10.1 Safety interlock mechanism status. This open/ground 28 VDC discrete shall be capable of sinking 250 milliamperes.

5.2.10.2 Safety interlock drive mechanism electrical power. This power line provides a maximum of 10 amps, 28 VDC power, and shall be in accordance with MIL-STD-704 emergency operation range.