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

4.3.2.1 Yield. The BRU yield load shall be 1.15 times the design limit load. No permanent deformation shall be allowed after application of the yield load.

4.3.2.2 Ultimate. The BRU ultimate load shall be 1.50 times the design limit 1oad. Failure of the BRU, upon application of the ultimate load, shall be defined as:

a. Separation of the store from the BRU, or b. Separation of the BRU from the aircraft.

Other structural breakage or permanent deformation of the BRU shall not constitute failure at the ultimate load level.

4.3.2.3 Pressure system.

a. Hydraulic system. Components of the pressure system exposed to hydraulic pressure shall be designed to a minimum proof pressure of 1.15 and a minimum burst pressure of 1.5 times the operational peak pressure of that system.

b. Gas system (hot and cold). Components of the pressure system exposed to gas pressure shall be designed to a minimum proof pressure of 1.5 and a minimum burst pressure of 2.5 times the operational peak pressure of that system.

4.3.3 Structural load requirements. Load analyses shall be conducted to determine the design loads.

4.3.3.1 Take-off and landing loads. The BRU shall withstand the maximum loads imposed by catapult take-off and arrested landing in accordance with MIL-STD-8591. Applicable inertial acceleration limits and loads shall be developed.

4.3.3.2 Captive flight loads. The BRU shall be designed for the maximum aerodynamic and inertial loads acting on the store and BRU throughout the captive flight Mach-altitude envelope of the aircraft (minimum store configuration). The design captive flight envelope and the inertial acceleration levels of the most severe aircraft/weapon station shall be used to develop worst-case BRU design loads in accordance with MIL-STD-8591.

4.3.3.3 Launch loads. The BRU shall be designed for the maximum aerodynamic and inertial loads acting on the store and BRU throughout the specified launch Mach-altitude envelope of the aircraft (minimum store configuration). Combined BRU loads shall include BRU ejector forces and the structural dynamic interactions which occur at store separation.

4.3.3.4 Jettison loads. The BRU shall be designed to withstand the combined effect of maximum ejection forces and the aerodynamic and inertial forces acting on the store/BRU combination over the specified jettison envelope.