××机旋翼大梁由 LD2铝材经浇铸、挤压成型、热处理和机械加工制成。旋翼大梁是空心变截面梁,毛坯横剖面示意图如图1所示。外表面需进行机械加工,内表面不加工。机械加工后,旋翼大梁根部厚度为19mm(图2实线所示),尖部厚度为3.75mm(图2点划线所示)。空心部分是密封的,并充气0.6个大气压。飞行中的转速为178转/分。在各种飞行状态下的应力幅Δσ=(5.0～11.0)kg/mm~2。服役期中曾发现个别旋翼大梁漏气,检查 XX machine rotor girder by LD2 aluminum by casting, extrusion molding, heat treatment and machining. Rotor beam is a hollow cross-section beam, blank schematic cross section shown in Figure 1. External surface to be machined, the inner surface is not machined. After machining, the root thickness of the rotor beam is 19 mm (solid line in Figure 2) and the tip thickness is 3.75 mm (dotted line in Figure 2). The hollow section is sealed and inflated to 0.6 atmospheres. Flight speed of 178 rev / min. The stress amplitude Δσ = (5.0 ~ 11.0) kg / mm ~ 2 under various flight conditions. During the service period, it has been found that some individual rotor-beam leaks and checks