PURPOSE: To permit the free constitution of a radio wave permeating structural body in accordance with a configuration having an acute angle part and the like, reduce the weight and keep the strength of the same, by a method wherein a radio wave permeating structural member, forming the profile of the same member, is arranged before the surface of a radio wave absorbing member, which is opposed to the direction of the radio wave.

CONSTITUTION: A honeycomb core 6 is provided between the fore beam 2 and the rear beams 3 of the leading edge of a main blade for an aircraft while a skin 4 is attached so as to cover these members. A leading edge skin 5 having a configuration with an acute angle part is provided on the leading edge especially. The leading edge skin 5 is constituted of a radio wave permeating material such as fiber reinforced plastics and the like. A radio wave absorbing material 7 is attached to the front surface of the fore beam 2 so as to cover the fore beam 2. Accordingly, the leading edge skin 5 is arranged before the radio wave absorbing member 7. According to this constitution, the radio wave absorbing member 7 and the radio wave permeating structural member 5 may be manufactured and assembled separately, the structural member 5 may be provided with any configuration freely, the weight of the same members will never be increased and a necessary strength may be obtained.