Описание8AT-2710-000
The main rotor blade is designed to create a lifting force.
The main rotor blade has a rectangular shape with a chord of 520 mm. The contours of the cross-sections of the blade are formed as follows: from section 1 to section 3, the profile NАСА-230 is applied, in the section from section 4 to section 22, the same profile is applied with a modification of the tail section (the rear edge of the profile is raised above the chord line). The section of the blade between sections 3 and 4 is transitional.
The relative thickness of the blade profile in the section between sections 1 and 3 is 12%, in the section from section 4 to section 22-11. 38 %. The blade has a geometric twist, i.e. the setting angle of the blade sections varies along the radius according to a linear law from 5° at section 4 to 0° at section 22.
The blade of the all-metal construction consists of a spar, a tail section , a steel tip , counterweights and the end part of the blade. It is equipped with a system for damaging the blade spar. The main power element of the blade is the spar, which is a hollow beam with an internal constant contour. The outer front surface of the spar is processed in accordance with the theoretical contour of the blade profile (taking into account the installation of a heating element of an electric thermal de-icing system on the toe of the spar). The spar is made by mechanical processing of a hollow billet pressed from an aluminum alloy AVT-1. Outside, the spar is strengthened by the method of riveting with steel balls on a vibrating stand with a depth of 0.3…0.4 mm.
The upper and lower shelves of the spar on the inner surface have smooth ribbing-thickenings. The first ribs from the toe are guides for installing counterweights. The thickenings located closer to the rear wall of the spar compensate for the reduction in the cross-sectional area of the spar caused by grooves on the outer surface of the spar for flanging the skin of the tail compartments.
The blade spar damage alarm system is pneumatic with a visual pressure indicator. The system consists of a sealed cavity of the spar, a valve with a spool and a pressure indicator.
