Method of manufacturing a helicopter rotor blade

• US 4,298,417 A
• Filed: 02/08/1980
• Issued: 11/03/1981
• Est. Priority Date: 02/28/1977
• Status: Expired due to Term

• Current Assignee: Aerospatiale Societe Nationale Industrielle
• Original Assignee: Aerospatiale Societe Nationale Industrielle
• Inventors: Beziac, Gilbert F. A., Euler, August H. L.
• Primary Examiner(s): Crane, Daniel C.
• Application Number:
  US06/119,912
• Time in Patent Office: 634 Days
• Field of Search: 29/156.8 B, 29/156.8 P, 416/230 A, 416/230 R, 416/226, 156/307.3, 156/307.7, 156/245, 156/228
• US Class Current: 156/228
• CPC Class Codes: B29D 99/0025 Producing blades or the like, e.g. blades for turbines, propellers, or wings
• CPC Class Codes: B64C 2027/4736 from composite materials
• CPC Class Codes: B64C 27/473 Constructional features
• CPC Class Codes: Y10T 29/49337 Composite blade

Abstract

A rotor blade, specially for a helicopter rotor, which blade is made of reinforced plastics and a process for making this blade in a single molding operation.

This blade comprises: a solid one-piece leading edge spar embodied by strands of glass fibre filaments extending lengthwise over the whole length of the blade; a core made of a lightweight cellular substance and placed contiguous with the spar rear face; a thick sheet-like member extending around the spar and the core and comprising at least one layer of a fabric consisting of parallel glass fibres disposed askew of the blade longitudinal axis so as to form a torque-tube; a rear filling element, and a covering extending around the torque-tube and the rear filling element. The airfoil portion of this blade is centered substantially in the front quarter of the chord of the blade cross-section and it has a very high torsional stiffness.

Claims

1. A process for manufacturing a rotor blade, especially for a helicopter, said process comprising the successive steps of impregnating certain components of the blade with polymerizable substances, placing said impregnated components in a single mould comprising two rigid partial moulds, one of which is a bottom partial mould and the other a top partial mould, the internal shape of each partial mould being adapted to the shape of the corresponding part of the blade with respect to variations of blade shape, thickness, chord and twist angle along a blade length, assembling said two partial moulds, and finally submitting the assembled mould to a thermal process for polymerizing the substances impregnating said blade components in the mould, and including the steps of

(a) placing seriatim in said bottom partial mould;

a lower-face part of a blade covering comprising also an upper-face part,

a lower-face part of a thick sheet of fabrics comprising also an upper-face part, and intended to subsequently form a torque-tube, said upper-face part being left unfolded outside of said bottom partial mould;

a substantially D-shaped bundle of strands of glass fibre filament having a rounded front face and a flat rear face and which is placed in the front part of said bottom partial mould and is intended to subsequently form a leading edge spar;

a core of a lightweight cellular substance, juxtaposed to the whole rear face of said D-shaped strand bundle;

(b) folding said upper-face part of said sheet of fabrics above said juxtaposed spar and core so as to wrap them up and preform a torque-tube;

(c) placing a cap on the front part of said preformed torque-tube intended to subsequently form the leading edge of the blade;

(d) placing a rear filling member in said bottom partial mould in juxtaposition to said folded sheet of fabrics;

(e) placing said upper-face part of said blade covering in said top partial mould;

(f) locking said top partial mould to said bottom partial mould; and

(g) placing the mould thus filled in an oven of about 120°

C. to polymerize the impregnating substances of the blade components.