Helicopter Rotor Spar Production

Helicopter rotor blades arc subject to a considerable degree of Hexing and vibration when in service, and since scratches and other surface defects can give rise to fatigue cracking it is of the utmost importance that blade members should be free from such faults. The standard method of building up a helicopter blade is to employ an extruded aluminium spar which is subsequently tapered by machining the external surfaces. The trailing edge of the blade is then built up with aluminium sheet, the parts usually being assembled with adhesives.