The result? The designs, materials, and manufacturing pro-


cesses for helicopter rotor blades, main and tail, followed the same path forged by makers of airplanes: better- performing, longer-lasting, more-consistent wings.


As It Ever Was Vertical Aviation Technologies has been building kit versions of the Sikorsky S-52 helicopter, including the main-rotor blades, for 30 years in their Sanford, Florida, facility. The aircraft sported the fi rst all-metal blades on an Amer-


ican helicopter, a design later revised for more consistent manufacturing, better performance, and longer life. The blades now comprise about 138 components, most of them manufactured on-site by Vertical Aviation, and all of them assembled, painted, and balanced per the company’s FAA-approved process specifi cations. Those components include an extruded aluminum spar,


which also functions as the leading edge; trailing-edge pockets of aluminum sheet (15 per blade in three diff erent confi gurations); phenolic spacers; custom blade-balancing hardware; and a steel cuff with a unique threaded collar for attaching the blade to the rotor head. There have been other improvements over the decades,


mostly in adhesives and paint, but the basic design remains safe and eff ective.


Opposite page: The S-52 blade assembly and balancing room at Vertical Aviation Technologies.


Top left: Beneath the end cap on each blade is this blade balance weight system.


Top right: The root end of two S-52L main- rotor blades, the lower one with just the pocket attached, the upper one complete with its unique threaded cuff nut for attaching the blade to the rotor head.


Bottom right: Trailing-edge pockets awaiting incorporation into blades.


SEPTEMBER 2022 ROTOR 51


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