Apr 142020
A concept circa 1968 for a Sikorsky “Advancing Blade Concept” troop transport. The ABC rotor system theoretically permits notably higher forward speed than is normal for helicopter, since the lift generator at high forward speeds is balanced (not the case for conventional choppers). The ABC rotor system was tested extensively in the 70’s with the Sikorsky S-69, but the design and materials of the time were not quite up to the challenge and the craft suffered from excessive vibration. In recent years the tech seems to have been more or less perfected with the S-97 Raider, which hopefully will go into production and finally fulfill the promise of the ABC rotor system.
