THE FOUR-BLADED MAIN ROTOR SYSTEM FOR THE AH-1W HELICOPTER

For nearly 20 years, the U. S. Marine Corps (USMC) attack helicopters have gone through a series of modifications as new technology and increased mission requirements came about. The engine package has been upgraded three times and many armament systems have been adapted to makeup the current configuration, the AH-1W with two General Electric T700 engines. With this weapons carrying capability and installed power, it is appropriate to upgrade the rotor system to accommodate more gross weight, power, maneuverability, and agility. A new four-bladed main rotor system based on the Bell Model 680 bearingless rotor technology was designed, fabricated and is currently undergoing flight testing on a modified AH-1W helicopter. Other systems that are also being incorporated under this program include a Liquid Inertia Vibration Eliminator (LIVE) pylon suspension system, an uprated main rotor transmission, and a Digital Automatic Flight Control System (DAFCS). This paper describes these advanced systems that are being evaluated. The results of the preflight component and system testing are presented. The accomplishments of the flight test program to date are discussed and the potential benefits of these systems to the USMC AH-1W attack helicopter are shown.