The work has been carried out primarily in CD-Adapco's unstructured Navier Stokes solver, STAR-CCM+, to the blind prediction of hub drag on two production
rotor hub geometries, the S-92A hub and the UH-60A hub.
"This condition, if not detected and corrected, could lead to further crack propagation, possibly resulting in main
rotor hub failure and consequent loss of the helicopter," Easa warned in a directive issued on March 15.
A steady course and no speed changes helped to minimize rocking of the ship and oscillation of the suspended
rotor hub. We also had two line tenders stabilizing the rotor head.
The two-bladed rotor, although in better shape dynamically than a single-bladed rotor, must accept very high cyclic loading if a rigid
rotor hub system is employed or provide a so called teeter bearing to allow the rotor blade to rock (as a pair) to alleviate blade, drive train and tower head loading.
50 hours is required to remove the 550 lbs of metal from the 55" dia titanium
rotor hub. Stock removal of up to 3/4" with milling tolerances ranging from .002" to .010".
The Transportation Safety Board of Canada determined rather quickly that the main
rotor hub and rotor blades had departed the aircraft in flight.
The largest castings, such as the
rotor hub, machine frame and baseplate, serve as the support system for the wind turbine's long, tall tower, gigantic rotor blades and machinery and gears.
Though NAVAIR said in January that much solid engineering work had been done on the EH101/US101 tail rotor, Canadian news reports in May said CH-149/EH101 maintenance officers still could not explain the rapid failure of tail
rotor hub halves.
After the parties left the site, the Marine maintenance control chief moved a CH-53 helicopter into the hangar for removal of the tail
rotor hub assembly.
The part also includes a
rotor hub with pockets and swept surfaces.
A novel design, which for the first time transferred the elastic element to the interior of the
rotor hub itself, took to the air in March 1971.
"The contract exempts the
rotor hub assembly from Bell responsibility.' In fact, the overhaul contract doesn't deal with the system's design.