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Tail Rotor Drive. S64F Model Helicopter. Drive Shaft Schematic. Tail Rotor Drive Shaft. The tail drive shaft extends from the tail takeoff flange on the the main gear box to the intermediate gearbox and from the intermediate gear box to the tail gearbox.
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Tail Rotor Drive S64F Model Helicopter 6-
Tail Rotor Drive Shaft • The tail drive shaft extends from the tail takeoff flange on the the main gear box to the intermediate gearbox and from the intermediate gear box to the tail gearbox. • The tail drive shaft consists of seven separate dynamically balanced, tubular aluminum alloy shaft assemblies. They are numbered 1 to 7 starting at the MGB. • The shaft sections are joined by flexible steel discs (Thomas couplings). • The shafts are supported at 5 points by a bearing in a viscous damper housing. 6-
Tail Rotor Drive Shaft Thomas Coupling Thomas Coupling 6-
Thomas Coupling • The Thomas couplings are installed between all tail rotor drive shaft sections and transmission gearboxes. • The coupling transmits torque, absorbs shock and vibrations, and adjusts for minor misalignment of drive shaft components. • The Thomas coupling is a flexible disc assembly consisting of a stack of thin steel discs with synthane isolators installed between each set of discs. 6-
Driveshaft & Mount Bearing Housing & Viscus Damper Thomas Coupling Driveshaft Mount 6-
Intermediate Gear Box • The IGB has an input housing, center housing, and output housing. The input and output housings contain input and output gears and flanges. • The center housing contains the idler gear, oil pump, sight glass, chip detector and oil pressure switch(with corresponding caution lights). • The IGB receives torque from the #6 drive shaft and changes the direction of rotation and angle to the tail rotor gear box (TRGB). • The IGB is air-cooled while the oil pump circulates oil for lubrication. 6-
Intermediate Cut Away Output Input Idler Gear Oil Pump 6-
Intermediate Gear Box Sight Glass Mount Lugs (x4) 6-
Intermediate Gear Box Right Side Pressure Switch Chip Plug Oil Pump 6-
IGB Allowable Leakage • Leakage from the IGB may be caused by a worn or poorly installed seal, gasket, packing, or shim. • Total dynamic oil leakage from all sources must not exceed a drop in oil level on sight gauge from FULL mark to midway between FULL and REFILL in ten flight hours. • The oil level should be checked 30 minutes after flight to determine level. • Allowable static oil leakage is ½ teaspoon (.25 cl.) per hour. 6-
IGB SB 64B35-11 • Service Bulletin 64B35-11 is for the inspection of cracks on the center housing mount lugs. • At every 100 flight hours or every calendar year a fluorescent penetrant inspection should be done on the IGB mount lugs. • Perform inspection on one lug at a time. Remove mount bolt, FPI, apply sealing compound to lug, and install bolt and torque. Repeat for remaining lugs. • If a crack is found, replace Intermediate Gear Box. • Compliance with the Service Bulletin is not required when center housing 6435-66408-103 is installed. This can be verified on the Yellow Tag or buildup sheet. 6-
Tail rotor Gear Box Cut Away Servo Shaft to Pitch Change Beam Servo Output Shaft Input Driveshaft 6-
Tail Rotor Gearbox Right Side Servo Installation Chip Plug 6-