Figure 17-12.--Automatic blade folding system schematic.
Pressure is sent through the blade rotation control
positioner drive unit. Fluid is also sent to engage the
rotor brake at this time.
valve to the blade positioner hydraulic motor. The
motor revolves the blade positioner, causing the
On later models, the rotor brake applies manually.
rotation of the rotary-wing head. When the No. 1 blade
The blade fold control valve is energized, sending
is properly positioned aft, the blade positioner control
hydraulic pressure through the rotor coupling to each
valve is energized in the opposite direction. The action
damper-positioner. The blades move against their
a u t o r o t a t ive s t o p s . T h e m e c h a n i c a l a c t i o n o f
stops positioning and disengaging of the blade