V-22 Osprey

Blade Fold / Wing Stow Sequence

Since the V-22 is going to replace the CH-46 it must be capable of being stored in roughly the same amount of space as the CH-46. Although the V-22 is roughly the same length as a CH-46 its wingspan makes it many times wider. Therefore, the Osprey must quickly fold into a compact shape for lowering on existing elevators and storage on the crowded hanger deck. It must also be capable of unfolding rapidly once back on deck. These requirement led to the development of the automatic wing fold / blade stow system.

To minimize storage area and still meet flight readiness times, the V-22 was required to quickly fold into a compact size. This meant that the wing/fuselage connection had to incorporate an automatic fold system. The V-22 has demonstrated its ability to fold and unfold for storage in just 90 seconds. Once folded, the V-22 has a wing stow and rotor blade fold arrangement which allows the aircraft to fit within U.S. carrier elevator limitations.

Once the sequence is initiated, the proprotors turn themselves to a predetermined position. This is called indexing the blades. When complete, one blade on each side is pointing inboard. The remaining four blades automatically fold until all six blades are pointing inward, parallel to the wing. Next, the nacelles begin rotating from the upward, helicopter position to the horizontal, cruise position. Simultaneously, the wing swivels clockwise until the starboard nacelle is positioned in front of the aircraft's nose and the port nacelle is positioned above the fuselage just forward of the vertical tails. This completes the wing stow / blade fold sequence.

The entire sequence takes less than 90 seconds to complete. It can be interrupted or stopped at any point to facilitate maintenance. Manual operation is possible in the event of a system failure. When folded, the V-22 fits into a space 63 feet long, 18 feet 5 inches wide, and 18 feet 1 inch high.

Two outboard blades of each rotor are folded inboard	Nacelles rotate to cruise mode
Wing begins rotating clockwise	Wing rotated 90 degrees within 90 seconds