In addition, at lower density altitudes, excessive tail rotor drivetrain and tailboom loads will be avoided by reducing the tail rotor blade angle limit.  This automated system safely controls the limit of tail rotor blade angle in all flight regimes.

The DAC controls the tail rotor blade angle to be the same as a standard UH-1H between Sea Level and 4000 feet density altitude;  from 4,000 to 14,000 feet density altitude the DAC gradually increases maximum left and right pedal tail rotor blade angles to compensate for the decreasing amounts of tail rotor authority as the aircraft climbs.  Above 14,000 feet density altitude, no further increases in blade angle are made.

When combined with our Tractor Tail Rotor mod, operators can gain a 28 percent increase in tail rotor authority, according to U. S. Army Test Report No. 63-37.

As this increase in tail rotor authority never exceeds the sea level tail rotor blade, hub or drive train loads above those that these components experience in a "stock" UH-1H, there is no need for a reduction in tail rotor component lives or a commensurate upgrade to these components.

The DAC system consists of four components:  A replacement walking beam assembly (pictured above,) a DAC Bellows, DC Drive Motor and an Electronic Control Box.

Installation is straightforward, and can be accomplished in house by an operator's own technicians.

For hot and high UH-1 operations, GHTI's DAC system can provide a significant increase in safety margins.