Helicopter hover stability and cruise gust effect alleviation

摘要

The pitch and roll channels of the stability augmentation system (inner loop) of a helicopter automatic flight control system are utilized to provide positional and attitude stability at low speeds and hover, and to reduce the attitude effects of wind gusts during essentially level, forward flight at cruise speeds. In the longitudinal or pitch channel, true longitudinal acceleration is summed with washed- out vertical gyro pitch in level flight below 60 knots, and washed-out vertical gyro pitch is used alone above 60 knots; in the lateral or roll channel, true lateral acceleration is summed with vertical gyro roll at speeds below 60 knots in essentially level flight, and vertical gyro roll is inputted alone above 60 knots whenever the heading hold logic has not been disengaged (indicating a roll has not been commanded to perfect a turn); thereby to provide positional and attitude stability at low speeds, and to provide attitude stability at cruise speeds.