TruTrak Sorcerer - Manual (Page 3)

3
General Introduction
The TruTrak autopilot can be defined as being an orthogonal rate system.
This means that gyroscopic rate sensors sense motion about each of the
major axes (roll, pitch and yaw). These sensors generate the fast signal
responses necessary to create an autopilot with the best possible dynamic
performance.
To fly an aircraft well about the axis controlled by the ailerons, velocity
of aileron movement must be directly proportional to the rate of roll for small
movement. This means that aileron position corrections do not lag behind
motion of the craft about the roll axis. Aileron control systems that use a
turn coordinator, which senses twice as much azimuth as roll rate, cannot do
this. Instead, yaw disturbances in turbulence cause undesired aileron
movement. In some aircraft this effect is so severe that the controls may
even momentarily move in the wrong direction.
The goal at TruTrak is to create systems with the very best dynamic
performance available—systems that do not need to be disengaged in
turbulence, but instead provide function when needed most.
The complete TruTrak autopilot system combines all the electronic and
sensing elements needed for the roll and pitch functions within a single
panel-mounted programmer/computer package. A rate-gyro-controlled yaw
damper can be added to the system.
Basic directional control is provided by digital selection of a GPS track.
This replaces heading selection on the DG and eliminates drift as well as
crosswind correction. In the GPS steering mode of operation, the system
responds to digital guidance information to fly a complex navigation
program.
The vertical portion of the system contains a digital altimeter and
associated altitude selector with selectable increments as small as fifty feet.
Altitude transitions can be made by airspeed, vertical speed, or horizontal
distance (VNAV) selection. If an upward vertical speed is selected which is
beyond the capability of the aircraft, there will be no stall. Instead, the
autopilot will cause the aircraft to climb at a pre-set minimum safe airspeed.
This is the only known system to provide this safety feature.
For any set of features all TruTrak computers are identical. Servos
likewise are identical in velocity response. Servos do differ according to
total torque required. By providing setup functions in the programmer for
system activity and torque, one TruTrak programmer-servo combination can
fly any aircraft.
As a starting point in understanding how to operate the TruTrak system,
the following describes the presentation of data, the operating controls, and
the procedures for selecting modes of operation.