TruTrak Sorcerer – Outdated User Manual

Operating Handbook

For

SORCERER, AP 100 AUTOPILOT

TRUTRAK FLIGHT SYSTEMS

1500 S. Old Missouri Road

Springdale, AR 72764

Ph. 479-751-0250 Fax [phone]

www.TruTrakap.com

1

Table of Contents

Operating Instructions

General Introduction....................................................2

Mode and Data Display...............................................3

Controls.......................................................................4

Lateral Modes..............................................................4

GPS Steering/GPS Nav Mode.....................................5

NAV/Loc Course Mode ..............................................5

Reverse Course Mode..................................................6

Gyro Back-Up Mode...................................................6

Yaw Damper................................................................7

Vertical Modes............................................................7

Altitude Hold Mode.....................................................7

Vertical GPS Steering Mode.......................................8

Barometer Set..............................................................8

Altitude Select Mode...................................................8

VNAV Mode...............................................................9

Minimum Airspeed......................................................10

Maximum Airspeed.....................................................10

Stopping the Transition to a Selected Altitude............10

Additional Operating Instructions

Initializing the Autopilot.............................................11

GPS Acquisition..........................................................11

Altitude Select with AP Off ........................................11

Gyro Set.......................................................................12

Engaging the Autopilot................................................12

Setting Pitch Trim .......................................................12

Power Loss..................................................................13

SORCERER, AP 100 Setup Procedure

Lateral Setup................................................................14

Pitch Setup...................................................................16

General Introduction

The TruTrak autopilot can be defined as being an orthogonal rate system.
This means that gyroscopic rate sensors are installed so as to 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, in turbulence, yaw disturbances cause undesired aileron
movement. In some aircraft this effect is so severe that the controls may
even move momentarily in the wrong direction.
The challenge at TruTrak is to create, beyond question, systems with the
very best dynamic performance available—systems that need not be
disengaged in turbulence, but instead provide function when needed most.
The complete TruTrak flight control system combines within a single
panel-mounted programmer/computer package which includes all the
electronic and sensing elements needed for the roll and pitch functions as
well as a rate-gyro-controlled yaw damper.
Basic directional control is provided by digital selection of a GPS track
to be flown. 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 so as to fly a complex
navigation program.
The vertical portion of the system contains a digital altimeter and
associated altitude selector capable of selection in 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.

2

POWER UP—AIRCRAFT STATIONARY

SEE INITIALIZING THE AUTOPILOT PAGE 11

Mode and Data
Display

This display normally
shows operating modes and
associated numerical data. It is
also used to display setup mode
screens and the setting of
associated numerical data.
When displaying operating
modes, the left side shows
lateral data and the right side
shows vertical data. (See figure
below) The upper left display
labeled
electronic DG slaved to GPS
track. When the GPS track is
not available
replaced by
means the autopilot now uses
its internal gyros for bank angle
control. The lower left display
labeled
direction of flight when in the
standard track mode. When in
the gyro mode, the lower left
shows the current selected bank
angle. The upper right display
shows altitude or selected
altitude, and the lower right
display shows either selected
vertical speed or selected
airspeed.

the left and right hand display
area is used to show pitch trim.
This display consists of four

TRK shows the

TRK will be

BANK, which

SEL shows the selected

The vertical space between

horizontal bars spaced
vertically as the rungs on a
ladder, and are made to move
up or down when the aircraft is
in need of being trimmed.

In the upper left where
direction is shown, a flashing
indicator is present in the center
left of the display. When there
is no GPS signal present the
display will show

NO GPS.

When there is no GPS po sition
information the indicator will
be a flashing period, and the
display will show

NO FIX.

Once GPS position data
becomes valid the indicator will
be a flashing asterisk, and the
display will show

GPS OK. If

GPS flight plan information is
being received over the serial
channel or if GPS steering
information is being received, a
flashing plus sign will indicate
the presence of a useable
steering (GPSS mode) or
waypoint to waypoint (GPS
NAV mode) signal.

A cursor in the form of an
underline is shown beneath the

SEL numerals. This is used to

indicate that an underlined
number will be set by rotation
of the encoder knob.

3

4

Controls

Switches labeled

[NAV] [REV] [SEL] [VNAV]

when depressed enter the
respective lateral and vertical
mode setup screens. When the
desired setup screen is
displayed, the numerical data to
be entered will be underlined.
The data is then set by rotating
the encoder knob and entered
by depressing and then quickly
releasing the knob. This will be
referred to hereafter as “enter”.
The [TRK] [ALT] [AP]
[GPSS] [GPSV] buttons do
not have setup screens; they
enter directly into the respective
modes.
Another means of entering
numerical data is the sequential
pressing of the vertical speed
rocker. Each ti me the rocker is
pressed, the vertical speed will
be changed in increments of
100 feet per minute. If the
vertical speed rocker is pushed
and held, the vertical speed will
slowly scroll up or down in the
desired direction. Still another
means of altering the display
presentation is engaging or
disengaging the autopilot. This
is accomplished by using the
[AP] switch on the
programmer. If GPS Steering
or Vertical GPS Steering is
available, the [GPSS] [GPSV]
switches will also engage the
autopilot. The control stick
switch located on the control
wheel or stick is yet another
means of engaging the

autopilot. The control stick
switch serves a dual purpose.
Momentary closure will
disengage the autopilot. If the
switch is held closed more than
two seconds, the autopilot will
engage upon release. This
means that in addition to
disengaging the autopilot, this
switch also provides the
function referred to as Control
Wheel Steering in that the
autopilot synchronizes to both
direction and vertical speed
upon being engaged.

Lateral Modes

Upon being engaged, the
autopilot will be in the basic
lateral mode, and it will be
synchronized to the track being
flown at the time. (See figure
on page 3.) Note: The number
following
direction) is underlined,
meaning that rotation of the
encoder will select a new
ground track. Rotation of the
knob when it is not depressed
will cause 5° steps of
when it is depressed the steps
will be 1°.
If the autopilot is in another
lateral mode, pushing the
[TRK] button will enter the
basic track mode.
When an external heading
source (DG or HSI) is present,
pressing [TRK] will toggle
between the
track mode. When in the

DG mode the heading “bug”

within the external DG or HSI

SEL (Selected

SEL and

EXT DG and the

EXT

will be used to control
direction.

GPS Steering/GPS
Nav Mode

Pressing the [GPSS]
button will enter either GPS
NAV or GPSS mode
depending on which, if either,
steering signal is available to
the autopilot.
In GPS NAV mode the
autopilot follows a flight plan
programmed into the GPS. The
autopilot will however overfly
each waypoint prior to turning
and intercepting the course line
to the next waypoint.

In the GPSS mode the
autopilot follows lateral
steering or bank commands
generated by a navigation
system (EFIS or GPS). If there
is a GPSS signal present, the
autopilot can also be engaged
with [GPSS] button, and it will
engage in the GPSS mode.

NOTE: If there is not a
GPS NAV or GPSS signal
present the [GPSS] button
will not function.

5

NAV/LOC Course
Mode

Pressing the [NAV] button
will bring up the

LOC COURSE setup screen

or
depending on which is selected
by the navigation receiver. The
setup screen for this mode is
shown below.

The course numerals are
underlined. This means that the

VOR/LOC course is to be set by

rotating the encoder. As the
encoder is rotated, knob out
equals 5° steps while knob in
equals 1° steps. When course
has been set press enter. The
cursor (underline) will now
move to intercept angle. The
default value will be 30°. The
intercept angle can be set from
15° to 45° by rotation of the
encoder knob. When the
desired intercept angle is set,
press enter.

The selected intercept
angle is now converted to an
intercept direction according to
which side of the course the
aircraft is on.

NAV COURSE