Honeywell VXP, System Maintenance Manual, Page: 39 / 105

System Operations
VXP System Maintenance Manual 3-3
3.1.5 FasTrak Optical Tracker
The FasTrak Optical Blade Tracker (shown in Figure 1-5) can operate either in the daytime or at
night. The FasTrak operates with the VXP system as follows:
• The FasTrak uses ambient sunlight during the day and an infrared light-emitting diode
(LED) to generate an optical signal at night. Day/Night mode is selected through a menu
item in the Display Program.
• The FasTrak generates precise timing pulses corresponding to the passing of the rotor
blades in its optical path.
• Its optical module is comprised of a protective glass daylight filter and a focusing lens
housed in an aluminum canister.
• One external four-pin cable connector near the Delrin mounting base provides for the
input power and ground, a day-night mode input signal, and the FasTrak timing signal
output.
The FasTrak relays all information directly to the Acquisition Unit for processing.
3.1.6 Strobex
The Strobex is a light-weight, hand-held strobe light that can be aimed at a reflective target. The
beam illuminates reflective targets on the main rotor to indicate rotor track, and on the tail rotor to
measure clock angle. The cable assembly to connect it directly to the AU is built into the unit. The
Strobex requires no operator adjustment. The unit flashes in sync with a command from the AU
from a single pulse to 250 pulses per second. The trigger switch on the handle has two functions:
• When no sync signal is present, pressing the trigger produces a single flash, indicating that
the unit is functional.
• When a sync signal is present, pressing the trigger causes the Strobex to flash at the sync
rate.
3.1.7 Photocell
The photocell is used primarily to generate a speed signal pulse for tail rotor smoothing. It consists
of a weather-tight optical probe housed in an all-metal enclosure that transmits a modulated light
pulse and receives the reflected signal from the retro-reflective target patches installed on the tail
rotor. It emits visible-red sensing beams to make alignment easy.
3.1.8 Accelerometer
The VXP system is compatible with a variety of accelerometers, including Charge Mode and Low
Impedance Voltage Mode (LIVM) types. Accelerometers employ a crystal and a mass to convert
acceleration into an analogous output signal.