Rigging And Adjustment Of Calco Flap System - Piper Navajo Chieftain PA-31-350 Service Manual

NAVAJO CHIEFTAIN SERVICE MANUAL
5-86. RIGGING AND ADJUSTMENT OF CALCO FLAP SYSTEM.
CAUTION
Ensure that all electrical power to the flap control system is
OFF. Pull flap control and motor circuit breakers, set battery
master switch OFF and have no external power applied to the
aircraft.
Following are definitions of terms used in the description and service information presented in the
following paragraphs:
RC-Control Rheostat Wiper
RL-Left Wing Flap Rheostat Wiper
RR-Right Wing Flap Rheostat Wiper
VC-Voltage at RC (Control)
VL-Voltage at RL (Left Flap)
VR-Voltage at RR (Right Flap)
A VCL-Voltage difference between VC & VL at flap-up position.
A VCR-Voltage difference between VC & VR at flap-up position.
A VRL-Voltage difference between RL & RR
RT2-Amplifier Trimmer Adjustment - Left
RT3-Amplifier Trimmer Adjustment - Right
VC-VC+(. 10 + 0.10/-0.05)
The Control rheostat operated by the Flap Selector will be referred to throughout this rigging procedure
as RC (rheostat control). The wing flap rheostats will be designated as RL (rheostat left) and RR (rheostat
right). The voltages present or read at the center taps will be referred to as VC, VL and VR respectively.
a. Proper operation requires that the rheostat (RL) on the left flap respond to any changes in the flap
position selector rheostat (RC) in the form VL and VC. It follows that the amount of the stroke travel, as well
as how it is centered with respect to the ends, will be determined by how RL is adjusted relative to RC. Since
VC is fixed and cannot be changed, a trimmer pot RT2 is provided in the control amplifier to allow adjustment
of VL to agree with VC.
b. Throughout all of the adjustment procedures it is very important that, whatever changes are made to
RL and RT2, must also be made to RR and RT3. It is the function of RR to track RL over the entire stroke
range and shut the system OFF if the outputs in the form of VL and VR deviate by more than 0.5 volt. This
voltage differential ( A V .) corresponds to a five degree asymmetrical flap condition. An additional function of
RR is to provide a voltage input to the control amplifier in order to provide an output to the flap position indicator.
NOTE
In general, the adjustments of RL, RR, RT2 and RT3 are always
made with the flaps in the DOWN position and the magnitude of
these adjustments will be based on the values of VC, VL and
VR measured with flaps in the UP position.
Revised: 3/31/94
SURFACE CONTROLS
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