Installation. MGL Avionics autopilot

function will commence. Under no circumstances should this function be activated in flight.

The function can exited by pressing any key on the EFIS which will also disengage the servos.

During the servo preflight check, verify the correct directional operation of each servo. The controls must not bind and the servos must not slip in any position. With the servos disengaged, verify that full manual control is present.

If a yaw control servo is being used, the pre-flight check will confirm if you would like the Yaw servo to be activated as part of the pre-flight. If your yaw servo is connected to a nose gear steering system, the combined force required to control the yaw may exceed the ability of the servo. If this is the case with your installation, select to not engage the yaw servo.

The yaw servo should be periodically tested on the ground with offending drag removed if required. On smaller aircraft this could be achieved by lifting the nose gear during the test.

Installation

Installation of the autopilot system consists of four steps:

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Obtain information from suitable sources as to best or recommended location and means for servo installation – if this is not possible, perform a test flight as outlined in the next chapter to determine suitability of the aircraft for installation of an autopilot.

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Physical installation of the servos, electrical and mechanical connections

Ground based configuration of the autopilot system

Test flight based calibration of the autopilot system

Physical installation of the servos

This phase starts with the identification of a suitable location for each servo. In many cases the aircraft manufacturer may have predetermined a suitable location and control linkage.

Installation of the servo should be carried out by a suitably qualified aircraft technician.

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The servo needs to be installed on a rigid platform. It must not move under any expected mechanical load.

Control linkages must be installed such that there is no play between servo bell crank and controls. Any play introduced here can seriously affect the autopilots ability to fly the aircraft properly.

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Electrical wiring should be installed to aircraft standards using suitably dimensioned cable. Please consult with the servo manufacturer for recommended wire types and core dimensions.

Servo power must be routed via a circuit breaker or switch easily accessible to the pilot. Servos will disengage if power to them is removed.

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Servo driven and undriven ranges

Applicable: Trio Gold Standard Servo

The Trio servo provides about +/- 40 degrees of active driven range from neutral position.

When the servo is not engaged the servo arm can move in a much larger arc.

The ideal installation will coincide the undriven (large) range with the full stop-to-stop range of the control surface so that the servo, once engaged is able to drive about 50%-70% of the range of the control surface. This is particularly important for higher performance aircraft. This improves the position accuracy and resolution of the servo system when very small adjustments may be needed in flight.

Further considerations:

With the control surface in neutral position, the servo arm must be as close to neutral as possible. There are 4 possible positions of the arm depending on how you mount the servo arm. If none of these positions are satisfactory, consider drilling four additional arm mounting holes to allow use of the arm in an offset position.

The servo arm provides three hole positions to mount the control linkage. Consider drilling a further hole in a more suitable position to lower the active driven range of the servo on the control surface if required.

Post installation checks:

DO NOT FLY THE AIRCAFT UNTIL THE FOLLOWING POST INSTALLATION CHECKS

HAVE BEEN CARRIED OUT AND FULL AND CORRECT FUNTIONS HAVE BEEN

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