(b)
Place hinge bolts through inboard and outboard hinges. Place elevator on balancing jig.
(c)
Avoiding rivets, place balancing tool on elevator with hinge centerline directly over control surface hinge line.
(d)
Adjust moveable trailing edge support to fit control surface width. Tighten set screw on trailing edge support.
(e)
Adjust trailing edge support vertically until beam is parallel with elevator chord line.
(f)
Remove tool from elevator. Balance tool by adding or removing nuts or washers from beam balancing bolt. When balancing tool, moveable weight must be at bar's hinge centerline.
°
(g)
After balancing tool, reattach to elevator. Keep beam position 90 from elevator hinge line.
(h)
Determine balance of elevator by sliding moveable weight along balance beam. Verify that weight is positioned between limits (0 +0/ -2 in.-lbs leading edge heavy).
NOTE: Read scale when bubble in level is centered. Since moveable weight weighs three pounds, every inch it moves from center of beam equals three inch-pounds of force. If elevator is trailing edge heavy, determine and correct cause of imbalance.
(i)
If elevator is leading edge heavy, remove material from balance weight until acceptable balance conditions exists.
() With balance check completed, install elevator assembly on aircraft as explained in this chapter.
Tape Trim Tab Level With Elevator
BalanceJig Center Line
Line
Refer to Control Surface BalancingTool
ElevatorBalancing
Figure 3
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Hinge
PIPER AIRCRAFT PA-42-720 (Advanced Trainer) MAINTENANCEMANUAL
A. Elevator (continued)
3 lb Movable Nuts and/or Weight with Washers Added Marked as Required to Balance Tool Itself
5 ft Extruded Channel BeamBalancing Bolt(Usedfor Balancingthe Tool Itself Once the Trailing Edge Support Has Been Set)
Mark Graduations in Inches -HingeCenterline Placed Directly Over Hinge Line of Control Surface
Horizontally Adjustable for Setting Tool to Surface Bubble Level
VerticallyandHorizontally Adjustable Trailing Edge Support
Line of Control Surface
Control Surface BalancingTool Figure 4
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PIPERAIRCRAFT
PA-42-720(AdvancedTrainer)
MAINTENANCEMANUAL
A. Elevator (continued)
8. ElevatorControlSystemFrictionMeasurement(Figure5)
CAUTION: THEELEVATORMUST BE ROTATEDWITHSTEADYMOVEMENT.FORCE READINGMUSTBE TAKEN WHENELEVATORPASSESTHROUGHNEUTRAL POSITION.DO NOT STOP ROTATIONWHENTAKINGREADING.
CAUTION: DO NOT EXCEED60 POUNDS OF FORCE FORANY MEASUREMENT.
The complete elevatorsystem,includingAutopilotif installed, must be rigged for propertravelsand
cabletensionspriorto determining frictionin system. (Referto 27-00-00)
Total friction in elevator system cannotexceed10pounds with elevatorin neutral position.
Determineactualfrictionin system as follows:
(a)
Attachspringscale to inboard trailingedge of elevatorand outboard of tab. (Shownin Figure 5.)
(b)
With spring scaleattached,positionelevator trailing edgedownapproximately2 inches from neutral position.
(c)
Recordforce required to raise elevator through neutralpositionuntil trailing edgeis approximately2 inches aboveneutral.
(d)
Recordrestrainingforce, lowering elevatorfrom2 inch up position, through neutral position,to original2 inch downposition.
NOTE: If system frictionis a high value, checkaft elevator controltube return spring. The springsapproximatefree length is 12.00 inches, with an initial tensionof 3.5 Ibs.
(e)
Repeataboveraisingand lowering processesuntil average forces are obtained.
(f)
Totalfrictionis obtained foreachmeasurementby subtracting up and downforces.
Elevator
Tab
50 Measure From Here
Elevator Friction Measurement
Figure5
9. CheckingElevator Trim TabFree Play
(a)
Position trim tab to neutral. (Trailing edge of tab in neutral position must be in line with trailing edgeof main surface.)
(b)
Total free play can not exceed 0.06 inch, measured from one extreme to an other, between outboard end of tab trailing edgeand trailing edge of main surface.
(c)
If excessive playis found, inspect elevator trim screw and hinge assemblies. Repair or replace wornpartsas required.
EFFECTIVITY:
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PIPERAIRCRAFT
PA-42-720 (Advanced Trainer)
MAINTENANCEMANUAL
A. VerticalStabilizer
NOTE:Theverticalstabilizercannotbe removedwithoutmajor structural repair.
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