The wingtip brake consists of a set of trailingedge surfaces for each wing. The lower half attachesto the wing structure with two external fixed hinges.The upper half is attached to the wing at the samewing station with two adjustable tension lengths. Aninterconnecting hinge between the upper and lowerhalves provides a common connection point for theactuating cylinders. The hinge provides symmetricaldeflection of upper and lower panels. Each panel canopen up to 60 degrees for a total angle of 120 degreesfor each wingtip brake. When retracted, they lie flushwith the wing surface. They can extend and hold atany angle between 0 and 60 degrees, depending uponthe amount of aerodynamic braking desired.A mode selector switch permits simultaneous orindependent operation of the wingtip and fuselagespeed brakes, with the speed brake control switchlocated on the right throttle quadrant power lever.Moving the SPD BRK switch to the forward positioncloses the brakes. Moving it to center position holdsthe brakes at any desired angle. Moving it aft opensthe brakes. The switch is spring-loaded to neutralfrom the aft position only.Selecting the open position energizes the selectorvalve, porting hydraulic pressure from the combinedhydraulic system to the extended side of the actuatingcylinder. When the switch is positioned to closed, theopposite solenoid energizes. Pressure is ported to theretract side of the actuating cylinders. With theswitch in neutral, hydraulic fluid is blocked from boththe extend and retract sides of the speed brakecylinders. This action hydraulically locks the speedbrakes. If the electrical circuit fails, the selector valveis de-energized as a fail-safe feature and the speedbrakes retracts.The wingtip speed brake control system normallydepends upon the hydraulic flow regulators tomaintain symmetrical extension of the left and rightbrakes.If a malfunction causes asymmetry ofextension, an electrical disparity signal is sensed bythe speed brake null detector. When the disparitybetween the extension of the left and right brakereaches 8 degrees, the null detector de-energizes theselector valves and causes the speed brakes to close.On some aircraft, the synchronization mechanism(fig. 9-41) consists basically of synchronizinglinkage, two torsional bungee assemblies, and a cablerun interconnecting the three mechanisms to amechanical synchronizing control valve. Thesynchronizing mechanism is a comparative linkagetype that senses unequal motion between the twobrake surfaces. Movement of either speed braketransmits through the torsional bungee assembly andthe cables to the synchronizing mechanism. Anyunequal movement upsets the synchronizingmechanism’s neutral position, displacing thesynchronizing valve shuttle. When the speed brakesare opening or closing, the valve is normally inneutral as long as the travel of both sides is equal.When unequal travel moves the valve shuttle out ofneutral, the valve will relieve hydraulic pressure fromthe speed brake actuating cylinder, producing thehugest opening angle. This decelerates the openingof the speed brake or bleeds down the speed brakewith the largest angle until the disparity is withinlimits and the shuttle returns to neutral. On latermodels this mechanical synchronization system hasbeen deleted.If the mechanical synchronization system fails tomaintain synchronization within 8 degrees, theelectrical fail-safe system operates and de-energizesthe selector valve to close the speed brakes. If thesynchronizing linkage becomes jammed, the torsionalbungee assembly can be forced out of detent, isolatingthe linkage from the speed brake and preventingdamage to the linkage because of overloads.The bungee in the synchronizing mechanismlinkage acts as a rigid length to the synchronizingvalve during normal operation of the wingtip speedbrake. If the valve becomes jammed, abnormal loadson the bungee will cause it to give and relieve theexcessive loads before damage to the valve, linkage,or bungee occurs.TRIM SYSTEMA trim system is provided in the flight controls tolessen the need for constant effort on the part of thepilot to maintain the desired heading and altitude.The trim system stabilizes the aircraft during flight.Lateral TrimThe aileron trim control system is shown infigure 9-42. The illustration represents a trim tabarrangement similar to that found on aircraft equippedwith conventional aileron systems.Operation of the lateral and longitudinal trimsystems is usually controlled by a five-position,four-throw, momentary ON contact switch with acenter OFF position.The switch is found on thecontrol stick grip. This switch electrically energizesthe trim control motor, which operates the trim9-48
Integrated Publishing, Inc. - A (SDVOSB) Service Disabled Veteran Owned Small Business