Trailing adge flaps

1..Purpose

The trailing edge flap system installed to provide additional lift during takeoff and landing by increasing the camber of the wing.

2.. system description

                The trailing adge flap system is installed consists of two sets of triple slotted flaps on each wing, one set inboard and one set outboard of the engine. Each set consists of a foreflap, a midflap and an aft flap that are mechaniclly separated of form slots when extended. The sections nest together and fair with the wing when retracted.

 Trailing adge flaps system

1.       General component locations
the falps control lever is on the pilot’s control stand. The flap control until and power unit are the main gear wheel well. A position transmitter mounted on each wing rear spar and indicator is in the flight compartment.

2.       General subsystem features
each flap assembly travel on two flap tracks. The torque tube drive system operates two transmission assemblies attahed to the midflap

3.       System interfaces
leading adge flaps and slats on each wing operate in conjunction with the trailing edge flaps to provide increased lift.

4.       General opertaion
normal operation of the trailing edge flaps is system B hydraulic power controlled by flap lever. Alternate operation is by an electric motor controlled by two switches on overhead panel.

COMPONEN FUNGTIONAL DESCRIPTION

FLAP LEVER

1.       Purpose
the flap control lever provides the pilots a means of regulating the position of the trailing edge flaps using hydraulic power.

2.       Location
the flap control lever is located on the upper right side of the control stand.

3.       Pysical desription/features
the lever assembly consists of a spring loaded telescoping handle that rotated a cable drum around a shaft in the control stand. The lever rotates around a quadrant which has detents at the flaps positions, graduated in units. The lever is spring loaded to lock in each detent.

4.       Operation
lifting the lever releases the lock and allows rotation. The quadrant contains gades at the 1 and 15 unit detents which prevent inadvertent lever movement past these detent positions. The lever must be lowered into the detent and passed under the  gate before further rotation can occur. The flap control lever rotates the cable drum to actuate cables which position a flap control quadrant above the right wheel well.

FLAP CONTROL UNIT

1.       Purpose
the flap control unit is installed to contain the flap control valve and associated mechanical linkages that regulate hydraulic operation of the flaps.

2.       Location
the flap control unit is mounted on the right wheel well ceiling near the aft bulkhead.

3.       Physical description/features
the flap control unit incoporates the mechanical linkage that operated both the trailing edge flap control valve and the leading edge flap control valve. These valve are mounted on the control unit, as well as a cable operated follow-up drum that operates theree cams. Seven cam operated electric switches are mounted on the forward side of the control unit.

4.       Control
normal hydraulic control of the trailing edge flaps is by cables from the flap control lever that operate the input linkage to the trailing edge flap control valve. A flap control cable tension switch is located below the cabin floor, near  the flap control unit quadrant. Tension on the near a reed switch. A cable break allows the spring to pull the target away and activate the switch.  This causes the flap bypass valve to move to the bypass position and prevents hydraulic operation of the flap power unit.

5.       Operation
the trailing edge are normally hydraulically operated.  Rotation of the control lever actuates the flap control unit linkage through the cables. This positions the trailing edge control valve to port system B hydraulic pressure to the flap hydraulic motor. The hydraulic motor powers the torque cables that rotate the follow up drum on the control unit. The follow up drum positions three cams. One cam returns the trailing edge control valve to null and stops the flaps at the desired  position. The second cam position the leading edge control valve and the third  actuates the respective electric switches.

6.       Monitor
actual trailing edge flap position is monitored by seven cam operated switches on the flap control unit actuated by the follow up system. These include alternate drive limit switches, a takeoff warning switch, a landing warning switch, a leading edge indication switch, a mach trim switch, and a stall warning switch. Individual switch operational will be discussed when the specification circuit is covered.