TM 55-1510-219-10
CHAPTER 2
AIRCRAFT AND SYSTEMS DESCRIPTION AND OPERATION
Section I. AIRCRAFT
2-1. INTRODUCTION.
The purpose of this chapter is to describe the
aircraft and its systems and controls which contribute to
the physical act of operating the aircraft. It does not
contain descriptions of avionics or mission equipment,
covered elsewhere in this manual. This chapter
contains descriptive information and does not describe
procedures for operation of the aircraft. These
procedures are contained within appropriate chapters in
the manual. This chapter also contains the emergency
equipment installed. This chapter is not designed to
provide instructions on the complete mechanical and
electrical workings of the various systems; therefore,
each is described only in enough detail to make
comprehension of that system sufficiently complete to
allow for its safe and efficient operation.
2-2. GENERAL.
The RC-12D is a pressurized, low wing, all metal aircraft
(figs. 2-1 and 2-2) powered by two PT6A41 turboprop
engines, and has all weather capability. Distinguishable
features of the aircraft are the slender, streamlined
engine nacelles, an aft rotating boom antenna, mission
antennas, antenna pods, wing tip pods, a T-tail and a
ventral fin below the empennage. The basic mission of
the aircraft is radio reconnaissance. Cabin entrance is
made through a stair-type door on the left side of the
fuselage.
2-3. DIMENSIONS.
Overall aircraft dimensions are shown in Figure 2-
3.
2-4. GROUND TURNING RADIUS.
Minimum ground turning radius of the aircraft is
shown in Figure 2-4.
2-5. MAXIMUM WEIGHTS.
Maximum takeoff gross weight is 14,200 pounds.
Maximum landing weight is 13,500 pounds. Maximum
ramp weight is 14,290 pounds.
2-6. EXHAUST DANGER AREA.
Danger areas to be avoided by personnel while
aircraft engines are being operated on the ground are
depicted in Figure 2-5. Distance to be maintained with
engines operating at idle are shown. Temperature and
velocity of exhaust gases at varying locations aft of the
exhaust stacks are shown for maximum power. The
danger area extends to 40 feet aft of the exhaust stack
outlets. Propeller danger areas are also shown.
2-7. LANDING GEAR SYSTEM.
The landing gear is a retractable, tricycle type,
electrically operated by a single DC motor. This motor
drives the main landing gear actuators through a gear
box and torque tube arrangement, and also drives a
chain mechanism which controls the position of the nose
gear. Positive down-locks are installed to hold the drag
brace in the extended and locked position. The down-
locks are actuated by overtravel of the linear jackscrews
and are held in position by a spring-loaded overcenter
mechanism. The jackscrew in each actuator holds all
three gears in the UP position, when the gear is
retracted. A friction clutch between the gearbox and the
torque shafts protects the motor from electrical overload
in the event of a mechanical malfunction. A 150ampere
current limiter, located on the DC distribution bus under
the
center
floorboard,
protects
against
electrical
overload. Rotation of the dipole antenna is controlled
through the actuation of the right main gear up limit
switch. Gear doors are opened and closed through a
mechanical linkage connected to the landing gear. The
nose wheel steering mechanism is automatically
centered and the rudder pedals relieved of the steering
load when the landing gear is retracted. Air-oil type
shock struts, filled with compressed air and hydraulic
fluid, are incorporated with the landing gear. Gear
retraction or extension time is approximately six
seconds.
a.
Landing Gear Control Switch. Landing gear
system operation is controlled by a manually actuated,
wheel-shaped switch placarded LDG GEAR CONTR,
UP and DN, on the left subpanel. The control switch
and associated relay circuits are protected by a 5-
ampere circuit breaker, placarded
2-1
