1 - The Black Vault

PRAETORIAN STARSHIP
additional thrust when it was desired to shorten
takeoff distance. The system was electrically controlled
and operated from the ATO control panel
mounted on the flight control pedestal. The units
were fired simultaneously and gave thrust until
the propellant was exhausted. After firing, the expended
ATO units could be jettisoned to reduce
airplane weight and drag. 12 The system was similar
to the space shuttle auxiliary boosters that
powered the space shuttle into orbit. It is important
to note that once the system was ignited,
there were no means to turn it off—the boosters
would burn until the propellant was consumed.
The Fuel System
The fuel system was a modified manifold flowtype,
incorporating a fuel cross-feed system, a singlepoint
refueling and defueling system, and a fuel
dump system. The system provided fuel supply
for the four engines and the gas turbine compressor.
Each engine could be supplied fuel either directly
from its respective main fuel tank or through
the cross-feed manifold system from any tank.
Wing and external tanks could be refueled or defueled
from a single-point ground refueling and defueling
receptacle located in the right aft landing
gear fairing. Fuel was routed from the single-point
receptacle through the refueling manifold. As an
alternate method of refueling the aircraft, tanks
could be fueled separately through a filler opening
in the top of each tank. 13
The Electrical System
All internal electrical power for the aircraft
came from five alternating current (AC) generators
or from the battery. Each engine supplied power
to operate its own 40-kilovolt ampere (KVA) AC
generator, and the air turbine motor operated an
additional 20-KVA AC generator. These AC generators
provided electrical power for airplane use:
28-volt direct current (DC); 200/115-volt, 400-
cycle, three-phase primary AC; and 115-volt, 400-
cycle, single-phase, secondary and primary AC.
The four engine-driven AC generators were connected
through a series of relays to four AC buses;
left-hand AC bus, essential AC bus, main AC bus,
and right-hand AC bus. The relay system operated
so that any combination of two or more of the
engine-driven AC generators would power all four
of the buses. With one generator operating, the generator
would power only the essential AC bus and
the main AC bus. The air turbine motor-driven
AC generator powered only the essential AC bus
at any time. 14
Both DC and AC external power receptacles
were located on the left side of the fuselage, just
aft of the battery compartment. DC power from
the external source was supplied through two current
limiters to the main DC bus. Any electrically
operated equipment on the airplane, except equipment
connected to the battery bus, could be supplied
from an external DC source. When an external
AC power source was connected to the
airplane, it supplied power to all AC buses, to the
DC buses through transformer-rectifier units, and
to the battery bus to charge the battery when the
DC power switch was in the battery position. 15
The Hydraulic System
A booster hydraulic system, utility hydraulic
system, and auxiliary hydraulic system made up
the power supply sources for all hydraulic components
on the aircraft. The booster system provided
hydraulic power to a portion of the surface
control boost system only. The utility system normally
operated the landing gear, wing flaps,
brakes, nose wheel steering, and a portion of the
surface control boost system. The auxiliary system
normally operated the ramp system and provided
emergency pressure for brake operation. It
also provided pressure for emergency extension of
the nose landing gear. 16
The Flight Control System
The flight control system included the aileron,
rudder and elevator systems, and a tab control
system. The main surfaces were controlled by mechanical
systems, consisting of cables, pushrods,
bellcranks, and torque tubes. Hydraulically driven
booster units provided most of the force required
to move the surfaces. The booster units were
driven by hydraulic pressure supplied simultaneously
by the booster and the utility hydraulic
systems, each of which served to power one portion
of the booster units. System operation was such
that failure or malfunction of any component of
either system in any booster unit would allow normal
function of the other system powering the same
unit. A loss of hydraulic pressure in either hydraulic
system resulted in a corresponding loss in the
booster unit, and a proportionate loss of power to
operate the unit. The airplane could be controlled
with complete loss of booster unit power through
trim tabs and engine power, along with coordinated
increased efforts by the pilot and copilot. The
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