pump room contains batteries for operation of
stand operator and who has been designated by
the C02 fire-extinguishing system. The fuel-filter
the activity's commanding officer to provide this
room contains a fuel flow measuring package in
addition to a fuel-filter separator.
The test facility operates on the principle that
All certified test cell operators must hold a
valid support equipment (SE) license and ensure
the accumulation of sufficient data for com-
that each particular engine and engine test system
parison with known or desired optimum values
will satisfactorily indicate the relative service of
is indicated on the license. Refer to OPNAV-
INST 4790.2 (series) for training and licensing
an engine under test. To accomplish this result,
you compare the engine performance and test cell
environmental data to standard day performance
Engine testing is accomplished primarily in a
criteria for the engine model being tested. Various
test cell or test house that is fully equipped to
controlling, sensing, and indicating systems
measure all of the desired engine operating
parameters. The building is usually of concrete
are provided to accurately measure engine per-
formance and test cell environmental conditions
construction and contains both the control and
during the test.
engine rooms, although in some installations only
Engine harness and hookups between engine
and connector panel, as well as special test items,
enclosed. Most of these cells have noise silencers
are the responsibility of the using activity.
installed in the inlet stack for noise suppression
A brief discussion of the purpose of each of
and a water spray in the exhaust section for
the major assemblies is given in the following
cooling. Many of the test cells use computers to
paragraphs. System description and operating
automatically record all instrument readings and
principles are also discussed.
correct them to standard day conditions. A typical
enclosed test facility is described in the following
Variable Height Stand Assembly
paragraphs. Portable universal engine runup test
systems and the engine test log sheets are also
The variable height stand assembly, or thrust
bed, is used to support, restrain, and position the
ENCLOSED TEST FACILITY
engine in the desired testing attitude. This
assembly is also used to transfer the engine from
the trailer to the thrust bed. The thrust bed
The test equipment is capable of handling
positioning system and the thrust measuring
30,000 pounds of jet thrust during performance
system are part of the variable height stand.
tests. The test facility building configuration has
an engine mass airflow capacity of 180 pounds
THRUST BED POSITIONING SYSTEM.--
per second, or approximately 17,000 pounds of
The thrust bed positioning system is essentially
thrust, including afterburner operation.
a pneumatic-powered, hydraulic oil-driven device
The complete test equipment consists of nine
capable of raising and lowering the test engine to
i n t e r c o n n e c t e d major assemblies. These
any attitude within operating range. Operating
assemblies are installed in the test facility building.
controls are mounted on the left front A-frame
The test facility building is constructed of
of the thrust bed.
reinforced concrete throughout. Removable con-
In addition to supplying lifting force for height
crete panels are provided in the primary intake
positioning of the thrust bed, oil pressure is used
and exhaust stack systems to permit airflow and
acoustic expansion of the test facility to a
controlled thrust pressure is required.
30,000-pound thrust capacity.
The test cell consists of horizontal primary and
THRUST MEASURING SYSTEM.-- The
secondary air intake stacks, a vertical exhaust
thrust measuring system becomes operative when
stack, an engine room, and a spray room.
the thrust button is acted against by the load cell
Immediately adjacent to the test cell is a one-story
as a result of slight forward motion of the engine
structure containing an engine control room, a
under power. If desired, the load cell may be
pump room, and a fuel-filter room.
preloaded by the preload unit. As thrust is
The pump room contains a cooling water
developed by the engine, the pressure between
the button and the cell produces an electric
set, and a 115-volt, 400-Hz ac generator set for
potential within the cell. The electric current thus
operation of the test facility. In addition, the