Cessna 188 Series Service Manual page 229

MODEL 188 & T188 SERIES SERVICE MANUAL
3. Drain line at airbox
exhaust crossover pipe and heat exchanger section.
c. Remove safety wire from mounting bolts and
is available for cabin heat and windshield defrost air
bolts securing airbox to fuel-air control unit, and
remove airbox with its gasket. 11B-51. INSPECTION.
Since exhaust systems of
d. Reverse the preceding steps for installation,
this type are subject to burning, cracking and gen-
using all new gaskets, align per figure 11B-4. eral deterioration from alternate thermal stresses
e.
Rig throttle and mixture controls according to and vibrations, inspection is important and should
paragraph 11A-53.
be accomplished every 100 hours of operation. Also.
f. Connect air inlet temperature probe wiring.
a thorough inspection of the engine exhaust system
should be made to detect cracks causing leaks which
11B-43. CLEANING AND INSPECTION. (Refer to could result in loss of engine power. To inspect the
Section 11A.) engine exhaust system, proceed as follows:
a. Remove engine cowling as required so that ALL
11B-44. INDUCTION AIR FILTER REPLACEMENT. surfaces of the exhaust assemblies can be visually
a. Remove left hand engine cowling,
inspected.
b. Remove wing nut on air filter, and remove
NOTE
filter cover.
c. Change filter element according to criteria in Especially check the areas adjacent to welds
section 2 or more often in dusty climates. and slip joints. Look for gas deposits in
surrounding area, indicating that exhaust
11B-44A.
INSTALLATION OF INLET DUCTS (Refer gases are escaping through a crack or hole
to Section 11A), or around the slip joints.
11B-45. ALTERNATE AIR VALVE CONTROL b. After visual inspection, an air leak check should
RIGGING. (See figure llA-5.)
be made on the exhaust system as follows:
a. Pull Alternate Air Control out approximately 1. Attach the pressurs side of an industrial
3. 375"
vacuum cleaner to the tailpipe opening, using a
b. Remove engine cowling as necessary for access. rubber plug to effect a seal as required.
It is possible to rig the rotary air valve with the
cowling installed.
NOTE
c. Rotate valve sleeve until alternate air port is
fully open. The inside of the vacuum cleaner hose should
d. Clamp control housing so sleeve arm (56) clears be free of any contamination that might be
housing (53) end by at least 1/8". blown into the engine exhaust system.
e. Connect control wire (55) to arm (56).
f. Push alternate air control in and insure approxi- 2. With vacuum cleaner operating, all joints
mate 1/8" cushion. in the exhaust system may be checked manually by
feel, or by using a soap and water solution and
11B-46. PROPELLER CONTROL. (Refer to watching for bubbles. All joints should be free of
Section 13.) air leaks.
11B-47. STARTING SYSTEM. (Refer to Section 11.) NOTE
11B-48. COOLING SYSTEM. Ram air for cooling At annual inspection of aircraft, LH exhaust
enters through an intake opening in the front portion tee & exhaust risers should be removed and
of the engine cowling. It is directed around the cyl- a visual inspection made of internal hea. ex-
inders with baffles, and is exhausted through fixed
changer.
cooling air exits on both side cowlings at the aft end.
A third exit is located underneath on the rear sections 11B-52. TURBOCHARGING SYSTEM. A turbo-
of both left and right cowlings. A cooling lip is in- charged engine exhibits some different character-
stalled in the lower outlet which facilitates engine istics from a normally aspirated engine. Following
cooling by directing airflow outward from the aircraft is a description pointing to some of the differing
contour at that point. characteristics. This turbocharged configuration
differs also, because of the Inflight-fixed waste gate.
11B-49. EXHAUST SYSTEM. (See figure 11B-7. ) Please read the following carefully to insure com-
plete understanding of the operational characteristics.
11B-50. DESCRIPTION. The exhaust gases from a. Induction air is taken in through an opening in
each cylinder pass thru riser assemblies into an ex- the left side of the cowling, ducted through an auto-
haust manifold. This manifold connects the risers motive type paper air filter, through the rotary air
to the turbocharger turbine inlet, and to the ground valve (closed position) and into the compressor sec-
adjustable wastegate. As the gases pass through the tion of the turbocharger, where it is compressed by
turbine, some of its energy turns the turbine wheel the turbine driven centrifugal compressor.
which in turn drives the compressor wheel.
The b. The pressurized air is directed through the
waste gate shunts a preset percent of exhaust to the
throttle body where it is metered according to throttle
tailpipe, thereby, controlling turbocharger speed, i.e. valve setting, into the induction manifold, and into
output. A heater, consisting of a shroud around the the individual cylinders.
Revision 1 11B-15