Lycoming IVO-540 Series, Operator'S Manual

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LYCOMING OPERATOR’S MANUAL SECTION 5
VO, IVO & TIVO-540 SERIES MAINTENANCE PROCEDURES
Each 10°F variation................................................................................................................. 0.27 in. hg.
Each 10°C variation ................................................................................................................ 0.47 in. hg.
The foregoing are flight conditions and the controls must be set as follows to obtain these settings.
(1) Install a 100 psi gauge to “Tee” at waste gate actuator.
(2) With the engine at 3200 RPM and collective set at low pitch, check inlet pressure setting. This
setting should be within engine oil pressure limits.
(3) Increase engine power to a minimum 26 in. to 28 in. MAP for 5 to 10 minutes until the filter air
and injector inlet air temperatures stabilize and recheck pressure. If tie down facilities are not
available, operate the helicopter in stabilized flight.
(4) Check injector inlet air temperature and full throttle manifold pressure. Compare reading with
curve, Figure 5-3. Results must be within limits of curve. Example: With injector inlet
temperature of 50°C (122°F), full throttle manifold pressure should be between 30.7 in. and 31.3
in. hg. If it is found that the manifold pressure is not within limits, the density controller must be
reset.
(5) To adjust the density controller breaker the lockwire and remove hex plug in end of controller
unit. Insert a screwdriver and turn counterclockwise to decrease and clockwise to increase the full
throttle manifold pressure. The unit is very sensitive and must only be adjusted in small
increments. 1/8 turn of the adjustment is equal to approximately 1 in. MAP.
NOTE
When adjusting the density controller a constant check must be made to the inlet gauge to see
that inlet pressure remains within specified limits.
d. Engine Ground Test Calibration for Density Controller – If conditions do not warrant using the
methods described in the preceding paragraph, an approximate density control adjustment can be
made as follows:
(1) Install a 100 psi gauge to “Tee” at waste gate actuator inlet.
(2) Install a 100 psi gauge at actuator outlet.
(3) Start the engine and operate at 3200 RPM in flat pitch. The actuator pressure must fall within the
limits of the curve for the deck pressure developed by the turbine. For example, see Figure 5-4, if
the deck pressure is 30 in. hg., and the supply pressure between 55 and 65, then the actuator
pressure must be between 24 and 28.5 psi on the outlet side of the actuator
(4) If the actuator pressure is not within limits the density controller must be adjusted as previously
described.
NOTE
It must be remembered the above method is only an approximate setting.
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