22-05-2012, 10:40 AM
SUPERCHARGING AND TURBOCHARGING
06 SUPERCHARGING AND TURBOCHARGING [EDocFind.info].ppt (Size: 1.21 MB / Downloads: 80)
POWER MANAGEMENT
The power created by a reciprocating engine is a product of MAP (manifold absolute pressure) and rpm.
If rpm remains constant and MP is increased, power output will be increased.
If MP remains constant and rpm is increased, power output will be increased.
FACTORS AFFECTING POWER
Humidity- water vapor in the air takes the place of oxygen molecules. The molecular weight of water vapor is less than oxygen; as a result moist air is less dense than dry air. Less dense air means decreased performance.
Temperature- temperature affects air density which affects performance: T↑, d↓, P↓
Mixture- fuel:air ratio
Ambient Pressure- the pressure altitude at the aerodrome affects air density and performance: p↓, d↓, P↓
POWER SETTINGS
The power setting used for cruise flight is a trade-off between fuel economy, engine longevity, and speed.
100% power is only used for takeoff and initial climb. 100% power will only be available under certain altitude and temperature conditions.
Normal cruise power setting is usually 65%.
RULES TO PROLONG ENGINE LIFE
Be aware of thermal shock. Avoid large power reductions. Reduce power in increments. Manage cowl flaps correctly.
Periodically warm the engine in prolonged power off descents.
Use full rich mixture when operating at full or near full power.