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7 Cards in this Set
- Front
- Back
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Define volatility and flashpoint
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volatility: measurement of a liquid's ability to convert to a vaporous state.
flashpoint: lowest temperature of a combustible substance that would ignite with a momentarily application of a flame |
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Describe the relationship between temperature, volatility, and flashpoint
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flash point and volatility rating are inversely related. fuel's volatility rating increases, flash point decreases.
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State the characteristic of common military aviation fuels.
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JP-4: Highly volatile with low flashpoint. Easier starting slower acceleration, lower operating temps, higher tendency to vapor lock, shorter range
JP-5: Navy's primary jet fuel. Thermally stable, low volatility and high flash point. JP-8: Air Force uses this. Similar to JP-5 but lower flashpoint. Can't use aboard ship. |
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Describe the function of the aircraft fuel system components
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Fuel tank: starting point for fuel. Reservoir, or holding cell, for jet propellent.
Gravity, pressure, inflight fueling are the common ways to fuel the tank. Boost pump: ensure an adequate supply of fuel to the engine-driven fuel pump. Prevents aeration of the fuel supply Emergency shutoff valve: handle in cockpit lets pilot shutoff fuel to engine in emergency Fuel pressure gauge: Indicates fuel pressure in cockpit Low pressure fuel filter: paper cartridge type filter, located downstream of boost pump to strain impurities from the fuel. Engine Driven pump: provide fuel in excess of engine requirements. The excess fuel ensures sufficient supply of high pressure fuel is available Fuel control unit: Sends measured fuel to satisfy fuel-flow requirements for flight. Senses inputs for proper flow from: PCL, compressor inlet temp, RPM's, Turbin temp -fuel control unit modes of operation: normal (automatic)operation manual/emergency operation Fuel flow guage: measures the fuel flow rate coming out of the FCU and converts it to electrical signal sent to the fuel flow gauge in cockpit. Fuel-Oil cooler/heat exchanger: preheats fuel and cools engine lubricant. heated fuel removes ice crystals and increases its volatility, efficient fuel ignite Fuel manifolds: delivers fuel to the engine burner section through a series of fuel nozzles Pressurizing and Dump valve: Drains the combustion manifold upon engine shutdown and to adjust fuel flow during engine starts. |
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Explain the operation of an afterburner fuel system.
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Fuel transfer valve supplies fuel to the afterburner fuel control unit. The FCU then meters fuel to the afterburner spray bars. Excess fuel is returned to the fuel pump inlet.
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Explain the operation of an afterburner fuel control unit.
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The FCU then meters fuel to the afterburner spray bars. Excess fuel is returned to the fuel pump inlet.
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Describe the three types of thrust ratings.
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Normal Rated Thrust: thrust produced at the max continuous turbine temp with no time limitation. Serves for cruising speed.
Military Rated Thrust: thrust produced at the max turbine temp. for a limited time, normally 30 min. Time constraint ensures turbine blades aren't damaged. Serves for take-off or when additional thrust is desired. Combat Rated Thrust: thrust produced with the afterburner in operation, not based on turbine temp limitations. |
