special missions aviation – Flashcards
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what does an X prefix denote on a afsc?
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a basic crewmember
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what does an Q prefix denote on a afsc?
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a flight examiner
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what does a K prefix denote on a afsc?
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a instructor
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what does a T prefix denote on a afsc?
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a formal training instructor (Tech School)
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what is a cradle-to-grave document that identifies life cycle education and training requirements?
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CFETP (Career Field Education and Training Plan)
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what is a 3 skill level called?
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Apprentice
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what is a 5 skill level called?
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Journeyman
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what is a 7 skill level called?
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Craftsman
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what is a 9 skill level called?
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Superintendent
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what method is used to drive an aircraft through the sky?
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jet propulsion
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what is the basic continuous 4 cycle process of a gas turbine engine?
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Intake, Compression, Turbine, Exhaust
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what are the major sections of a gas turbine engine?
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Air inlet, Compression, Diffuser, Combustion, Turbine, Exhaust, and Accessory
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what are the 2 functions of the air inlet section of a gas turbine engine?
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to recover as much total pressure as possible and deliver it to the front of the engine; deliver air to the compressor with minimum turbulence and pressure variation
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what is the primary function of the compressor section of a gas turbine engine?
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to supply air in sufficient quantity to produce the required engine thrust
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what are the main elements is the compressor made up of?
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rotor and stator
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what is a rotor?
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a rotating section of blades that force air rearward
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what is a stator?
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stationary fixed blades that act as a diffuser; they slow the velocity and increase pressure of the air coming from the rotors
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what is the diffuser section of a gas turbine engine?
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the section that directs compressor discharge air into the combustion section; this is the section that bleed air is drawn from
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what is the combustion section of a gas turbine engine?
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the section made up of a combustion chamber or burner cans; this is where the air and fuel mixture is ignited and set on fire
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what components are located in the combustion section of a gas turbine engine?
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fuel nozzles and igniter plugs
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Does the ignition process continue throughout operation of the gas turbine engine?
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No, after initial startup the combustion process is self sustaining and does not require the igniter plugs to continue operating
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what section of a gas turbine engine transforms exhaust gases into mechanical energy?
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the turbine section
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how much of the pressure energy, from the exhaust gases is absorbed by the turbine section?
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60-80%
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what components make up the turbine section of a gas turbine engine?
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rotors and stators (turbine guide vanes)
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what is the purpose of the exhaust section of a gas turbine engine?
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to direct the flow of exhaust gases
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what is the purpose of the accessory section on a gas turbine engine?
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to serve as an attachment point for generators and fluid pumps
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what are characteristics of a turbojet engine?
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they operate at high altitude and high speeds best; the disadvantage is that they require long runways for takeoff and climb-out capabilities are poor
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what type of engine uses a propeller to generate thrust?
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a turboprop
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what percentage of power derived from exhaust gases is converted to shaft horsepower to drive a propeller?
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90% to propeller, 10% exits through the exhaust nozzle
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what components in a turboprop engine are joined by an extension shaft?
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a reduction gear assembly and the gas turbine unit
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what transmits power from the engine to the reduction gear on a turboprop engine?
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the extension shaft
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where are accessories mounted on a turboprop engine?
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on the rear case of the reduction gear assembly (AC generator, Hydraulic pump, tachometer, oil pump, and pneumatic starter)
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what are the advantages/disadvantages of a turboprop engine?
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they develop high thrust at low altitudes and are ideal for lifting heavy loads using short to medium length runways; efficiency drops off as airspeed and altitude increase
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what percentage of thrust is the fans of a turbofan engine capable of producing?
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30-85%
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what are the advantages/disadvantages of a turbofan engine?
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they are very efficient and work well at all altitudes and produce a high amount of thrust and make minimal noise; there is no major disadvantage
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what is an engine rating?
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a rating established by the manufacturer that an engine develops under various operating conditions
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how is the thrust rating of a turbofan and turbojet measured?
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in pounds of thrust
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how is the thrust rating of a turboprop measured?
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shaft horsepower
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what are the 3 conditions that influence engine power?
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temp of the atmosphere, pressure of the atmosphere, and amount of bleed air extracted
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what is the primary indication of power output by a turboprop engine?
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torque
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how are most power settings on an engine accomplished?
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in reference to the turbine inlet temp (TIT)
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thrust is used to overcome what force?
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drag
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how many cycles are there in a gas turbine engine?
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4
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what component can be used to provide ground operation to an aircraft without AGE?
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an auxiliary power unit (APU)
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Is an auxiliary power unit (APU) self monitoring?
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yes
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what systems does an APU supply air for during ground operation?
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the air conditioning system, engine starting, and shaft power to operate the AC generator
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what will an APU power inflight during an emergency?
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backup bleed air and electrical power
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what must an APU receive from an aircraft in order to operate?
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fuel from the main fuel tanks (supplied through gravity feed) and electrical starting power from the aircraft battery
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what are the compartments around an APU enclosed with?
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titanium firewalls to prevent the spread of fire
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what is the most important thing an APU provides to an aircraft
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ground operation to the aircraft without ground support equipment (AGE)
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the APU operates on similar principles as what?
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A gas turbine compressor (GTC) ; the GTC supplies air rather than shaft horsepower to operate the AC generator
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what is propeller slip?
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the distance a propeller would advance in one rotation through a solid medium compared to the actual distance the propeller travels (Geometric pitch vs. Effective pitch)
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what are the 4 different blade angles on a propeller?
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positive (leading edge is forward), negative (leading edge is rearward), zero (blade angle is at a right angle to the propeller shaft), and feather(the leading edge is straight forward)
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why are propellers twisted?
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to allow the inner sections to take a bigger "bite" of air and to increase propeller efficiency
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what amount of torque is absorbed by the propeller?
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80%, 20% is lost through friction and slippage
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what are propeller blades constructed of?
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solid aluminum alloy with partially hollow shanks
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what are the functions of the barrel?
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to hold the propeller blades, transmit torque to the propeller blades, and provide a means for attaching the propeller to the engine shaft
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how long must the 2 halves of a barrel stay together?
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for service life
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what is the dome of a propeller system?
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the assembly that contains the mechanism for changing the propeller blade angles
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what is the spinner of a propeller system?
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a streamline housing that encloses the dome, barrel, and control assemblies
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what is the control assembly of a propeller system?
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the stationary section that houses the hydraulic fluid reservoirs, pumps, control valves, and associated components
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what are the 2 sections of a propeller system called?
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rotating and stationary
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what blade angle on a propeller allows for reverse thrust?
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negative
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what is the most important part of a helicopter?
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the main rotor
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what is the largest component of a helicopter?
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the transmission and drive system
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what component allows the main rotor to adjust blade angles?
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the swashplate assembly
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what is the main rotor head mounted on?
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the main gear box/ main transmission
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what component provides directional control of a helicopter?
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the tail rotor
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what percentage of engine power is the tail rotor responsible to absorbing?
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30%
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how large is the tail rotor in comparison to the main rotor?
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1/4 the size
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what is the main rotor hub?
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a component that spindle assemblies, hydraulic dampeners, pitch control rods, and anti flapping assemblies mount to
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what is a droop stop?
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a component that limits droop of the main rotor blades when a helicopter is slowing down or stopped
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what is a bifilar vibration absorber?
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a component that absorbs vibrations and provides for a smoother ride and increases component life through stress reduction
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what is a pitch control rod?
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a component that transmits all movement of the flight controls from the rotating swashplate to the main rotor blades
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what is a dampener?
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a component that reduces hunting (lead and lag) of rotor blades
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what is an anti flap assembly?
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a component that prevents main rotor blades from flapping when the main rotor head is slowing down or is stopped
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what is a swashplate?
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a component used to transmit flight control movement to the main rotor head through the pitch control rods
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what is the tail rotor head?
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a mounting point for the tail rotor blades and provides a means to change the pitch of the tail rotor blades
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what does the tail rotor provide to a helicopter?
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anti torque and directional control
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what component extends between the rotating swashplate and the main rotor blades?
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pitch control rods
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what component allows the engine to disengage from the transmission in the event of engine failure, an autorotation, or whenever engine RPM drops below main rotor RPM?
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a free-wheeling unit
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what component take power from the engines and transfers it at a reduced RPM to the main and tail rotors?
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the main gear box/main transmission
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what is an intermediate gear box and where is it located?
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it is a gear reduction that located at the base of the tail pylon
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what is the tail gear box and where is it located?
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it provides a mounting point for the tail rotor head and is located at the top of the tail pylon
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what is mounted on the accessory drive of a helicopter?
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hydraulic pumps, generators, and rotor brake discs
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what component connects gearboxes?
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driveshaft sections
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what mode allows the CV-22 to fly in airplane mode?
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APLN
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what mode allows a CV-22 to fly in helicopter mode?
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VTOL
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what mode allows a CV-22 to fly in airplane/helicopter mode?
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CONV
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how do the rotor rotate on a CV-22?
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the counter rotate in an outward motion
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what is the CV-22 rotors comprised of?
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(2) 3 bladed 38 foot rotors
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are the blades of a CV-22 interchangeable?
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No
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what are the colors of a CV-22 blades?
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red, green, and white
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what is the primary purpose of a drive system on a CV-22?
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to transmit torque from the engines to the prop-rotors
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what happens if one engine fails on a CV-22?
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the other engine will power the engine that is not operating
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how is current measured in an electrical system?
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in amps
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what is an electrical current?
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the moving element of electricity
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what is voltage?
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electrical pressure
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what is voltage measured with?
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volts
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what is resistance measured with?
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ohms
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what is resistance in an electrical system?
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the opposition to current
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what is a capacitor?
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a device used to temporarily store electrical energy
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what is inductance?
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the property which opposes any change in current flow
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what is an electrical cycle?
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when a current passes through a series and returns to its starting point, this makes 1 cycle
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what is frequency?
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the number of cycles completed per second
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what is frequency measured in?
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Hertz (Hz)
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what is an open circuit?
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a broken circuit that current is not able to pass through
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what is a closed circuit?
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when electrons can flow in an uninterrupted path
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what is a short circuit?
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when electrons flow in a shorter path than intended by design
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what is a diode?
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an electrical check valve
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what is a ground?
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a large, conductive body in an electrical circuit
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what is a bus?
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a plate or bar, made of copper, on which electrical power is centralized
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what is static electricity?
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electrical charges that come from friction. It is difficult to control
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what is dynamic electricity?
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the flow of current through a circuit
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what is magnetism?
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an invisible field that has the ability to accomplish mechanical work through attraction and repulsion
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what is an electromagnet?
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a temporary magnet that needs an electrical current to produce a magnetic field
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how many paths of electricity does a series circuit have?
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1
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how many paths of electricity does a parallel circuit have?
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more than one
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what is a series-parallel circuit?
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a combination of series and parallel
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what is a thermocouple?
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2 dissimilar metals that generate voltage when heat is applied
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what is the definition of thermoelectric method?
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converting heat to electricity or using electricity to create heat or cold
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what are the most common type of electrical heat generators used on a jet engine?
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thermocouples
