Block 1 Day 2 Flashcards
In order to be efficient, a helicopter engine must turn at a ___________ _________
Constant speed
The speed of the helicopter engine is __________ for safe operation of of the rotor system
too high
A speed reduction device, known as ________________ must be uses between a helicopter engine and a rotor system
Transmission gearboxes
How do transmissions and drive shafts carry the rotational energy (engine torque) through gearboxes?
Engine torque is transmitted to an input gearbox
Engine torque RPM is reduced and the direction is changed so it can be input
Drive shafts sections are connected to the _______________ and are interconnected to the ________________________________________
back of the main transmission
intermediate and tail boxes
Drive shafts transmit ________________ to their respective gear boxes
rotational energy
Intermediate gearboxes change __________, and change the _________ of the drive shaft to the tail gearbox
speed
angle
The tail gearbox reduces ________ and changes the _________of the drive shaft to the tail which provides anti-torque and directional control
RPM
angle
Transmission and Drive System components:
Are the largest and most important component of a helicopter
Carries engine torque to the main and tail rotor
Transmits engine power at a reduced rate to the main and tail rotor systems
A free wheeling unit is incorporated to permit either or both engines to disengage from the transmission in the event of:
Single engine failure
Autorotation
Whenever engine RPM drops below main rotor RPM
Transmission and Drive System Components include:
Main Gearbox/Main transmission Intermediate Gearbox Tail Gearbox Accessory Gearboxs/Drives Driveshaft sections
What is the location of the main gearbox/main transmission?
It is centrally located
Where is the intermediate gearbox located?
At the base of the tail pylon
Where is the tail gearbox located?
At the top of the tail pylon
What component takes power from the engine(s) at a reduced rate and then transmits that power to the helicopter’s main and tail rotor drive systems.
Main gearbox/main transmission
What drives both the main rotor mast as well as the tail rotor drive components.
Main/gearbox/main transmission
What component carries transmission torque to the tail rotor gearbox?
Intermediate gearbox
What component changes the angle of the drive into the tail gearbox?
Intermediate gearbox
What component reduces tail shaft input speed (gear reduction)?
Intermediate gearbox
What component provides the mounting point for the tail rotor head?
Tail gearbox
What component changes the angle of the drive?
Tail gearbox
What component provides a RPM reduction for the tail rotor?
Tail gearbox
What drives the accessory gearboxes/drives?
The main gearbox
What component provides for an angle of drive change and also for gear reduction?
Accessory gearboxes/drives
What provides a mounting and drive for essential components such as: hydraulic pumps, generators, rotor brake discs, etc.?
Accessory gearboxes/drives
All the gearboxes covered are interconnected and driven by…
Sections of driveshafts
What connects the engines to the transmission systems, driving the main and tail rotor systems?
Driveshaft sections
What are the different modes of flight for a prop-rotor system?
VTOL mode
CONV mode
APLN mode
What is the VTOL mode and when is it used?
Vertical take off and landing. It provides lift and control like a helicopter
What is the CONV mode and when is it used?
Conversion. Provides lift and thrust
What is the APLN mode and when is it used?
Airplane. Provides thrust like any turboprop or C-130
Prop-rotor systems are powered by the engines through the ____________
Prop-rotor gearboxes
Prop-rotor systems provide __________ and _______ by a right and left counter-rotating prop-rotor system
lift
thrust
What three colors are used to color code prop-rotor blades?
Red, Green, White
Are the left and right blades in a prop-rotor system interchangeable?
No
The diameter of prop-rotor and twist of blades are a ___________ between helicopter and propeller aerodynamics.
compromise
Prop-rotor blades are synchronized by ______________, which also allows for single engine operation
Inter-connecting Driveshaft
Prop-rotor blades are ___________ rotating. The left rotates ________ and the right ___________
counter
CCW
CW
What are the components of a Prop-rotor system?
Prop-rotor blades
Drive System
Swashplate
What is the primary function of the drive system in a prop-rotor aircraft?
Transmits torque from the engines to the propellers
What is the secondary function of the drive system in a prop-rotor aircraft?
Provides synchronization of the prop-rotors while enabling single engine operation
The drive system on a prop-rotor aircraft consists of…
2 prop-rotor gearboxes 2 tilt axis gearboxes 2 nacelle heat exchangers midwing gearbox emergency lubrication system interconnecting shafting system
What transmits flight control inputs to each prop-rotor hub and blade assembly on a prop-rotor aircraft?
swashplate
How are control inputs from the pilots transferred to the swashplate?
Via hydraulic actuators
The flow or movement of electrons through a conductor
Current
Current is measured in ______
amperes or amps
Electrical pressure
Voltage
The force that pushes electrons through an electrical circuit is measured in _______
Volts
Opposition to current in an electrical circuit or device
resistance
Resistance is measured in ______
ohms
If voltage is increased the current increases proportionately. If resistance is increased , the current will decrease proportionately
Ohms law
Device used for the temporary storage of electrical energy
Capacitor
The electrical energy stored in a capacitor is later discharged as ____________
Voltage drops
Property that opposes change in current flow through a coil
Inductance
AC circuit, whenever the current passes through a series of changes and returns to the starting point
Cycle
The number of times a cycle occurs in one second
Frequency
Frequency is depicted as _________
Hertz (Hz)
A complete elapsed cycle as measured from a reference point
Phase
Phase is expressed in ___________
Degrees
A complete path through which current can flow
Electric circuit
Circuit is broken so that the current is no longer able to pass
Open circuit
Electrons flow in a complete uninterrupted path
Closed circuit
Path of electrons is able to follow a shorter path than intended by design
Short circuit
Devices connected end-to-end so that current has only one path along which to flow
Series circuit
Devices connected so that current has more than one path in which it can flow
Parallel circuit
Electrical device which restricts current flow to one direction or an electrical check valve
Diode
A large, conductive body in the electrical circuit
Ground
A circuit of current flowing through all of the elements, from the power source to component and then back in an unbroken course
Continuity
A simple plate or bar, usually made of copper
Bus
Electrical power is _________ on the bus and then ____________ to other buses and components
centralized
distributed
Non-moving electrical charge usually caused by friction
Static Electricity
With ____________ , positively charged electrons jump from one object to another
Static Electricity
__________ drastically effects communications and electronic equipment on the aircraft
Static Electricity
Voltage is measured in
Volts
Where are in-flight static eliminators installed to dissipate static build-up?
The wing tips and tail assembly trailing edges
On the ground aircraft are equipped with static eliminators called _______________
ground wires
_____________reduce the possibility of a fire during refueling
ground wires
What are the two types of dynamic electricity?
Alternating current (AC) Direct current (DC)
Invisible force that has the ability to accomplish mechanical work by attraction and repulsion.
Magnetism
Flow of current through a circuit
Dynamic electricity
A temporary magnet that needs electrical current to produce a magnetic field
Electromagnet
The strength of an electromagnet is determined by:
The number of windings of wire around a metal core
The type of metal core
The amount of current passing through the wire
Electricity is most commonly _________________
Dynamic electricity
The movement of free electrons through conductors
Electricity
Movement of electrons is referred to as _________
Electric current
Strength of electric current flowing in a circuit is measured in ___________
Amperes or amps
Tool used to measure current
ammeter
The four types of electrical circuits
Series circuit
Parallel circuit
Series parallel circuit
Open/closed circuit
Type of electrical circuit in which current can flow in only one path
Series Circuit
Type of electrical circuit in which two or more electrical devices are connected across, or are connected independently, to the same source of electrical power and current has more than one path in which to flow
Parallel circuit
Type of electrical circuit which is a combination of both the series and parallel circuits
Series Parallel Circuit
Open/Closed Circuit
Open= Broken Wire = No current flow Closed = Complete Circuit = current flows
Does current flow in an open or closed circuit?
Closed circuit
Is a broken wire part of an open or closed circuit?
Open circuit
An invisible force that can produce light, heat, and magnetism
Electricity
Electricity used by aircraft is produced in these three ways:
Thermoelectric Method
Chemical Method
Mechanical Method
The method in which voltage is produced through the direct conversion of heat into electricity
Thermoelectric Method
Two dissimilar metals that are bonded together
Thermocouple
TIT
Turbine Inlet Temperature
EGT
Exhaust Gas Temperature
A _________ is a source of chemical energy used to produce DC power for the aircraft
battery
A battery supplies _________ during an emergency such as the loss of all AC or DC power
DC power
A battery is connected to a _____ circuit
DC
When the battery control switch is placed to ON, a ___________ action takes place and DC voltage is produced
chemical
The three types of batteries are:
Lead acid battery
Nickel Cadmium battery (NICAD)
Dry cell battery
The type of battery that works like a car battery
Lead acid battery
Lead acid batteries are being replaced by ________
NICADs
The type of battery used for high current demand because of their ability to hold an electrical charge longer
Nickel-Cadium Battery (NICAD)
______________ used in both NICAD and lead acid batteries store electrical energy
Liquid chemicals
Energy is released as ______________ when the battery circuit is complete
voltage
__________ are very durable and require less maintenance than lead acid batteries
NICADs
Most common type of battery
Dry cell battery
Battery used when small amounts of current are needed for short, irregular intervals
Dry cell battery
What 3 things are needed to produce an electrical current mechanically?
Conductors
Magnetic fields
Rotating motion
Whenever there is current flow in a conductor, _________ are produced.
Magnetic fields
Magnetic fields are used to operate components such as:
solenoid valves, pumps and motors
A solenoid valve can be moved to an ________ or ____________ position
open
closed
Rotating armature passing through a series of stators also produces ____________
electric current
Whenever a conductor, like a wire or an armature, cuts magnetic lines of force, _____________ is produced in the conductor
Voltage
What is the principle of generator operation?
Rotating motion
How do AC/DC generators work to create electricity?
Rotating motion
What is the general term for a device used to control the electrical system and components?
Circuit control devices
A pole on a switch that moves and makes or breaks a connection; it starts and stops current flow
Toggle
A switch that is locked in a set position to prevent inadvertently placing the switch in the wrong position at a critical time
Lever Lock
A type of switch that is a variable resistor with a knob that when rotated to the right, current flow increases and when rotated to the left current flow decreases. It also stops and starts the current flow
Rheostat
A type of switch used primarily as a limit switch, which automatically controls circuits, preventing dangerous operation
Micro-switches
A type of switch that takes the place of several switches
Rotary selectors
What is the primary purpose of fuses?
To protect electrical components and wiring
How do fuses work?
A current flows through a conductor producing heat. The greater the current, the hotter the conductor. If the current is greater than the fuse rating, the heat produced melts the metal strip, opening the circuit
What are two types of fuses?
Glass tubular and Current limiter
A type a fuse which uses a strip of low melting-point metal and is rated by amperage
Glass Tubular
The type of fuse found in heavy-current-draw circuits such as generators
Current limiter
Current limiter fuses are usually made of __________ because strips of this material can survive large amounts of current for short periods of time
copper
Which type of fuse allows momentary overload to occur without opening the circuit
Current Limiter
Why are circuit breakers used instead of fuses?
Because it is easier to close a circuit in flight by resetting the breaker than by replacing a fuse
With a circuit breaker, when the current exceeds the breaker’s rating, the circuit breaker __________, opening the circuit and stopping the current
“trips”
What are the two types of circuit breakers
Push to reset circuit breakers
Push-pull circuit breaker
Type of circuit breaker that is normally recessed, pops out when overloaded and then pushed to reset (example GFI)
Push to reset circuit breaker
Type of circuit breaker that is normally retracted, the button pops when overloaded; it has a white band to indicated it’s popped or open and has a knob to manually pull when necessary
Push-Pull Circuit Breaker
The type of switch that is electrically operated and used for remote control of heavy-current circuits
Relays
Relays are usually located __________ the source of power and the component to be operated
between
_______ allow the cables carrying heavy current to have a short run to the component
Relays
_________ are small electromagnet switches
Relays
What do most large aircraft use for primary electric power
Alternating Current (AC)
AC is a _______, _________ power source which is necessary to operate electric motors, valves, computers and flight and engine instruments reliably
stable, regulated
AC power distribution units save a great deal of ______ because the wiring and system components are smaller and lighter than for DC
weight
What is the voltage of an AC generator?
115/200 volts
The type of generator in which voltage output is produced by the rotating field (magnet) passing the fixed stators
Three phase generator
A ___________ is constructed of three stator coils around a common rotating field
Three Phase Generator
Generator phases are referred to as ______ phase, _____ phase, ______ phase
A, B, C
When the rotating field of the generator (armature) rotates from 0 degrees to 360 degrees it has completed ___________
One cycle
The number of times a cycle repeats itself each second is called
Frequency
Frequency is measured in cycles per second or_____
“Hertz” or HZ
The difference in degrees between generators phases is referred to as _______
Phase
___________ operates certain valves, supplies control power to relays for operating AC motor and pump assemblies
DC power
_________ is used as an emergency power supply when all AC power is lost
DC power
DC Power Distribution Components include:
Transfer-Rectifier (T/R) Reverse Current Relay (RCR) Batteries Main DC Buses Emergency DC Buses
Most aircraft use a _______ to step down (transform) AC voltage and rectify it to DC voltage
Transfer-Rectifier (T/R)
A Transformer-Rectifier (T/R) steps down 115/200 volt, 3 phase, 400 HZ AC to _____ volts DC
28
A _____________ is the primary source of DC power on most aircraft
Transfer-Rectifier (T/R)
A ______________ acts as a safety device, preventing any reverse flow of current, allowing current to flow in one direction only. It opens id the current reverses.
Reverse Current Relay (RCR)
A ____________ is installed between a DC power source and the DC buses being supplied power
Reverse Current Relay (RCR)
DC power distribution components include both ___________ and __________ batteries
Lead Acid and NICAD
The primary purpose of ___________ is to supply 28 volt DC power to relays that operate certain motors and pumps
Main DC buses
Main DC buses receive 28 volt DC power from _______________
transformer-rectifiers (T/Rs)
_____________ receive 28 volt DC power form transformer-rectifiers and/or the 24 volts from the battery and are located on most aircraft
Emergency DC buses
During preflight checks, the boost pump is run to pressurize the fuel system so that internal leaks in the fuel manifold can be detected. This is called:
Running pressure checks
When a boost pump is used to transfer fuel between any two tanks
Transferring fuel
Engines normally receive fuel from their designated tanks. During _____________, the engines receive fuel from other tanks
Cross feeding
Having to use fuel from another tank due to boost pump failure in the main tank would be an example of…
Cross-Feeding Fuel
SMAs may be in charge of fueling their respective aircraft as it is the SMA’s job to ensure the safety of the refueling operations when __________________ are not available
Maintenance Personnel
____________ may be required if your mission profile changes, fuel tanks need maintenance, or an increase in cargo causes the new gross weight to exceed takeoff limits
Defueling
Refueling an aircraft on the ground with engines running.
Hot Refuel
Since hot refueling is significantly more dangerous, it is performed only when operations require _______________
Rapid turnaround of aircraft
Hot refueling _________ the aircraft’s capability and better _________ the mission requirement allowing it to be refueled on the ground without shutting down its engines
Enhances
Supports
Hot refueling can be accomplished:
Aircraft to aircraft
Refueling truck to aircraft
Fuel bladders or ground tanks to aircraft
