Block 1 continued Flashcards
What do engine ratings represent?
The thrust that an engine develops during various operating conditions such as takeoff, climb, cruise or for continuous operation
Engine manufacturers establish engine rating in terms of __________
Pounds of Thrust
The three basic conditions which influence the power output of the engine
Temperature of the atmosphere
Pressure of the atmosphere
Bleed air extracted from the engine for system operations
The relationship between the temperature of the atmosphere and the power output of the engine
high temp = less power
low temp = more power
The relationship between the pressure of the atmosphere and the power output of the engine
low pressure = less power
high pressure = more power
From where does almost all of the propulsive force from a turboprop engine come from?
The propeller
The engine performs most of its work:
Driving a shaft which turns the propeller
The primary indication of power output on the turboprop engine
Torque
Most power settings are accomplished in reference to ____________ indications
Turbine Inlet Temperature (TIT)
The ability of the engine to produce a constant maximum thrust over a wide temperature range
Flat-rated
How might an APU be used during an inflight emergency?
To provide backup air bleed to remain pressurized or for heating and cooling and/or to provide electrical power for lights and aircraft equipment at night
APUs operate independently except for:
Starting and Fuel
Electrical starting power for an APU is usually generated by the ________________ or sometimes by a ______________________
Aircraft battery
A hydraulically driven starter motor
How is fuel for the APU supplied?
The aircraft main fuel tanks
What does APU stand for?
Auxillary Power Unit
What is another name for an APU?
GTC or Gas Turbine Compressor
A Gas Turbine Compressor (GTC) is primarily used with which aircraft?
C-130
The three major sections of an APU
Compressor assembly
Power turbine
Accessory drive assembly
APUs have their own:
Oil system
Fire warning/detection
Fire extinguishing system
Are APU inlet and exhaust doors usually open or closed inflight or while not in use?
Closed
How is fuel supplied to the APU?
By gravity feed from the aircraft’s main fuel tanks or some aircraft use a battery powered pump
What components of the APU are designed to isolate and prevent the spread of fire?
It is enclosed in a titanium firewall
Each component is thermally insulated with an insulation blanket
Fire detection and extinguisher systems are provided
A propeller system is a _____________ attached to a ______________ through a __________________
rotating airfoil
jet engine
reduction gear assembly
Why is a propeller used?
A propeller is used because it is extremely efficient at low altitude and low air speed
Propellers have controllable ____________ that provides forward and reverse ____________
- pitch
2. thrust
What does the propeller assembly consist of?
Two or more blades; each having an airfoil cross section like that of a wing
How is thrust created in a propeller system?
Air flows over a propeller blade, producing a different pressure between the front and rear surfaces, causing thrust to push the aircraft forward
What are the two types of propeller slip taken into consideration during the design of the aircraft?
- Geometric Pitch
2. Effective Pitch
Define Geometric Pitch
Theoretical rotation thru the air (a solid).
Define Effective Pitch
Actual rotation of thru the air
What is the difference between geometric pitch and effective pitch?
Slip
Adjusting the blade angle of a propeller is a means adjusting the ______ on the propeller in order to control engine ______ and ultimately _______.
Load, torque, thrust
What are the four types of blade angles?
- Zero
- Positive
- Negative
- Feather
Zero blade angle =
No Thrust (Idle)
Positive Blade Angle =
Positive Thrust (Normal operation)
Negative Blade Angle =
Reverse Thrust (Thrust reverse for landing on short runways)
Feather Blade Angle =
No Thrust (Engine Shutdown) (Slow or no rotation/ 90 degrees)
What absorbs power from the engine and convert the energy into aircraft forward motion.
Propeller
Blades are _____ to maintain angle of attach down the entire length of the propeller blade.
Twisted
Rotational velocity is _____near the hub and ______ near the tip.
- Low
2. High
To be efficient the propeller must be able to change its….
Blade angle for varying flight conditions.
What is the result of shape and angle of the propeller blade?
Thrust
____ of the engine torque absorbed by the propeller, ____ lost to friction & slippage.
80%, 20%
Adjusting the blade angle changes the load on the propeller which will…
increase or decrease engine torque
Propeller System components consists of the following traits?
- Four Blade
- electro-hydromatic
- constant speed
- full feathering,
- reversible pitch propeller.
In a Propeller System controllable pitch =
Forward & reverse thrust
The Propeller System is a self contained unit containing….
Rotating and stationary components.
Propeller blades are made of ______ ______ _______
Solid aluminum alloy
Propeller blade shank (Base) is partially hollow…
For weight reduction
Propeller blades incorporate a fairing made of plastic foam covered with reinforced nylon rubber to…
Direct airflow into the engine.
The barrel performs 3 main functions
- Retain blades within the prop assembly
- Transmit engine torque to the blades
- Provide a means to attach the propeller to the engine shaft
The barrel ______ & _______ ______ bolted together to retain blades
Front & rear half
What are the four parts of the propeller rotating section?
- Propeller blades
- Barrel
- Dome
- Spinner
What rotating section component contains mechanisms for changing propeller blade angles?
Dome
What rotating section component is a streamlined housing that encloses the dome, barrel and control assemblies.
Spinner
Stationary section -
Control assembly
What consists of hydraulics, control valves, and components to provide for rotating section
Control assembly
How are both the main rotor and tail rotor driven?
By engines through the transmission system.
What is the most important part of the aircraft?
Main rotor
The main rotor provides:
Lift to fly, control to move laterally, make turns and change altitude
The main rotor must be incredibly ________
Strong
The angle of the rotor blades are adjusted with each revolution of of the hub by the _____________
swashplate
The main rotor head is mounted on and driven by the ___________
main transmission shaft
What part of the main rotor provides attachment points for the main rotor blades and allows the blades to change pitch?
The main rotor head
Rotor blades are _________ to maintain the angle of attack down the entire length of the blade
twisted
The tail rotor provides…
anti-torque and directional control
The aircraft want to rotate in the opposite direction of the rotor blades. This effect is known as __________
torque
To counteract torque, the aircraft utilizes a _______
tail rotor
The tail rotor is _________, giving it the ability to steer
directional
What are the main rotor system components?
Main rotor hub Droop stops Bifilar Vibration absorbers Pitch control rods Hydraulic dampers Anti-flap assemblies Swashplate assembly
The mounting point for hydraulic dampers, pitch control rods and anti-flapping assemblies in a main rotor system
Main rotor hub
Part of the main rotor system that limits the droop of the main rotor blades when the main rotor head is slowing down or at a complete stop
Droop stops
Part of the main rotor system that absorbs vibrations and stresses, increasing component life and providing a smoother ride
Bifilar vibration absorbers
Part of the main rotor system that transmits all movement of the flight controls from the rotating swashplate to the main rotor blades
Pitch control rods
Part of the main rotor system that restrains hunting (lead and lag) motions of the blades during rotation and absorb rotor head engagement loads
Hydraulic dampers
Part of the main rotor system that prevents the main rotor blades from flapping when the rotor head is slowing down or at a complete stop
Anti-flap assemblies
Part of the main rotor system that transmits flight control movement to the main rotor head through the pitch control rods. It can tilt in any direction following the motion of the flight control inputs.
Swashplate assembly
The tail rotor system component are:
Tail rotor head
Tail rotor blades
The part of the tail rotor system that provides a mounting point for the tail rotor blades and provides a means to change the pitch in the tail rotor blades
Tail rotor head
The part of the tail rotor system that is similar to the main rotor blades aerodynamically but smaller
Tail rotor blades
The tail rotor blades are about _______ the diameter of the main rotor blade disk area
1/4th
An auxiliary power unit is a _____________ support unit
self-contained
A small gas turbine engine that operates on similar principles as a jet engine and provides ground support to aircraft without ground support equipment
Auxiliary Power Unit (APU)
An APU provides shaft power to drive an ____________
AC generator
What does an Auxiliary Power Unit (APU) do?
Supplies air for ground operation of the air conditioning systems; engine starting; shaft power to drive an AC generator
On some aircraft the APU also supplies air to an air turbine motor which in turn drives a ______________
hydraulic pump
An APU is _____________ and will shut down ____________ for most malfunctions
self-monitoring
on its own
APUs are intended for ____________
Ground Use
