Aircraft Systems 1 Flashcards
What is the load per unit area of a cross-section?
Stress
What is the deformation caused by stress?
Strain
What is the maximum load the designer would expect an airframe to experience in service?
Design Limit Load
What are the two types of heating of an airframe?
Local and Kinetic
What are the 2 types of corrosion?
Chemical
Stress
What 5 factors are taken into consideration when choosing a material?
Strength Stifness Lightness Cost Ease of construction/production
What are the advantages of using composite materials over metals?
Readily engineered, designed and manufactured to complex shapes
What are the primary and secondary considerations when designing the fuselage?
Primary: accommodate the payload
Secondary: Aerodynamic
What are the three fuselage structures?
Truss
Monocoque
Semi-Monocoque
What is the function of the frames in a fuselage?
Maintain shape
improve stability of stringers
What type of bulkhead reacts to loads in tension?
Curved pressure bulkhead
What is the primary structural part of a modern fuselage?
The skin
What loads do longerons support?
Direct tension and compression
What loads do longerons support?
Direct tension and compression
Longitudinal loads due to fuselage bending
What function do stringers have?
Stabilise and reinforce the skin by accepting some of the flight loading
What are the 4 components of a wing?
Skin
Stringers
Ribs
Spars
What is an advantage of a high wing?
Ease of cargo (un)loading
What is an advantage of a mid-wing?
Small RCS / stealth
What advantages are there of a low wing?
Shorter undercarriage
Crash protection
In what direction do the tips of anhedral wings point?
Downwards
In what direction do the tips of dihedral wings point?
Upwards
Why do some aircraft have dihedral wings?
Roll stability
Why do some aircraft have dihedral wings?
Roll stability
What makes up an aircraft’s empennage?
Tailplane, fin and associated control surfaces
What is the only ground adjusted surface on an empennage?
Fixed tab (yaw trim)
What are the moveable surfaces on an empennage?
Elevator
Rudder
Trim Tab
What is an advantage of an all flying tailplane?
Trim control for changing CoG with minimal increase in trim drag
What is a control surface which is attached to the tailplane and provides both pitch and roll control?
Taileron
How are tailless aircraft controlled about the lateral axis?
Elevons
trailing edge elevators
How does a V-Tail cause Yaw?
Both control surfaces are moved in equal magnitude and opposite directions.
How does a V-Tail cause pitch?
Both control surfaces are moved equally in the same direction.
Describe the advantage of a canard.
Reduces trim drag at high speeds.
What 4 factors need to be taken into consideration for the design of a Combat Aircraft?
Powerplant
Payload (fuel, undercarriage, weapons)
Aerodynamics (low frontal area and smoothing of cross-section)
Stealth
What 4 main factors determine the fuselage size of a Transport aircraft?
Cabin length
Cabin width
Freight Volume
Passenger and Freight distribution to correct CoG
What are the two primary types of aviation internal combustion engines?
Piston
Gas Turbine
What cycle describes how a Piston engine produces torque?
Otto cycle
What cycle describes how a Gas Turbine engine produces Thrust?
Brayton Cycle
Briefly describe the 4 stages of the Otto cycle in a piston engine.
Suck - Fuel/air mix drawn into the cylinder
Squeeze - Inlet valve closes, the piston compresses fuel/air mix
Bang - Ignition forces the piston downwards
Blow - The exhaust valve opens, gasses are expelled
Briefly describe the 4 stages of the Otto cycle in a piston engine.
Suck - Fuel/air mix drawn into the cylinder
Squeeze - Inlet valve closes, the piston compresses fuel/air mix
Bang - Ignition forces the piston downwards
Blow - The exhaust valve opens, gasses are expelled
Which limitation of a piston engine causes increased stress and wear on engines if exceeded?
RPM limit
Which limitation of a piston engine causes a breakdown of cylinder wall lubrication and distortion if exceeded?
Temperature limit (CHT)
What are the 4 types of Gas Turbine Engines?
Turbojet
Turbofan
Turboprop
Turboshaft
List the stages in a Gas Turbine Engine.
Intake Compression Combustion Turbine Exhaust
In a Gas Turbine Engine, what is the function of the Intake?
Direct air into the compressor at the correct velocity (subsonic, 0.5M)