Fundementals Flashcards
What is acceleration due to gravity
9.8 m/s2
Force formula
Mass x acceleration
Weight formula
Mass x acceleration due to gravity
Newton conversion
Kg x m/s2
GTE Working cycle
- Induction
- Compression
- Combustion
- Exhaust
Work done formula
Force x distance
SI Unit = Joules
Power formula
Work / Time
SI Unit = Watts
What are the 2 types of mechanical energy
Potential and kinetic
What is potential energy
Energy a body has due to a virtue of position
What is kinetic energy
Energy a body has by virtue of motion
Newtons first law
Law of inertia
Newton’s second law
Acceleration produced in a mass by a force acting on it directly proportional to the force and inversely proportional to the mass
Newton’s third law
Every action has an opposite and equal reaction
What is the brayton cycle
Working cycle of GTE
What is a piston engine peak pressure
Excess of 1000psi
Within the Brayton cycle what increases
Velocity of air & Pressure energy
What happens during combustion in regards to volume and pressure
Pressure of air doesn’t rise during combustion however volume does
What is isobaric heating
Heating at constant pressure
What’s the difference between piston engine and GTE working cycle
Piston is intermittent whereas GTE is continuously
How is energy converted back to kinetic energy
High velocity jet efflux
What’s the function of aircraft engines
Creates necessary movement on aircraft which is thrust
Supplies hydraulic power , electric power , bleed air for pneumatic system
2 types of engines
Piston engine and Gas Turbine
Advantage of piston aircraft
More efficient
Disadvantages of piston aircraft
Performance decreases as altitude increases
Too large for aircraft as ratio of weight to power decreases
What is Jet Propulsion
Force to move aircraft forward
How does a reaction engine work
Use newtons law of motion
What’s needed to accelerate air
Pressure needs to be increased
What are the 4 types of Gas Turbine
- Turbojet
- Turbofan
- Turboprop
- Auxiliary Power Unit
What is bypass ratio
Air coming into fan duct vs air into core
How can you identify a turbojet engine
No fan in front of
How can you identify a Turbofan aircraft
Fan in front
How can you identify a Turboprop aircraft
Propeller in front of
When is a turbojet engine used
High speed aircraft
Disadvantage with turbojet engine
Very loud and inefficient
What is turbofan engine a combination with of
Combines advantages of turbojet & turboprop
Turbofan engine is what kind of engine
Twin or triple spool
What is total thrust in turbofan engines
Thrust developed by core engine + Fan
Advantage and disadvantage of turboprop engines
Efficient but not at high speeds
In a turbofan how much thrust does the fan produce
More then 80% of total thrust
Turbofan bypass ratio
Between 4:1 & 9:1
Aircraft engine bypass ratio
90:1
Advantage of aircraft engine in terms of fuel
Use 20% less fuel then high bypass engines
2 types of engine construction
Modular and non-modular
What is modular construction
Engine can be separated into sub major modules
What is non-modular construction
Weight saving construction but complicated to repair and difficult to access parts
What’s aluminium alloy used for
Low loaded parts of fan module such as gearbox housing & fan stator castings
Where is ceramic alloy used
Heat and corrosion protection such as combustor and HP turbine
Where is steel alloy used
N1 drive shaft
Engine bearings
Main structural frames on engines
Intermediate case & turbine exhaust
Where is cobalt alloy used
High heat resistance when stator in first stage of high pressure turbine
Where is Titanium alloy used
High centrifugal force areas such as LP compressor & front stage of HP compressor
Where is nickel base alloy used
High centrifugal loads at high temperatures
HP Compressor & combustion section for high and low pressure turbines
