Unit 1 Flashcards
Newtons first law of motion is also considered the definition of what term?
Inertia
What does Newtons first law of motion state?
A body at rest remains at rest and a body in motion continues to move at a constant speed in a straight-line, unless an external force act upon
What is Newtons second law of motion?
An unbalanced force on a body produces or tends to produce acceleration in the direction of the force and that the acceleration, if any, is directly proportional to the force and inversely proportional to the mass of the body
Which of Newton’s laws best explains why a jet engine produces forward thrust?
Newtons third law
What two words can best sum up Newtons third law of motion?
Action and reaction
What does Bernoulli’s principal state?
When the speed of a stream of gas increases, the pressure of the gas decreases, and when the speed of the gas decreases, the pressure increases
What type of duct is used to decrease pressure and increased velocity?
Convergent duct
How does the design of an airfoil influence pressure above and below the airfoil to produce lift?
The wing or airfoil of an aircraft is designed to increase the velocity of the airflow above its surface; thereby decreasing pressure above the airfoil. Simultaneously, the impact of the air on the lower surface of the airfoil increases the pressure below. This combination of pressure decrease above the airfoil and pressure increase below the airfoil produces lift
What is defined as the ability to do work?
energy
A force moves an object
Work
The tendency of an object to maintain its direction and speed
Inertia
Sometimes thought of as physical effort
Work
Commonly expressed as the British thermal unit
Heat
Reduced by using lubricants
Friction
Equals force times distance
Work
Kinetic and potential
Energy
The rate of doing work
Power
A type of energy that results from molecular motion
Heat
What type of energy does a falling object possess?
Kinetic
How does one form of energy become a different form?
When an object is in motion, it has Kinetic Energy; however, as it moves to a stable position from which force must be exerted to make it move to another position, is said to have potential energy
Which jet engine section produces the large volumes of air required for the production of thrust?
The compressor
What does the combustion section do to support the production of trust?
Introduces fuel and burns it in the airstream behind the compressor. Burning the fuel increases the air temperature and expands the air
Which engine section drives the compressor?
The turbine
What is the energy that is expanded through the exhaust nozzle used for?
It propels the aircraft forward
What is used to create the propulsive force for a turboprop engine?
The propeller
Which terms are used to express the thrust produced by a T56 engine?
Horsepower and pounds of torque
Which term is used to define theoretical power of a frictionless engine?
Indicated horsepower
What is frictionless horsepower?
Indicated horsepower minus brake horsepower. It is used by an engine in overcoming the friction of moving parts, drawing in fuel, expanding exhaust, driving Oil and fuel pumps, and the like
Which type of horsepower determines the performance of the engine-propeller combination?
Equivalent shaft horsepower also known as thrust horsepower
What can you determine if you know the BTU content of a gallon of fuel want and how much the gallon of fuel weighs?
The potential horsepower of fuel
What type of fuel do today’s jet engines use?
A kerosene/gasoline hybrid called JP-8
Describe the thermal efficiency equation of a jet engine
Energy produced by an engine, divided by the energy of the fuel that is consumed by the engine
What two factors determine what proportion of the energy of the fuel is actually used to propel an aircraft forward?
Thermal and propulsive efficiency
Define the term “barometric pressure”
The force being exerted by the mass of a column of air above the point where the pressure is being measured
What instrument is used to measure barometric pressure?
A barometer
Why is a measurement of 14.7 psi sometimes referred to as a “standard day” atmospheric condition?
Because it’s a Mercury: one square inch by 29.92 inch high were weighed it would weigh 14.7 pounds
Why was a US standard day condition developed?
Because some standard was necessary as a reference point for calculating and communicating factors governing air density
What two factors tend to cause variations in the temperature of the atmosphere?
Altitude and latitude
Define the term density, as it applies to air
Material mass per unit volume
List three methods by which heat can be transferred
Conduction, convection, and radiation
Where’s the point of highest pressure within a jet engine?
The diffuser section because of its divergent design
On a jet engine that does not have an afterburner where’s the point of highest temperature?
The combustion section
When a jet engine reaches idle speed, what determines how the fuel control regulates engine speed?
The power lever setting
What two forms of energy does a jet engine produce?
Thrust and heat
Approximately what percentage of the energy produced by the fuel is needed to maintain the jet engine operating cycle?
60%
Why does the airflow velocity of the exhaust gases increase within the turbine stator?
The convergent design of the turbine stator
What component directs the gases that strike the turbine wheel blades?
Turbine stator
Where is the point of highest velocity in a jet engine?
At the ejector nozzle
What is the purpose of the turbine stator?
To increase the velocity of the gas that hits the turbine blades by means of airfoil shaped Vanes
After the gases leave The turbine section what two types of velocity do they have?
Axial and tangential
After the gases leave the turbine section and enter the exhaust section, what velocity do they possess?
Axial
What straightens the flowpath of gases in the exhaust case?
The vanes in the exhaust case
In a multistage turbine, what is the arrangement of the shafts?
One shaft is hollow, permitting the other shaft to operate inside of it
Which turbine drives the front compressor on the dual spool engine?
The rear turbine
