AGK Engines Chapter One

What concept is applied when considering work done to twist a shaft?

The force x distance concept is applied.

How is 'torque different from 'moment of force'?

They describe the same thing, but torque usually refers to a twisting action on a shaft, while moment of force describes the action of a lever.

What is the Imperial unit of torque?

The Imperial unit of torque is the foot pound (ft lb).

What is the SI unit of torque?

The SI unit of torque is the Newton metre (Nm).

What three quantities does the amount of torque depend on?

The force applied, the length of the lever arm, and the angle between the force and lever arm.

What is the formula for rotational force (torque)?

Torque = force x distance (lever arm length).

What is torque?

Torque is the tendency of a force to rotate an object around an axis, often described as a 'twist'.

If a force of 1000 Newtons moves an object at 40 metres per second, what is the power in watts?

Power = 1000 N x 40 m/s = 40,000 watts (or approximately 40 kilowatts).

How many watts are approximately equivalent to one horsepower?

One horsepower is approximately 740 watts.

How can power be expressed using force and speed?

Power = Force x Speed.

What is the formula for energy when a force moves an object?

Energy = Force x Distance.

How is work done by a force calculated?

Work done is equal to the force multiplied by the distance moved in the direction of the force.

What is the unit of power in the International System of Units (S.I.)?

The watt (W), where one watt is one joule per second.

What is the formula for power in S.I. units?

Power (watts) = Energy (Joules) / Time (seconds).

What is thrust?

The force which moves an aircraft through the air, defined as mass x acceleration.

Why must a greater acceleration be given to the air as an aircraft's speed increases?

To produce the same level of thrust since the speed difference (V_jet - V_flight) decreases.

What two things does the thrust produced by a jet or propeller depend on?

The mass (amount) of air propelled rearwards and the acceleration imparted to it.

In the thrust formula, what does each symbol represent?

F is thrust, M is the mass of air, V_jet is the speed of the air exiting the engine, and V_flight is the speed of the aircraft.

What is the formula for thrust?

F = M x (V_jet - V_flight)

How do gas turbine engines produce thrust?

By heating the air to increase its volume and velocity, which generates thrust as exhaust gases accelerate rearwards.

How do piston engines produce thrust?

By increasing air pressure within a cylinder to produce power to rotate a propeller.

What does an internal combustion engine do as its name implies?

It burns fuel with air internally.

Where does combustion occur in a gas turbine engine?

Combustion occurs inside a chamber.

Where does combustion occur in a piston engine?

Combustion occurs inside a cylinder.

What is the main function of internal combustion engines in aircraft?

They convert the chemical energy of the fuel to heat energy.

What do both piston engines and gas turbine engines have in common?

They are both internal combustion engines.

What are the two main types of engines used in conventional aircraft?

Piston engines and gas turbine engines.