Grnd-45 Theory of Flight 1 Laws of Motion and Fluid Dynamics

Definition of Force

A push or pull that tends to produce or retard motion

Four basic forces acting upon an aircraft

Thrust, Drag, Lift, Weight

What are Newton’s Laws

1. Law of inertia (equilibrium)

2. Law of acceleration

3. Law of reaction

Define the law of inertia

A body at rest tends to stay at rest and a body in motion tends it stay in motion in a straight line and constant velocity until acted upon by some unbalanced force.

Balanced forces = state of equilibrium

Define the law of acceleration

The acceleration is direction proportional to the force and inversely proportional to the mass of the object in the direction of an unbalanced force. a=f/m

Define the law of reaction

For every action there is an equal and opposite reaction

Atmosphere makeup

78% Nitrogen 21% Oxygen 1% other

What is static pressure P_S?

The weight of the column of air above a certain area.

Standard Sea Level Pressure 14.7psi

What is density?

The mass per unit volume measured in slugs per cubic foot

How does static pressure, density, and temperature change with altitude?

They all decrease with altitude

What is True Air Speed (TAS)?

The speed of the aircraft relative to the air mass through which it is flying

What is dynamic pressure P_D?

The pressure caused due to motion through the air mass. It is a form of kinetic energy

What is Bernoulli’s equation?

P_T = P_S + P_D

Total pressure equals static pressure plus dynamic pressure

How is Indicated Air Speed (IAS) calculated?

It is the difference from the P_T measured from the pitot tube and the P_S measured from the static port

How does TAS and IAS change with altitude?

At sea level they are the same, as altitude increases, TAS increases relative to IAS