Principles of Aerodynamics – Basic Aerodynamics

4 Forces of Flight
  • Weight:
    • Weight acts down towards the centre of the earth (due to gravity)
    • What is makes up the weight on our RPAS? (The RPAS, Battery & Camera) (In an airline A/C this would be the A/C, fuel, Passengers & Freight
    • Weight is represented through the Centre of Gravity (C of G)
  • Lift:
    • Lift is created from every curved surface, but especially the wings (this is an important design feature)
    • Lift acts perpendicular
    • Lift is represented through the Centre of Pressure (C of P)
  • Thrust:
    • Thrust acts inline with the centre of power generation, therefore the position of the engine will change the aerodynamics.
  • Drag:
    • Drag is created by any surface that is in the airflow, but also as a bi product of lift itself…..
What is a Force

force is a push or pull upon an object resulting from the object’s interaction with another object.

A force is a vector quantity – it has both magnitude and direction.

It is common to represent a force by an arrow.

Because forces are vectors, the effect of an individual force upon an object is often cancelled by the effect of another force.

A force is represented diagrammatically as an ‘arrow’, the length of the arrow representing magnitude, and the direction the arrow points represents the direction of the force.

Acting Forces
Components of a Force

A force acting on a point can be broken up into it’s horizontal (x) and vertical (y) components:-

This is relevant to aviation when we manoeuvre the aircraft… 

Rotating a Force

Note:

For Straight & Level flight

The vertical component of Lift = Weight