What is relative wind? How about "the hill" ?

What is Relative Wind?

Relative wind is something you sure hear a lot about in conversations about jumping – but, what exactly is relative wind?

The term originated to describe one relationship between an aircraft traveling through the air – and the air. However, when it was adopted for skydiving use – a human body replaced an aircraft or airfoil in the equation.

As a body exits the aircraft (we will use the example of a stable, belly-to-earth body position,) that body is said to: “ride the hill” initially upon encountering the outside air. What does this mean? It means that initially, the body in is faced with relative wind from the direction the aircraft is traveling (since this is also the direction the body itself is initially traveling.) As gravity begins to exert its force; and the body settles into its belly-to-earth position, it will encounter relative wind coming from a different angle. As the body picks up speed during freefall – the force of the relative wind against the form increases. In actuality, it is the body passing through the air that causes the resistance and friction – not the wind.

Related Topics

Terminal Velocity

You have be in motion to have relative, so it is the wind that is created by you the skydiver being in motion, weather it is in the door of the aircraft, on the hill or in freefall, the common denominator is you are in motion, and in reality it is  not wind it is pressure created by you being in motion.