Published: July 10, 2020
The most common number you will find when searching for information about how quickly you fall while skydiving is 120 miles per hour. Is this true? The answer is both yes and no. Let's investigate a little bit...
This term refers to the fastest an object can travel as it falls from the sky. Gravity is a constant force that pulls at everything by the same amount, but that is not all that we must consider. How big and how heavy things are is what causes them to speed up, but the shape of an object, and again how big it is - creates drag through the air causing it to slow down. The maximum speed at which something can fall with these forces all working on it is its terminal velocity.
How Does This Work For Skydiving?
A tandem skydiving pair is made of an instructor, a student and a parachute system. Every person is a unique size and form, so even if a bunch of tandem pairs weighed exactly the same, our bodies are shaped a little differently and will likely cause a little more or a little less drag than others. Drag can also be affected by clothing - with tight clothes being more aerodynamic and thus faster than baggy ones.
When skydivers jump together and want to join up with each other in freefall, they manipulate all these things so they can move around. This can be done by wearing weights to go faster, baggy jumpsuits to go slower - or most importantly by adjusting their body position to create more drag or less drag. Creating drag (or not) in the correct way is crucial to building freefall skills. If one part of your body is going faster than another, your body will lean in that direction - and the angle created then deflects air with specific purpose to create movement.
When you think about how fast a skydiver falls, the picture in your head is very likely of someone going straight down, but when you jump out of a plane, terminal velocity isn't immediately achieved - it takes a little time. At the instant you first jump out you are actually thrown forward on the same trajectory as the plane (that is going forwards at around 100mph). Over the course of the next 10 seconds or so, this forward momentum is overtaken by the effect of gravity as you travel on a big graceful arc into freefall. This is referred to in skydiving as "going down the hill" as it visualizes and indeed feels like a hill or a curve.
The terminal velocity of a skydiver is not a constant thing. 120mph is what you hear most because it is kind of true and is a nice round number that people have a frame of reference for. However, the true terminal speed of a single skydiver or a tandem pair can change not only from one person to the next, but also during a single skydive as small alterations in body position affect how fast you are skydiving. Fall rate can even be changed by the weather. On a cold day the air is denser than on a hot day, which means the molecules are smooshed closer together and your body has to work harder to fall through them - which means you go slower.
How Terminal Velocity Feels
The most important thing about the speed of a tandem skydive is how fast it feels. The terminal velocity of a tandem skydive is around about 120mph. A little more, a little less. There are mechanised methods of going faster than this out there in the world, but there is something particularly exciting about the sensation of speed created from gravity alone that separates it from other experiences where you go fast for thrills. The sensation of pure speed created solely by gravity and the weight of your own body is like nothing else, and it is this reason that skydiving is something that every single person should experience in their lifetime. Ready?