Flight Numbers

Disc Golf Flight Numbers Explained

Flight numbers are a system used to rate the flight characteristics of a disc. They are typically displayed as a four numbers, with each number representing a different aspect of the disc's flight: Speed, Glide, Turn, Fade.  Flight numbers are a tool to communicate how a disc might fly compared to another disc around the same speed.   

Each manufacturer determines their own flight numbers and method for assigning flight numbers so it may not always make sense to compare numbers between manufacturers. Because of this the flight numbers created by manufacturers may not match the flight numbers in the TechDisc simulator, especially Turn. You can still match up the simulator flight numbers to a specific disc you know well by adjusting the flight numbers until the simulated flight path matches the real-world flight path. Then you can make relative changes to the flight numbers or weight to see how those changes affect the flight. 

Speed: 1 to 14

Speed is a rating for how easily a disc can cut through the air. Discs with higher drag will have lower Speed numbers (more drag is less speedy,) while discs with more aerodynamic shaped profiles will have less drag and higher Speed numbers.  Commonly, the Speed number may be determined by a disc's rim width and is, mostly, standardized across manufacturers.  Rim width is around (10 + Speed) millimeters. For example, most 17mm rims are 7 speeds, 19mm is 9 speed, 23mm is 12 or 13 speed.

Glide: 1 to 6

Glide is a rating for a disc's ability to remain aloft during flight. Higher Glide discs will stay in the air longer than discs with a lower Glide number. A disc flies as a cambered airfoil, more camber means more lift at the same angle of attack.  Glide is often related to how much "dome" a disc has.  

Note: camber/dome can vary even for the same mold due to the variety of plastic blends and environmental factors. 

Turn: -5 to +1

Turn and Fade are both ratings for the same thing: where the center of pressure is for the disc.   During the initial part of the flight when velocity is high there is a lot of lift, so it is rising, and Turn relates how much the disc wants to roll (or turn over) when its nose is flat or down (0 deg. or < 0 degrees). 

A disc with a +1 rating is most resistant to turn, while a disc with a -5 rating is most likely to turn. 

Fade: 0 to 5

Fade is a rating of a disc's tendency to fade back towards the ground at the end of its flight. A disc with a 0 rating will finish straightest, while a disc with a 5 rating will fade hard to the left. 

As the disc slows down, its angle of attack increases because it is now falling, this means the center of pressure moves toward the front of the disc and it begins fading. 

How to Use Flight Numbers

Flight numbers can be used to compare discs and to choose the right disc for the right shot. For example, a disc with a high Speed and low Turn rating is a good choice for long-distance shots, while a disc with a low Speed and high Turn rating is a good choice for short-range shots.

It is important to note that flight numbers are not measurements, but rather general guidelines. The actual flight of a disc will be affected by factors such as the thrower's arm speed, release angle, and the wind conditions.

There are multiple resources online to dive deeper into Flight Number ratings. Some great starting points are below:

• TryDiscs
• Marshall Street Flight Guide