Factors Affecting Disc Flight
The same disc will fly differently for different throwers and can even fly differently for the same thrower under inconsistent conditions. In this regard, actual field experience may deviate from the flight paths shown in this guide. There are many reasons why this is the case, and while not an exhaustive list, the following are the most common examples of things that will impact a disc’s flight path:
- Player Arm Speed and Power
- Release Angle
- Plastic Type
- Disc Weight
- Disc Condition
- Parting Line Height
- Air Density
Player Arm Speed and Power
The flight paths in the inFlight Guide assume that players have the appropriate arm speed, skill, and power levels necessary for a disc to achieve the lines shown. For example, for a player that can throw a drive with a maximum distance around 350′ (player A), a disc with a 350′ distance rating should correspond to the flight path depicted. On the other hand, if a player is capable of throwing a drive with a maximum distance of 250′ (player B), it is highly improbable that they will be able to throw a disc with a distance rating of 350′ within that distance range or with the same flight path. To this end, for players that throw discs at less than the expected speed/power level, the flight will have a higher HST value (e.g. less right‐turning) and diminished distance. The result will be a final position shorter in range and further to the left on the x‐axis when compared to the inFlight Guide chart. Likewise, for a player that is capable of throwing a 450′ drive (player C), it is likely that they will be able to throw a disc with a 350′ distance rating much further and with a more pronounced flight path. For players that throw discs at greater than the expected speed/power level, the flight will have a lower HST value (e.g. more right‐turning) and extended distance. The result will be a final position much greater in range and further to the right on the x‐axis when compared to the inFlight Guide chart.
To demonstrate this effect, displayed below are charts showing the flight path of the same disc thrown by the three players described above:
Understanding the speed/power requirements necessary for a disc to achieve the lines shown is an important aspect in interpreting the flight charts in the inFlight Guide. Using your own maximum drive distance, the following table is a reference for determining which discs are within your speed/power level. These discs should correspond to the same lines depicted in the flight charts:
|Your Max Drive Distance||Discs in Your Speed/Power Level|
|200′||225′ and under|
|250′||275′ and under|
|300′||325′ and under|
|350′||375′ and under|
|400′||450′ and under|
|450′||500′ and under|
|500′||All of them|
These flight paths will also apply (with some subtle variation) to a left-handed forehand (LHFH) throwing technique. For players that use a right-handed forehand (RHFH) or left-handed backhand (LHBH) technique, the flight path would be inverted along the y-axis with HST indicating the amount to which a disc banks to the left and the LSF indicating the amount to which a disc hooks to the right.
Anhyzer releases will have the effect of decreasing the HST values, with more of a right-turning line. Hyzer releases will have the effect of increasing the HST values, with less of a right-turning line. Elevated nose angles on release will have a combined effect of increasing both the HST and LSF, causing a more pronounced fade with reduced distance. Off axis torque (OAT) occurs when the rotational force of a disc is not centered on an axis that goes through the center of the disc in a direction perpendicular to the flight plate at the time of release. When the angle of release is lower than angle of the disc, the disc will tend to have a lower HST value with more of a right-turning line. When the angle of release is higher than angle of the disc, the disc will tend to have a higher HST value with less of a right-turning line.
Tailwinds will tend to push discs forward and have the effect of increasing HST values, with less of a right-turning line and the potential for more distance. Headwinds will tend to push against discs and will have the effect of decreasing HST values, with more of a right-turning line. Right-to-left crosswinds will tend to increase both HST and LSF values, pushing down discs with a lower Net Stability and lifting discs with a higher Net Stability. Left-to-right crosswinds will tend to decrease both HST and LSF values, lifting discs with a lower Net Stability and pushing down discs with a higher Net Stability.
Although not as significant as other factors affecting disc flight (such as speed/power levels), the type of plastic can influence how a disc flies. As a general rule, the discs made of more durable (e.g. premium) plastic will have a more overstable flight and discs made of less durable (e.g. base) plastic will have a less overstable flight. Additionally, base pastic will tend to cut through the air better than premium plastic and will have a greater distance. To this end, premium plastics will have greater HST and LSF values with less of a right-turning line and decreased distance. Base plastics will have lower HST and LSF values with more of a right-turning line and increased distance.
Changes in disc weight do not inherently affect the stability of a disc. However, as disc weight decreases, the speed/power required to throw the disc also decreases and more effort can be put toward throwing the disc. Discs thrown with more speed/power will have a lower HST value with more of a right-turning line and increased distance. Discs thrown with less speed/power have a higher HST value with less of a right-turning line and decreased distance.
As discs wear, these subtle changes to the shape of the disc will impact how the disc flies. A brand new disc will have the greatest HST and LSF values. As the condition of the disc decreases, the HST and LSF values will also decrease, resulting in a more right-turning line.
Parting Line Height
The parting line is the thin line of plastic that is left on the outside edge of a disc after it has been injection molded and can be an indicator of disc stability. When comparing two discs of the same mold, all other things being equal, the disc with a higher parting line height (PLH) will tend to have a higher Net Stability and will be more overstable. The disc with a lower PLH will tend to have a lower Net Stability and will less overstable.
Differences in atmospheric conditions will influence the flight of the disc. Specifically, air density changes are inversely proportional to changes in altitude, temperature, and humidity. Taken individually, if altitude, temperature, or humidity increases, the air density (e.g. air resistance) decreases. Likewise, if altitude, temperature, or humidity decreases, the air density increases.
Higher air density means discs will slow down faster, but the cruising speed window is lower as well. This means discs will begin to turn at a lower speed threshold and discs will begin to fade at a lower speed. Lower air density would have the opposite impact. Discs will maintain speed better with a higher overall cruising speed window where discs will require more speed to turn and fade. In very general terms, increases in altitude, temperature, or humidity will tend to make discs less overstable. In the same fashion, decreases in altitude, temperature, or humidity will tend to make discs more overstable.