Hook-In Weight

This is the total combined weight of the pilot, clothing, harness, parachute, helmet, and any and all other items attached to or carried on the pilot’s body or harness. The range of hook in weights given is the range for which the glider complies with the performance, stability, control and structural requirements of the HGMA Airworthiness Standards, or, in the case of a glider that does not meet HGMA standards, it is the range for which the glider is approved for operation. Since the hook in weight range represents the complete range of weights at which the glider can be operated while meeting minimum performance, stability, control and structural standards, there is substantial overlap in the hook in weight ranges for different sizes of the same model. Therefore, hook in weight range is not the best specification to use when choosing the best size of a given model for a given pilot weight. Compare this to Optimum Pilot Body Weight.

Optimum Body Weight

This is the weight range within which a given glider offers the optimum combined levels of performance and control. In general, this weight range is specified without overlap between successive sizes of the same model, so that it can serve as a clear recommendation, for a given pilot, of which size glider is considered optimum. It is expressed as body weight, rather than as hook in weight, because most pilots more accurately know their body weight, and because changes to hook in weight that involve adding or subtracting weight in the harness or accessories do not have the same implications for which glider size is optimum as do changes in the pilot’s body weight. (For example, you don’t get stronger when you add weight to your harness.) Pilots who are near the dividing line of optimum body weight between two sizes of a given model glider can elect to go to the larger size if they wish to optimize for sink rate performance in light conditions, while sacrificing somewhat in control authority in stronger conditions and glide performance at higher speeds, or to the smaller size if they wish to optimize for control authority in stronger conditions and glide performance at higher speeds, while sacrificing somewhat in sink rate performance in light conditions. It is generally not true that landing becomes easier by going to the larger size glider – in general, the slightly slower minimum flying speed advantage is more than offset by the reduction in landing flare authority on the larger size. For pilots near the dividing line, a lower level of pilot skill or experience generally indicates that the better choice is the smaller size. Compare this to Hook In Weight.

Vne

The placarded maximum speed that should not be exceeded for safety when flying in smooth air and in straight flight.

Va

The placarded maximum speed that should not be exceeded for safety when flying in turbulence or when maneuvering.

Vms

The speed at which the minimum descent rate is obtained.

Vd

The maximum steady state speed, at minimum recommended wing loading, for a pilot in a normal prone position, pulled all the way in.