Nock name by which this nock is identified in the database. For more details about the menu options use the Arrow Assembly Name info button above.
Optional manufacturer's name. May be used in future updates to reduce data input.
Go to manufacturer's web site if you are connected to the internet. Will open in the default browser.
Enter the shoulder to nock - valley distance. Used for calculating the standard arrow length.
Enter the aerodynamic length i.e. from shaft shoulder to tip.
Enter the CoG point relative to the shoulder. A positive value indicates the CoG is forward of the shoulder, and a negative value to the rear. Due to the typically light mass of the nock, this measurement need not be too accurate!
Enter the largest diameter, including any collar. This is used to calculate the nock's contribution to the arrow's drag. Nock drag is proportional to its diameter squared, so smaller is better!
If the nock diameter is less than that of the shaft, then how the nock is treated it depends on the shaft type. If the shaft is barrelled, then it is assumed the shaft is gently tapered to the nock diameter. If the shaft is not barrelled, then the nock diameter is made equal to the shaft diameter.
This is the effective width of the nock at the valley. It is used, along with some bow parameters, for estimating the initial placement of the upper nock point on the string.
Enter mass of the nock. Used for arrow mass, CoG and FoC calculations.
The nock's impact on an arrow's total drag is likely to be around 10% (see arrow>aerodynamics). This shows an opportunity for significant drag reduction by improved design. A long tapered and fared design that does not interfere with the string or hand is needed!
This highlights the potential benefits of barrelled shafts, allowing a reduction in nock diameter and hence drag. Low total arrow drag reduces cross-wind sensitivity, a highly desirable feature. Halving the diameter using a barrelled shaft is likely to reduce total drag by 7.5%, corresponding to perhaps 70 mm less wind drift in a 5 m/s wind over 90 m.