bullwhip

Most quality bullwhips are constructed using kangaroo hide, which is both very thin and one of the strongest forms of leather available. While less expensive whips may be produced of other types of hide, virtually all of the whips used for sport cracking or S&M are of kangaroo hide. Synthetic materials (usually nylon) are also sometimes used in practice whips.

The bullwhip is distinguished from other singletail or long whips by its construction details, featuring a rigid handle, a body or lash section, a fall (usually a single piece of latigo leather) and finally a synthetic fiber cracker. The lash or main section of the whip is formed by 2 or more concentric braids over a core of leather strips. The lash is tapered both by braiding using tapered stock and by reducing the number of active plaits in the braid (the ends of the discontinued plaits being hidden in the core). Most bullwhips use an initial outer braid of 12 or more plaits. Plait counts from 8 to 16 are common.

The tapered geometry of a whip is essential to it's usage. The loud crack which can be effected by a correct throw of a whip is generated when the tip (of the cracker) exceeds the speed of sound. It has been reported that a whip crack actually involves the cracker achieving double the speed of sound (Mach 2). (Shape of a Cracking Whip Physical Review Letters Vol. 88 #24 June 2002).

There are dozens of ways to crack a whip, however they all utilize the reversal of direction of the whip. The crack happens at the point in time that the far end of the whip (cracker) comes into tension with respect to the thrower. The tapered nature of the structure dictates that as the whip becomes taught, the still-moving section is of progressively smaller cross section (and therefor reducing mass). Becuase energy is conserved the velocity originally induced at the handle translates to an increasing velocity as progressively smaller mass is accelerated. When the tip of the (very small indeed) cracker finaly reverses direction the mass goes to zero (or more accurately, the acceleration of the tip to supersonic velocity introduces a high-energy shock wave into the surrounding air). Not surprisingly, this shock wave is highly directional.

Other forms of singletail whips include the "snake whip", which is largely similar to the bullwhip, differing in that it does not have a distinctly rigid handle (the supple core and braid are the handle of the whip). This is similar to the "signal whip", which differs further in that it is usually a shorter whip, and it has no fall, rather the cracker is directly braided into the body of the whip. Both snake and signal whips usually incorporate a lead weighted "shot bag" near the handle which increases the initial mass and therefore provides increased acceleration and power.