One of a class of
whips generally known as "singletails" (as compared
with the more common multi-tail
flogger or
Cat o' nine tails).
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.