PHYSICS OF ANCIENT INDIAN RING WEAPON

Abstract

Various types of small arms were used in ancient India. Before the use of gunpowder, wars were fought mainly with swords, bows and arrows. While a sword or knife is still used for close combat, projectile weapons like bow and arrow were all replaced by guns. Indian scriptures describe a weapon thrown by hand at the enemy, known as Chakram (Rudnick). Although mythological texts mention this to be a weapon of Lord Vishnu, in medieval times, historical work Akbarnama has a war-scene depicting the use of Chakra. In pre-modern times, Sikh warriors have used Chakra made of metal ring with saw-toothed (serrated) edge. Chakra rotates and flies. Some of the features of stability and flight can be accessed by knowledge of school physics. Rotational motion is taught with examples of rolling wheel spinning of top, etc. The spinning ring attains the rigidity in a way similar to the rigidity of a spinning top. The ring also flies. So, unlike a solid metal ball, it attains more range. It gets lift due to its motion in the air. Some of the old rings have airfoil different than flat sheet. It generates more lift compared to a flat plate. The early users and inventors of this weapon were perhaps concerned with the performance. With the advancement of science and technology, it has been discovered how it gets stability during flight and what gives it a lift (Lorenz). Modern variant of this ancient weapon are recreational toys. For weapon, metals like iron, copper, etc were used, while for toys, plastic is the material of choice due to safety concerns. In 1957 a toy manufacturer obtained trademark–Frisbee for their flying disc toy. In order to improve its range, an inventor found the reference of ancient Indian weapon and designed the product in a ring shape, with asymmetric curved top.