दारुविहङ्गः — The Wooden Flying Bird: Text, Principle and Feasibility

The two most quoted verses of the Samarāṅgaṇasūtradhāra describe a great bird of light wood with a "mercury-machine" in its belly and fire beneath it, which carries a man far through the sky "by the air driven by the beating of its two wings and by the power of the mercury within" (31.95–96). This article reads the verses closely and tests them against the physics of flight. Three possible means of lift are considered: flapping wings, heated air, and heated mercury. Mercury provides no thrust (Article 10). Heated air lifts only when it is held in a large, light envelope, which the text does not describe. Flapping wings can in principle carry a person, but the power needed is about five to ten times what a human can sustain, and the only human-powered ornithopter ever to fly (Toronto, 2010) needed a 32-metre wing and modern ultralight materials to stay up for 19 seconds. A human-carrying wooden bird of the kind described could not have flown. The article then asks what the verses do show: an exact understanding that a flying machine must be light, rigid and well joined; that the wing must drive air; and that a source of power is needed. It compares them with other early flying devices — Archytas' wooden dove, the gliding attempts of ʿAbbās ibn Firnās and Eilmer of Malmesbury (Bhoja's contemporary) — and with the literary flying machines of Sanskrit narrative. Article 12 of the series Yantravidhāna Studies (SSD-31), on chapter 31 of Bhoja's Samarāṅgaṇasūtradhāra. Verses discussed: 31.95–96. Web version: sanskritmanthan.in/a/ssd-31-12-daru-vihanga