Trigonometry is basic to kite physics. When a kite line is swept thru space like a compass, it defines a triangle whose properties reflect performance parameters. “Cosine Loss” was identified in AWE as the relative loss of crosswind power at the edge of the kite window, away from the power zone. The equal and opposite “Cosine Gain” is a proportional increase in potential energy by altitude and/or upwind position in the kite window.

Another key application of Cosine relations is in the distribution of forces in a Tri-Tether junction, aka the Rigger’s Triangle. By setting the angles in particular ways, forces can be amplified by mechanical advantage, like how a bowstring is drawn, or the way a kite is bridled. The Tri-Tether is the simplest possible variable mechanical transmission, and has huge applicability in kite design, under Cosine math.