Drag curves for an aircraft with a given weight in flight.
<ul><li>The <b><a href="https://en.wikipedia.org/wiki/parasitic_drag" class="extiw" title="en:parasitic drag">parasitic drag</a></b> increases with the square of flight velocity;</li>
<li>The <b><a href="https://en.wikipedia.org/wiki/lift-induced_drag" class="extiw" title="en:lift-induced drag">lift-induced drag</a></b> decreases with the square of velocity.</li></ul>
As a result, the <b>total drag</b> (the sum of both components) typically has a minimum value. In practice, the validity of these curves is limited by the occurrence of <a href="https://en.wikipedia.org/wiki/Stall_(fluid_mechanics)" class="extiw" title="en:Stall (fluid mechanics)">stall</a> on the left side, and by compressibility effects on the right side.
<a href="//commons.wikimedia.org/wiki/User:Ariadacapo" title="User:Ariadacapo">Olivier Cleynen</a>
2016-10-01
<span class="int-own-work" lang="en">Own work</span>