Ref Chapter 5<\/p>\n
Ans:<\/strong><\/p>\n <\/p>\n Whenever an airfoil is producing lift, the pressure on the lower surface of it is greater than that on the upper surface (Bernoulli\u2019s Principle). As a result, the air tends to flow from the high pressure area below the tip upward to the low pressure area on the upper surface. In the vicinity of the tips, there is a tendency for these pressures to equalize, resulting in a lateral flow outward from the underside to the upper surface. This lateral flow imparts a rotational velocity to the air at the tips, creating vortices that trail behind the airfoil.<\/p>\n As the air (and vortices) roll off the back of your wing, they angle down, which is known as downwash.<\/p>\n Downwash points the relative wind downward.<\/p>\n When you have more downwash, your lift vector points back more, causing induced drag.<\/p>\n <\/p>\n\n