vikkyvik From United States of America, joined Jul 2003, 10759 posts, RR: 26
Reply 1, posted (2 years 7 months 1 week 6 days 17 hours ago) and read 13775 times:
Quoting mawingho (Thread starter): As I know, Induced Drag is caused by Lift. When turning / rowing, upper wing's lift increase and lower wing's lift decrase which means that the induced drag in total is the same, right?
No. It is true that the upper and lower wing have slightly different amounts of lift in a turn, but in a standard turn without loss of altitude, they are both ABOVE regular unbanked lift.
When you bank, you tilt the lift vector by the bank angle. Gravity doesn't tilt with it, though, so now you have less vertical lift than gravity, and the airplane will start to descend. So you apply back pressure to maintain altitude, which increases the lift coefficient of the wings, which equals more induced drag.
So for a 30 degree bank, for example, the wings have to produce: