# Why do the wings on a banked plane have different angles of attack? **URL:** \ **Category:** Factual Questions\ **Created:** [January 6, 2019, 4:02am UTC](https://boards.straightdope.com/t/why-do-the-wings-on-a-banked-plane-have-different-angles-of-attack/827283 "2019-01-06T04:02:26Z")\ **Posts on this page:** 5\ **Page:** 2
**Author:** ![Dr.Strangelove](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dr.strangelove/32/6613_2.png) [@Dr.Strangelove](https://boards.straightdope.com/u/Dr.Strangelove)\ **Post date:** [January 8, 2019, 7:29am UTC](https://boards.straightdope.com/t/why-do-the-wings-on-a-banked-plane-have-different-angles-of-attack/827283/21 "2019-01-08T07:29:47Z")
> [@scr4](#): > > Similarly, on a rocket, the position of the engine doesn’t matter, but the center of aerodynamic drag does matter. Yup. It’s always difficult to talk about aerodynamics stuff because sometimes you can’t easily tease apart the different contributions. As you say, with a rocket it doesn’t matter where the thrust comes out as long as it’s on the centerline. But on the other hand, engines are one of the heaviest parts of the rocket and if you put them on the top, you’ve moved the CoM forward, and that _does_ make the rocket more stable, all else being equal. But of course it’s not the engine location that matters, it’s the mass distribution, and engine placement just changed the distribution (never mind that orbital rockets almost never depend on aerodynamic stability…). ---
**Author:** ![dstarfire](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dstarfire/32/5762_2.png) [@dstarfire](https://boards.straightdope.com/u/dstarfire)\ **Post date:** [January 9, 2019, 9:00pm UTC](https://boards.straightdope.com/t/why-do-the-wings-on-a-banked-plane-have-different-angles-of-attack/827283/22 "2019-01-09T21:00:25Z")
> [@Dr.Strangelove](#): > > Possibly a clearer way of looking at it: > As said, the lift vector on a plane always points down (from the plane’s perspective). High or low mounted wings don’t change this, nor does dihedral or anhedral. The wings are symmetrical and any lateral lift is completely canceled. > > However, lift is not the complete story. Wings don’t have a zero cross-section, and the fuselage has to be shaped to support the wing. And this is (one place) where other effects come into play–the fuselage shadowing effect you mentioned, and the weathervaning effect I mentioned (and really these two effects overlap). Probably there are other effects as well. > > This only arises if the airflow is not directly down the main axis–either because of sideslip or loss of altitude. So the usual explanation is still wrong. Thank you, that explains it a lot better. I was trying to picture the wings flexing. But guess an asymmetric change in the lift would effectively alter the angle of attack. To the stability tangent, (which was also covered in that video): bottom-mounted wings are tilted slightly upwards towards the outer edge (like a very shallow v) to counter the roll-enhancing effect of this asymmetric angles-of-attack. High-mounted wings have the opposite problem, because the fuselage acts sort of like a pendulum. So they tilt the wings slightly downwards to enhance a roll so the aircraft can actually bank decently. At least, that’s according to the mentour aviation host (a professional 737 pilot). ---
**Author:** ![Kedikat](https://avatars.discourse-cdn.com/v4/letter/k/ed655f/32.png) [@Kedikat](https://boards.straightdope.com/u/Kedikat)\ **Post date:** [January 10, 2019, 4:11am UTC](https://boards.straightdope.com/t/why-do-the-wings-on-a-banked-plane-have-different-angles-of-attack/827283/23 "2019-01-10T04:11:57Z")
I admit I skipped a bunch of replies. I want to know if a wing with no fuselage experiences a difference in angle of attack. Suppose a craft with engines at each end of a single wing. The craft is only banking with no correction. So side slipping, not turning. How could there be a difference in angle of attack? ---
**Author:** ![md2000](https://avatars.discourse-cdn.com/v4/letter/m/73ab20/32.png) [@md2000](https://boards.straightdope.com/u/md2000)\ **Post date:** [January 10, 2019, 6:34am UTC](https://boards.straightdope.com/t/why-do-the-wings-on-a-banked-plane-have-different-angles-of-attack/827283/24 "2019-01-10T06:34:52Z")
I still say “no”. If the only vector you are looking at is the “lift” of the wing, i.e. the force on the wing perpendicular to the surface, the torqueing force, yes, wings are balanced despite any or no dihedral. However, the force being balanced is gravity. Gravity pulls down on each square foot of wing (and fuselage) equally - however, the counter force to gravity is the vertical component of the lift, determined by the horizontal component of wing surface area. On an aircraft with a normal dihedral, the lift force on the lower wing is greater because it has a greater horizontal component (until the aircraft is on its side). This is not a torque left vs. right fuselage rotating force. This is a torque left wing upward force component vs gravity, right vs gravity. The more level wing wins. (The horizontal component tends to cause the plane to slip sideways as a simple force diagram will show, or turn if matched with rudder to help banking) As mentioned, with a high wing, the pendulum effect of the fuselage weight can have the same effect - the body protrudes toward the upside wing, pulling that side down to level. ---
**Author:** ![md2000](https://avatars.discourse-cdn.com/v4/letter/m/73ab20/32.png) [@md2000](https://boards.straightdope.com/u/md2000)\ **Post date:** [January 10, 2019, 6:46am UTC](https://boards.straightdope.com/t/why-do-the-wings-on-a-banked-plane-have-different-angles-of-attack/827283/25 "2019-01-10T06:46:19Z")
> [@Kedikat](#): > > I admit I skipped a bunch of replies. > I want to know if a wing with no fuselage experiences a difference in angle of attack. Suppose a craft with engines at each end of a single wing. The craft is only banking with no correction. So side slipping, not turning. How could there be a difference in angle of attack? Angle of attack is the angle of the aircraft wing cross-section vs air flow. Unless the wing is very weird and fancy, the cross-section is fairly consistent and the wing is not twisted, so angle of attack is constant for each wing. This, the angle of attack is easily defined too as the angle of the fuselage to the airflow, since that is fixed to the wings. But, the defining flight characteristic is wing’s angle of attack to the airflow. It’s difficult to imagine, but… in a slip, the aircraft is not going straight, the fuselage is not pointing straight into the airflow. So the real “angle of attack” is a flow not straight across a wing, but across at an angle The airflow on an angled wing in slip could be considered similar to - what is the slope if you slide straight down a ski hill, vs. slide down it at an angle to the hill? Going down a slope at a sideways angle to “straight down” is a lesser slope. If the wings are not a single straight-across flat wing, then the angle on each wing that it encounters the air will be different. [Previous page](https://boards.straightdope.com/t/why-do-the-wings-on-a-banked-plane-have-different-angles-of-attack/827283.md?page=1)