# Aircraft turns from headwind to tailwind - loss of IAS? **URL:** \ **Category:** Factual Questions\ **Created:** [December 23, 2009, 10:59pm UTC](https://boards.straightdope.com/t/aircraft-turns-from-headwind-to-tailwind-loss-of-ias/522386 "2009-12-23T22:59:27Z")\ **Posts on this page:** 3\ **Page:** 7
**Author:** ![Isilder](https://avatars.discourse-cdn.com/v4/letter/i/cc9497/32.png) [@Isilder](https://boards.straightdope.com/u/Isilder)\ **Post date:** [April 29, 2016, 3:42am UTC](https://boards.straightdope.com/t/aircraft-turns-from-headwind-to-tailwind-loss-of-ias/522386/121 "2016-04-29T03:42:34Z")
I commend the author of the quoted report in his attempt to shut up all the “its your speed in the airmass, the pilot musta let off the throttle” talk… Consider two cars… The fist doing a U turn on an oval bank, and a Don Johnson Miama Vice hand brake turn… Its possible to do the equivalent of the Don Johnson handbrake turn in the plane… its a flip turn,its done in too short a time…Mostly Its done with rudder and/or pitch … the various thrusts haven’t had time to redirect or add momentum… there hasn’t been thrust to keep air speed up… When you bank, and don’t pitch, and don’t use much rudder, you are using lift to make the turn, and lift is a significant thrust … you are only turning because your airpspeed is enough to create the lift ! If you are losing lift, your turn stops, so banking is safe… When you are in the bank, and you use the other control surfaces, you wipe off air speed fast and can complete the turn in a short time… thus the need for engine power to restore air speed. Thus the idea that the pilot neglected air speed … perhaps distracted by the ground rushing past, and the feeling that they are descending because they pitched down and its easily corrected by pitching up… No they have lost air speed, and they can’t generate lift… pitch won’t stop that descent. ---
**Author:** ![agustincabreze](https://avatars.discourse-cdn.com/v4/letter/a/ce73a5/32.png) [@agustincabreze](https://boards.straightdope.com/u/agustincabreze)\ **Post date:** [May 13, 2016, 2:23pm UTC](https://boards.straightdope.com/t/aircraft-turns-from-headwind-to-tailwind-loss-of-ias/522386/122 "2016-05-13T14:23:36Z")
I’ve read this in another webpage: "Unless the wing moves or the airflow is drastically different on the outer wing from the inner wing, the angle of attack will be constant across the board. Now, the airspeed at which the outer wing travels is greater than the inner wing, therefore at a given G, the inner wing will stall first." Wont both wings stall at the same AOA regardless the airspeed? ---
**Author:** ![agustincabreze](https://avatars.discourse-cdn.com/v4/letter/a/ce73a5/32.png) [@agustincabreze](https://boards.straightdope.com/u/agustincabreze)\ **Post date:** [May 17, 2016, 1:23pm UTC](https://boards.straightdope.com/t/aircraft-turns-from-headwind-to-tailwind-loss-of-ias/522386/123 "2016-05-17T13:23:25Z")
> [@Francis\_Vaughan](#): > > In a turn the relative forward airspeed over the wings varies along the length of the wings. The wing tip on the inside of the turn has the lowest airspeed, and the tip on the outside the highest. The angle of attack is the vector sum of the forward speed in the air and the vertical speed. The plane is solid lump, so the vertical speed is the same for all parts of the plane. > > So, in a turn, along the wings, the vertical speed is the same, but the forward speed varies. The wingtip on the outside of the turn has the lowest angle of attack, and the angle varies continuously over to the tip on the inside of the turn, which has the highest angle. Thus it is possible to create a situation where part of the wing on the inside of a turn stalls. During a level turn, once you begin rolling you got different vertical path described by the inner and outer wing, therefore you got different AOAs, related to the roll damping effect and lateral stability. That occurs while you keep your aircraft rolling. Once you stop rolling your aircraft (you stop increasing or decreasing your banks angle) there wont be a vertical motion now, cause even tought your plane is in a CONSTANT angle of bank, it is no rolling at all. So vertical speed at that time doesnt exist, and the only thing that you have is two wings travelling at different speeds but describing the same horizontal path, so there AOA must be the same. Do you agree with me?. Regards, Agus. [Previous page](https://boards.straightdope.com/t/aircraft-turns-from-headwind-to-tailwind-loss-of-ias/522386.md?page=6)