PPRuNe Forums - View Single Post - AF 447 Thread no. 4
View Single Post
Old 3rd July 2011 | 19:44
  #717 (permalink)  
OK465
10 Anniversary
 
Joined: May 2011
Posts: 543
Likes: 2
From: BOQ
In swept wing aircraft at high AOA, "aileron drag" or "adverse yaw" is due to increased induced drag (as well as parasite drag) from the down going aileron causing yaw opposite the roll input. Not because the aileron is stalled.

I flew the "poster child" aircraft which exhibited this nasty tendency, the F-100 Super Sabre. At high AOA it was a "rudder" aircraft for roll (if you felt lucky, you could "tweek" in some opposite aileron to assist the rudder).

The F-4 was also prone to this.

Conversely, when unloaded or pushing over establishing a lower AOA, or simply at a lower AOA, in any swept wing machine, the rudder is relatively ineffective for roll anyway, and ailerons must be used for roll control.

Rudders can roll a swept wing aircraft at high AOA, because of the large differential in lift being produced by the wing being yawed forward versus the wing yawing aft relative to the vertical axis which results in rolling. Straight wing aircraft just don't exhibit this to any great degree.

At 0 AOA in a swept winger, you get no roll from the rudder, only yaw. At negative AOA, you can get "proverse" yaw from the up going aileron.

Post stall, swept wing jet transport aircraft can also exhibit "adverse yaw" to varying degrees with aileron/spoiler inputs. Generally it is minor, but it is disconcerting to be commanding roll in a particular direction and not be getting what you think you should get.

*********************************************

Nothing is leveling the wings in Alt 2 law but the pilot
In the A330, in ALT1 or Normal, nothing is leveling the wings but the pilot either. The wings are not automatically leveled when you release the SS input in either ALT1 or Normal laws. If the bank is more than 33 degrees in either law, ALT1 or Normal, true, the aircraft will return to 33 degrees of bank if you "let go da SS".

In ALT2, while hand flying pitch, the A330 is not the "squirrel" it is being portrayed as. Nor in roll.

Last edited by OK465; 3rd July 2011 at 20:02. Reason: ALT1 or Normal
OK465 is offline