RE: alula

["Norton, Patrick" <Patrick.Norton@state.me.us>]

Stan Friesen wrote, in part:

>>The alula is on the leading edge of the wing Do you refer to the flaps   
on the trailing edge of a wing or are there also flaps on the leading   
edge (I aint a plane person).<<

>Yes, there are "flaps" on the front of the wing, at least on commercial
airliners.<

Leading edge flaps and slats are designed to optimize airflow over the   
upper surface of the wing when increases in the angle of attack begin to   
compromise lift, typically during take-off and landing.  Some, but not   
all, leading edge slats function like the avian alula by creating a slot   
at the leading edge of the airfoil. Air forced through this narrow slot   
increases in velocity over the top of the wing, thereby avoiding a stall.   
 That is essentially how an alula works.  On a commercial airliners, you   
can watch the slat (I think these are called the Handley-Page slat)   
separate from the leading edge of the wing by sliding forward, creating   
the slot. Not all planes have these slats, as Jim C has already   
mentioned. I don't think you find them on smaller planes.