Micro VGs as developed by NASA's Langley Research Center are small, trapezoid-shaped vertical fins or blades attached to wing surfaces. According to NASA, as air normally flows over the wing of an aircraft in flight, the air "sticks" to the surface of the wing, producing lift. If the airflow loses its adherence and separates from the wing, aircraft performance can suffer in the form of increased drag, loss of lift, and higher fuel consumption.
Micro VGs control this flow detachment by producing miniature, controlled tornadoes called vortices. The micro VGs sweep away uncontrolled airflow separation over the airplane's wings and flaps. Wind-tunnel tests using micro VGs showed a 10-percent increase in lift, 50-percent reduction in drag, and a 100-percent increase in lift-to-drag ratio - huge gains for such a simple, inexpensive device.
General aviation quickly jumped on the micro VG bandwagon, especially for piston twins, because they lower single-engine minimum control speeds. Micro VGs also have been approved for a variety of piston singles including the Cessna 150 and 172 and various Piper Cherokee models.
Manufacturer Micro Aerodynamics, Inc. claims that its micro VGs lower the 150's stall speed 8 to 10 percent, improve aileron response, and reduce the takeoff and landing roll. Its micro VG kit for the 150 consists of 88 vortex generators glued to the wing just aft of the leading edge, and 26 more mounted on the vertical fin forward of the rudder.
If you get the chance to fly a micro VG-equipped airplane, one way to test their effectiveness is to make a series of steep turns while gradually reducing airspeed. The first hint of an accelerated stall should occur at a noticeably lower airspeed than without the devices. Of course, it's a good idea to enlist the help of your flight instructor when attempting this informal trickle-down technology test.
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