Principles of Aerodynamics – Other Aerodynamic Effects

Wingtip vortices and hence induced drag occurs all the time, but when there is moisture in the air that’s when we can see it.

HOW DO WINGS WITH A HIGH ASPECT RATIO REDUCE VORTEX DRAG?

The farther a vortex is from the main body of the wing, the less influence it has on the wing. So long, narrow wings, like those of an airliner, or this Lockheed U-2 spy plane, will produce less vortex/induced drag than a short, stubby wing with the same surface area. But to make long wings strong enough adds weight and reduces maneuverability.

BUT LOW ASPECT RATIO WINGS HAVE ADVANTAGES TOO

An attack aircraft, like the Douglas A4-C Skyhawk, has shorter wings to enhance its maneuverability. Short wings also reduce the drag from shock waves that begin to develop at speeds approaching that of sound. Short wings also take up less space—no small matter on an aircraft carrier.

Glider

Reduced Induced Drag due to a reduction in wingtip vortices produced.

Airbus A380 – the biggest airliner’s Wing loading

To be certified the wings must prove they are strong enough to take 3.8g loading Plus another 50%

An aircraft will stall at the wing’s critical angle of attack, not necessarily the same speed. High speed stalls can also occur.

• At Stall Speed
• Pronounced nose drop
• Possible wing drop:
  • Maybe caused by Aileron / Rudder use
  • Wind Gusts / Turbulence
  • Flow Strips
• Increased Buffeting
• Increasing Rate of Descent