Using Ground Effect

The lack of respect many pilots give to ground effect sort of makes it the Rodney Dangerfield of aerodynamics. Its that momentary sag right after takeoff, and that little bit of float on landing. We know about it, but its often an afterthought: Oh, thats how I screwed up that flare. We all should know ground effect is only encountered...well, close to a flat surface, be it liquid or solid, but sometimes we forget.

Editorial Staff

Friday, September 25, 2015 at 12:00 AM ET

Verified

Key Takeaways:

Ground effect is a reduction in induced drag experienced by an aircraft when flying very close to a flat surface, caused by the deflection of downwash.
This phenomenon improves aircraft performance, allowing for greater acceleration, slower flight, or maintaining altitude with reduced thrust, with the effect being stronger the closer the aircraft is to the surface.
Pilots primarily use ground effect for soft-field takeoffs, to get airborne quickly and accelerate, and during landings to reduce touchdown speed and minimize stress on the airframe.
Exiting ground effect during takeoff or entering it during landing reverses these effects, requiring pilots to anticipate increased drag and changes in stability, and to manage controls with a gentle touch.

See a mistake? Contact us.

The lack of respect many pilots give to ground effect sort of makes it the Rodney Dangerfield of aerodynamics. It’s that momentary sag right after takeoff, and that little bit of float on landing. We know about it, but it’s often an afterthought: “Oh, that’s how I screwed up that flare.” We all should know ground effect is only encountered…well, close to a flat surface, be it liquid or solid, but sometimes we forget.

Ground effect is a result of an airfoil’s so-called “downwash” changing velocity when a solid surface is close by. But how do we use it, and why? Any instructor worth his or her E-6B teaches students how to use ground effect on takeoff, especially from soft fields, so we all should know the basics. We can use it for other operations, too, and for other purposes.