Aerodynamics: Ground Effect Overview

Questions and Answers

What is ground effect?

The result of the interference of the surface of the Earth with the airflow patterns about an airplane. (correct)

The result of an alteration in the airflow patterns increasing induced drag about the wings of an airplane.

The result of the disruption of the airflow patterns about the wings of an airplane to the point where the wings will no longer support the airplane in flight.

Floating caused by the phenomenon of ground effect will be most realized during an approach to land when at?

Less than the length of the wingspan above the surface. (correct)

A higher-than-normal angle of attack.

Twice the length of the wingspan above the surface.

What must a pilot be aware of as a result of ground effect?

Wingtip vortices increase creating wake turbulence problems for arriving and departing aircraft.

Induced drag decreases; therefore, any excess speed at the point of flare may cause considerable floating. (correct)

A full stall landing will require less up elevator deflection than would a full stall when done free of ground effect.

An aircraft leaving ground effect during takeoff will?

<p>Experience an increase in induced drag and a decrease in performance.</p> Signup and view all the answers

Ground effect is most likely to result in which problem?

<p>Becoming airborne before reaching recommended takeoff speed.</p> Signup and view all the answers

Study Notes

Ground Effect Overview

Ground effect results from the interference of the Earth's surface with airplane airflow patterns.
It leads to a reduction in upwash, downwash, and wingtip vortices, resulting in decreased induced drag.
As a consequence, lift produced by the wings increases in ground effect at a given angle of attack compared to out of ground effect conditions.

Recognition During Landing

Ground effect is most noticeable when an airplane is within half of its wingspan above the surface.
It can extend up to a full wingspan length above the surface.
Induced drag decreases within this zone, necessitating less thrust at low speeds, which can lead to significant floating during landing flares if excess speed is present.

Pilot Awareness

A key concern for pilots is that excess speed during flare can cause floating, as ground effect reduces induced drag.
Pilots should be vigilant of wingtip vortices, which can create wake turbulence issues for nearby aircraft during landing and takeoff.

Aircraft Performance During Takeoff

As an aircraft exits ground effect during takeoff, it experiences increased induced drag and a decrease in performance.
This requires a higher angle of attack to maintain the same lift coefficient.
Pilots must also anticipate decreased stability and a nose-up change in the aircraft's moment.

Potential Problems Induced by Ground Effect

Ground effect can lead to premature liftoff before reaching the recommended takeoff speed due to lowered induced drag.
If an aircraft becomes airborne at insufficient speed, it may settle back to the runway after leaving ground effect, resulting in marginal initial climb performance.
Problems include the potential for abrupt settling to the surface during landing if excess lift is not managed properly.

Description

Explore the fascinating concept of ground effect and its significance in aviation. This quiz covers the mechanics of ground effect, its impact during landing, and the awareness pilots must maintain to ensure safe landings. Test your understanding of how ground effect influences lift and drag characteristics.