Welcome Guest. Sign in or Signup

2 Answers

How does induced drag change of an aerofoil with configuration(flaps)?

Asked by: 7616 views , ,
Aerodynamics

The reason I am asking this is because in the ATPL books and also other documentations that I tried, effect of flaps on drag mostly considered in an aspect of total or parasite drag. I could not find information about the effect on induced drag.

Ace Any FAA Written Test!
Actual FAA Questions / Free Lifetime Updates
The best explanations in the business
Fast, efficient study.
Pass Your Checkride With Confidence!
FAA Practical Test prep that reflects actual checkrides.
Any checkride: Airplane, Helicopter, Glider, etc.
Written and maintained by actual pilot examiners and master CFIs.
The World's Most Trusted eLogbook
Be Organized, Current, Professional, and Safe.
Highly customizable - for student pilots through pros.
Free Transition Service for users of other eLogs.
Our sincere thanks to pilots such as yourself who support AskACFI while helping themselves by using the awesome PC, Mac, iPhone/iPad, and Android aviation apps of our sponsors.

2 Answers



  1. Bill Trussell on Jun 04, 2013

    First, see the following site for a decomposition of the formula for Drag:

    http://www.grc.nasa.gov/WWW/k-12/airplane/drageq.html

    Second, recall there is a direct relationship between lift and induced drag. The more lift, the more induced drag. The reason you can not find the complete answer is that typical flap configurations produce varying degrees of each type of drag depending on flap type and deployment amount. Typical fowler flap deployment includes a increase in surface area first, then a larger increase in form drag with increased deployment. As you see with the surface area impact on the drag equation, any increase will increase total drag.

    Wing form also causes variations in the division of drag among the various types of drag.

    +2 Votes Thumb up 2 Votes Thumb down 0 Votes



  2. oktay karahan on Jun 04, 2013

    let me put the question in a different way… Think of a level flight so L=W then you set say flaps 10; after compensating for the balooning effect it will be level flight again thus the lift will not change… So if we stick to the formula induced drag should not change. Reasoning that we are just decreasing AoA and CL is going to be the same also S will be same…

    nonetheless after doing some research on the web, I found out flaps will change the elliptical distribution of lift which in turn will increase induced drag…

    http://www.grc.nasa.gov/WWW/k-12/airplane/induced.html

    In return, I just want to understand what really happens to induced drag… does it differ from assumption to assumption?

    0 Votes Thumb up 1 Votes Thumb down 1 Votes


The following terms have been auto-detected the question above and any answers or discussion provided. Click on a term to see its definition from the Dauntless Aviation JargonBuster Glossary.

Answer Question

Our sincere thanks to all who contribute constructively to this forum in answering flight training questions. If you are a flight instructor or represent a flight school / FBO offering flight instruction, you are welcome to include links to your site and related contact information as it pertains to offering local flight instruction in a specific geographic area. Additionally, direct links to FAA and related official government sources of information are welcome. However we thank you for your understanding that links to other sites or text that may be construed as explicit or implicit advertising of other business, sites, or goods/services are not permitted even if such links nominally are relevant to the question asked.