Tuesday, February 14, 2012

Top 10 Reasons to Analyze Your Airfoil

Here are my top ten reasons (no particular order) to analyze your airfoil shape.  

10.  Bricks make terrible airfoil shapes.  Circular shapes do not provide any lift (unless they are spinning).  The airfoil shape makes a difference even if it is not the dominant parameter.

Brick analysis by MultiElemnet Airfoils 5.0: see http://www.hanleyinnovations.com/mefoil.html

9. You can perform airfoil analysis free of cost using XFoil (albeit you cannot analyze the above bricks with this program).  Price is no excuse not to analyze your airfoil.  See: http://web.mit.edu/drela/Public/web/xfoil/

8.  You are forced to learn about Reynolds number and how it can ruin the looks or your airplane (but possibly save your life).  Investigating the behavior of the airfoil shape as a function of Reynolds number can improve the safety of your designs.

7.   Some shapes provide better lift than others at the same angle of attack and speed.  Find out which ones can make or break your project.

Lift Coefficient vs. Angle of Attack. Computed with VisualFoil 5.0

6. Some shapes can provide the required lift (desired loading characteristics) without the increased expense of drag.  This helps you to win races, save fuel and have a good feeling about your design.

Lift Coefficient vs. Drag Coefficient. Computed with VisualFoil 5.0

5.  Some good looking airfoils turn out to provide bad stall behavior. Use analysis to determine the stall angle and maximum lift coefficient of your cross sectional shape.

Lift Coefficient vs. Angle of Attack (showing maximum lift). Computed with VisualFoil 5.0

4.  The moment of truth.   Some airfoils (especially those that provide high lift) often demand in return a huge horizontal stabilizer for longitudinal stability.    You do not want your design to have a high sink rate due to tail drag.

Moment Coefficient vs. Angle of Attack. Computed with VisualFoil 5.0
3.  Speed can slow you down.  It is necessary to know the transonic behavior and the drag divergence Mach number of your airfoil if you design propellers, turbines and jet airplanes.
Drag divergence of an airfoil.  Analysis by VisualFoil Plus:  http://www.hanleyinnovations.com/air_16.html
2.  Airfoil analysis inspires you to find more about airfoil characteristics and terms.  You will learn about reflexed airfoils, laminar flow airfoils, high lift airfoils, cambered shapes, split flaps, slotted flaps ....... and how they can be beneficial to your design and project.

1.  VisualFoil 5.0 is a powerful and user-friendly tool for airfoil analysis and design.  It has a built-in library of 1000s of airfoils including the NACA 4, 5 & 6-digit shapes.  Users can also enter custom airfoils as coordinates or .dxf files (line & arc entities).   Hanley Innovations can provide help with setting up your airfoil project, interpretation of the results and provide recommendations.  There is no reason not to produce a successful design.
More information about airfoil analysis and VisualFoil can be found at Hanley Innovations.  Please visit http://www.hanleyinnovations.com/

What are your reasons for airfoil or CFD analysis?

Thanks for reading.

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