Airfoil Design

Right click the following link so you can open it in a new browser window https://www1.grc.nasa.gov/beginners-guide-to-aeronautics/foilsimstudent/ which will open an airfoil simulator created by NASA Glenn Research Center.

Arrange the two browser windows so you can view this site and the simulator site side-by-side.   You can then follow the instructions on this site and see the results of simulation on the simulation site.

Click on the "Flight" button.  It will turn yellow.  The Flight Test drop-down menu allows selection of Earth, Mars, Water or Venus.  Keep the default setting of Earth - Average Day.  The Flight button allows the speed of the airfoil (or the speed of the air flow over the airfoil) and the altitude of the airfoil to be adjusted.  The default values for the atmospheric pressure, temperature, and humidity are displayed which do not need to be adjusted.  By default, the speed is set at 100 mph and the altitude to 0 ft.  Keep the altitude at 0 ft since we are interested in how airfoils perform very near the surface of the earth.

Click the "Shape" button to adjust the cross sectional shape of the airfoil.   Select plate in the Airfoil Shape drop-down menu.  Select the Angle-deg (angle of attack) to 0.  Set the Camber-%c (camber as a percent of chord) to 5%.  You will see the cross sectional shape of the airfoil in the upper left along with air flow streamlines.

Click the "Size" button to set the size of the airfoil.  Set the Chord-ft to 0.1 (1.2 inches) and the Span-ft to 5 ft.  As you can see, with these parameters, we have a Lift/Drag Ratio of 72.408.  Most commercial airplanes have Lift/Drag Ratios of around 20.  The Aspect-Rat (aspect ratio) is 50.

Several questions arise:

Consider a Black Box which contains a device which consumes power (Power In) and produces power (Power Out) as illustrated below.

The component in he above video corresponding to the Black Box is illustrated below.

According to the existing laws of physics, the Power Out must always be less than the Power In, and all possible devices must have an operating point in the Possible region of the following illustration so that the Power Out is always less than the Power In.

Consider a device as shown in the YouTube video above which contains an airfoil with a camber of 0% of the chord - in other words,  an airfoil that is a flat plate.  In that case, no matter how large the input power is, the output power will always be 0 as illustrated below.

Consider a device as shown in the YouTube video above which contains an airfoil with a camber of 1% of the chord.  In that case, the beam will spin at some RPM greater than 0, and the Power Out will be greater than 0 as illlustrated below.

Consider a device as shown in the YouTube video above which contains an airfoil with a camber of 3% of the chord.  In that case, the beam will spin at some RPM greater than 0 and the Power Out will be greater than 0 as illlustrated below.

Consider a device as shown in the YouTube video above which contains an airfoil with a camber of 5% of the chord and a very high Lift/Drag Ratio.  In that case, the beam will spin at some RPM greater 0 and it may be possible that the Power Out will be greater than the Power In as illlustrated below which was previously thought to be impossible.

If you have questions or comments, please email me at phil.white.ecc@gmail.com.