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Upside Down Wings
Activity
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If so instructed by your teacher, print out a worksheet
page for these problems.
Explanation
From the FoilSim program, you have learned that there are many
factors that affect lift . Now look at two of these properties: the
Shape and the Size of the airfoil. Use the Probe of
FoilSim to create a data table that is a map of the flow of air over
and under an airfoil as the camber and area are being adjusted. Then
generate a multiple line graph that represents the data collected.
Using this data, hypothesize airflow graphs for objects as they are
elongated from a sphere to an airfoil shape.
Step 1.
Become familiar with the use of the
FoilSim
Probe.
You can display either local velocity or pressure by pushing the probe buttons.
Use the sliders beside and below the gauge to move the probe.
Be careful when reading the gauge because the answer is given in Scientific Notation.
Step 2.
Set the following set of parameters and complete the data tables
for each of the independent runs of the airfoil. (Numbers 1, 2, and
3)
PARAMETERS FOR THE 3 DIFFERENT SHAPED AIRFOILS
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First
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Second
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Third
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Airspeed (mph)
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100
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100
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100
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Altitude (feet)
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0
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0
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0
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Angle (degrees)
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0
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0
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0
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Thickness
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12.5%
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12.5%
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12.5%
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Camber
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0
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25.0%
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-25.0%
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Area (sq.ft.)
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1.0
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10
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100
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Step 3.
Use the probe to collect data on the top and the bottom of each
airfoil. Try to keep the probe close to the surface of the airfoil
and also keep it at the same distance from the front of the airfoil,
preferably near the center of the shape.
WIND SPEED AND AIR PRESSURE DATA FOR PARAMETERS 1, 2, AND
3
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First
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Second
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Third
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Airspeed A Top
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Pressure A Top
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Airspeed B Top
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Pressure B Top
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Airspeed C Top
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Pressure C Top
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Airspeed A Bottom
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Pressure A Bottom
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Airspeed B Bottom
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Pressure B Bottom
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Airspeed C Bottom
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Pressure C Bottom
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Step 4.
Plot the Airspeed vs. the Pressure for each of the three parameter
settings for the different shaped airfoils.
Step 5.
Answer the following questions:
a) What was the relationship between the different shapes
of airfoils?
b) Is there a relationship between airspeed and pressure?
c) Comment on the answers obtained for different values of
camber. What happens at -25%?
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