Objectives:

1. The students will be able to calculate the LIFT of an airplane given the LIFT constant, density of the air, velocity of air traveling over the airplane's wing, and area of the wing.

    

2. The students will be able to verify their calculated LIFT by using NASA's "FoilSim" program which allows design of and realtime interaction with an airfoil.
   Download FoilSim

    

3. The students will be able to do a dimensional analysis of the LIFT EQUATION.

    

4. The student will be able to determine the relationships between LIFT and Altitude (density), LIFT and angle of attack, LIFT and Velocity and LIFT and Wing area.

    

5. The students will be able to graph the relationships involving LIFT and other variables such as velocity.

    

6. The students will be able to determine the LIFT EQUATION by regression.

Materials

1. Calculator

    

2. Computer with the "FoilSim" program

    

    

3. Data charts

Background

L = .5 * Cl * r * u² * A

L		LIFT		in Newtons
Cl		LIFT Constant		has no dimensions
r		density of air		in kg / m3
u		velocity of flowing air		in m / s
A		wing area		in m2

Note: The LIFT constant is the result of the airfoil's camber, thickness and angle of attack.

1. Do a dimensional analysis of the LIFT EQUATION to verify that LIFT should be measured by Newtons.
   
   
2. Use the data from Data Chart #1 with the LIFT equation to calculate the LIFT for each plane.
   
   
3. Use the data from Data Chart #2 with the "FoilSim" program to find the LIFT for each plane.

    

   • Use the Shape and Size input screens in FoilSim.
     
     
   • Make sure the units are in metric.
     
     
   • Insert the data into the boxes by clicking on each box typing in the data and HIT ENTER.
     
     
   • Record the LIFT data as shown below the Graphics Window.

    

4. Use the data from one of your planes. Change the altitude (density) and look at the trend of the values for the LIFT.
   
   
5. Use the data from one of your planes. Change the angle of attack and look at the trend of the values for the LIFT.
   
   
6. Use the data from one of your planes. Change the velocity and look at the trend of the values for the LIFT.
   
   
7. Use the data from one of your planes. Change the wing area and look at the trend of the values for the LIFT.

Optional activities

Repeat procedure 4 and record 8 sets of data points. Let density be the independent variable (X) and LIFT be the dependent variable (Y). Graph the data and draw a curve through the points. Determine the relationship between the variables. With a graphic calculator (eg. TI-85) do a regression of the points and determine the equation of the relationship. This activity can be done for procedures 5-7.

Questions

1. Compare the calculated LIFT to the LIFT generated by the program. Do the answers agree?
   
   
2. Why or why not would each plane fly?
   
   
3. As the density increases the LIFT would?
   
   
4. As the altitude increases the LIFT would?
   
   
5. As the angle of attack decreases the LIFT would?
   
   
6. As the velocity decreases the LIFT would?
   
   
7. As the wing area increases the LIFT would?

Click here to go to Data Charts

Click here for a MASS CONVERSION ACTIVITY using real plane data

Click here for a VELOCITY CONVERSION ACTIVITY using real plane data