UPLIFTING CALCULATIONS
Activity
Objectives:
 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.
 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
 The students will be able to do a dimensional analysis of the
LIFT EQUATION.
 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.
 The students will be able to graph the relationships involving
LIFT and other variables such as velocity.
 The students will be able to determine the LIFT
EQUATION by regression.
Materials
 Calculator
 Computer with the "FoilSim" program
 Data charts
Background
The LIFT EQUATION in its elementary form is:
L = .5 * Cl * r
* u^{2} * A
L


LIFT


in Newtons

Cl


LIFT Constant


has no dimensions

r


density of air


in kg / m^{3}

u


velocity of flowing air


in m / s

A


wing area


in m^{2}

Note: The LIFT constant is the result of the airfoil's
camber, thickness and angle of attack.
Procedures
 Do a dimensional analysis of the LIFT EQUATION to
verify that LIFT should be measured by Newtons.
 Use the data from Data
Chart #1 with the LIFT equation to calculate the
LIFT for each plane.
 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.
 Use the data from one of your planes. Change the altitude
(density) and look at the trend of the values for the
LIFT.
 Use the data from one of your planes. Change the angle of
attack and look at the trend of the values for the
LIFT.
 Use the data from one of your planes. Change the velocity and
look at the trend of the values for the LIFT.
 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. TI85) do a regression of the points and determine
the equation of the relationship. This activity can be done for
procedures 57.
Questions
 Compare the calculated LIFT to the LIFT
generated by the program. Do the answers agree?
 Why or why not would each plane fly?
 As the density increases the LIFT would?
 As the altitude increases the LIFT would?
 As the angle of attack decreases the LIFT would?
 As the velocity decreases the LIFT would?
 As the wing area increases the LIFT would?
Related Pages:
LIFT Home Page
Aeronautics Activities
Aerospace Activities Page
Aerodynamics Index
