Velocity Effects

Directions

Print the worksheet page before starting the project if the teacher hasn't already printed them for you. (Print it double sided if possible.)

Then, for each of the tables below:

Determine the square of each velocity.

Enter your answers in the tables in the second column.

Go to the FoilSim applet page.

Click the Reset button to set the following conditions:

Change the Angle-deg value to 0.0 and hit the ENTER key.
Change the Camber-%c at 0.2.
Change the Thick-%crd value to 15.0 and hit the ENTER key.
The screen should now look like this:

Change the Input option to Flight Test.
Leave the Speed at 100.0 until we start entering in the values from the tables.
Leave the Altitude-ft at 0.0.
The screen should now look like this:

Leave these values (except for velocity) the same for all of the wing planforms in the tables.

Change the Input option again... this time to Size.
Change the AR correction to on.
The screen should now look like this:

For each of the three wing planforms in the table do numbers 1 - 5:

Change the Chord-ft value to the value you had in column four of the Wing Areas Worksheet. Hit the ENTER key. Copy that value to the table for the current wing planform.

Change the Span-ft value to the span value you had in column three of the Wing Areas Worksheet. Hit the ENTER key. Copy that value to the table for the current wing planform.

Change the Area-sq ft to the value you put in the column for Area of Two Wings of the Wing Areas Worksheet. Hit the ENTER key. Copy that value to the table for the current wing planform.
{Remember: Lift and Area are directly proportional.
If the area is over 1000 sq ft, then divide area by 100, the span by 10 and the chord by 10 and enter those numbers.
When you get the lift, multiply it by 100 to get the real value!}

Change the Input option back to Flight Test.

Begin changing the velocity to each of the values in column one in the current table. Record the lift generated by each velocity in your table. {Remember: If you entered an area divided by 100, a span divided by 10, and a chord divided by 10, you need to multiply the Lift by 100 to get the real value!}

Repeat steps 1 - 5 for each of the other two planform tables.

Keeping in mind that the Lift is directly proportional to the square of the Velocity, calculate and record the Constant for each entry in each table.

Worksheet

*Wright Brothers*	Area of two wings:	Span of two wings:	Chord of one wing:
Velocity:	Velocity²:	Lift:	Constant:
0
25
50
75
100
125
150
175
200
225
250

*F-18*	Area of two wings:	Span of two wings:	Chord of one wing:
Velocity:	Velocity²:	Lift:	Constant:
0
25
50
75
100
125
150
175
200
225
250

*Boeing 747*	Area of two wings:	Span of two wings:	Chord of one wing:
Velocity:	Velocity²:	Lift:	Constant:
0
25
50
75
100
125
150
175
200
225
250

Student Names: __________________________________________________________________________

Questions:	Answers:
Are the constants exactly the same for all entries in each individual table? Why or why not? List possible sources of error.
Are the constant values the same for each aircraft? Discuss and list some reasons for this.
Which values were kept the same in FoilSim for all aircraft in this activity?
Which values in FoilSim differed from aircraft to aircraft in this activity?
The "Constant" values you calculated come from the values that are held constant (not changed). Now, which values do you think are included in the "Constant" value for each aircraft?
Could these values ever be considered variables? If so, when and how? If not, why not?
Now, suppose *your aircraft from the Wing Areas worksheet* is loaded down with cargo and extra fuel for a long flight so that it weighs 12,500 pounds before takeoff. What speed will it need to acquire before it has enough lift to get airborne? {Hint: On the ground the altitude and angle are both zero. Also, use 0.5 for the camber and 15.0 for the thickness.}

Velocity Effects

Investigating the effects of velocity on Lift

Velocity Effects

Directions

Worksheet