How Far Will it Fly?
Introduction
Paper airplanes are fun and easy to make. Just fold a piece of paper into a simple plane and send it soaring into the sky with a flick of your wrist. Watching it float and glide in the air gives you a very satisfying and happy feeling.
But what allows the paper plane to glide through the air? And why does a paper plane finally land? To find out, we will talk about the science behind flying a paper plane and the different forces that get a paper plane to fly and land. These same forces apply to real airplanes, too. A force is something that pushes or pulls on something else. When you throw a paper plane in the air, you are giving the plane a push to move forward. That push is a type of force called thrust. While the plane is flying forward, air is moving over and under the wings and is providing a force called lift to the plane. If the paper plane has enough thrust and the wings are properly designed, the plane will have a nice long flight.
But there is more than lack of thrust and poor wing design that gets a paper plane to come back to Earth. As a paper plane moves through the air, the air pushes against the plane, slowing it down. This force is called drag. To think about drag, imagine you are in a moving car and you put your hand outside of the window. The force of the air pushing your hand back as you move forward is drag. Finally, the weight of the paper plane affects its flight and brings it to a landing. Weight is the force of Earth's gravity acting on the paper plane. Figure 1 below shows how all four of these forces, thrust, lift, drag, and weight, act upon a paper plane.
Figure 1. When a paper plane is flying, the four forces of thrust, lift, drag, and weight are acting upon the plane, affecting how well its journey through the air goes.
Experimental Procedure
Flying the Planes
Follow the instructions for one of the airplanes found within the template guide (look at the bottom of this website).
Build two more so that you have a total of three paper planes. They should all look identical.
Go to a large area to fly your paper plane. Make sure that there is no foot or car traffic at the area. A long hallway or outside your house is a good location. If you are flying your plane outside, like in a baseball field or on a basketball court, do your experiment on a day when there is no wind.
Mark off a line somehow. This will be the starting line from which you will fly the paper planes. If you are doing this science project outside, you could use a line of sticks or rocks to mark the starting point.
Practice throwing or launching the paper planes. You will want to launch the planes in exactly the same way every time. Hold the planes at exactly the same spot on the plane every time you launch a plane.
Once you have finished practicing, it is time to start the experiment. Place your toe on the starting line you prepared earlier and then throw one of your planes.
Use the tape measure to measure how far (in centimeters or meters) the paper plane flew from the starting line. Record this distance in the data table in the spreadsheet that was provided.
This will be "Flight 1" for "Plane 1."
Repeat steps 7-8 four more times using the same plane, trying to throw the plane as similarly as possible. Doing these repeats will help ensure that your data is accurate and reproducible.
Before you fly the plane, make sure that it is in good condition and that the folds and points are still sharp.
Record the distances in the data table in your spreadsheet all in the same row as "Plane 1," as "Flight 2," Flight 3," "Flight 4," or "Flight 5."
Once you have flown plane 1 five times, add flaps to the back of the plane to increase its drag, as shown in Figure 2.
Cut four slits that are each roughly 2.5 cm long along the back edge of the wings. One in the center of each wing, and one where each wing meets the central fold.
This will result in four tabs (two on each wing). Fold two of the tabs up 90 degrees, and two of the tabs down 90 degrees, as shown in Figure 2.
How do you think this increases the plane's drag?
Figure 2. Left: the original plane. Right: a plane with flaps added to the back to increase drag.
Using plane 1 with added drag, repeat steps 7-9.
Record the distances the plane flies in your data table in the row titled "Plane 1 with Added Drag."
Repeat steps 10-11 using one of the other two planes you made.
Record the distances the plane flies in the row titled "Plane 2" and then "Plane 2 with Added Drag."
Repeat steps 10-11 using the last of the three planes you made. (This plane should not have been flown previously.)
Record the distances the plane flies in the row titled "Plane 3" and then "Plane 3 with Added Drag."
If you are looking to make a more complex plane, here is a link:
Credit goes to Joseph D. for finding this; thanks man!
What are flaps?
Flaps are usually mounted on the wing trailing edges of a fixed-wing aircraft. Flaps are used to reduce the take-off distance and the landing distance. Flaps also cause an increase in drag so they are retracted when not needed.
