Airfoils Aeronautics Rachelle Oblack rachelle.oblack@nasa.gov Welcome to the Summer of Innovation. I’m NASA Curriculum Specialist Rachelle Oblack. Today I present “Airfoils”, a lesson in the Aeronautics unit. Rachelle Oblack rachelle.oblack@nasa.gov

Jet engines help, but what keeps a plane in the air? Paper airplanes have no jets, yet stay aloft. Why? These are the questions we need to ask our students.

Let’s Get Silly! So lets get silly. That’s me, several years ago, playing in a mock-up of an astronaut suit at Johnson Space Center. I wanted to draw a picture of an astronaut on this bag, but it turns out I can’t draw! So why am I wearing a bag over my head now? I’m actually demonstrating an incredibly important concept for today’s presentation. Can anyone tell me why I am wearing this mask?

I’m actually demonstrating Bernoulli’s Principle! Bernoulli’s principle is a fundamental part of how planes are able to fly in the sky.

Bernoulli’s Principle Swiss scientist Daniel Bernoulli first introduced this idea in the 1700s. Bernoulli’s Principle states that fast-flowing fluids, such as air and water, exert less pressure than slower moving fluids. In other words, the airflow over the top of a wing of a plane, or other curved structure is moving more rapidly than air flow underneath. Camber is the curved structure over the top of a wing. The camber causes the air that flows over the top of the airfoil to move faster than the air that flows beneath it. Thus, a low pressure zone exists above the wing and a higher pressure zone is below. Lift is generated when the differences in pressure create a force.

Blowing on the strip of paper in my mask produces lift.

Paper Airplanes – YEAH! Excellent demo or activity to activate students brains Use models online Build your own paper airplane Can be used later An excellent way to get students interested in this activity is to give them something fun to do. Students can build a model of a paper airplane and observe the behavior of their particular plane. You can find paper cut-outs of planes with directions for completion online. Or, students can fold one of their own. No matter how you choose to make the models, students will later use their models for the airfoils experiment.

What Is an Airfoil? We commonly call a wing an airfoil, and use the words interchangeably, but this is not entirely correct. An airfoil is an aerodynamic surface used for testing the reaction from the air through which it moves. All the surfaces of an airplane can be shaped as an airfoil. This includes fuselage, wing, rudder, aileron, and propeller blades.

Spinning Fan Blades Let’s look at a demonstration. (fan with strings) Where is the zone of lowest pressure and how do you know?

I believe you also have a copy of this activity in your binder of materials. This is the summer of Innovation lesson on Air foils.

The airfoils experiment we will do today is part of the NASA “Why” files: The Case of the Challenging Flight. The guide is correlated to the standards, includes background material, assessments, and more. Overall, this Educator Guide is more than 70 pages long, making it a “challenge” to complete all of the activities. The focus is on the Airfoils activity on page 21 of the guide.

There is only one activity in this lesson There is only one activity in this lesson. However, you may want to do some of the other activities in your individual classrooms at some point in the future. You can download the full NASA Educator Guide at Nasa.gov. The airfoils experiment asks: How does an airfoil cause lift? Let’s start by gathering the materials we need. (demo)

It is best to put students in groups of 2-4 students, depending on equipment availability. I highly recommend just two students, but four is also possible. You will need a protractor, fan, a wooden block, stiff wire, such as copper A bead Scissors, glue and tape Six 10-cm pieces of yarn or string Thin carboard, such as posterboard paper A small nail and a drill A science journal is also very important. Students will be designing and testing an airfoil during the activity and will need to record observations, procedures, conclusions, and more.

Making an Airfoil Use poster board, cardstock paper, or manila folders Cardboard is also easy to use. Fold and tape Attach strings The first step is to create an airfoil. Use poster board, cardstock paper, or manila folders for the most flexibility.

Step 1 Lay cardboard flat and measure 15 mm from one end and 24 mm from the other end and make a line on each.

Make a camber top by lining the edge of the paper to the 24 mm side. Step 2 Fold in half Make a camber top by lining the edge of the paper to the 24 mm side.

Step 3 Make a hole in the bottom and top, through the widest part. Attach string with tape.

Attach wire to base. Add bead to top. Secure loosely at 70°. Step 4 Attach wire to base. Add bead to top. Secure loosely at 70°.

Step 5 Observe and then set to 40°. Turn plane upside-down and repeat same procedures. Predict: What will happen? At 70 it moves up. At 40 it goes faster. Upside down causes the opposite effects.

Foam board Craft wire Play dough 2 String hooks Substitutions Foam board Craft wire Play dough 2 String hooks

Paper Airplanes Again Connect to real work – Wind tunnel testing Dip deeper into student though processes Improving on an experimental design Students need a connection to the work of real scientists. For instance, wind tunnels are designed to show airflow on a surface. (demo) Often, students complete one experiment, confirm the results, and move on to the next scientific concept. Instead, you should dig a bit deeper by coming back and re-addressing the paper airplanes the students made at the beginning of class. Ask them if they think they can improve upon their experimental design once they learn about angle of attack and the rate at which lift increases.

Goal? I want to know the maximum angle of attack for my airplane before it stalls. I want to make an airplane that… Flies farthest Climbs highest Etc. What do you want your airplane to do? Each student or group of students should make a goal for their paper airplanes and design improvements for their paper airplanes.