How to Build a Model Wind Tunnel

Some wind tunnels are big enough to accomodate an entire airplane.

Wind tunnels are used to to test aerodynamic properties. Basically a long horizontal tube, a wind tunnel shows how air travels over and around objects. Cars, planes and even architectural pieces take their turn in a wind tunnel to make sure they will stand up to the wind speeds they will encounter in the real world. Making a wind tunnel can be very complex but doesn't have to be. Basically there are three parts: a wind source, a diffuser, and a tunnel.

Things You'll Need

• 3-4 egg cartons
• craft knife
• duct tape
• 6 inch corrugated box,
• 4 feet of 6 inch diameter metal duct pipe
• tin snips or metal shears
• clear plastic sheet
• 2 suction cup hooks
• thread
• small toy airplane
• Fan

Instructions

Making a Simple Wind Tunnel

1. Trim around the edges of the egg carton that holds the eggs. Using the knife, slice off the bottom of each egg cup. You will be left with a series of twelve small funnels. Repeat for all of the egg cartons.

2. Open both sides of the corrugated box. Fold the tabs inside the box. It makes the box stronger.

3. Tape the egg cartons to one open side of the box. Make sure it completely covers the box. Seal any cracks with tape.

4. Cut a hole near one end of the metal duct with the tin snips. Make sure that it is an inch smaller than the plastic sheet. Tape the plastic over the hole. Make sure that all edges are sealed with tape.

5. Stick one of the the suction cup hooks on the top of the duct in front of the window. The other goes on the bottom. String the toy between the two hooks with thread.

6. Place the box against the end of the pipe farthest from the window. Place the pipe right up against the egg cartons. Tape the box to the duct wherever possible.

7. Place fan in box and turn on.

Tips & Warnings

• If the toy airplane pulls the suction cups off the tunnel, then you know the toy is not very aerodynamic. Try different toys in the wind tunnel. Try different speeds or even different fans.

• Be very careful when cutting the metal duct. The edges will be very sharp.

References

• Flights of Inspiration: Make a Bigger Windtunnel
• Flights of Inspiration: Make a Simpler Windtunnel
• NASA: Building a Windtunnel