Balsa Wood Flying Models

balsa wood airplanes, model airplanes
These sticks can fly!

Level: Middle to H.S.

Time involvement: 10-15 minutes.

Materials/Procedure: This series of small models illustrate the invention of an airplane from the simple concept of lift to the ability of an airplane to maintain stable flight. The “wing” in the foreground is a simple flat surface. In succession are 2 “wings” with increasing dihedral angle (wing tips higher than center give roll stability). Adding a horizontal stabilizer (tail) prevents nose from pitching up and down. The next model is a complete airplane capable of stable flight. The tail first model is termed a “Canard”. The foam Wright Flyer is non-flying but illustrates the general proportions of the “first flyer”.

dihedral angle in airplane
Simple illustration of dihedral angle. Click on image for more in-depth explanation at Wikipedia.

The turkey feather is a good example of Nature’s ability to “grow” lightweight efficient aerodynamic parts. Terms of Lift, Gravity, Thrust and Drag are explained. Roll, Pitch, and Yaw describe how a plane or bird moves.

Discussion: The Wright brothers and others watched the birds carefully and discovered how to construct a glider and eventually a powered controllable airplane. What separated the Wrights from other experimenters was the ability to maintain level flight and make a controlled turn by warping the wings and changing the lift. The choice of a tail first horizontal stabilizer and a pusher engine and propellers was unique for the early airplanes since most experimenters chose to follow nature and place the horizontal stabilizer at the back, exactly like nature chose in designing a bird. Since placing the horizontal stabilizer in the front worked but appeared unusual the French word “canard” meaning hoax came into use. A few modern aircraft designs are canards. The record setting (1986) globe circling without refueling, Voyager incorporated a forward stabilizer.

At the time of the Wright brothers there was great interest in creating a successful “flying machine”. The word airplane did not exist yet! The most vexing problem encountered by all would-be-inventors was to understand and solve the problem of stability. Building a table that would not tip over was relatively simple because it rested on a solid surface. Building a machine that was supported by an invisible fluid was similar to the modern problem of barefoot water skiing. If the skier is too slow or does not know how to precisely hold his/her feet they will “crash” into the water. Merely creating lift itself was relatively easy. Kites had been flown for over a thousand years. Large kites could even carry significant weight. Most inventors grasped the idea that to support a person the wings would need to be much larger than bird wings.

Learn More: The internet and books abound with description of the forces and construction of aircraft. See the companion lesson: Poor Man’s wind tunnel for a more detailed discussion of the principles of flight. The photo below shows model aircraft propellers and a propeller toy. The similarity between the blades of the propeller’s and a wing is evident. A helicopter is, in effect, an airplane with an engine powered rotating wing.