American Eagle exhibit

 Unique Features of the American Eagle Biplane 

The most notable feature of the American Eagle is that it has two wings that classify it as a “biplane.” Because of its lower wing and upper wing many museum visitors take note of this and question why it does not just have a single wing, known as a monoplane, and also why the vast majority of modern airplanes are monoplanes?

Early Biplane

Early Monoplane

In a biplane aircraft both wings contribute to the total lift (the upward force on the airplane) although they do not produce twice as much lift as a single wing would create. As the airplane moves forward through the air the airflow around the two wings of a biplane interfere with each other resulting in inefficiencies.

When two sets of wings are used the wings have to be braced by wires and solid streamlined lengths of metal braces called “struts” to secure the wings in position and to absorb the forces on the wings in flight and on the ground. These devices have a resistance to the air that is moving over them in flight which is known as “drag.” In order to overcome the drag of these devices additional power is required from the engine which overall will tend to slow the airplane in flight. This is a negative feature of a biplane as they require a lot more fuel to travel a given distance as compared with later more efficient designs.