Model aircraft

Let's take a look!

What type of experiment is this?

Experimental procedure and explanation:

• Let us fly a model airplane by rotating a propeller using rubber power.
• In this experiment, we use a commercially available model kit. The rubber power part is the propeller shaft with rubber attached to it.
• First, rotate the propeller in the reverse direction to twist the rubber.
• The propeller rotates when you release the hand holding the propeller. Then, the wind blows backward. At this time, the propeller pushes the air backward, and therefore, the rebound (reaction) causes the airplane to move forward.
• When viewed from the plane moving forward, the wind hits from the front. There is an angle between the direction of the wind and the fuselage, and the wings are inclined at an angle with respect to the wind (angle of attack); thus, the scenario is the same as for “Flat Plate Airfoil,” and an upward lift is generated. This allows it to float in the air. In an actual airplane, flat-plate wings are not used due to poor performance; instead, an airfoil (with a round front, a pointed rear, and curved upward as a whole. The Principle behind Airfoil) is used.

[Keywords]	Rotary wing, Momentum theory
[Related items]	Wind-powered vehicle, Wind-powered ship, Flat Plate Airfoil, The Principle behind Airfoil
[Reference]	“The Wonders of Flow”, Japan Society of Mechanical Engineering, Kodansha Blue Backs, P192-197. “Illustrated Fluid Dynamics Trivia,” by Ryozo Ishiwata, Natsume Publishing, P152-153, P218-219, and P222-223.

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