Elastic Launched Glider Fundamentals
what is elastic launched glider
An elastic launched glider is model plane that is launched into the air by elastic potential energy. Many science and engineering competitions, such as Science Olympiad and the Academy of Model Aeronautics, host elastic and catapult launched glider competitions to help teach basic physic concepts to students.
In this post, we will outline the basic concepts needed to consider when creating an elastic launched glider and how to optimize those aspects of your device for the best results.
what to consider
Weight
To achieve the highest time aloft, the weight of your glider should be minimized.
There are 4 forces of flight that act on a plane, thrust, weight , lift and drag. The more the plane weighs, the more lift will be needed to keep it flying. Therefore, to maximize the necessary lift to allow the plane to glide, the weight of the plane should be minimized.
Wingspan
To achieve the longest time aloft, the wingspan of your glider should be maximized. By maximizing the wingspan of your glider, you are able to generate more lift, the upwards force on the plane, which allows the plane to stay aloft for a longer period of time.
Wing chord length
To achieve the longest time aloft, the wing chord length of your glider should be maximized. By maximizing the wing chord length of your glider, you are able to generate more lift, the upwards force on the plane, which allows the plane to stay aloft for a longer period of time.
It is important to note that having a wing chord length that is between 1/2 to 1/4 of the plane’s wingspan is ideal for model gliders.
fuselage length
When constructing a plane or glider, it is best to have the fuselage be at least as long as the plane’s wingspan. It is sometimes better to have the fuselage longer than the wingspan because it requires much less weight to adjust the plane’s center of gravity.
It is important to note that Science Olympiad competitions reward a longer fuselage, further incensing the use of a longer fuselage.
center of gravity
While the placement of a plane’s center of gravity is different depending on the model, accurately adjusting it is vital for a smooth glide. However, for most gliders, it is usually best to keep the center of gravity between the forward half of the plane’s wing.
Angle of Incidence
Angle of incidence refers to the angle that the wing sits at on the fuselage. By increasing the angle of incidence, you are able to increase your planes lift, allowing you to achieve a smooth glide and transition without modifying the plane’s center of gravity.
For beginners, it is best to keep the angle of incidence at 0, let the wing sit flat on the fuselage, and adjust other elements of the plane instead, because even the smallest adjustments to incidents will lead to drastic changes.