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 discuss how to balance your elastic launched glider.
balancing your glider
Why is balance important?
If you have ever tried to test fly your glider right after you built it, you may have noticed that your glider either stalls and flops to the ground or it dive bombs. And, if you were as naive as a 7th grade me, then you might have though that the glider was trash and would never work.
However, there is definitely a work around solution for the symptoms my glider was experiencing: balance. The true reason that my glider was not properly gliding was because its center-of-gravity was off its optimal position (along with poor build quality of my glider).
Although it is true that weight, size, and other factors play a large role in your glider’s performance, it is the center-of-gravity that trumps them all. In fact, I would go as far to say that if you built a maximum weight glider that had an optimized center-of-gravity compete against a minimum weight glider with an unoptimized center-of-gravity, it is almost certain that the heavier glider would win.
Center-of gravity if the point on an object where its distributed mass equates to zero. In other words, its the point where an object is completely balanced and stable.
The best way to visualize center-of-gravity and how it affects stability, is by bending down. When you bend down, notice that your hips protrude backwards as your body leans forward. This helps maintain your body’s center-of-gravity and stability. Now, stand against a wall and bend down. You hips should be prevented from protruding, your center-of-gravity will be pushed too far forward, and you will lose stability.
This same concepts applies to elastic launched gliders, you want to focus on finding the correct place for your center-of-gravity to prevent your glider from stalling or nosediving, and getting a smooth glide.
How to balance your glider
If you want to adjust the center-of-gravity of you elastic launched glider then you first need to find where your current center-of-gravity is. To find out where you glider’s center-of-gravity is try to balance your glider on your finger. It is a finicky process but you will be able to accurately find the center-of-gravity though this method.
After finding the center-of-gravity of your glider, you want to analyze its position. Generally, you want your glider’s center-of-gravity to be under its wings. The exact location, however, is very much dependent on your specific glider and its build quality.
If your glider’s center-of-gravity is in front of its optimal position, then your glider will nosedive. If the opposite is true, then your glider will stall instead. To adjust your glider’s center-of-gravity you you take some modeling clay and stick it either on the nose of your glider if its center-of-gravity is too far back or on the tail of your glider if its center-of-gravity is too far forward.