Aaron's Gravitational Potential Energy to Launch Projectile Science Competition

In summary, Aaron, a high school senior from northeastern Kentucky, is designing a pneumatic system for a science competition that will convert gravitational potential energy into air pressure to launch a projectile a specific distance. He plans to use two double action pneumatic cylinders, with one acting as a bellow and the other striking the projectile. He is seeking advice on the proper dimensions of the pistons to optimize energy transfer. Additionally, there are several design constraints and rules for the competition, including the use of unmodified projectiles and the device fitting within a specific size limit. Another competitor, Lucas from Missouri, is also having trouble with his launcher and is interested in calculating its efficiency.
  • #1
ahoback
4
0
Hello my name is Aaron! I am a high school senior from northeastern Kentucky designing a pneumatic system of sorts for a science competition and need some help. I will be building a device that converts gravitational potential energy, from a falling mass, into air pressure (or possibly the movement of air depending on the design) to launch a projectile a specific distance (max distance needed is 8.25 m).

What I am thinking about doing is using one double action pneumatic cylinder (DAPC) as a bellow in which a falling mass (max 3.500 kg at a max 90 cm) would strike its piston shaft, creating positive pressure within the system. With that positive pressure another DAPC’s piston would simultaneously strike our projectile sending it airborne in theory. Below there is an illustration of my idea, sorry about the poor quality.
c1clFl0yxwioJCn7boRf9R7B6hJq7N6cJYfL9t62lA=w1419-h881-no.png
So what I need help determining is would this design work before I start buying parts? If so what approximate sizes should the two cylinders be and should they be different sizes to maximize the force exerted on the projectile? If you have any other ideas concerning the design or any questions about the project PLEASE feel free to share! Below are some of the design rules that pertain to this project along with some notes in italics about them. Thank you very much for your time in advance!
  • Description:
    • Prior to competition, teams will design, construct, and calibrate a single device capable of launching projectiles into a target and collect data regarding device parameters and performance.
  • Design Constraints:
    • The launching force must be entirely supplied by the gravitational potential energy from a falling mass less than or equal to 3.500 kg. Any device part whose potential energy decreases and provides launch energy is considered part of the mass. The mass may consist of multiple discrete parts, which together count as the total mass.
    • During each launch, the gravitational potential energy must be converted to air pressure or air movement, which is then used to launch the projectile, either directly (e.g., pop gun style, etc.) or indirectly (e.g., using a pneumatic cylinder to swing an arm, etc.)
    • All device air chambers must start at ambient air pressure and must automatically return to ambient air pressure.
    • The launching device http://gallery.scioly.org/albums/2/normal_a2j_DSC_0004.jpg [Broken], including the projectile and all components, must fit within a 75.0 cm x 75.0 cm x 1.00 m box in ready-to-launch configuration, in any orientation chosen by the team. Weights used to stabilize the device must be within the box.
    • The triggering device (would look something like this except elevated with a mass suspended ready to be released) in not considered part of the device and must not contribute energy to the launch. It must extend out of the launch area, allow for the competitors to remain at least 1.00 m away from the launch area, and does not need to return to the launch area after launch. The triggering device must not pose a danger to anyone due to flying parts or excessive movement outside the launch area.
    • Teams must provide unmodified tennis, racquet, ping pong, and/or plastic practice golf balls to be used as projectiles. Teams may change projectiles for each launch.
    • The launching device must be designed and operated in such a way to not damage or alter the floor.
    • Electrical components are not allowed as part of the device or triggering device.
  • The Competition:
    • Two targets, designated by small marks on tape on the floor or panels lying on the floor, must be placed in front of and centered on an imaginary line parallel to the launch direction that bisects the launch are. Supervisors are encouraged to place sand, cat litter, or similar substance in the area around the targets to help indicate landing spots.
    • The targets must be placed in front of the launch area at distances between 2.00 m and 8.00 m (in intervals of 10 cm). A distance of at least 2.00 m must separate the targets. Target distances must not be announced until after impound is over and must be the same for all teams. Room ceiling height should be considered when setting the distances.
 
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  • #2
Thanks for the post! Sorry you aren't generating responses at the moment. Do you have any further information, come to any new conclusions or is it possible to reword the post?
 
  • #3
Yes I can. What I am really needing help with is determining the proper dimensions of the pistons. Should the bellow piston have a greater working volume than the striking piston? Should the bellow piston have a greater bore diameter than the striking piston? I am just trying to achieve the best transfer of energy from the falling mass, through a pneumatic system, to projectile. Thank you for your time!
 
  • #4
Do they have to be separate devices connected by a small bore pipe? How about two pistons in one pipe - perhaps with a large bore flexible coupling pipe between them to reduce losses? Do you even need a piston in the launching side or could the projectile be the piston? Just some ideas to play with.
 
  • #5
Thank you for the response! I was actually planning on using a large bore flexible coupling pipe between the two pistons. When you say could the projectile "be the piston" are you thinking about loading the projectile into a tube (somewhat like a potato gun) and having the pressure created from the bellow piston launch it?
 
  • #6
Yes. Why accelerate (put energy into) the mass of a perhaps unnecessary piston.
 
  • #7
Hi my name is Lucas and I'm from Missouri and I'm in a similar event. I've been having trouble getting mine to launch the projectile far enough and I was wondering if you have had any luck with getting yours to work.
 
  • #8
Hi Lucas,

It would be interesting to calculate the efficiency of the launcher. Calculate the available energy (the PE in the falling weight) and the energy in the projectile (idealy measure the launch velocity but you could calculate it from the range achieved and use KE=0.5mv^2). The ratio would give you the efficiency of the conversion.
 
  • #9
Thanks for the input but I got it figured out after more looking.
 
  • #10
Hey, I'm doing a similar Air trajectory layout, I was wondering how did your setup go ahoback? Did the two pistons work better then using one piston connecting to a PVC pipe tube to launch the ball? After making the layout and competing did you find anything you wish you had changed or modified?
 

1. What is "Aaron's Gravitational Potential Energy to Launch Projectile Science Competition"?

"Aaron's Gravitational Potential Energy to Launch Projectile Science Competition" is a scientific competition that challenges participants to design and launch a projectile using gravitational potential energy as the main source of propulsion. It aims to promote creativity and understanding of the principles of potential energy in the field of science.

2. Who can participate in this competition?

The competition is open to individuals or teams of all ages who have a passion for science and a desire to learn and innovate. Students, professionals, and enthusiasts are all welcome to participate.

3. What are the rules and guidelines of the competition?

The rules and guidelines may vary depending on the specific competition, but generally, participants are required to design and build their own projectile launchers using materials and tools of their choice. The projectile must be launched solely using gravitational potential energy and must meet certain parameters set by the competition organizers.

4. How will the winners be determined?

The winners will be determined based on various criteria such as the distance or accuracy of the launched projectile, creativity and innovation in design, and adherence to the competition guidelines. A panel of judges or a voting system may be used to determine the winners.

5. What are the benefits of participating in this competition?

Participating in this competition can provide a platform for individuals or teams to showcase their scientific knowledge and skills, as well as foster teamwork and critical thinking. It can also lead to opportunities for networking, learning, and potentially winning prizes or recognition for their achievements.

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