This project was COMPLETED.
Date completed: March 2016.
Image Credits and References:
http://www.youtube.com/watch?v=YYNCGZCul1Q is a video showing students at Purdue University’s College of Technology firing a Ping-Pong ball to supersonic speeds
http://www.youtube.com/watch?v=I9zBGgpzl0I is a video lecture by Dr. Mark French on how to build a Ping-Pong ball cannon
The task is to design and build a compressed-air/vacuum cannon that accelerates a Ping-Pong ball to velocities beyond Mach 1.0. By rupturing a plastic diaphragm, high-pressure air is injected into a converging-diverging nozzle (de Laval), which enables the escaping air and Ping-Pong ball to achieve supersonic speeds. The barrel of the cannon is evacuated so that the ball can ride the pressure wave without working against air resistance. The high-speed ball breaks the vacuum diaphragm at the barrel’s muzzle and strikes the target. In this special experiment, the nozzle inlet diaphragm will be a metalized Mylar film that is ruptured by an electromagnetic pulse from an external coil. The result is a fast-acting triggered pressure wave.
Level of Difficulty: Medium
Gustaf de Laval, C-D nozzle, choked flow, plenum, shock, “design condition,” magnetic induction, skin effect, eddy current, Lenz’s law, spark gap
“A Supersonic Ping Pong Gun,” by Mark French, Craig Zehrung, and Jim Stratton, Department of Mechanical Engineering Technology, Purdue University, Submitted January 22, 2013 http://arxiv.org/ftp/arxiv/papers/1301/1301.5188.pdf
“Ping-Pong Gun Fires Balls at Supersonic Speeds,” by Brian Dodson, Gizmag, February 3, 2013, http://www.gizmag.com/how-to-build-a-supersonic-ping-pong-gun/26082/
Electrical Engineer (2) – Electrical Engineers on the project are responsible for the design, construction, and development of an electromagnetic coil and capacitor-discharge system that destroys the nozzle inlet diaphragm on command. The system includes a pulse-discharge capacitor, power supply, triggered spark gap, high-voltage trigger chassis, and safety enclosures.
Mechanical Engineer (2) – Mechanical Engineers on the project are responsible for the high pressure plenum, vacuum system, and barrel section of the supersonic cannon. The mechanical design includes gauge instrumentation for pressure and vacuum levels. The MEs are also responsible for developing safe operating practices when using targets. The cannon must be made safe for public viewing, which includes hearing protection for spectators.
Aerospace Engineer (2) – Aerospace Engineers on the project are responsible for the design, modeling, and fabrication of the de-Laval nozzle section on the supersonic cannon. Modeling calculations will predict pressure, temperature, and flow speed through the C-D nozzle and barrel. The AEs will work closely with the EEs to fit the working cannon with an electromagnetic coil to initiate an inlet diaphragm rupture.
Computer Scientist (2) – Computer Scientists on the project are responsible for the design, construction, and operation of the diagnostic devices on the supersonic cannon. Most importantly, the diagnostic cluster includes high-speed optical measurements of the Ping-Pong ball’s speed and acceleration. Computer Scientists will also participate in nozzle modeling.
Designer (2) – The Designers will work closely with the engineering team to model/calculate stress and safety factors for all the cannon components. Designers on the project also validate the system assembly with CAD illustrations and supervise all component manufacturing.
Journalist (1) – The Journalist documents the project’s progress on the website, issues information to the press, communicates through social media, and is responsible for a final report to the principal sponsors and Power Mountain Engineering. The whole project is your project.
Multimedia Artist (1) – The Artist also documents the project’s progress on the website and works with the Journalist to maintain the project’s presence on social media. Additionally, the Artist designs and organizes all public relations events to assure spectator safety and to enhance the community’s awareness of science and technology. The whole project is your project.
Business Manager (1) – The Business Manager is responsible for reporting the project’s progress against a predetermined schedule, determines critical path items to completion, and tracks project spending to assure that costs remain within a fixed budget. The whole project is your project.