Skip to Content
Uncategorized

How to Build a Supersonic Ping-Pong Gun

If your ping-pong gun fails to impress, a simple mod will give it supersonic powers, say engineers

If there’s one thing wrong with Ping Pong Guns, it’s that they can’t fire their ammunition at supersonic speeds. At least, that’s the feeling of Mark French, a mechanical engineer at Purdue University in Indiana, and his graduate students Craig Zehrung and Jim Stratton.

The dire performance of ping pong guns has forced these guys to take matters into their own hands. Today, they reveal the fruits of their work in the form of a bespoke gun capable of launching ping pong balls at speeds of over 400 metres per second. That’s about Mach 1.2. 

Their design is simple. It consists of a pressure chamber sealed with two or three layers of Duck Tape. When the pressure exceeds about 620 kPa, the tape bursts allowing a pressure wave into a special nozzle and from there into the barrel where it propels a ping pong ball.

The design of the nozzle is important because it generates a supersonic pressure wave. For this, French and co use a so-called de Laval nozzle, named after the Swedish engineer who invented it in the 19th century.

A de Laval nozzle consists of a tube with a pinch in the middle. As the air enters the nozzle it accelerates as it is compressed.  At the pinch, the air flow matches the speed of sound and then becomes supersonic as the tube begins to expand.

This supersonic flow then enters the gun barrel where it accelerates a ping pong ball to supersonic speeds.  

French and co have used a high speed video camera to measure the ball velocity as it exits the barrel. They say they have video evidence of speeds in excess of 400 metres per second. That’s faster than an F-16 flying flat out at sea level.

That’s sterling work, no doubt. But let’s hope these guys never turn their attentions to toothpaste dispensers.

 Ref: arxiv.org/abs/1301.5188: A Supersonic Ping Pong Gun 

Deep Dive

Uncategorized

Our best illustrations of 2022

Our artists’ thought-provoking, playful creations bring our stories to life, often saying more with an image than words ever could.

How CRISPR is making farmed animals bigger, stronger, and healthier

These gene-edited fish, pigs, and other animals could soon be on the menu.

The Download: the Saudi sci-fi megacity, and sleeping babies’ brains

This is today’s edition of The Download, our weekday newsletter that provides a daily dose of what’s going on in the world of technology. These exclusive satellite images show Saudi Arabia’s sci-fi megacity is well underway In early 2021, Crown Prince Mohammed bin Salman of Saudi Arabia announced The Line: a “civilizational revolution” that would house up…

10 Breakthrough Technologies 2023

Every year, we pick the 10 technologies that matter the most right now. We look for advances that will have a big impact on our lives and break down why they matter.

Stay connected

Illustration by Rose Wong

Get the latest updates from
MIT Technology Review

Discover special offers, top stories, upcoming events, and more.

Thank you for submitting your email!

Explore more newsletters

It looks like something went wrong.

We’re having trouble saving your preferences. Try refreshing this page and updating them one more time. If you continue to get this message, reach out to us at customer-service@technologyreview.com with a list of newsletters you’d like to receive.