Like many of us, Matthias Wandel spent a lot of Talk about cheap transportation — how about a jet time robotically swapping disks in and out of his engine made from a couple of commuter coffee CD burner, ripping music, and doing backups. Then mugs and a sink strainer? Amateur designer Larry he thought he could rig up something to perform Cottrill welded the parts together after realizing the tasks for him. He was right. By pulling together that the cups’ graceful lines form the perfect shape some electronics design, mechanics, coding, and for what’s known as a “ramjet,” a jet engine that woodworking, Wandel built a Linux PC-controlled uses moving air to compress volatile gases. contraption that rips through stacks of CDs. This Starbucks-inspired idea could be space-
A hinged wooden finger opens and closes via aged or simply spaced-out, but Cottrill plans to test solenoid, conveying the CDs by grabbing and releas- his creation this summer. Meanwhile, the Iowa-based ing them by their centerholes. Motorized pulleys inventor has earned serious cred for his designs on move the grabber. This CD transport mechanism is an online forum for exotic engines, pulse-jets.com. It’s run by an external controller board full of solid-state a site populated by hobbyists looking for alterna-relays, retired lab equipment that Wandel bought tives to expensive turbine engines currently at a University of Waterloo surplus sale. The relays available for model airplanes. act as a bridge between the Linux machine and the A prolific designer of mongrel flyers, Cottrill mechanicals, translating digital commands from the recently wowed the online forums with a blueprint for computer’s printer port into motor-capable voltages. a “focused-wave valveless pulsejet.” The basic design
CD burner functions are done with the standard has been around since World War II. Cottrill’s setup Linux utility cdrecord. By making calls to cdrecord and makes strides in the affordability of materials, his own C routines, Wandel can load, rip, and stack simplicity of design, and the thrust of the engine. It CDs from the command line and run batch jobs was successfully constructed in 2004 by hobbyists in by calling a simple shell script. In other words, the Connecticut and Pennsylvania, and by Cottrill himself, whole thing works. But now, after having proven the who says the sound was so loud he needed a set of concept, he’s partially dismantled the contraption. plastic ear muffs over his foam ear plugs. “There’s He wants to use those solid-state relays for some really nothing like a pulsejet. It roars much louder other projects he’s been thinking about. than a diesel train whistle; it’s unbelievable.”
—Paul Spinrad —Bob Parks
Photography by Matthias Wandel (Batching It) and Larry Cottrill (AlternaJets)
>>Matthias Wandel: sentex.net/~mwandel
>>Coffee Mug Ramjet:
References:
Archives