Gallery: Mechanical Marvels Hide in Plain Sight

: You don't have to trek out to the dusty hell of Burning Man in order to see inspired feats of mechanical art and engineering. In fact, the back rooms and museums of your hometown may conceal feats of industrial genius that would put any steampunk artist to shame. Take San Francisco's Fisherman's Wharf.

Tourists know it for picturesque views of the bay, vendors selling clam chowder in bread bowls and bad street-corner buskers. But tucked into the corners of the San Francisco waterfront are such marvels as the most advanced mechanical computer ever made, prototypes of a gigantic clock intended to run for 10,000 years and a working steam engine three stories tall. "It just occurred to me -- the most mechanical geek I know -- that if I didn't put these things together, the rest of San Francisco didn't either," says Alexander Rose, one of the organizers of a one-day, self-guided tour of San Francisco's mechanical marvels.

The tour, dubbed Mechanicrawl and sponsored by the Long Now Foundation, where Rose works, will take place on July 12. Wired.com got an early preview of some of the day's attractions, which include special access to exhibits at the Exploratorium, the Long Now Foundation's offices, a World War II submarine and Liberty ship, and the Musée Mécanique . Left: One of the stops on the tour is San Francisco's hands-on museum, the Exploratorium .

During the tour, volunteer docents will point out exhibits that are particularly interesting to the mechanically minded. Here, kids pedal to generate electrical power in an exhibit built by museum founder Frank Oppenheimer. The generator is mounted on an early 20th-century cast iron lathe.

Photo: Jim Merithew/Wired.com : Caution: 2,000-Degree Sparks The Exploratorium's "Catch a Falling Spark" exhibit gives visitors a chance to turn a hand-cranked grinding wheel, spinning it against a thick piece of twisted steel cable to generate white-hot sparks and a distinct odor of burnt clutch. Although the sparks are 2000 degrees Fahrenheit, they're so small that it's safe to let them bounce off your bare hand. Photo: Jim Merithew/Wired.com : Loop Dreams The Exploratorium's "Rope Squirter" is a simple powered flywheel that throws a loop of rope into the air, forming an appealing curve of string that you can play with.

The museum's "head explainer" Ken Finn says he took this exhibit to a meeting of the American Geophysical Union, where it sparked a controversy about whether the shape of the rope's arc is parabolic or not. Of course, the exhibit is equally appealing to children, making it a good vehicle for stimulating mechanical imagination in young and old alike. "My six-year-old can enjoy it and I can watch geophysicists argue about it," says Finn.

Photo: Jim Merithew/Wired.com : Visible Sound The Exploratorium's Kenn Finn shows how the museum's "Oscylinderscope" works: An oversized "guitar" with extra-long nylon strings is set up in front of a spinning drum that has alternating bands of black and white. As the drum spins, you can actually see the vibrating strings' waveforms against the moving stripes. Pluck the strings closer to their middles and you get nice, round sine waves; pluck them closer to the guitar's bridge and you get sharper saw-tooth waves that correspond to the harsher sound.

Photo: Jim Merithew/Wired.com : Never Needs Winding At the offices of the Long Now Foundation , visitors check out some of the foundation's recent work. The foundation is designing and building a clock intended to run for 10,000 years -- an engineering challenge that requires designers to anticipate problems like the accumulation of dust and the fact that ball bearings will freeze up if they sit for long periods without moving. In the middle of this picture is a mechanical orrery -- a kind of planetarium -- designed to show the current positions of the six planets visible to the naked eye.

Photo: Jim Merithew/Wired.com : Mechanical Binary Computing The mechanism of the Long Now Foundation's orrery lies underneath the model planets. It consists of a stacked set of geared wheels. The rotation of each wheel corresponds to the rotation of one of the planets in the orrery above.

The orrery's mechanism is a binary mechanical computer with 28 digits of precision for calculating each planetary period. The wheels and levers of each layer comprise a mechanical code for calculating the rotational speed of each planet (for example, 224.68 Earth days for Venus, 11.862 Earth years for Jupiter). The gear-and-lever design of the orrery resembles that of Charles Babbage's Difference Engine No.

2 , although the Difference Engine operates on decimal (base 10) numbers instead of binary (base 2). Photo: Jim Merithew/Wired.com : Equation of Time Some early clockmakers used a kidney-shaped cam to convert between clock time and solar time. That's because the Earth does not revolve around the sun at a constant speed, so solar noon (when the sun is at its highest point) varies from clock noon by as much as several minutes, depending on what time of year it is.

The shape of these cams was governed by something known as the equation of time . The Long Now Foundation's clock uses an equation of time, too, because it resets itself daily based on local solar noon, ensuring continued accuracy over the millennia it will be working. However, the Earth's orbit varies slightly from year to year.

For a clock that's expected to run for 10,000 years, those differences mean that a single cam would be reasonably accurate only for a relatively short time (just a few hundred years at most). To overcome that problem, the clock's designers came up with a three-dimensional cam, whose cross-section gradually changes shape along its vertical axis. This complex, compact shape enables the clock to compute the difference between solar time and clock time for every day over a period of 12 millennia (there's a grace period of 1,000 years on either end of the cam's expected useful life).

The numbers along the cam correspond to years (02000, at the bottom, is the year 2000). The Long Now's Equation of Time cam is available in the foundation's gift shop for $500. Photo: Jim Merithew/Wired.com : Torpedo Targeting Volunteer docent Richard Pekelney shows off the torpedo data computer (TDC) aboard the U.S.S.

Pampanito , a World War II-era diesel submarine docked on San Francisco's waterfront. The TDC was built in 1943. It was -- and may still be -- the most-sophisticated mechanical computer ever made.

It used a combination of clockworks, electric motors, dials and levers to compute the angles at which torpedoes should be launched in order to hit their targets. Torpedo targeting wasn't the only computation-intensive problem at the time. High-powered naval guns developed in the early 20th century proved difficult to aim, because of their long trajectories, the effects of wind and even the Earth's rotation.

As a result, research into mechanical and electronic computing proceeded hand-in-hand with weapons research throughout the 1930s and 1940s. "Most of what we consider early computing was driven by the need to aim these long guns," says Pekelney. Photo: Jim Merithew/Wired.com : Stay on Target The Pampanito 's torpedo computer was hand-built in the 1940s in New York, primarily by Jewish émigrés from Germany, says Pekelney.

Left: One of the stops on the tour is San Francisco's hands-on museum, the Exploratorium . During the tour, volunteer docents will point out exhibits that are particularly interesting to the mechanically minded. Here, kids pedal to generate electrical power in an exhibit built by museum founder Frank Oppenheimer.

The generator is mounted on an early 20th-century cast iron lathe. Photo: Jim Merithew/Wired.com : Caution: 2,000-Degree Sparks The Exploratorium's "Catch a Falling Spark" exhibit gives visitors a chance to turn a hand-cranked grinding wheel, spinning it against a thick piece of twisted steel cable to generate white-hot sparks and a distinct odor of burnt clutch. Although the sparks are 2000 degrees Fahrenheit, they're so small that it's safe to let them bounce off your bare hand.

Photo: Jim Merithew/Wired.com : Loop Dreams The Exploratorium's "Rope Squirter" is a simple powered flywheel that throws a loop of rope into the air, forming an appealing curve of string that you can play with. The museum's "head explainer" Ken Finn says he took this exhibit to a meeting of the American Geophysical Union, where it sparked a controversy about whether the shape of the rope's arc is parabolic or not. Of course, the exhibit is equally appealing to children, making it a good vehicle for stimulating mechanical imagination in young and old alike.

"My six-year-old can enjoy it and I can watch geophysicists argue about it," says Finn. Photo: Jim Merithew/Wired.com : Visible Sound The Exploratorium's Kenn Finn shows how the museum's "Oscylinderscope" works: An oversized "guitar" with extra-long nylon strings is set up in front of a spinning drum that has alternating bands of black and white. As the drum spins, you can actually see the vibrating strings' waveforms against the moving stripes.

Pluck the strings closer to their middles and you get nice, round sine waves; pluck them closer to the guitar's bridge and you get sharper saw-tooth waves that correspond to the harsher sound. Photo: Jim Merithew/Wired.com : Never Needs Winding At the offices of the Long Now Foundation , visitors check out some of the foundation's recent work. The foundation is designing and building a clock intended to run for 10,000 years -- an engineering challenge that requires designers to anticipate problems like the accumulation of dust and the fact that ball bearings will freeze up if they sit for long periods without moving.

In the middle of this picture is a mechanical orrery -- a kind of planetarium -- designed to show the current positions of the six planets visible to the naked eye. Photo: Jim Merithew/Wired.com : Mechanical Binary Computing The mechanism of the Long Now Foundation's orrery lies underneath the model planets. It consists of a stacked set of geared wheels.

The rotation of each wheel corresponds to the rotation of one of the planets in the orrery above. The orrery's mechanism is a binary mechanical computer with 28 digits of precision for calculating each planetary period. The wheels and levers of each layer comprise a mechanical code for calculating the rotational speed of each planet (for example, 224.68 Earth days for Venus, 11.862 Earth years for Jupiter).

The gear-and-lever design of the orrery resembles that of Charles Babbage's Difference Engine No. 2 , although the Difference Engine operates on decimal (base 10) numbers instead of binary (base 2). Photo: Jim Merithew/Wired.com : Equation of Time Some early clockmakers used a kidney-shaped cam to convert between clock time and solar time.

That's because the Earth does not revolve around the sun at a constant speed, so solar noon (when the sun is at its highest point) varies from clock noon by as much as several minutes, depending on what time of year it is. The shape of these cams was governed by something known as the equation of time . The Long Now Foundation's clock uses an equation of time, too, because it resets itself daily based on local solar noon, ensuring continued accuracy over the millennia it will be working.

However, the Earth's orbit varies slightly from year to year. For a clock that's expected to run for 10,000 years, those differences mean that a single cam would be reasonably accurate only for a relatively short time (just a few hundred years at most). To overcome that problem, the clock's designers came up with a three-dimensional cam, whose cross-section gradually changes shape along its vertical axis.

This complex, compact shape enables the clock to compute the difference between solar time and clock time for every day over a period of 12 millennia (there's a grace period of 1,000 years on either end of the cam's expected useful life). The numbers along the cam correspond to years (02000, at the bottom, is the year 2000). The Long Now's Equation of Time cam is available in the foundation's gift shop for $500.

Photo: Jim Merithew/Wired.com : Torpedo Targeting Volunteer docent Richard Pekelney shows off the torpedo data computer (TDC) aboard the U.S.S. Pampanito , a World War II-era diesel submarine docked on San Francisco's waterfront. The TDC was built in 1943.

It was -- and may still be -- the most-sophisticated mechanical computer ever made. It used a combination of clockworks, electric motors, dials and levers to compute the angles at which torpedoes should be launched in order to hit their targets. Torpedo targeting wasn't the only computation-intensive problem at the time.

High-powered naval guns developed in the early 20th century proved difficult to aim, because of their long trajectories, the effects of wind and even the Earth's rotation. As a result, research into mechanical and electronic computing proceeded hand-in-hand with weapons research throughout the 1930s and 1940s. "Most of what we consider early computing was driven by the need to aim these long guns," says Pekelney.

Photo: Jim Merithew/Wired.com : Stay on Target The Pampanito 's torpedo computer was hand-built in the 1940s in New York, primarily by Jewish émigrés from Germany, says Pekelney. "What you've got here is the precision of a fine Swiss watch," says Pekelney. In order to perform its calculations, the TDC incorporated data about the sub's location, bearing and speed as well as those of the target ship.

The computation involved multiple differential equations, integrations and mathematical operations. The TDC resides in the Pamapanito 's conning tower, an area of the sub usually off-limits to visitors. However, it will be open to Mechanicrawl visitors on July 12.

For people interested in how the targeting computer worked, the complete TDC manual is available online. Archivists have also digitized rare audio recordings of a successful torpedo attack utilizing a TDC. Photo: Jim Merithew/Wired.com : Torpedo Tube World War II-era torpedoes could make a single turn, shortly after being fired from the sub, so the TDC computed the radius of that turn, then transmitted the setting to the torpedo by means of a remote servo before the torpedo launched.

The servo controlled a small rod, which extended into the torpedo tube and connected with a mechanical linkage on the torpedo itself. This image shows a close-up of the hatch on the back of a torpedo tube. The painted-on flag represents a Japanese ship sunk by a torpedo fired from that tube.

According to Pekelney, submarines were among the most dangerous places to work during World War II, but also were one of the war's most effective weapons. Submariners represented less than two percent of the fleet's personnel, but they were responsible for more than half of enemy ships sunk by the Navy. Photo: Jim Merithew/Wired.com : Three-Cylinder Steam Engine In the berth next to the Pamapanito floats the S.

S. Jeremiah O'Brien , a World War II Liberty ship. This vast cargo ship has been restored to working order and the O'Brien now makes occasional fundraising cruises in the San Francisco Bay.

The O'Brien , like other Liberty ships, is powered by an enormous three-cylinder steam engine. It was designed to be very simple to build and very reliable. This photo shows the engine's three cylinder heads.

High-pressure, superheated steam enters the smallest cylinder on the right, then passes to a larger, lower-pressure cylinder in the middle, and finally goes to the largest, lowest-pressure cylinder on the left. This design, known as a triple expansion steam engine design, enables the engine to capture as much of the steam's energy as possible. At cruising speed, the engine spins at just 76 RPM, pushing the metal hulk through the water at 7 knots.

Although the ship will remain docked, the engine will be running during the Mechanicrawl event July 12. Photo: Jim Merithew/Wired.com : Wrench Collection At least 2,715 Liberty ships were built; only a few survive. The Jeremiah O'Brien was restored in the 1970s but, says the Long Now Foundation's Alexander Rose, many of the people who restored the ship are no longer living.

Rose hopes that the Mechanicrawl will inspire a new generation to begin restoring and caring for mechanical treasures like the O'Brien . "The steampunk crowd, they go all the way to the point of dressing up in period clothing and restoring old steam engines. It would be really awesome if they'd help the Jeremiah O'Brien maintain its steam engine," says Rose.

Plus, then they'd get to play with cool tools, like these enormous wrenches in the Jeremiah O'Brien's engine room. Photo: Jim Merithew/Wired.com. Fri Jun 2008 02:06 (6 months, 3 weeks ago)