Wind Wagons

Stumbling around the web this week, seeking a respitefrom terrorists and exploding fertilizer plants and rising floodwaters, I came across an article on Harper's about Peppard's Folly. Back in 1860, 26 year-old millwright Samuel Peppard built a prototype wind wagon. No images of his craft survive, but it was a rather narrowfour-wheeled cart with a seven-foot mast and a canvas sail. He and some friends set out from Oskaloosa, Oklahoma on May 9th, making it 500 miles before a small tornado destroyed the craft just short of Denver. Eventually, Sam gave up on gold mining, served in the Union Army, got married, and settled down back in Oskaloosa.

He wasn't the only land sailor, either -- a number of others gave it a shot over the years, trying to sell their creations to the military or to investors for moving freight. I imagine it made more sense when the prairies were literally an inland, grassy sea, uncut by rails, roads, or fences. Reports from antiquity claim the Chinese had similar contraptions for crossing their vast western lands. Here in America, the utility of windwagons was somewhat limited by the prevailing winds -- west-to-east -- which were generally contrary to the desired direction of travel. 


Windwagon, via the Kansas Historical Society

Today, folks have taken to racing land yachts. Modern land use and development has restricted the geographic possibilities to dry lake beds, old airport runways, beaches, and deserts. The landspeed record is held by the Greenbird, which looks like a spaceship with a wing growing out of its roof. This airfoil sail is rigid, steerable, and can generate a lot more force than a cloth sail, especially with indirect wind. 

The Greenbird can move 3-5 times the speed of the propelling wind, due to extreme aerodynamic efficiency. Unlike a boat, which has overwhelming hydrodynamic drag on the hull, a land yacht is relatively unrestrained. However, that same hydrodynamic drag also keeps the boat firmly entrenched in the water. Land yachts are frighteningly prone to overturning -- they are very lightweight, top-heavy, and wind can get under the body, pushing up. 

Other modern sailors have looked to the past as inspiration, re-creating the old wind wagon designs with new hardware. An intrepid Swedish crew built the Astrakan and took it to Burning Man last year, getting up to considerable speed under sail on the playa. It's much bigger than Peppard's machine, with two masts and four sails. 

The Evonik Wind Explorer crossed Australia on a combination of wind and electric power, using a stowable kite to take advantage of tailwinds. The kite is an intriguing third way (instead of sail or airfoil), as it is easier to take advantage of asymmetric winds. On the other hand, it is only useful in ares without power lines, trees, or other line-fouling obstacles. When parked, the Evonik put up a portable wind turbine to charge its batteries. The mast setup seemed rather complicated and impractical, but it is a demonstration project. 

A simpler alternative is the Whike, a three-wheeled recumbent bike with a small plastic sail. Designed by the bike-crazy Dutch, it takes advantage of wind-whipped lowlands by the sea. The sail can fold down if headed directly into the wind, and the pedals make for a viable hybrid power source.

Another Dutchman,Theo Jansen, has been building wind-powered walking sculptures for years. He calls his creations Strandbeests (beach beasts), as they rely on strong shoreline wind. Each is a complicated mechanism, made of off-the-shelf PVC pipe parts, that produces a remarkably animal-like walking motion. He's been at this since 1990, and has built hundreds of machines. The latest prototypes use soda bottles and inflatable bladders to store potential energy and keep the beasts in motion after the wind has died. He explains his work in his own words below:

I don't know that all these wind machines are practical, but they are inspiring, evoking a sort of freedom that is hard to imagine when I'm hunkered down on my bike, being punished by the Chicago wind on the lakeshore path. Maybe one day I'll have a chance to try one out. Or build one . . .