The test team views the use of a pulley as an intermediate step only, and has planned to shift to a reliance on windlasses like those that apparently were used to hoist sails on Egyptian ships.
"The whole approach has been to downgrade the technology," Gharib said. "We first wanted to show that a kite could raise a huge weight at all. Now that we're raising larger and larger stones, we're also preparing to replace the steel scaffolding with wooden poles and the steel pulleys with wooden pulleys like the ones they may have used on Egyptian ships."
For Gharib, the idea of accomplishing heavy tasks with limited manpower is appealing from an engineer's standpoint because it makes more logistical sense.
"You can imagine how hard it is to coordinate the activities of hundreds if not thousands of laborers to accomplish an intricate task," said Gharib. "It's one thing to send thousands of soldiers to attack another army on a battlefield. But an engineering project requires everything to be put precisely into place.
"I prefer to think of the technology as simple, with relatively few people involved," he explained.
Gharib and Graff came up with a way of building a simple structure around the obelisk, with a pulley system mounted in front of the stone. That way, the base of the obelisk would drag on the ground for a few feet as the kite lifted the stone, and the stone would be quite stable once it was pulled upright into a vertical position. If the obelisk were raised with the base as a pivot, the stone would tend to swing past the vertical position and fall the other way.
The top of the obelisk is tied with ropes threaded through the pulleys and attached to the kite. The operation is guided by a couple of workers using ropes attached to the pulleys.
No one has found any evidence that the ancient Egyptians moved stones or any other objects with kites and pulleys. But Clemmons has found some tantalizing hints that the project is on the right track. On a building frieze in a Cairo museum, there is a wing pattern in bas-relief that does not resemble any living bird. Directly below are several men standing near vertical objects that could be ropes.
Gharib's interest in the project is mainly to demonstrate that the technique may be viable.
"We're not Egyptologists," he said. "We're mainly interested in determining whether there is a possibility that the Egyptians were aware of wind power, and whether they used it to make their lives better."
Now that Gharib and his team have successfully raised the four-ton concrete obelisk, they plan to further test the approach using a ten-ton stone, and perhaps an even heavier one after that. Eventually they hope to obtain permission to try using their technique to raise one of the obelisks that still lie in an Egyptian quarry.
"In fact, we may not even need a kite. It could be we can get along with just a drag chute," Gharib said.
An important question is: Was there enough wind in Egypt for a kite or a drag chute to fly? Probably so, as steady winds of up to 30 miles per hour are not unusual in the areas where pyramids and obelisks were found.
(c) 2001 Caltech
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