1894, EARL’S COURT LONDON GIGANTIC WHEEL, 94 M.
London wanted to build an even bigger when than that of Ferris in Chicago, the Earl’s Court Gigantic Wheel, 94 m tall, called in wikipedia called “Great Wheel”.
The Ferris wheel was stall, but also incredibly heavy. To build an even bigger wheel at Earl’s Court in London, engineers had to find a new way to drive its massive frame around. So in 1894 the british engineers capitalized the tremendous success of Ferris wheel; Just one years after the Chicago wheel. London now plans plan to build its own wheel.
The engineer in charge is the ex-naval engineer Walter Basset. He want to build a 94 m high wheel. Calling it the Gigantic Wheel, 94 meters high, It will be much heavier than that of Ferris.
The problem is how to drive it. With such a heavy structure you can’t simply drive the wheel from the hub. If you do this, you put pressure on the steel spokes, stretching them and eventually making them to break (just as the video shows with a small model).
Bassett so decided to drive the wheel instead from the rim, to reduce stress on the spokes; but coupling engine to the rim isn’t easy. Having spent many years in the Navy, Bassett came to a simple solution: to use anchor chains, that are strong and cheap and can be driven using special winches called capstan to pull the chain.
So Bassett decided to use this technology to drive his Earl’s Court wheel. He loops two 300 meters long chains around the rim; the chains then run underground where 5 tons weights hold them tight.
Two steam engines turn the capstans that pull the chains. These drive this rim without putting strain on the spokes
When it opens in 1895, the Gigantic Wheel in Earl’s Court is one of the tallest structures of any kind in London. It’s an instant landmark, a symbol of british engineering superiority.
But its success was short. Just after few days after the opening, one of the weights that keeps the chains tight went loose. The chain turned slack and jammed between the rim and one of the carriages.
One evening ten months later, the wheel brakes down again. Butthis time around seventy people are stuck in the cars and there is no way of getting them down. Two ex sailors climbed the frames to get food and beverages to the stranded passengers
Eventually, 15 hours after the wheel jammed, engineers managed to get the wheel work again and bring the passengers safely to the ground.
It’s a public relations disaster, but Bassett it’s on the way to turn this adversity into an opportunity. He give every passenger who’s been stuck on the wheel a five pound note (a great amount for those days); word of his generosity soon spreads and the day after thousands of people went again on the wheel hoping it would stuck again to get the note.
Bassett’s idea to drive the wheel from the rim created a new model still used today in the biggest sky wheels in the world, such as Singapore Flyer.
But Singapore Flyer is 70 meters higher than Earl’s Court Wheel so engineer would have to rub around the rim half a kilometer of chain that eventually would become so heavy that would break under its own weight. So engineers came to an elegant solution; using the strong grip of rubber wheels to slowly drive the rim around. They took solid rubber tires, of the kind used on forklifts, and positioned them on a special rail on the rim, so slowly driving it around.