Eleanor Harris: An Eye On British Airways i360

Unique Engineering

This week we released a fascinating film about how the tower was built on YouTube. It therefore seems a good time to talk about the engineering behind the tower. The i360 is a real feat of engineering and its design is a world-first.
Most people imagine the i360 must be a lift. Actually, the two things couldn’t be more different. A lift is a hugely energy-expensive mechanism that uses electricity to raise and lower its passengers in the lift cabin. The i360 is the world’s first ‘Vertical Cable Car’: it uses gravity and a giant 70 tonne counterweight inside the tower to manage its load. When the pod goes up, the counterweight goes down; so when the pod is at the bottom, the counterweight is at the top.

The counterweight weighs slightly less than the empty pod and this makes it very energy efficient, because the motor is only ever lifting the difference between the pod and the counterweight, never the whole weight of the pod. It also means that the i360 can never get stuck (thank goodness!). If we lose all power then we will use gravity and the brakes to bring the pod back down to ground safely.
Another unique aspect of the design, is the fact that the i360 has been designed to allow you to walk around the pod to enjoy the view from different angles unlike all the other ‘moving observation towers’ such as the Weymouth Eye where you are required to sit down. It is even perfectly safe for all the guests to stand on the same side of the pod at the same time if they really want to!
Its incredibly slender design is only 4.5m in diameter, 3.9m if you remove the cladding. It has a “slenderness ratio” of 1:40, which is quite remarkable making it the slimmest tall tower ever built. The Shard, for instance, has a ratio of 1:6.
With the i360, Brighton is not just getting an attraction that will help it compete as a tourist destination – it is getting innovation on an international scale, a true engineering one-off.
Twitter: @TheBrightoni360 @Eleanor_Harris, Facebook: Brighton-i360, Pinterest: Brightoni360, www.brightoni360.co.uk
YouTube channel: Brighton i360