It will feature six wind turbines with a maximum height of 64 metres and a maximum blade diameter of 71 metres.

BBC: ?22m Tyrone wind farm 'to bring 20 jobs'

Driven by a six-blade mahogany fan (see top picture) with a diameter of 9.1m, the tunnel was used to test full-sized aircraft prototypes like the Spitfire.

BBC: NEWS | UK | Magazine | Concrete steeped in history