Building one of the most advanced jet fighters in the world is a challenge for any aerospace company - but the one thing you might think you do not have to worry about when you start such a job is the gravitational pull of the moon.
But that is exactly the challenge faced by workers at BAE Systems on the Lancashire coast every time the Typhoon build process begins – because the moon's gravitational pull actually causes the ground to move beneath their feet.
So fine are the tolerances now used to build the Typhoon that even the movements of the tide could throw the jet fighter tolerances out. Martin Topping, Typhoon final assembly operations manager, explains: “Every time the moon pulls the tide in and out, the ground under our feet actually moves by between one and two millimetres. That might not sound a lot but, given the tolerances we are working to on Typhoon, two millimetres is two millimetres too much.”
To get around the problem, BAE Systems has spent over £2.5million putting in special automated alignment facilities that use laser trackers and computer-automated jacks. But what really ensures that each Typhoon’s airframe is built as close to perfection as is humanly possible are the giant ‘floating’ concrete rafts on which the aircraft and measuring equipment sit.
Martin Topping says: “Each of these concrete rafts is over three metres deep and 18 metres long. All nine automated jacks and both laser trackers are positioned on one surface, ensuring all movement is relative and achieving near-perfect alignment whatever the moon may be doing.”
The result is one of the most perfectly aligned fast jet airframes in the world. Although 15 metres long from tip to tip, every Typhoon that leave BAE Systems in Warton varies from true no more than the thickness of a match stick - and that helps its ‘fly by wire’ computer system accurately control the aircraft, which is designed to be unstable but hugely agile.
Because of this build accuracy there is minimal need to ‘trim’ the flying surfaces and pilots can fly the fighter to its maximum potential. On a typical sortie, this build precision will save enough fuel to fill up an average family car (60 litres). The advanced manufacturing technology pioneered on the Typhoon is now also being used on the F-35 Lightning II. The F-35 Lightning II will be the world's first and only stealthy, supersonic, multi-role fighter.
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