In civil aviation it is mainly to achieve fuel benefits, but in other fields it can help increase manoeuvrability or an aircraft's load-bearing capacity.

ECONOMIST: MONITOR

This added manoeuvrability means that they can be aimed to destroy an incoming Scud by hitting it at high speed, rather than exploding nearby.

ECONOMIST: Military technology

They move backwards to give greater manoeuvrability at speed.

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As a result of limitations like these, he said, the Japanese craft Kaiko had limited manoeuvrability and needed a custom-built ship for spooling out the reams of heavy cable required to attach it to the ship.

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