Supermarine Spitfire Mk XVIII

The Mk 18 was never meant to be a new aeroplane. It kept the Griffon 65 and the cockpit improvements of its predecessor and differed in two respects that mattered to anyone flying it a long way from home: a revised, stronger wing structure and extra fuel, which addressed precisely the shortcoming Jeffrey Quill had identified in the Mk XIV. Its handling was so close to the earlier mark that it was never put through a performance trials programme of its own.

Production ended in early 1946 with some 300 aircraft between the F and FR versions. By then the war was over and the RAF was standing squadrons down, so the type waited a year in store: not until January 1947 did 60 Squadron, based at RAF Seletar in Singapore, re-equip with it. Other Far East and Middle East units followed.

The Mk 18's operational career was quiet. Its only notable combat work came in the Malayan Emergency, flying ground-attack sorties against communist guerrillas, a task in which the speed and ceiling of an air-superiority fighter counted for little. In 1947 the Royal Indian Air Force bought twenty ex-RAF examples.

Sitting between the Mk XIV, which earned its reputation in combat, and the F.21 and its successors, which introduced an entirely new wing, the Mk 18 is the least known link in the Griffon branch. It nevertheless marks the point at which the classic Spitfire airframe reached its most mature form before Supermarine replaced it with something else.