Britain is Flying World's Most Powerful Two of the Sapphire jets installed in a Gloster Meteor 8 fighter. Performance details of the engine are still secret. Compressing the power of four Super-Fortress engines in its 2,500 pounds bulk, the Armstrong Siddeley Sapphire has been disclosed as the world's most powerful jet. The Sapphire Just secret list, has another achievement to its credit - its designers have in a large measure, countered the high fuel consumption that was the drawback of earlier