Avro Lincoln
The Avro Type 694 Lincoln is a British four-engined heavy bomber, which first flew on 9 June 1944. Developed from the Avro Lancaster, the first Lincoln variants were initially known as the Lancaster IV and V; these were renamed Lincoln I and II. It was the last piston-engined bomber operated by the Royal Air Force (RAF); the later Avro Shackleton, though piston-engined, served in maritime patrol rather than bomber roles.