Light fighter in 1938 and remained in production throughout the war. The empty weight of the Battle of Britain-era Spitfire IIA was 2,142 kg (4,723 lb), increasing to 2,984 kg (6,578 lb) in a later variant. It was highly maneuverable and was generally a match for its German opponents. Most Spitfires had a Rolls Royce Merlin engine, but later variants used one of the most powerful engines of the war – the Rolls Royce Griffon. The Spitfire was produced and improved throughout the war but was complex to build and had limited range. In other respects it was considered an outstanding fighter.
General Electric/Rolls-Royce F136 program. This marked the first complete engine assembled following US Government validation of the F136 design in 2008. The milestone was achieved one month ahead of schedule. Citing the Weapon Systems Acquisition Reform Act of 2009, the GE Rolls-Royce Fighter Engine Team submitted an unsolicited fixed-price offer for the F136 to the Pentagon on 28 September 2009. The fixed-price approach would cover initial F136 engine production, beginning with the F136 second production lot. According to the GE Rolls-Royce Fighter Engine Team, the proposal would shift significant cost risk from taxpayers to the Fighter Engine Team until head-to-head competition begins between