The Valiant had a shoulder-mounted wing and four Rolls-Royce Avon RA.3 turbojet engines, each providing up to of thrust, installed in pairs in fireproof bays in each wing root. The design of the Valiant gave an overall impression of a clean aircraft with swept-wing aerodynamics. George Edwards described the Valiant appropriately and simply as an "unfunny" aircraft. The root chord thickness ratio of 12% allowed the Avon engines to be within the wing rather than on pods as in the contemporary Boeing B-47. This "buried engine" installation contributed to the aircraft's aerodynamic cleanness, and was British practice at the time. It made engine access for maintenance and repair difficult and increased the risk that an uncontained failure of one engine would cause damage to the adjacent engine; it also increased the complexity of the design of the main spar which had to be routed around the engines.