Amstrong Whitworth 45. Some proportionally large engine pods/nacelles. AW dwg AW92438, dated 23/10/39. Pair of Rolls Royce Merlins. One notable feature is several rows of large "recessed louvres in skin for exit of cooling air" at rear of fuselage, ahead of the vertical fin. The air enters fuselage via ducts at leading edge of wing, inboard of engines, and is routed inward to fuselage.