Emerging from extensive development and modifications as the Series la, the Handley-Page Halifax II, one of England's trio of four-engine heavy bombers, has gained approximately 10 percent in both maximum and cruising speed. Thus, on the basis of previously claimed top speed of 285 mph, the Series la today can do in the neighborhood of 315 mph.
This added efficiency has been achieved by a combination of engine change and extensive modifications to the fuselage and armament. Early Halifaxes were powered by Rolls-Royce Merlin 20s which, in one stage of the transformation, were replaced by Merlin 22s and much more efficient exhaust stacks that added to speed.
Most noticeable fuselage change is the new nose, which looks very much like the type employed on late model Boeing B-17 Flying Fortresses. The original Halifax nose, it will be recalled, had a tight belt-in-the-middle profile due to installation of a two-gun power turret above the bombardier's compartment. Operational experience, however, proved that head-on attacks were rare, so the power turret, was replaced by smoother-contoured nose with horizontal transparent strips just above and below the center line and a large rounded transparent section below.
This arrangement, however, afforded no provision for gun installation so it, in turn, was succeeded by the present B-17-type nose in which is mounted a hand-operated Vickers K gun.
Another important armament change has been made in the top fuselage turret. Originally the Halifax mounted a two-gun turret similar to that installed in the Lockheed Hudson, but during the transformation this was replaced by a four-gun turret of. the type installed in the Boulton Paul Defiant. In addition to the added fire power, the Boulton Paul turret is said to contribute materially to the Series la's greater speed, since it sits much lower in the fuselage.
This article was originally printed in the September, 1943, issue of Aviation magazine, vol 42, no 9, p 232.
The original article includes 3 photos: