XB-45 Tornado prototype 45-59479 on test from Muroc AFB in 1948.

The second XB-45, 45-59480, over California on test from Muroc AFB during the summer of 1948. The B-45 was America’s first four-jet bomber to fly, the prototype making its first flight on March 17, 1947.

Close-up of a B-45A's engine pod, showing the neatly cowled J47 turbojets.

The B-45 first prototype, XB-45 45-59479 seen during a speed calibration run at Muroc Dry Lake, California in February 1948. The large tailplane dihedral allowed adequate clearance for the efflux of the four 4,000lb-thrust General Electric turbojets.

Close-up of B-45 fitted with later multi-framed cockpit canopy and reinforced nose glazing. The earlier Plexiglas canopies invariably suffered from cracking and even blew out completely at high altitude.

B-45s were fitted with upwards-sliding bomb doors. The B-45A could carry up to 10 tons of bombs and had a maximum combat radius of 800 miles.