Was the C-69 Constellation transport faster than a Zero fighter?

The Constellation was born as a long-range commercial aircraft ordered by TWA and Pan American, but after the attack on Pearl Harbor the US government took over Lockheed's production lines. The L-049 model was renamed C-69 and assigned to transporting personnel and materiel for the Army Air Forces. The prototype, painted olive green and gray but carrying the civilian registration NX25600, left the workshop in December 1942 and flew for the first time on January 9, 1943.

Sources agree that the C-69 could reach a top speed higher than that of the Mitsubishi A6M Zero, the carrier-based fighter that symbolized Japanese aviation in the Pacific. The Spanish-language encyclopedia gives the exact figures: a top speed of over 600 km/h, a cruising speed of 550 km/h (340 miles per hour, as it was measured at the time), and a service ceiling of 24,000 feet, about 7,300 m. For a four-engine passenger aircraft with a pressurized cabin, this was an exceptional performance, the result of a wing very similar to that of the P-38 Lightning fighter, though on a larger scale, and of the Wright R-3350 Duplex-Cyclone engines.

The comparison does not mean the C-69 could be a match for a fighter: the Zero was far more agile and was armed, while Lockheed's transport carried no weapons. What the figure shows is just how far ahead of its time the Constellation's design was. Its engines, moreover, caused plenty of problems: after the crash of an XB-29 that also used the R-3350, every aircraft with that engine was grounded until the investigation concluded. By the end of the war only 22 C-69s had been built.