Considerable development problems, largely associated with the original J40 engines, had delayed the introduction of the Skywarrior until 31 March 1956. The A-3 was, by far, the largest and heaviest aircraft ever designed for routine use on an aircraft carrier, though ironically it was the smallest proposal among other proposals that could only be deployed on even larger carriers not yet in service. As had been predicted by Heinemann early on, the Skywarrior had been designed to carry larger and bulkier bombs than it ever would in service due to the rapid improvements made in weapons technology. Despite this, at the Navy's insistence, the aircraft was qualified for an 'overload' payload capacity of , the testing of which would establish a weight-related record for carrier operations. Because of its cumbersome size, and less-than-slender profile, it was nicknamed "The Whale".