Rails, trolleys, and the catapult bottleneck

The compressed-air catapults were designed to accelerate a two-and-a-half-ton fighter to about 140 kilometres per hour or a five-ton bomber to about 130. Aircraft were to reach them on collapsible trolleys running through a rail system, then have their trolleys recovered and recycled below deck. Rolling takeoffs were reserved for emergencies and would have forced aircraft to sacrifice fuel or ammunition. The catapults could theoretically launch eighteen aircraft at thirty-second intervals, but emptying the compressed-air reservoirs meant a fifty-minute recharge. Since normal takeoffs were expected to use the catapults, reserving enough capacity for a replacement combat air patrol would compete directly with launching a full strike. The launch rate therefore concealed a serious question about how the carrier would sustain repeated air operations during an attack.