Only time I've EVER got a torpedo run to work as expected was in the Pearl Harbour arena, with ack-dialed WAY down.... (and the yanks forced to wait for 1st attack)
Torpedoes are useless and a complete waste of time anywhere besides scenarios/events
Get either JU88s or KI67s. Formation. Locate fleet, fly parallel to its course outside of AA range (as low as possible). Get several miles ahead of it, make a big 180 degree turn directly into the path of the carrier. If you are in the JU88s, pop your dive brakes. If you are in the KI67s, just pull the throttles back. You want to be about 10mph below max drop speed. Line up on the bow of the carrier (you can actually get in your bombsight, go into calibration mode, raise up the crosshairs [careful not to move them left or right, just up], and then use rudder to steer your plane). As soon as the first AA tracer goes by you, drop the torpedos. If the 5 inch guns are manned, you will need to drop from further out. They will decimate your formation. Blam! It's off to Davy Jones Locker for the CV.