Stoney,
This is a fix that I have used when fiddling with other Torpedo planes that have results, similar to yours. Not sure what Torpedo you're using, but it's been my experience that the Torpedo's DP file is usually the cause of the "dud" problem. Go to your OBJECTS_DP folder, then make a copy of the Torpedo's original DP file for safe keeping. Open the Torpedo's original DP file with a text editor like Notebook, and look for the following entry:
[MISC_DATA]
unit_family=4
category=37
max_weight=540
weapon_type=9
The "dud" problem seems to be generated by the bottom entry, weapon_type=9. The fix that works for me, is to change that bottom entry to weapon_type=10, so that the entry now looks like this:
[MISC_DATA]
unit_family=4
category=37
max_weight=540
weapon_type=10
Save the edited DP file, and delete your plane's CDP file in your aircraft folder [CFS2 will automatically make a new one]. To test this out, fire up your TDB in free flight, load up your edited torpedo and go to Lae, where there is a merchant ship sitting at anchor in the stock scenery. Take off, fly out a few miles, turn to port, and you should be more or less lined up for a torpedo attack run on the merchant ship. If the edited torpedo DP is working, the ship will explode but not sink, and CFS2 will register a hit. Again, I'm not sure what torpedo you use, but when I have a "dud" torpedo problem, it's been the torpedo's DP that was the culprit. Hope this helps, and happy hunting.
AER_DaddyO
"Don't just stand there... get one up!"