Grumman TBM Avenger
The Avenger was the heaviest single engine aircraft of WW2. It might have been a more effective torpedo bomber had the Navy's torpedoes been working properly. Unfortunately, peacetime penny-pinching had resulted in torpedoes that were essentially untested and failed to explode as advertised. This problem dogged both submariners and Avenger pilots for the first half of the war in the Pacific until it was sorted out. Until it was, most Avengers were shooting blanks.
Cool stuff for Avenger lovers:
The excellent Squadron Signal book, TBF/TBM Avenger - Walk Around No. 25, offers a detailed look at the TBM which model builders and artists are sure to appreciate.