The Douglas TBD was designed to carry several different loads under its fuselage and had a stores bay to accommodate some of them.
- Mk 13 torpedo
- Mk 7 torpedo
- Two or three 500-lb bombs
- One 1000-lb bomb
There were three bomb racks, two forward on the belly and one aft, located at the roof of the stores bay, which was also the floor of the gunner's compartment.
There were several different panels that closed off some or all of the stores bay depending on what was being carried. Originally, there also fairings provided between some of the stores and the belly to reduce drag.
In this picture, all the close-out belly panels are installed.
The 500-bombs were mounted directly on the bomb racks.
A panel with an opening was provided when the aft 500-lb bomb was carried.
The 1,000-lb bomb and the torpedoes were attached using straps between the two forward bomb racks.
Like the torpedoes, the 1,000-lb bomb protruded into the stores well and specific panels were provided for its installation.
In addition to the various belly panels, ballast weights were provided to be loaded on the aft bomb rack depending on the loading configuration. For example, ferry flights with no crew other than the pilot and no armament required that the maximum ballast of 500 lbs be loaded on the aft bomb rack.
In addition to the bomb/torpedo loading options under the fuselage, panels were provided that could be mounted on the wings outboard of the landing gear and inboard of the wing fold on which several small bombs could be carried.
For a comprehensive description of the Douglas TBD Devastator, obtain the following monograph from Amazon.com or directly from Steve Ginter (http://www.ginterbooks.com/NAVAL/NAVAL.htm)