PBJ-1 with APS-3 radar in the starboard wingtip
In the early stages of radar integration into B-25 bombers, both the U.S. Army Air Forces (AAF) and the U.S. Navy took parallel paths, though with some differences in operational focus and implementation.
Radar Integration in B-25 Models
- The Marines outfitted nearly all their PBJ (the Navy designation for the B-25) variants with sea-search radar sets. Initially, these systems used nose- and wing-mounted Yagi antennas. During the 1943-44 period in the Pacific, the 341st Bomb Group employed this radar for “bombing through overcast” (BTO) missions.
- These early radar sets, which operated on lower frequencies, were eventually replaced by centimetric (microwave) radar systems. The new systems required only an enclosed fairing to protect the scanner, which was less obtrusive and more efficient.
- The AAF’s operational deployment of radar-equipped B-25s was more limited compared to the Marines. Initially, they used similar sea-search radar sets as the Marines, but their primary radar-equipped missions were focused on the home front and antisubmarine warfare (ASW) tasks. Additionally, radar-equipped B-25s were used for training radar operators.
- AAF B-25s typically mounted their radar scanners in the ventral fuselage, where the retractable gun turret had previously been. Later, the AAF transitioned to centimetric radar, leading to configurations with ventral radomes, which were often bulbous or thimble-shaped, akin to the British H2S design. These radars were sometimes fitted in the extreme nose of the aircraft for specific mapping missions.