Lockheed Ventura, B-34, B-37, PV-1 and PV-2

The Lockheed Ventura was a medium bomber ordered for the RAF after the early success of the Lockheed Hudson, but was not as successful as the earlier aircraft, entering service too late to serve in the day bomber role it was designed to perform.
The Lockheed Model 37 was the USAAF designation given to 264 Ventura II medium bombers taken over from RAF orders after Pearl Harbor.
The Lockheed B-34 was the lend-lease designation given to the Lockheed Ventura, but of the 200 aircraft produced under this designation only 66 actually went to the RAF or Commonwealth airforces (as the Ventura IIA), while the remaining 124 were retained by the USAAF
The Lockheed B-37 was a medium bomber based on the Ventura, produced in very small numbers for the USAAF.
The Lockheed PV-1 was the designation given to the Ventura bomber in service with the US Navy.
The Lockheed PV-2 Harpoon was the final production version of the Ventura bomber, modified to make it a better maritime patrol aircraft.