Bristol Blenheim Mk.1F

The Bristol Blenheim Mk.IF was a short-nosed light bomber converted into a long-range fighter (roughly 200 units) to fill a critical need for fighters in the early years of WWII. Serving primarily as a night fighter in 1940, it featured an under-fuselage pack of four .303 machine guns. While it secured early night victories during the Blitz, it was quickly replaced by the Beaufighter. 
 
Key Roles and Usage in WWII
Night Fighter: The Mk.IF was the primary, although early, RAF night fighter during the 1940–1941 Blitz, using AI (Airborne Interception) radar to tackle German bombers.
Day Fighter (Limited): Initially used as a long-range day fighter, the Mk.IF proved too slow and vulnerable to Luftwaffe Bf 109s, resulting in heavy losses (e.g., 600 Squadron in May 1940) and rapid withdrawal from daylight, offensive operations.
Convoy Patrols: Utilized for long-range, coastal, and shipping protection patrols during the "Phony War" and early 1940.
Operational Training: Due to its obsolescence as a front-line fighter by late 1940/1941, many Mk.IFs were relegated to training units to teach crews night fighting, radar, and interceptions. 
 
Specifications and Design
Armament: The defining feature was a pack under the fuselage containing four .303 Browning machine guns. This was in addition to the standard, single .303 wing-mounted gun and a dorsal Vickers K gun.
Crew: Typically a three-man crew (pilot, navigator/wireless operator, and gunner).
Appearance: Early versions, often referred to as "short-nosed," were sometimes painted in matte black for night operations.