Northrop's Twin Engine Night Fighter
By Stephen Sherman, Sept. 2002. Updated January 26, 2012.
The P-61 was thefirst U.S. aircraft designed from the start to be anight fighter. By the time it arrived with combat squadrons inmid-1944, targets were rather scarce. Thus, while it didn't pile up alarge score of enemy planes destroyed, it was an extremely capable anddeadly aircraft.
It originated in the Battle of Britain, when the British urgentlyneeded a night fighter. Because early radars were so heavy and becausethe British requirement called for a night-fighter that could stayairborne for a long time, only a twin-engined aircraft would work.Northrop began working on the project in late 1940. Northrop'sproposal, submitted in November, followed the general outline ofLockheed's P-38: a big, twin-engined fighter, with crew and guns in thefuselage, and two engine nacelles extending back into twin boomsconnected by a long horizontal stabilizer.
The armament was quitedifferent though; the P-61 housed two dorsal turrets, each with four.50 caliber machine guns.
While there had been primitive efforts to develop night fighterssince 1921, by 1940, radar promised to make them practical. The Britishhad first developed Airborne Interception (AI) radar and also developedthe cavity magnetron, which permitted short wavelength radars. Using aBritish cavity magnetron, by early 1941, engineers from MIT andseveral American electronics companies had built the first microwaveradar, the forerunner of the SCR-270 used in the P-61.
Meanwhile, Northrop struggled with the P-61 aircraft, by far thebiggest contract it had ever tackled. Meeting the Army's requirementfor a three-man crew was one of many challenges faced by the designteam. Throughout 1941, indeed throughout the entire war, requiredengineering changes continually cropped up, delaying the development ofthe P-61. Guns were relocated; fuel tanks were added; and controlsurfaces were redesigned. The first XP-61 prototype flew in May,1942, with test pilot Vance Breese at the controls.
The second prototype flew that November and had radar installed inApril, 1943.
Flights with the YP-61's revealed that the dorsal machinegun turret caused severe tail buffeting. Thus it was removed entirelyfrom many early P-61A's, and when added back, only mounted twoguns.
Service deliveries started in May, 1944, when the 348th NightFighter Squadron (NFS) of the 481st Night Fighter Group (NFG) receivedtheir Black Widows. While the P-61 was exceptionally maneuverable forsuch a large plane (thanks to the large and well-designed flaps), itremained troublesome. In June, deliveries increased to three a day. Thefirst P-61 kill was recorded on June 30, 1944 (some sources say July6), when a Black Widow of the 6th NFS downed a 'Betty" bomber over thePacific. In Europe, the crews continued training while debates ragedover the night-fighting virtues of the Black Widow, the Mosquito, andthe Bristol Beaufighter.
Once the Black Widow did get into action in Europe, it found successagainst a variety of targets: fighter planes, bombers, V-1 buzz bombs,and ground targets like locomotives and truck convoys. Some ETO NFsquadrons did not convert until spring of 1945, when the war was almostover. In the Pacific, the 418th and 421st NFS adopted the P-61 inmid-1944, and in the CBI, the 426th and 427th NFS transitioned to theP-61 later that year.
706 P-61's were built in total.
P-61 Black Widow Units of World War 2 ,(OspreyCombat Aircraft 8) by Warren E. Thompson
The first aircraft to be purposely designed as aradar-equipped nightfigher, Northrop's P-61 Black Widow was heavilyinfluenced by early RAF combat experience with radar-equipped aircraftin 1940/41. Built essentially around the bulky Radiation LaboratorySCR-720 radar, which was mounted in the aircraft's nose, the P-61proved to be the largest fighter ever produced for frontline service bythe USAAF. Twin-engined and twin-boomed, the Black Widow was armed witha dorsal barbette of four 0.50-in Browning machine guns and twoventrally-mounted 20 mm cannon.
After initial structural and radar problems, the aircraft wasfinally issued to a frontline unit [the 481 st NFG] in March 1944, andboth ETO and Pacific squadrons went into action almost simultaneouslythat spring - the honour of scoring the first kill [a Japanese 'Betty'bomber] went to the 6th NFS on 6 July 1944. Some 704 Black Widows werebuilt in three distinct variants by Northrop, and the type saw actionas a night intruder operating against ground targets as well as in itsdesignated role. This volume features all the frontline users of themighty P-61, and includes many first-hand accounts from pilots andgunners who saw action in the Pacific, Mediterranean and WesternEurope.
