The P-61 was the first
U.S. aircraft designed from the start to be a night fighter. By the
time it arrived with combat squadrons in mid-1944, targets were rather
scarce. Thus, while it didn't pile up a large score of enemy planes
destroyed, it was an extremely capable and deadly aircraft.
It originated in the
Battle of Britain, when the British urgently needed a night fighter.
Because early radars were so heavy and because the British requirement
called for a night fighter that could stay airborne for a long time,
only a twin-engined aircraft would work. Northrop began working on the
project in late 1940. Northrop's proposal, submitted in November,
followed the general outline of Lockheed's P-38: a big, twin-engined
fighter, with crew and guns in the fuselage, and two engine nacelles
extending back into twin booms connected by a long horizontal
stabilizer. The armament was quite different though; the P-61 housed
two dorsal turrets, each with four .50 calibre machine guns.
While there had been
primitive efforts to develop night fighters since 1921, by 1940, radar
promised to make them practical. The British had first developed
Airborne Interception (AI) radar and also developed the cavity
magnetron, which permitted short wavelength radars. Using a British
cavity magnetron, by early 1941, engineers from MIT and several
American electronics companies had built the first microwave radar, the
forerunner of the SCR-270 used in the P-61.
struggled with the P-61 aircraft, by far the biggest contract it had
ever tackled. Meeting the Army's requirement for a three-man crew was
one of many challenges faced by the design team. Throughout 1941,
indeed throughout the entire war, required engineering changes
continually cropped up, delaying the development of the P-61. Guns were
relocated; fuel tanks were added; and control surfaces 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 in April, 1943.
Flights with the
YP-61's revealed that the dorsal machine gun turret caused severe
tail buffeting. Thus it was removed entirely from many early P-61A's,
and when added back, only mounted two guns.
started in May, 1944, when the 348th Night Fighter Squadron (NFS) of
the 481st Night Fighter Group (NFG) received their Black Widows. While
the P-61 was exceptionally manoeuvrable for such a large plane (thanks
to the large and well-designed flaps), it remained troublesome. In
June, deliveries increased to three a day. The first P-61 kill was
recorded on June 30, 1944 (some sources say July 6), when a Black Widow
of the 6th NFS downed a 'Betty" bomber over the Pacific. In Europe, the
crews continued training while debates raged over the night fighting
virtues of the Black Widow, the Mosquito, and the Bristol Beaufighter.
Once the Black Widow
did get into action in Europe, it found success against a variety of
targets: fighter planes, bombers, V-1 buzz bombs, and ground targets
like locomotives and truck convoys. Some ETO NF squadrons did not
convert until spring of 1945, when the war was almost over. In the
Pacific, the 418th and 421st NFS adopted the P-61 in mid-1944, and in
the CBI, the 426th and 427th NFS transitioned to the P-61 later that
706 P-61's were built
(Northrop P-61A Black Widow)