P-61 Black Widow
The Black Widow
The first American night fighter designed just for that purpose, the P-61 was as big as a medium bomber, with two 2,000-hp Pratt & Whitney R-2800-10 Wasps, twin rudders supported by tail booms, and tricycle gear. The central nacelle had radar, the pilot’s cabin with a gunner above and behind him, and finally a radar operator’s enclosure. Retractable ailerons permitted flaps the full length of the wing’s trailing edge. An ACR-720A radar transmitter designed for the P-61 had a rotating reflector dish in the Plexiglas (later fiberglass) nose, permitting location of targets ten miles away; depending on altitude and conditions.
Armament consisted of four 20-mm fixed guns with 800 rounds in a bulge below the fuselage, and four .50- caliber with 1,600 rounds in a top remote-controlled turret. The latter guns were usually fired forward like the cannon by the pilot, but could be unlocked and aimed by either gunner as flexible defense for the upper hemisphere.
Without waiting for the test aircraft’s completion, the USAF ordered P-61A production begun with a 150-plane contract approved September 17, 1941, and increased to 560 by a new order approved February 26, 1942. On May 26, 1942, Vance Breese flew the first XP-61 at Hawthorne, and the second, with full-span flaps, flew November 18.
Production aircraft were slow to appear, for the first YP-61 was not finished until February 1943, or accepted until August 6, and the first P-61A-1 was accepted in October. Replacement of magnesium with aluminum in the structure added weight, and the P-61A added armor glass windshields to the crew’s front armor.
Only the first 50 YP-61 and P-61A-1s had top turrets, because tail buffeting troubles and B-29 priority caused turret omission on 327 later ships. Forty-five P-61A-1s were followed by 35 P-61A-5s with provision for water injection, 100 P-61A-10s with the R-2800-65, and 20 P-61A-11s added fixtures for two 165-gallon drop tanks or bombs. Most of these entered service with two crewmen and the glossy paint that went with the Black Widow’s official name.
Delivery of 163 P-61B-1 to P-61B-10s began in July 1944 with mechanical improvements including SCR-720C radar in a longer nose. The P-61B-10 had under wing fittings for four 1,600-pound bombs, or drop tanks of 165- or 300-gallon size. Four-gun turrets were restored on 286 P-61B-15 to P-61B-20, since the buffeting condition had been improved and turret deliveries had met B-29 needs.
Despite its size, the Black Widow was remarkably maneuverable. Its first success was won by the 6th Night Fighter Squadron, which landed on Saipan with P-61As on June 21, 1944, scored its first victory June 30, and the second July 6. Ten P-61 squadrons were deployed against the Japanese Empire by March 1945, two squadrons entered combat from England in July 1944, and four night fighter squadrons served the 12th Air Force. After the war, a dozen P-61Bs were used by the Marines as F2T-l trainers.
A program to improve performance by using turbosupercharged engines was begun in November 1943 with plans for a P-61C production model, preceded by two XP-61C prototypes prepared by Goodyear, an important Northrop sub-contractor. A P-61A-5 and an A-10 were flown to Akron in May 1944 for modification and, after a engine model change from the planned R-2800-77 altered their designation to XP-61D, flight tests began with 2,800 hp R-2800-57 Wasps and CH-5 turbos in November 1944.
The first P-61C-1 with R-2800-73s was accepted on July 14, 1945, just before V-J Day curtailed production, and only 41 were delivered, the last on January 28, 1946. Top speed had increased from 366 to 430 mph and speed brakes on the wings could prevent the P-61C from overshooting targets, but this model was too late for combat.
The XP-61E was a long-range day fighter with radar and turret removed to provide a smaller, more streamlined fuselage. Two crewmen sat under a bubble canopy ahead of a fuselage fuel tank, while four .50-caliber nose guns supplemented the usual four 20-mm belly guns. Converted from a P-61B-10 with R-2800-65 Wasps, the first prototype flew on January 3, 1945. A second prototype was wrecked in April, but the AAF had already decided on the P-82B Twin Mustang as its long-range fighter, and developed the Northrop as a photo-reconnaissance type.
With cameras replacing guns, the XP-61E was modified to the XF-15 and flew on July 3, 1945, while a turbosupercharged XF-15A, a modified P-61C, flew October 17. Production as the F-15A Reporter was ordered in June 1945, but post-war deliveries were limited to 36, delivered from September 1946 to April 1947.
The 706 Black Widows served adequately during the war’s last year as the standard AAF night fighter. By then the Axis was on the defensive and no saturation raids were met. Generally, P-61s fought alone on their sorties, ambushing individual enemy raiders, and were credited with 127 victories up to the last night of the war. Postwar service continued until 1948, when they were replaced by the Twin Mustang.