Als erstes, von vorn herein als Nachtjäger entwickeltes US-Flugzeug war die Black Widow (Schwarze Witwe) gegen Ende des II. Weltkriges das Standard-Nachtjagd-Einsatzmuster der USAF. Nach Konstruktionsbeginn, etwa zur Zeit der auf die Luftschlacht um England 1940 folgenden Nachtangriffe der Luftwaffe gegen die Britische Insel, war es Northrop noch möglich, alle dort gewonnenen Erfahrungen im Nachtjagdeinsatz bei dieser neuen Maschine zu berücksichtigen. Der Prototyp XP-61 war bereits ein recht großes Flugzeug mit Gewicht und Abmessungen eines mittleren Bombers und hatte einen Doppelrumpf und eine Mittelgondel für die Besatzung, Bewaffnung und Radarausrüstung. Die dreiköpfige Besatzung bestand aus dem Piloten, dem Radarbeobachter/Schützen und dem Funker/Schützen, letztere saßen oben rückwärts bzw. im rückwärtigen Kabinenraum. Die vom Piloten bediente Starbewaffnung bildeten vier Bordkanonen 20mm in einer Bodenwanne, während die in einem ferngesteuerten Drehturm zusammengefassten 4 MG’s 12,7mm von jedem Besatzungsmitglied wahlweise bedient werden konnten. In der zweiten Hälfte des Jahres 1943 begann die Auslieferung der ersten Serienmaschinen. Diese ersten P-61A besaßen zwar noch den Drehturm, der jedoch wegen großer technischer Schwierigkeiten im Einsatz bei den meisten A-Serienflugzeugen weggelassen wurde. Die eine, aus diesem Bausatz herzustellende P-61B ‘Lady of the Dark’ (Dame der Nacht) kam bei der 548. Nachtjagdstaffel im Pazifik zum Einsatz. Am 14. August 1945 startete sie von la Shima aus mit der Besatzung Lt. Clyde als Piloten und Lt. Lefford als Radarbeobachter, um japanische Oscar-Jäger abzufangen.

Spätnachts bekam sie Radarkontakt mit einem dieser Jäger und griff an. Im Laufe der nun folgenden Manöver gerieten beide Maschinen immer dichter an die Wasseroberfläche heran, bis das japanische Flugzeug - ohne einen Schuss von beiden Seiten - auf dem Wasser aufschlug. Als die Dame der Nacht im Morgengrauen des 15. August 1945 auf ihrem Stützpunkt landete, war der Krieg in Ostasien bereits beendet. Die Besatzung hatte den letzten Abschuss des II. Weltkrieges erzielt.

Mit zwei Pratt & Whitney Double Wasp Doppelsternmotoren von je 2250 PS erreichte die P-61B eine Höchstgeschwindigkeit von ca. 540 km/h. Normal betrug die Reichweite etwa 1500km, mit Zusatzbehältern maximal rund 3000km.

Neben der erwähnten Bewaffnung konnten bis zu 3 Tonnen Bomben zugeladen werden.
Abmessungen: Spannweite 20,12m; Länge 14,91m; Höchstfluggewicht 17100kg.

P-61 Black Widow

Northrop's Twin Engine Night Fighter

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 magenetron, 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.

Meanwhile, Northrop 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.

Service deliveries 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 year.

706 P-61's were built in total.

The first aircraft to be purposely designed as a radar-equipped nightfigher, Northrop's P-61 Black Widow was heavily influenced by early RAF combat experience with radar-equipped aircraft in 1940/41. Built essentially around the bulky Radiation Laboratory SCR-720 radar, which was mounted in the aircraft's nose, the P-61 proved to be the largest fighter ever produced for frontline service by the USAAF. Twin-engined and twin-boomed, the Black Widow was armed with a dorsal barbette of four 0.50-in Browning machine guns and two ventrally-mounted 20 mm cannon.

After initial structural and radar problems, the aircraft was finally issued to a frontline unit [the 481 st NFG] in March 1944, and both ETO and Pacific squadrons went into action almost simultaneously that 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 were built in three distinct variants by Northrop, and the type saw action as a night intruder operating against ground targets as well as in its designated role. This volume features all the frontline users of the mighty P-61, and includes many first-hand accounts from pilots and gunners who saw action in the Pacific, Mediterranean and Western Europe.

The P-61 Black Widow was the first United States aircraft designed from the start to find and destroy other aircraft at night and in bad weather. It served in combat for only the final year of World War II but flew in the European, Mediterranean, Pacific, and China-Burma-India theaters. Black Widow crews destroyed 127 enemy aircraft and 18 robot V-1 buzz bombs.

Jack Northrop's big fighter was born during the dark days of the Battle of Britain and the London Blitz in 1940. British successes against German daylight bombers forced the Luftwaffe (German Air Force) to shift to night bombing. By the time Royal Air Force (RAF) Spitfires could launch, climb out, and then try to intercept these raids, the bombers crews had usually dropped their loads and turned for home. An aircraft was needed to patrol the skies over England for up to seven hours during the night, and then follow radar vectors to attack German aircraft before they reached their target. U.S. Army Air Corps officers noted this requirement and decided that America must have a night fighter if and when it entered the war.

The Army awarded a contract to Northrop on January 30, 1941. The resulting design featured twin tail booms and rudders for stability when the aircraft closed in behind an intruder. It was a large aircraft with a big fuel load and two powerful engines. Armament evolved into four 20 mm cannons mounted in the belly firing forward and a powered, remote-controlled turret on top of the center fuselage equipped with four .50 cal. machine guns. The three-man crew consisted of the pilot, a gunner seated behind him, and a radar observer/gunner at the rear behind the gun turret. Only the pilot could fire the cannons but any of the three could operate the machine guns.

Simultaneously, work was proceeding, at a laboratory run by the Massachusetts Institute of Technology, to develop the airborne radar set. The Army tested an early design in a Douglas B-18 in 1941. The much-improved SCR-520 set was ready by early 1942. Meanwhile, Army enthusiasm for the XP-61 produced another contract on March 10, 1941, for 13 service-test YP-61s. Even before these airplanes flew, Northrop received orders for 410 production machines! Northrop test pilot Vance Breeze flew the aircraft on May 26, 1942. Although the Black Widow was nearly as large as a medium bomber, it was a true fighter. The only prohibited flight maneuvers were outside loops, sustained inverted flight, and deliberate spins.

As Northrop advanced the design toward production, supply problems arose and modifications became necessary. The 4-gun top turret was the same type fitted to the top forward position on the Boeing B-29 Superfortress (see NASM collection) and that bomber had production priority over the P-61. As a result, several hundred P-61s did not have this turret. Those that did experienced buffeting when the turret was traversed from side to side and a fix took time. By October 1943, the first P-61s were coming off the line. Training started immediately, and the first night fighters arrived in the European Theater by March 1944. Combat operations began just after D-Day (June 6) and the Black Widows quickly departed from their original role as defensive interceptors and became aggressors. They flew deep into German airspace, bombing and strafing trains and road traffic and making travel difficult for the enemy by day and at night.

P-61s arrived in the Pacific Theater at about the same time as the European Black Widows. For years, the Japanese had operated lone bombers over Allied targets at night and no U. S. fighters could locate and attack them. However, on June 30, 1944, a Mitsubishi BETTY (see NASM collection) became the first P-61 kill in the Pacific. Soon, Black Widows controlled the night skies. On the night of August 14-15, a P-61 named "Lady in the Dark" by her crew encountered an intruding Nakajima Ki-43 Hayabusa (Peregrine Falcon) OSCAR (see NASM collection) and eventually forced it into the sea without firing a shot. Although the war was officially over, no one was sure that all of the Japanese had heard the message and stopped fighting. The American night fighters flew again the next night and "Lady in the Dark" again found a target. It was a Nakajima Ki-44 Shoki (Demon) TOJO and the fighters maneuvered wildly as they attempted to gain an advantage. The P-61 crew lost and reacquired the Ki-44 several times then finally lost it for good and returned to base. The next day ground troops found the wrecked TOJO. In the darkness, Lady in the Dark's crew had forced the Japanese pilot to fly into the ground, again without firing a shot.

With the war over, the Army cancelled further production. Northrop had built 706 aircraft including 36 with a highly modified center fuselage. These F-15As (later redesignated RF-61C) mounted a number of cameras in the nose and proved able reconnaissance platforms. Many of these airplanes participated in the first good aerial photographic survey of the Pacific islands. A few, plus some special purpose P-61s, stayed in active service until 1950.

NASM's Black Widow is a P-61C-1-NO, U. S. Army Air Forces serial number 43-8330. Northrop delivered it to the Army on July 28, 1945. By October 18, this P-61 was flying at Ladd Field, Alaska, in cold weather tests and it remained there until March 30, 1946. This airplane later moved to Pinecastle Air Force Base, Florida, for participation in the National Thunderstorm Project. The project's goal was to learn more about thunderstorms and to use this knowledge to better protect civil and military airplanes that operated near them. The U. S. Weather Bureau and the National Advisory Committee for Aeronautics (NACA) undertook the study with cooperation from the Army Air Forces and Navy. With its radar and particular flight characteristics, the P-61 was capable of finding the most turbulent regions of a storm, penetrating them, and returning crew and instruments intact for detailed study.

Pinecastle personnel removed the guns and turret from 43-8330 in July 1946 to make room for new equipment. In September, the aircraft moved to Clinton County Army Air Base, Ohio, where it remained until January 1948. The Air Force then assigned the aircraft to the Flight Test Division at Wright-Patterson Air Force Base, Ohio. After declaring the airplane surplus in 1950, the Air Force stored it at Park Ridge, Illinois, on October 3 along with important aircraft destined for the National Air Museum.

But 43-8830 was not done flying. NACA asked the Smithsonian to lend them the aircraft for use in another special program. The committee wanted to investigate how aerodynamic shapes behaved when dropped from high altitude. The Black Widow arrived at the Ames Aeronautical Laboratory, Naval Air Station Moffett Field, California, on February 14, 1951. NACA returned the aircraft and delivered it to the Smithsonian at Andrews Air Force Base, Maryland, on August 10, 1954. When the engines shut down for the last time, this P-61 had accumulated only 530 total flight hours. Smithsonian personnel trucked it to the Paul Garber Facility in Suitland, Maryland, where it remains today. Wingspan: Length: Height: Weight: Empty,

When the War broke out, not many people understood the importance of night bombings, or night-fighters in the war to come. More countries had tried to develop. or looked at the possibility of aircraft that could perform their task during darkness. Until World War 2, however, the technology was mostly inadequate. The development of long range radio sets in (small) aircraft and even radar enabled pilots for the first time to navigate precisely, or spot an enemy beyond visual range (which is rather short during the night).

The first night fighters were modifications of twin-engined fighters, and were used by the British to counter the night-offensive of the Luftwaffe during the end of 1940 - beginning 1941. In order to succesfully intercept night intruders or night bombers the fighters already had to be airborne, and only twin-engined aircraft had the range and endurance to be up in the air for a long time. Also, when an aircraft was intercepted it could relatively easy escape, so the first burst of the attacking fighter needed to be lethal, or heavily damaging. This was also a strength of twin-engined aircraft, which usually had a nose (in front of the cockpit) where additional or heavy armament could be installed, later together with Air Interception Radar.

So it came that the first nightfighters were modifications of the Bristol Blenheim (fast and light bomber) and the Bristol Beaufighter (twin-engined again). These aircraft were to counter the night-intruder campaign of the Luftwaffe, which was mostly carried out by Dornier Do 17 bombers and Messerschmitt Bf 109 JaBo fighter bombers. A team of officers from the USAAC (later USAAF) visited Great Birtain to learn about the British night fighters at the end of 1940. The USAAC realised that night-fighting would become a major element in the air war and set about the creation of an American night-fighting capability. In the short term the best that could be achieved was an extemporized type, the Douglas P-70 Havoc based on the A-20 attack bomber, but for the longer term the USAAC understood that a purpose-designed type would be necessary. In October 1940 an outline requirement was communicated to John K.Northrop, and a mere two weeks later Northrop and his chief assistant, Walter J.Cerny, visited the USAAC’s Air Material Command headquarters at Wright Field, which was located outside Dayton, Ohio, to present the results of their initial thinking. Discussions with the appropriate USAAC officers proved most stimulating, and in December 1940 Northrop offered a full design to the Air Material Command. This resulted in a January 1941 order for two XP-61 prototypes.

The NS-8A design was singularly advanced, and was based on a twin-engined powerplant and an all-metal airframe that was very large by the fighter standards of the day. The core of the structure was a central nacelle and wing center section. The nacelle was of light alloy semi-monocoque construction and carried the crew, air interception radar and much of the armament, the last consisting of four 20 mm fixed forward-firing cannon in the wing leading edges and six 0.50 inch (12,7 mm) Browning machine guns with 500 rounds per gun in a power-operated dorsal four-gun barbette and power-operated ventral two-gun barbette: the barbettes could be locked to fire directly forward under control of the pilot, or unlocked for use defensively as trainable weapons under the remote control of the gunner. The shoulder/mid-set and slightly dihedraled wing center section was of light alloy stressed-skin construction and of the constant-chord type. Installed under the outer ends of this center section were the nacelles for the two wing-mounted engines and their fuel supply, and these nacelles were extended rearward as light alloy semi-monocoque booms that supported the tail unit of two vertical surfaces, each with a rudder, separated by a constant-chord horizontal surface with a single elevator. The flying surfaces were completed by the outer wing panels, which were set at a less acute dihedral angle than the center section, and were tapered in thickness and chord; virtually the whole of the trailing edges was occupied by small outboard ailerons supplemented by spoilers, and long-span inboard flaps that were originally of the Zap type but later of the slotted type. The airframe was completed by the tricycle landing gear, which comprised a nosewheel unit that retracted rearward into the underside of the central nacelle below the cockpit, and two mainwheel units that retracted rearward into the nacelles behind the engines.
The selected powerplant was 2 × Pratt & Whitney R-2800-A5G (or R-2800-25 in USAAC terminology) radial , rated at 2,000 hp (1491 kW) at optimum altitude each, and intended to drive a four-blade Curtiss Electric metal propeller of the constant-speed type. Pending the availability of this propeller type, a four-blade Hamilton Standard Hydromatic metal propeller of the constant-speed type was selected.
In April 1941 a USAAC team inspected the XP-61 mock-up and asked for several changes, including the relocation of the cannon from the wing leading edges to the underside of the central nacelle, and the elimination of the ventral barbette. The USAAC team’s reasoning for the elimination of the ventral barbette was that it would improve the airflow over this part of the airframe and simplify the night-fighter’s maintenance, but the change meant considerable revision of the central nacelle’s structure. Various other considerations then added further delays, but in September 1941 the USAAF ordered an initial 150 production aircraft and in February 1942, shortly after the USA’s entry into the War as a result of the Japanese attack on Pearl Harbor (and the Philippines) in December 1941, contracted for a further 410 aircraft.
The first XP-61 made its maiden flight in May 1942, and in its subsequent manufacturer’s trials revealed generally good handling characteristics and impressive performance, although considerable concern was expressed about the reliability of the R-2800 engine even in its improved R-2800-10 version. The second XP-61 was completed in November 1942. The SCR-720 radar was installed after the aircraft had been delivered for their official trials, and after a number of additional modifications had been made the XP-61 was accepted as the basis for the production model.

Version list:

·                                 Northrop P-61A Black Widow

·                                 Northrop P-61B Black Widow

Further pictures:

Northrop P-61 Black Widow in full flight. The central fuselage is clearly visible with it's barbette.


Northrop P-61 Black Widow in full flight. This time the underside is more visible.

Here is a quick overview of all different versions, without the full technical specifications:

Operational remarks:

The P-61A entered service in the middle of 1944 in Florida, where the 481st Night-Fighter Group was established as the parent of the 348th, 349th and 420th Night-Fighter Squadrons, and in Great Britain where the 422nd and 425th Night-Fighter Squadrons re-formed in the type. The first sorties were flown from Britain in July 1944, but it was in the Pacific that the first kill of the P-61 was scored in the same month when a P-61A of the 6th Night-Fighter Squadron claimed a Mitsubishi G4M ‘Betty’ bomber of the Imperial Japanese Navy Air Force in the central Pacific. A steady increase in the number of operational squadrons was possible as teething problems with the P-61A fighter and its temperamental radar were eliminated, and soon the type was operational in Europe, the Pacific, New Guinea and China.
Regretfully I lack further interresting information on this fascinating aircraft.

Strengths:

·                                 Good handling

·                                 Excellent performance

·                                 Very heavy armament, and heavy bombload as well (later versions)

Weaknesses:

·                                 Medium climb rate