P-61 Black Widow Night Interceptor

The Northrop P-61 Black Widow.

A common refrain about World War II aviation is that the Luftwaffe (and to a lesser extent the Japanese) had all sorts of superior aircraft, but they just "came along too late to make a difference." Often overlooked, however, is that the Allies also had many superior aircraft that came along too late to make a difference. Obviously, the Allies won and didn't need anything to go differently in terms of the war's outcome. However, the allied air forces also had planes which missed their period of maximum impact because they entered service a little too late in the conflict. One of these was the Northrop P-61 Black Widow night interceptor.

As with so many U.S. World War II aircraft, the P-61 had its origins before the United States entered the war. During the height of the Battle of Britain in August 1940, the United States Army Air Corps (USAAC) developed intelligence about the utility of airborne radar. The Henry Tizard technical mission, which arrived in the U.S. in late September 1940, brought the latest British radar equipment and top secret information about technical issues in the air war. With the onset of Luftwaffe night bombing of London that month, the British required night interceptors and asked manufacturers to develop them. The U.S. Air Technical Service Command (ATSC) collected the RAF data and began the process of supplying the RAF with what it needed. John C. (Jack) Northrop, founder of the Northrop Corporation and who conveniently sat on the ATSC board, reviewed the RAF data and realized the likelihood that the USAAC would issue specifications for a night fighter after a period of review. Northrop immediately began working on his own plans based upon the RAF's information, though he could not tell anyone, even in his own company.

Things moved fast. On 22 October 1940, Northrop met with his Chief of Research, Vladimir H. Pavlecka. Pavlecka told Northrop that he had been in contact with the ATSC and now had (verbally) their latest informal requirements for a night fighter. This itself was unusual, because there had not yet been issued in formal specifications - it was just a casual, "Hey could you guys work on this for us" phone call. With the "cat out of the bag," Jack Northrop now revealed his own sketches for the night fighter that he had been working on for a month already. Within a week, Northop and Pavlecka had a preliminary design, greatly aided by the "inside information" Northrop had acquired from his own position with the ATSC. The company submitted its proposal to the USAAC on 5 November 1940. The design called for a two-engine interceptor which would carry radar equipment in its nose. The USAAC immediately approved the design, and Northrop and Pavlecka began working on a prototype. This was an astonishingly fast conception for a successful military plane, without the usual competitive bidding and other processes, but the situation in Europe was dire. Another way of putting it is that Jack Northrop saw an unusual opportunity, and grabbed it.

Northrop's task was to develop an entirely new aircraft category, the night fighter. Both the Luftwaffe, with the Bf 110, and the RAF, with the Bristol Blenheim and Bristol Beaufighter, were experimenting with night fighters and using them with gradually increasing success. However, the Luftwaffe and RAF interceptors were converted daytime aircraft, not originally designed for operation after dark. Among other things, there was so little experience with night fighters that even the most basic issues such as proper size for a night fighter and appropriate weaponry were unclear. Northrop's design was huge (14 meters, or 45.5 feet, long and 20 meters, or 66 feet, wide) and carried two four-gun (12.7 mm, or .50 caliber, Browning machine guns) turrets, operated with three crewmen. Basically, the P-61 looked and was armed like many then-standard bombers and thus was unusual for a fighter design. However, since the RAF already was using converted bombers in a night fighter role, and the Luftwaffe was edging in that direction, it was not quite as big a departure as might first appear.

Northrop worked closely with the USAAC in developing the P-61. Based on their wishes, the machine guns were changed to 20 mm (.79 inch) Hispano M2 cannons which the RAF and Luftwaffe were beginning to use. Basically, the European conflict was a huge testing laboratory for development of the P-61, and initial findings from that conflict worked their way into the Northrop P-61 design. After some further modifications, the USAAC approved Northrop's "final" design with a 17 December 1940 Letter of Authority For Purchase, with $1.367 million authorized for wind-tunnel tests and two prototypes (some sources place final approval on 30 January 1941). This was less than two months after the arrival of the Tizard Mission had first raised the issue of a need for a night fighter at all. The P-61 project certainly was one of the fastest and most unusual procurement processes in U.S. military history, especially in peacetime. The aircraft's initial designation was XP-61.

Diagram of the P-61 Black Widow.

Northrop had a mockup of the XP-61 prepared for USAAC review on 2 April 1941. Once again, the defensive armament was a major issue, and the M2 cannons were repositioned from the wings, as in daytime fighters, to the aircraft's ventral (bottom) area in a "step," or enlargement of the fuselage. This "step" configuration was a favored USAAC design technique because it made aiming more accurate - the guns could fire straight ahead rather than be angled to "converge" on a target. Placing the guns in the fuselage also opened up more wing space for fuel tanks. There were some other changes, such as placing flame dampers on the engine exhausts, but nothing out of the ordinary and far fewer modifications than with many other designs. It was a clean design that worked.

The USAAC was ramping up production of all of its classes of warplanes in anticipation of war, and this began to create bottlenecks for aircraft at earlier stages of design and construction such as the P-61. These problems included such mundane issues as the availability of specific aircraft parts, which were allocated first to heavy bombers such as the Boeing B-17 which were ready for use. The bottleneck problem only got worse after the Japanese attack on Pearl Pearl Harbor on 7 December 1941, as the USAAC, now the U.S. Army Air Force (USAAF), suddenly needed to get planes of proven design in the air fast. In addition, the RAF was experiencing fewer problems from Luftwaffe bomber attacks following the German invasion of Russia on 22 June 1941, which saw the Luftwaffe commitment on the Channel Front greatly lessened as planes shifted eastward. For many reasons, the pace of P-61 development slowed.

The XP-61 prototype, with test pilot Vance Breese at the controls, first flew on 26 May 1942, powered by twin P&W R-2800-10 radials providing 1,490 kW (2,000 HP) each. The test flights were successful, and the USAAF ordered thirteen more prototypes for testing. Northrop did not deliver these until August/September 1943. These were quickly followed by the first production version, designated P-61 A-1-NO (all P-61s were built at Northrop's Hawthorne, California plant, and NO is that plant's designation). However, the war was proceeding, and the need for a night fighter was great. Just as the European combatants had done, the USAAF began converting other aircraft, in this case the Douglas A-20 Havoc bomber, for use as night fighters.

The first batch of production models went to the training base of the 348th Night Fighter Squadron in Orlando Army Air Base, Florida. This training lasted into 1944, and the first two P-61 night fighter squadrons, the 422nd and 425th, sailed to England aboard the RMS Mauretania and Queen Elizabeth, respectively. The P-61 squadrons, however, had difficulty getting assignments because USAAF generals and the British considered the P-61, capable of flying 366 mph (589 km/h) at 20,000 ft (6,095 m), to be slower than alternatives already on hand, such as the de Havilland Mosquito, and definitely slower than modern Luftwaffe fighters. While British rejection of new designs was nothing new - even the initial versions of the legendary P-51 Mustang had issues being accepted by the RAF at first - this led to an unusual series of "fly offs" between the P-61 and RAF planes. These produced results that some say favored the P-61, and others say favored the Mosquitos, but regardless of a slight edge in either direction, the reputation of the P-61 as a slow plane persisted. In hindsight, the Mosquito and P-61 were reasonably comparable planes in terms of performance, but the Mosquito "got there first."

Twin-engine fighters in general did not have a good reputation in the ETO. To be candid, the USAAF in England would have preferred to use Mosquito bombers for night fighter missions instead of the P-61 and kept the latter for training purposes. However, the available Mosquito bombers were fully utilized elsewhere, and a formal request along those lines to the RAF was denied. The USAAF thus began to "work" on the P-61, much in the manner of later hot-rodders tooling around with carburetors. Finally, a specially tweaked P-61 out-flew a Mosquito on 5 July 1944, and it was cleared for combat. Operational missions began in mid-July 1944, but encountered no Luftwaffe planes until mid-August. The 422nd scored the first victory by a P-61 on the night of 14/15 August 1944, against either a Bf 110 or a Fw 190. At least one P-61 was lost in the same encounter, so it was apparent that the P-61 was competitive, but hardly a dominant aircraft.

The Luftwaffe by now was flying jet-powered aircraft, and even some rocket-powered Me-163s. Quite simply, these Luftwaffe aircraft proved too fast for the P-61 in chase situations. In fact, it is believed that P-61s never engaged in combat with either type of Luftwaffe plane, because every time a German jet pilot (and some non-jet pilots) spotted a P-61, he simply sped away back to base. Since this was not the sort of thing that USAAF generals liked to hear, one can understand their ambivalence about the P-61.

Among other things, experience showed that the P-61 turrets were unnecessary. Since the turrets, which were the same as those used in USAAF bombers, were in short supply, most P-61s wound up flying without the dorsal turret, with an extra fuel tank in its place. Without the turret, the gunner became unnecessary, so many P-61s flew with a two-man crew. However, there were three seats, and the flights at night were long and tedious, so the gunner was often brought along anyway for company and to "help out," whether that meant scouring the skies for targets or just playing the (civilian) radio. When flying with only two men, and after the 425th moved its radar operators into the empty gunner's seat further forward from his usual seat in the rear, the P-61 had a different center of gravity and reportedly handled a bit better.

By late 1944, the Luftwaffe was dying despite its successful new jets. While air battles continued to the end of the war, the P-61 provided its main contributions during the December 1944 "Battle of the Bulge." Somewhat incongruously, during this time of maximum use the P-61 was switched from night fighter operations to daytime operations. So weak was the Luftwaffe by this time that even slow USAAF P-61 night fighters painted black, and thus painfully obvious with snowy backdrops, were successful in smashing Wehrmacht locomotives and troop convoys. Ultimately, the European Theater of Operations produced just two aces, an accolade shared by the pilot and his radar operator who handled the guns. The P-61 aces were (pilot first):

• Herman Ernst and Edward Kospel, ETO, 6 kills
• Paul Smith and Robert Tierney, ETO, 6 kills
• Carrol Smith and Philip Porter, PTO, 5 kills.

The two ETO ace pairings each included one V-1 cruise missile in their kills, but they met the requirements of aces regardless.

The first P-61s arrived in the Pacific Theater of Operations (PTO) not long after the first had arrived in England, in June 1944. Unlike their ETO colleagues, however, the USAAF generals in the PTO had no qualms about the P-61 and were eager to slot them into operations. As a stopgap measure, the USAAF had been using converted Douglas A-20 Havocs as night fighters, designated P-70 "Nighthawks," until the "real" night fighters (namely, the P-61) became available. Thus, there were fairly high expectations for the new planes, but, by the time they had arrived and the P-70 crews re-trained to fly them, the period of crisis had passed. The first P-61 mission, by the 6th Night Fighter Squadron operating out of Guadalcanal, occurred on 25 June 1944. The 6th NFS notched the first PTO victory (and first anywhere, apparently) on 30 June 1944, a Mitsubishi G4M "Betty" bomber. The new plane thus had "proved" itself, but there weren't many more kills to be had because Japanese night missions were dwindling. In other words, the P-61s turned out to be an excellent solution for a problem that no longer existed.

If many missions in the ETO were long and boring, those in the PTO were even worse in that regard. P-61s flew long, uneventful missions over the ocean, with nothing to break the monotony. However, when P-61s did spot Japanese planes, they tended to be in swarms, so the few battles that developed became real melees. The victories, however, were few and far between for P-61s, and, as noted above, the PTO produced only one ace crew, with five kills.

P-61s, while rather average aircraft in terms of relative performance, were reliable aircraft. They also were available in fairly plentiful supply, with 700 being built while incurring relatively few losses. These attributes led to their use in various special missions. For instance, P-61s are said to have shot down nine or more V-1 cruise missiles, which is not a fantastically high number of the thousands launched by the Germans, but it was of some use. In another situation, a P-61 was used successfully to distract Japanese guards at a POW camp in the Philippines while U.S. Army Rangers prepared an attack.

Northrop heard about the complaints regarding the P-61's speed, and in November 1943 developed the P-61C, which featured turbocharged R-2800-73 radials providing a maximum power of 2,090 kW (2,800 HP). These were farmed out to the Goodyear plant in Akron, Ohio. When P-61Cs finally rolled off the assembly line in early 1945, they were significantly faster than earlier versions, reaching a respectable 690 kph (430 mph) at altitude. These did not arrive in units until July 1945, however. None saw combat, and thus the P-61C cannot be considered relevant to World War II.

While the P-61 did not become "operational" until long after D-Day, there are photographs of P-61s in Overlord markings which suggest that they were pressed into service (along with virtually everything else that could fly) on 6 June 1944.

The P-61 Black Widow was not a dominant aircraft. It was serviceable, adequate for its purposes, on a par with similar aircraft of its generation, but came along after its main purpose, interception of Axis night bombing attacks, had largely ended. The P-61 proved useful because it was available when other, equally capable or more capable, aircraft types were fully occupied elsewhere, but otherwise it added little to the Allied arsenal. The end of the war terminated further development, with only 41 more P-61s being produced in early 1946 before production was cancelled for good. The final adaptation of the P-61 was as an unarmed photo-reconnaissance plane designated F-15A, which served until the spring of 1949. The last P-61s were replaced by the F-82 Twin Mustang and then the Northrop F-89 Scorpion, and the final F-15A and P-61 (one of each) were declared surplus in April 1955. A handful were converted to civilian uses such as photographic surveying and fire-fighting and served in that purpose throughout the 1950s.

Today, there is not a single flyable P-61, the last having crashed on 6 September 1968 during fire-fighting operations near Hollister California. However, for lovers of classic aircraft, there is hope, as four non-flying P-61s exist. Reportedly, one of those, owned by the Mid-Atlantic Air Museum and recovered from its crash site in New Guinea, is being restored to flight condition in a very long and difficult process that already has lasted more than two decades





2017