By:       Norm Goyer

Last week I wrote about the outstanding F-82 Twin Mustang that proved to be the successor to the Northrop P-61 Black Widow night fighter. This prompted a reader to write and request more information about that aircraft and other Northrop aircraft involved in World War II. After a day of intense research both through my personal aviation research books and the Internet I came to the following conclusion. The history of Northrop is quite complicated for such a relatively small wartime aircraft production company.

The Northrop P-61 Black Widow was the first aircraft designed to carry air-borne radar.

In 1939 Jack Northrop, a very skilled designer, formed Northrop Aircraft Incorporated in Hawthorne, California. The first Northrop aircraft was a patrol bomber float equipped aircraft for the Norwegian Air Force. No others were ever built. The three-place, single-engine, cantilevered low-wing monoplane patrol bomber had two floats attached by full cantilever pedestals to the left and right wings. The first flight test took place on November 1, 1940 at Lake Elsinore, California. The Northrop N-3PB was soon identified as the world’s fastest military sea plane. Twenty four aircraft were ordered by Norway on 12 March 1940. Within the short span of eight months, the first production aircraft rolled off the Northrop assembly line. The only surviving N-3PB is on display in a museum in Oslo, Norway.

Note the long wing and layout of the gun platforms on the fuselage.

Meanwhile World War II was raging on and the British realized that they had to have aircraft suitable for fighting at night in an attempt to head off the German bombers which were headed to bomb London. These night raids were causing havoc with civilians and destroying much of London and its suburbs. It was well known that the Royal Air Force were looking for new aircraft capable of carrying the very heavy new radar units that had just been introduced. Some had been installed in existing British twin-bombers such as the Mosquito and Beaufort but both lacked the lifting power and the extra fire power to destroy enemy aircraft that the radar revealed. About the same time the United States sent out a veiled request for an aircraft that would carry a lot of weight and be well armed. No mention of radar was in the specifications. Jack Northrop, reading between the lines, knew instantly what both countries wanted and needed the same type of aircraft. Northrop engineers working around the clock with innovative ideas came up with the outstanding P-61 Black Widow, the first aircraft to be designed to carry radar and be able to detect and destroy enemy planes. The P-61 Black Widow was born of wartime need.

The radar scanner was located in the forward nose and was operated by a trained radar technician.

The P-61 was a very large aircraft which featured a crew of three: pilot, gunner, and radar operator. It was armed with four 20 mm Hispano M2 forward firing cannons mounted in the lower fuselage, and four .50 caliber in a remotely-aimed dorsally mounted turret. The two Pratt & Whitney R-2800-25S Double Wasp engines had two-stage, two-speed mechanical superchargers.

The P-61 did not have ailerons. Aside from the full-span retractable Fowler type flaps, all control of the aircraft, about the roll axis, was through the use of curved, tapered spoilerons located in the wing which would rotate out of the wing’s upper surface into the airstream, reducing lift over that wing, causing it to drop. Even though the P-61 was first flown in 1942 it never reached combat squadrons until  1944. A series of sub-contractor supply problems involving the turret, propellers and other items plagued the project from the beginning. Another problem was Jack Northrop’s fascination with the flying wing project which was on the boards at the same time as the Black Widow. Towards the end of the P-61’s production run, manufacturing of the P-61 was turned over to Goodyear, so that Northrop could concentrate on the flying wing, which made its first flight in 1946.

Four Northrop Black Widow P-61s survive and are on display in museums including Wright Patterson in Dayton, Ohio.

The ultimate disappointment came when the P-61s finally arrived in combat zones. By that time, there were very few enemy planes for the Black Widow to engage in combat. The P-61was not fast enough for the new German Me. 262 jet fighters, but did manage to destroy a number of slower twin-engine aircraft and slow moving Stuka dive bombers History states that the Black Widow was not a poor night fighter nor was it an excellent one, just that it did the job required of it. Pilots found when used in low level strafing runs the heavy forward mounted firepower was deadly to trains and trucks on the ground. There are four remaining P-61s in museums including Wright-Patterson and Air & Space.

Specifications P-61B-20-NO

• Crew: 2–3 pilot, radar operator, optional gunner

• Length: 49 ft 7 in

• Wingspan: 66 ft 0 in

• Height: 14 ft 8 in

• Wing area: 662.36 ft²

• Empty weight: 23,450 lb

• Loaded weight: 29,700 lb

• Max takeoff weight: 36,200 lb

• Powerplant: 2, Pratt & Whitney R-2800-65W Double Wasp radial engines, 2,250 hp

• Propellers: four-bladed Curtis Electric propeller

• Fuel capacity:

  • Internal: 640 gal of AN-F-48 100/130-octane rating gasoline

  • External: Up to four 165 gal or 310 gal tanks under the wings

Performance

• Maximum speed: 366 mph at 20,000 ft

• Combat range: 610 mi

• Service ceiling: 33,100 ft

• Rate of climb: 2,540 ft/min

• Wing loading: 45 lb/ft²

• Power/mass: 0.15 hp/lb

• Time to altitude: 12 min to 20,000 ft, 1,667 fpm

This entry was posted on Friday, February 19th, 2010 at 12:11 am and is filed under UnderTheRadar. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.