Tag Archives: Northrop Field

26 May 1942

Northrop Corporation XP-61 Black Widow at Hawthorne.
Northrop Corporation XP-61 prototype 41-19509 at Northrop Field, 1942. (U.S. Air Force)

26 May 1942: The prototype Northrop XP-61-NO Black Widow, 41-19509, made its first flight at Northrop Field, Hawthorne, California, with free-lance test pilot Vance Breese at the controls. (Breese had taken the North American Aviation NA-73X, prototype of the Mustang, for its first flight, 20 October 1940.)

Northrop XP-61 41-19509 taking off from Northrop Field. (U.S. Air Force)

The first American airplane designed specifically as a night fighter, the XP-61 was the same size as a medium bomber: 48 feet, 11.2 inches (14.915 meters) long with a wingspan of 66 feet (20.117 meters) and overall height of 14 feet, 8.2 inches (4.475 meters). The prototype was equipped with a mockup of the top turret. Its empty weight was 22,392 pounds (10,157 kilograms), gross weight of 25,150 pounds (11,408 kilograms) and maximum takeoff weight of 29,673 pounds (13,459 kilograms).

Northrop XP-61 41-19509 retracts its landing gear after takeoff. (U.S. Air Force)

The XP-61 was powered by two air-cooled, supercharged, 2,804.4-cubic-inch-displacement (45.956 liter) Pratt & Whitney Double Wasp SSB2-G (R-2800-10) two-row, 18-cylinder radial engines with a compression ratio of 6.65:1. The R-2800-10 had a Normal Power rating of 1,550 horsepower at 2,550 r.p.m. at 21,500 feet (6,553 meters), and 2,000 horsepower at 2,700 r.p.m. for takeoff, burning 100-octane gasoline. The R-2800-10 had a 2:1 gear reduction and drove four-bladed Curtiss Electric constant-speed propellers which had a 12 foot, 2 inch (3.708 meter) diameter. The R-2800-10 was 4 feet, 4.50 inches (1.334 meters) in diameter, 7 feet, 4.47 inches (2.247 meters) long, and weighed 2,480 pounds (1,125 kilograms), each.

The prototype Black Widow had a top speed of 370 miles per hour (595 kilometers per hour) at 29,900 feet (9,114 meters) and a service ceiling of 33,100 feet (10,089 meters). The maximum range was 1,450 miles (2,334 kilometers).

Prototype Northrop XP-61 Black Widow 41-19509 in camouflage. (U.S. Air Force)

The night fighter was crewed by a pilot, a gunner and a radar operator. A large Bell Laboratories-developed, Western Electric-built SCR-720 air search radar was mounted in the airplane’s nose. The gunner sat above and behind the pilot and the radar operator was in the rear fuselage.

SCR-720 Air Search Radar mounted in nose of a Northrop P-61 Black Widow night fighter. (NOAA)

The Black Widow was armed with four Browning AN-M2 .50-caliber machine guns in a remotely-operated upper turret, and four AN-M2 20 mm aircraft automatic cannons, grouped close together in the lower fuselage and aimed directly ahead. This was a superior arrangement to the convergent aiming required for guns mounted in the wings. The fire control system was similar to that used by the B-29 Superfortress. The guns could be fired by either the gunner or the radar operator. The Black Widow carried 200 rounds of ammunition for each cannon.

The eight guns of a P-61 Black Widow converge on target during test firing.
Northrop P-61A-1-NO Black Widow 42-5507 in olive green camouflage. (U.S. Air Force)
Northrop P-61A-1-NO Black Widow 42-5507 in olive green camouflage. (U.S. Air Force)

The XP-61 was built with a center “gondola” for the crew, radar and weapons, with the engines outboard in a twin-boom configuration, similar the the Lockheed P-38 Lightning. The Black Widow did not use ailerons. Instead, it had spoilers mounted on the upper wing surface outboard of the engines. Roll control was achieved by raising a spoiler, decreasing lift on that wing and causing it to drop. A similar system was employed on the Boeing B-52 Stratofortress ten years later.

Northrop P-61A three-view illustration with dimensions. (U.S. Army Air Forces)

The P-61 got its nickname, Black Widow, from the glossy black paint scheme that scientists at the Massachusetts Institute of Technology (M.I.T.) had determined was the best camouflage for a night fighter. Over 700 P-61s were built, with 36 built as the F-15 photo reconnaissance variant. They served in both the Pacific and European Theaters during World War II, and were also used during the Korean War. After the war, the radar-equipped fighter was used for thunderstorm penetration research.

Northrop P-61C-1-NO Black Widow 43-8353 at the National Museum of the United States Air Force. (U.S. Air Force)
Northrop P-61C-1-NO Black Widow 43-8353 at the National Museum of the United States Air Force. (U.S. Air Force)
Northrop P-61C-1-NO Black Widow 43-8353 at the National Museum of the United States Air Force. (U.S. Air Force)

© 2018, Bryan R. Swopes

21 October 1947

Northrop YB-49 42-102367 takes off from Northrop Field, Hawthorne, California. (U.S. Air Force)

21 October 1947: At Northrop Field, Hawthorne, California, Northrop Corporation Chief Test Pilot Max R. Stanley took off in the first YB-49, 42-102367, and flew it to Muroc Air Force Base for flight testing. The co-pilot was Fred C. Bretcher and Orva H. Douglas served as flight test engineer. The Flying Wing landed at Muroc 34 minutes later.

(Pasadena Star-News, 26 October 1947, Page 40, Columns 2–4)

An estimated 4,000 spectators lined the streets surrounding Northrop Field. The YB-49 was escorted by a Lockheed P-80A Shooting Star and a Northrop P-61 Black Widow as it climbed to 10,000 feet (3,048 meters) en route to Muroc. Over Lancaster, California, the P-61 caught fire and was abandoned by its crew.

42-102367 had been converted from the second YB-35 pre-production test aircraft. The original Flying Wing’s four Pratt & Whitney Wasp Major (R-4360-21) radial engines were replaced by turbojet engines and several aerodynamic improvements were made.

Chief Test Pilot Max R. Stanley. (Photograph courtesy of Neil Corbett, Test and Research Pilots, Flight Test Engineers)

The YB-49 was a very unusual configuration for an aircraft of that time. There was no fuselage or tail control surfaces. The crew compartment, engines, fuel, landing gear and armament were contained within the wing. Air intakes for the turbojet engines were placed in the leading edge and the exhaust nozzles were at the trailing edge. Four small vertical fins for improved yaw stability were also at the trailing edge.

Northrop YB-49 42-102367. (U.S. Air Force)
Northrop YB-49 42-102367 at Northrop Field, Hawthorne, California. (Unattributed)

The YB-49 had a length of 53 feet, 1 inch (16.180 meters), wingspan of 172 feet (52.426 meters) and overall height of 15 feet, 2 inches (4.623 meters). It weighed 88,442 pounds (40,117 kilograms) empty and its Maximum Takeoff Weight (MTOW) was 193,938 pounds (87,969 kilograms).

The Wing defined the airplane. The leading edge was swept aft 26° 57′ 48″, and the trailing edge, 10° 15′ 22″. The wing’s total area was 4,000 square feet (371.6 square meters). It had an aspect ratio of 7.4:1. At the root, the chord was 37 feet, 6 inches (11.430 meters), tapering to 9 feet, 4 inches (2.844 meters) at the tip. There was 0° angle of incidence at the root, -4° at the wing tips, and 0° 53′ dihedral.

Northrop YB-49 42-102367 in flight near Muroc Air Force Base. (U.S. Air Force)

The YB-49 was powered by eight General Electric-designed, Allison Engine Company-built J35-A-5 engines. (This same engine variant was used in the North American Aviation XP-86, replacing its original Chevrolet-built J35-C-3.) The engines were later upgraded to J35-A-15s. The J35 was a single-spool, axial-flow turbojet engine with an 11-stage compressor and single-stage turbine. The J35-A-15 had a Normal Power rating of 3,270 pounds of thrust (14.546 kilonewtons) at 7,400 r.p.m. The Military Power rating was 3,750 pounds (16.681 kilonewtons) at 7,700 r.p.m. The engine was 14 feet, 0.0 inches (4.267 meters) long, 3 feet, 4.0 inches (1.016 meters) in diameter and weighed 2,400 pounds (1,089 kilograms).

The YB-49 had four vertical fins extending above and below the trailing edge of the Wing. (U.S. Air Force 090706-F-1234K-048)

During testing the YB-49 reached a maximum speed of 428 knots (493 miles per hour/793 kilometers per hour) at 20,800 feet (6,340 meters). Cruise speed was 365 knots (429 miles per hour/690 kilometers per hour). The airplane had a service ceiling of 49,700 feet (15,149 meters). The YB-49 had a maximum fuel capacity of 14,542 gallons (55,047 liters) of JP-1 jet fuel. Its combat radius was 1,403 nautical miles (1,615 statute miles/2,598 kilometers).

The maximum bomb load of the YB-49 was 16,000 pounds (7,257 kilograms), though the actual number of bombs was limited by the volume of the bomb bay and the capacity of each bomb type. While the YB-35 Flying Wing was planned for multiple machine gun turrets, the YB-49 carried no defensive armament.

Northrop YB-49 42-102367 takes off from Northrop Field, Hawthorne California. Note teh crowds of onlookers and residential housing along W. 120th Street, on the north side of the airport. (U.S. Air Force)
Northrop YB-49 42-102367 takes off from Northrop Field, Hawthorne, California. Note the crowds of onlookers and residential housing along W. 120th Street, on the north side of the airport. (Unattributed)

Only two Northrop YB-49s were built and they were tested by Northrop and the Air Force for nearly two years. Though an additional nine YB-35s were ordered converted, the B-49 was not placed into production.

A Northrop YB-49 with a Boeing XB-47 Stratojet. (U.S. Air Force)

The second ship, YB-49 42-102368, disintegrated in flight during a test flight north of Muroc Air Force Base, 5 June 1948, killing the entire crew, which included Captain Glen Edwards. The name of Muroc was changed to Edwards Air Force Base in his honor.

YB-49 42-102367 was destroyed by fire following a taxiing accident at Edwards, 15 March 1950. The program was cancelled on the same day.

© 2024, Bryan R. Swopes