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)
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)
This photograph shows LZ-5 backing out of its floating shed on Lake Constance, just before its first flight. (George Grantham Bain Collection, Library of Congress)Ferdinand Adolf Heinrich August Graf von Zeppelin (Bundesarchive)
26 May 1909: The creation of Count Ferdinand von Zeppelin, the rigid airship LZ-5 made its first flight at Lake Constance (Bodensee).
This was an experimental airship, 442 feet (136 meters) long, with a diameter of 42 feet (13 meters). Powered by two Daimler engines producing 105 horsepower each, it was capable of 30 miles per hour. The structure of the airship was a framework built of a light alloy covered with a fabric skin. Buoyancy was provided by hydrogen gas stored inside the envelope.
LZ-5 was purchased by the army and renamed ZII. It was destroyed in a storm 24 April 1910.
George S. Welch with North American YF-100A 52-5754. (North American Aviation, Inc.)
25 May 1953: North American Aviation Chief Test Pilot George S. Welch took the YF-100A Super Sabre, U.S. Air Force serial number 52-5754, for its first flight at Edwards Air Force Base. The airplane reached Mach 1.03.
Development of the Super Sabre began with an effort to increase the speed of the F-86D and F-86E Sabre fighters. The wings had more sweep and the airfoil sections were thinner. A much more powerful engine would be needed to achieve supersonic speed in level flight. As design work on the “Sabre 45” proceeded, the airplane evolved to a completely new design. Initially designated XF-100, continued refinements resulted in the first two aircraft being redesignated YF-100A.
North American Aviation Chief Test Pilot George S. Welch in the cockpit of YF-100A 52-5754 at Los Angeles International Airport. (North American Aviation, Inc.)
The two YF-100As, 52-5754 and 52-5755, were 46 feet, 2.4 inches (14.082 meters) long with a wingspan of 36 feet, 9.6 inches (11.217 meters) and height of 14 feet, 4.8 inches (4.389 meters). The Super Sabre had a 49° 2′ sweep to the leading edges of the wings and horizontal stabilizer. The wings were swept to 45° at 25% chord, and had 0° angle of incidence, 0° dihedral, and no twist. The total wing area was 376 square feet (34.932 square meters). The ailerons were placed inboard on the wings to eliminate their twisting effects at high speed. The airplane had no flaps, resulting in a high stall speed in the landing configuration. The horizontal stabilizer was moved to the bottom of the fuselage to keep it out of the turbulence created by the wings at high angles of attack. The pre-production prototypes weighed 18,279 pounds (8,291 kilograms) empty; had a combat weight of 24,789 pounds (11,244 kilograms); and maximum takeoff weight of 28,965 pounds (13,138 kilograms).
The YF-100A had a fuel capacity of 757 U.S. gallons (2,866 liters) in five fuselage tanks, and could carry two external drop tanks for another 550 gallons (2,082 liters).
The new air superiority fighter was powered by a Pratt & Whitney Turbo Wasp XJ57-P-7 engine. The J57 was a two-spool axial-flow turbojet which had a 16-stage compressor section (9 low- and 7 high-pressure stages) and a 3-stage turbine (2 high- and 1 low-pressure stages). The XJ57-P-7 had a Normal Power rating of 7,250 pounds of thrust (32.250 kilonewtons) at 5,570 r.p.m., N1/9,630 r.p.m, N2; Military Power rating was 8,450 pounds thrust (37.587 kilonewtons) at 5,850 r.p.m./9,630 r.p.m., for 30 minutes; and 13,200 pounds thrust (587.717 kilonewtons) at 5,850 r.p.m./9,630 r.p.m. with afterburner, limited to five minutes. The engine was 20 feet, 3.0 inches (6.172 meters) long, 3 feet, 5.0 inches (1.014 meters) in diameter, and weighed 5,126 pounds (2,325 kilograms). Later production aircraft used a J57-P-39 engine, which had the same ratings.
Cutaway illustration of a North American Aviation F-100A Super Sabre. (Boeing)North American Aviation YF-100 Super Sabre 52-5754, 19 May 1953. (North American Aviation, Inc.)The prototype North American Aviation YF-100A Super Sabre, 52-5754, with the North American F-100 team. Chief Test Pilot George S. Welch is in the center of the front row, seated. (North American Aviation, Inc.)
The YF-100A had a maximum speed of 634 knots (730 miles per hour/1,174 kilometers per hour) at Sea Level, and 573 knots (659 miles per hour/1,061 kilometers per hour) at 43,350 feet (13,213 meters). The service ceiling was 46,000 feet (14,021 meters). The combat radius was 422 nautical miles (486 statute miles/782 kilometers), and maximum ferry range, 1,410 nautical miles (1,623 statute miles/2,611 kilometers).
During testing, 52-5754 reached Mach 1.44 in a dive. On 29 October 1953, Colonel Frank K. Everest set a world speed record of 1,215.298 kilometers per hour (755.151 miles per hour) with 52-5754.¹
In service with the United States Air Force, the Super Sabre’s mission changed from air superiority fighter to fighter bomber. It was used extensively during the Vietnam War. North American Aviation, Inc., built 2,294 single and tandem-seat Super Sabres between 1954 and 1959.
The F-100 pushed the State of the Art in the 1950s. There was a very steep learning curve back then. They remained in service with the USAF until 1979, and with the Republic of China Air Force until 1988. They also flew for France and Turkey.
In USAF service, 889 were destroyed in accidents, resulting in the death of 324 pilots. During the Vietnam War, the F-100s flew more combat sorties that all of the 15,000+ P-51 Mustangs during World War II. 186 Super Sabres were shot down by antiaircraft fire, but none were lost to enemy fighters.
North American Aviation YF-100A Super Sabre 52-5754 over Edwards Air Force Base, California, 25 May 1953. (North American Aviation, Inc.)North American Aviation YF-100A Super Sabre 52-5754 lands on the dry lake at Edwards Air Force Base, California. (North American Aviation, Inc.)
George Welch was born George Lewis Schwartz, in Wilmington, Delaware, 10 May 1918. His parents changed his surname to Welch, his mother’s maiden name, so that he would not be effected by the anti-German prejudice that was widespread in America following World War I. He studied mechanical engineering at Purdue, and enlisted in the Army Air Corps in 1939.
North American Aviation YF-100A Super Sabre 52-5754 banks away from a chase plane during a flight test. (U.S. Air Force)
George S. Welch is best remembered as one of the heroes of Pearl Harbor. He was one of only two fighter pilots to get airborne during the Japanese surprise attack on Hawaii, 7 December 1941. Flying a Curtiss P-40B Warhawk, he shot down three Aichi D3A “Val” dive bombers and one Mitsubishi A6M2 Zero fighter. For this action, Lieutenant General H.H. “Hap” Arnold recommended the Medal of Honor, but because Lieutenant Welch had taken off without orders, an officer in his chain of command refused to endorse the nomination. He received the Distinguished Service Cross. During the War, Welch flew the Bell P-39 Airacobra and Lockheed P-38 Lightning on 348 combat missions. He had 16 confirmed aerial victories over Japanese airplanes and rose to the rank of Major.
Suffering from malaria, George Welch was out of combat, and when North American Aviation approached him to test the new P-51H Mustang, General Arnold authorized his resignation. Welch test flew the P-51, FJ-1 Fury, F-86 Sabre and F-100 Super Sabre. He was killed 12 October 1954 when his F-100A Super Sabre came apart in a 7 G pull up from a Mach 1.5 dive.
North American Aviation pre-production prototype YF-100A Super Sabre 52-5754 with drag chute deployed on landing at Edwards Air Force Base, California. The extended pitot boom is used to calibrate instruments early in the flight test program. (U.S. Air Force)North American Aviation YF-100 Super Sabre 52-5754 with external fuel tanks, parked on the dry lake at Edwards Air Force Base, California. (U.S. Air Force)
North American Aviation test pilot Robert C. Chilton standing on the wing of P-51B-10-NA Mustang 42-106435. (North American Aviation, Inc.)
20 May 1941: North American Aviation, Inc., test pilot Robert Creed Chilton took the first XP-51 for its maiden flight at Mines Field, Los Angeles, California. The XP-51 was the fourth production Mustang Mk.I built for the Royal Air Force, AG348 (North American serial number 73-3101).
The Mustang was reassigned to the U.S. Army Air Force, designated as XP-51, serial number 41-038, and sent to Wright Field, Dayton, Ohio, for evaluation.
North American Aviation Mustang Mk.I AG348 at Mines Field, California, 1941. North American Aviation, Inc., photograph 73-0-9. (Ray Wagner Collection/SDASM)North American Aviation Mustang Mk.I AG348, Mines Field, California, 1941. North American Aviation, Inc., photograph 73-0-10. (Ray Wagner Collection/SDASM)North American Aviation Mustang Mk.I AG348 at Mines Field, California, 1941. North American Aviation, Inc., photograph. (Ray Wagner Collection/SDASM)
Later, the XP-51 was extensively tested by the National Advisory Committee for Aeronautics (N.A.C.A.) at the Langley Memorial Aeronautical Laboratory, Langley Field, Hampton, Virginia.
Today, the restored XP-51 is in the collection of the E.A.A. AirVenture Museum at Oshkosh, Wisconsin.
North American Aviation XP-51 41-038 at the NACA Langley Memorial Aeronautical Laboratory. (NASA)
The Mustang Mk.I (NAA Model NA-73) was a single-place, single engine fighter primarily of metal construction with fabric control surfaces. It was 32 feet, 3 inches (9.830 meters) long with a wingspan of 37 feet, 5/16-inches (11.373 meters) and height of 12 feet, 2½ inches (3.721 meters). The airplane’s empty weight was 6,280 pounds (2,849 kilograms) and loaded weight was 8,400 pounds (3,810 kilograms).
North American Aviation XP-51 41-039 at NACA Langley. Note the increased length of the carburetor intake. (NASA)
The Mustang was powered by a liquid-cooled, supercharged, 1,710.597-cubic-inch-displacement (28.032 liter) Allison Engineering Company V-1710-F3R (V-1710-39) single overhead cam (SOHC) 60° V-12 engine with a compression ratio of 6.65:1. The -F3R had a Normal Power rating of 880 horsepower at 2,600 r.p.m., at Sea Level, and 1,000 horsepower at 2,600 r.p.m. at 11,000 feet (3,353 meters). It had a Takeoff and Military Power rating of 1,150 horsepower at 3,000 r.p.m., to 11,800 feet (3,597 meters). The engine turned a 10 foot, 9 inch (3.277 meter) diameter three-bladed Curtiss Electric constant-speed propeller through a 2.00:1 gear reduction. The V-1710-F3R was 7 feet, 4.38 inches (2.245 meters) long, 3 feet, 0.54 inches (0.928 meters) high, and 2 feet, 5.29 (0.744 meters) wide. It weighed 1,310 pounds (594 kilograms).
The Mustang Mk.I had a maximum speed of 382 miles per hour (615 kilometers per hour) at 13,700 feet (4,176 meters), the Allison’s critical altitude, and cruise speed of 300 miles per hour (483 kilometers per hour). The service ceiling was 30,800 feet (9,388 meters) and range was 750 miles (1,207 kilometers).
North American Aviation XP-51 41-038 at NACA Langley Memorial Aeronautical Laboratory, right profile. (NASA)
The Mustang Mk.I was armed with four air-cooled Browning .303 Mk.II aircraft machine guns, two in each wing, and four Browning AN-M2 .50-caliber machine guns, with one in each wing and two mounted in the nose under the engine.
North American Aviation XP-51 41-038 at NACA Langley Memorial Aeronautical Laboratory, right three-quarter view. (NASA)
The Mk.I was 30 m.p.h. faster than its contemporary, the Curtiss P-40 Warhawk, though both used the same engine. Below 15,000 feet, the Mustang was also 30–35 m.p.h faster than a Supermarine Spitfire, which had a more powerful Roll-Royce Merlin V-12.
The XP-51 would be developed into the legendary P-51 Mustang. In production from 1941 to 1945, a total of 16,766 Mustangs of all variants were built.
North American Aviation XP-51 41-038 at NACA Langley Memorial Aeronautical Laboratory, rear view. (NASA)
Robert Creed Chilton was born 6 February 1912 at Eugene, Oregon, the third of five children of Leo Wesley Chilton, a physician, and Edith Gertrude Gray. He attended Boise High School in Idaho, graduating in 1931. Chilton participated in football, track and basketball, and also competed in the state music contest. After high school, Chilton attended the University of Oregon where he was a member of the Sigma Chi fraternity (ΣΧ). He was also a member of the Reserve Officers Training Corps (ROTC).
Bob Chilton enlisted as an Aviation Cadet in the U.S. Army Air Corps, 25 June 1937. He was trained as a fighter pilot at Randolph Field and Kelly Field in Texas, and was commissioned as a Second Lieutenant in 1938. Lieutenant Chilton was assigned to fly the Curtiss P-36 Hawk with the 79th Pursuit Squadron, 20th Pursuit Group, at Barksdale Field, Louisiana. Because of a medical condition, he was released from active duty, 1 April 1939.
At some time prior to 1940, Bob Chilton, married his first wife, Catherine. They lived in Santa Maria, California, where he worked as a pilot at the local airport.
In January 1941, Chilton went to work as a production test pilot for North American Aviation, Inc., Inglewood, California. After just a few months, he was assigned to the NA-73X.
Chilton married his second wife, Betty W. Shoemaker, 15 November 1951.
On 10 April 1952, Bob Chilton returned to active duty with the U.S. Air Force, with the rank of lieutenant colonel. He served as Chief of the Republic F-84 and F-105 Weapons System Project Office, Air Material Command, at Wright-Patterson Air Force Base, Dayton, Ohio, until 9 March 1957.
From 1958, Chilton was a vice president for Horkey-Moore Associates, an engineering research and development company in Torrance, California, founded by former North American aerodynamacist Edward J. Horkey. In 1961, he followed Horkey to the Space Equipment Corporation, parent company of Thompson Industries and Kerr Products, also located in Torrance. Chilton served as corporate secretary and contracts administrator.
Chilton married his third wife, Wilhelmina E. Redding (Billie E. Johnson) at Los Angeles, 26 July 1964. They divorced in 1972.
In 1965, Bob Chilton returned to North American Aviation as a flight test program manager. He retired in 1977.
Robert Creed Chilton died at Eugene, Oregon, 31 December 1994, at the age of 82 years.
North American Aviation XP-51 at Wright Field. (Charles M. Daniels Collection, San Diego Air & Space Museum Archives, Catalog #: 15_002838)
19 May 1934: Soviet test pilot Mikhail Mikhaylovich Gromov made the first flight of the Tupolev ANT-20 Maxim Gorky. This was the largest airplane of its time. Designed by Andrei Tupolev to carry 72 passengers, the giant airplane was operated by eight crew members.
Used primarily as a Soviet propaganda tool, it also carried a powerful broadcast radio station, a printing shop, and loudspeakers.
Constructed of corrugated sheet metal for rigidity and strength, the ANT-20 was 107 feet, 11¼ inches (32.899 meters) long, with a wingspan of 206 feet, 8¼ feet inches (62.998 meters) and height of 34 feet, 9¼ inches (10.598 meters). Its empty weight was 62,700 pounds (28,440.2 kilograms) and the maximum takeoff weight was 116,600 pounds (52,888.9 kilograms)
Tupolev ANT-20 six-engine civil transport. Two additional engines would be added later. (Tupolev)
The ANT-20 was powered by eight liquid-cooled, supercharged, 2,896.1-cubic-inch-displacement (46.928 liter) Mikulin AM-34FRN single overhead cam (SOHC) 60° V-12 engines, rated at 1,200 horsepower at 2,000 r.p.m., each. They drove two-bladed propellers. Two of the engines were mounted above the fuselage, in a push-pull configuration.
Corrugated sheet metal was used for the skin of the ANT-20’s wings and fuselage.
Maxim Gorky had a maximum speed of 137 miles per hour (220.5 kilometers per hour), a service ceiling of 4,500 meters (14,764 feet) and a range of 750 miles (1,207 kilometers).
Just 364 days after its first flight, 18 May 1935, Maxim Gorky crashed following a mid-air collision during a formation flight over Moscow. 45 people were killed.
The ANT-20 flies over Red Square with an airplane off each wing.M.M. Gromov, 1917
Mikhail Mikhaylovich Gromov was born 24 February 1899, at Tver, about 110 miles (180 kilometers) northwest of Moscow. He was the son of Mikhail Konstantinovich Gromov, an “intellectual” who had studied medicine at Moscow University, and Lyubov Ignayevna Gromov, a midwife. The family were of the nobility, but poor.
The younger Gromov attended the Resurrection Real School, and then the Moscow Higher Technical School for Aviation. He graduated in 1917. Gromov was taught to fly by Boris Konstantinovich Welling, a pioneer in Russian long-distance flights. After working as a flight instructor, Gromov began test flying. He became the chief test pilot for the Tupolev Design Bureau. By the outbreak of World War II, he had test flown twenty-five different airplanes.
In 1926, Gromov made a non-stop long-distance flight in a Tupolev ANT-3, from Moscow via Berlin, Paris, Rome, Vienna, Prague, Warsaw and back to Moscow. The flight took 34 hours. In 1934, he flew a Tupolev ANT-25 12,411 kilometers (7,712 miles) in a closed circuit over 75 hours. For this accomplishment, he was named a Hero of the Soviet Union.
From 12–14 July 1937, Gromov set a world record for distance in a straight line, flying an ANT-25 from Moscow to San Jacinto, California, a distance of 10,148 kilometers (6,306 miles).¹ The duration of this flight was 62 hours, 17 minutes.
n March 1941, Gromov became the first director of the Flight Research Institute at Zhukovsky, southeast of Moscow. The Institute was later named the M.M. Gromov Flight Research Institute, in his honor.
In 1942, during The Great Patriotic War, Gromov commanded the Soviet long range air forces on the Kalinin Front. He next commanded the 3rd Air Army, 1942–1943, and the 1st Air Army, 1943–1944. In 1945, he returned to test flying.
Colonel General Mikhail Mikhaylovich Gromov, 1946
Following the War, Gromov continued to work in the aviation industry, but following a disagreement with the Minister of Aviation, Pyotr Vasilyevich Dementiev, over the issue of quality vs. quantity and the safety of the test pilots, he retired. Later, he entered politics and was twice elected to the Supreme Soviet.
During his military career, in addition to the Gold Star Medal of Hero of the Soviet Union, Colonel General Mikhail Mikhaylovich Gromov was awarded the Order of Lenin four times, the Order of the Red Banner (four), and the Order of the Red Star (three). He died 22 January 1985.
