Category Archives: Aviation

31 July 1923: Browning Machine Gun, Caliber .50, AN-M2

Aviation, , , , ,
This photograph shows SSGT Maynard H. Smith with a Browning .50-caliber machine gun at the left waist position of a B-17 Flying Fortress. (U.S. Air Force)

31 July 1923: The original patent application, Serial No. 654,955, for the legendary Browning .50-caliber machine gun was filed with the United States Patent Office on 31 July 1923. Patent Number 1,628,226 was issued to the estate of John Moses Browning by the Patent Office on 10 May 1927.

The majority of United States combat aircraft during World War II were armed with the Browning Machine Gun, Caliber .50, AN-M2. The machine gun could be mounted as a fixed weapon in the aircraft’s wings or nose, in flexible mounts, or power-operated turrets.

Three Browning .50-caliber machine guns and belted ammunition installed in the left wing of a Vought-Sikorsky F4U-1 Corsair, 11 August 1942. (Vought-Sikorsky)

The  basic aircraft Browning machine gun, cal. .50, AN-M2. . . is an automatic, recoil-operated, belt-fed, air-cooled machine gun. The metallic link disintegrating belt is used in all firing of the gun. The gun is designed for all cal. .50 aircraft machine gun installations. By properly repositioning some of the component parts, ammunition may be fed into the gun from either the right or the left side.

—TM9-225 War Department Technical Manual, BROWNING MACHINE GUN, CALIBER .50, AN-M2, AIRCRAFT, BASIC, 28 January 1947, Section II., Paragraph 3. General, at Page 2

Illustration of the basic .50-caliber Browning machine gun, AN-M2. (War Department)
John Moses Browning

The Browning Machine Gun (“BMG”) was designed by John Moses Browning, who had also designed the Automatic Pistol, Caliber .45, M1911, the standard sidearm of the U.S. military for 74 years;  the Rifle, Caliber .30, Automatic, Browning, M1918 (best known as the “Browning Automatic Rifle” or “BAR”); the Browning Machine Gun, Caliber .30, M1919; and the Browning Hi-Power, a 9 × 19 mm double-action semiautomatic pistol designed for Fabrique National (FN) of Herstal, Belgium.

The AN-M2 aircraft machine gun has an overall length of 56.25 inches (1.429 meters) and weighs 61.00 pounds (27.67 kilograms). The barrel is cylindrical, and 36.00 inches (0.91 meters) long. It is surrounded by a barrel jacket with ventilation holes to dissipate heat. The bore has 8 rifled-grooves with a right-hand twist, making one complete turn in every 15.00 inches (0.381 meters).

John Browning with a water-cooled version of his .50-caliber machine gun. (Museums at Union Station/The Wall Street Journal)

The basic AN-M2 gun could be modified to be manually fired with the substitution of a “spade grip” back plate. It could also be changed from left-hand ammunition feed to right hand by reversing some internal parts.

The M2 machine gun had a rate of fire of 750 to 850 rounds per minute.

Armorers load disintegrating-link belts of .50-caliber ammunition for the eight machine guns of a Republic P-47 Thunderbolt. (U.S. Air Force)

Ammunition is ball, armor-piercing, armor-piercing-incendiary, tracer, blank (no bullet), and dummy. The armor-piercing cartridge, M2, has a muzzle velocity of 2,840 feet per second (866 meters per second) and maximum range of 7,275 yards (6,652 meters). Some .50-caliber rounds have muzzle velocities as high as 3,450 feet per second (1,052 meters per second), though most range from 2,730 fps to 2,900 fps (832–884 m/s). The ammunition produces chamber pressures of approximately 55,000 pounds per square inch (3,792 bar).

A gunner fires the two Browning .50-caliber machine guns of a B-17’s ball turret. (U.S. Air Force)

The .50 BMG cartridge is 5.45 inches (13.843 centimeters) long (NATO 12.7 × 99). The rimless, tapered bottleneck case is 3.91 inches (9.931 centimeters) long, with diameters of 0.560 inches (14.224 millimeters) at the neck, 0.735 inches (18.669 millimeters) at the shoulder, and 0.804 inches (20.422 millimeters) at the base. The bullet is 2.31 inches (58.67 millimeters) long, with a maximum diameter of 0.510 inches (12.954 millimeters) and weighs 706.7 grains (1.6 ounces, 45.8 grams).

Lieutenant Clark Gable with a belt of linked .50-caliber machine gun cartridges. The colored tips of the bullets identify armor piercing, incendiary or tracer ammunition.
Armorers carry Browning AN-M2 .50-caliber machine guns and belts of linked ammunition to a P-51 Mustang. (U.S. Air Force)

© 2018, Bryan R. Swopes

31 July 1901

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(Bröckelmann (Hrsg): Wir Luftschiffer, Ullstein, 1909)

31 July 1901: At “10 minutes before 11 in the morning,” the gas balloon Preussen (Prussia) began to ascend from Tempelhofer Felde at Berlin, capital city of the Königreich Preußen (Kingdom of Prussia) and the German Empire.

Reinhard Joachim Süring, 1907

Carried aloft in the open gondola were two men, Reinhard Joachim Süring of the Prussian Meteorological Institute, and Josef Arthur Stanislas Berson.

There was a light wind from the northwest, and the air temperature was 23.4 °C. (74.1 °F.). The air pressure was 762.0 millimeters (30.0 inches) of Mercury.

The balloon was made by Continental Caoutchouk und Guttapercha-Compagnie, Hannover, at a cost of 20,000ℳ. To inflate the balloon at the airfield, 1,080 pressurized cylinders containing 5,400 cubic meters (190,700 cubic feet) of hydrogen were used. When fully inflated at altitude, the spherical envelope had a maximum volume of 8,400 cubic meters (296,643 cubic feet).

Josef Arthur Stanislas Berson, 1901

In the gondola were four 1,000 liter (35 cubic foot) cylinders of oxygen for breathing, and 8,000 kilograms (17,637 pounds) pounds of ballast contained in 63 kilogram (139 pound) sand bags and 36 kilogram (79 pound) bags of iron filings.

Süring and Berson reached an altitude of 5,000 meters (16,404 feet) in 40 minutes. The air  temperature was -7 °C. (19.4  °F.). The envelope had reached its maximum volume by this time.

After 3 hours, Preussen had ascended to 8,000 meters (26,247 feet), and in four hours, it reached 9,000 meters (29,528 feet). There, the air temperature was -32 °C. (-25.6 °F.).

The aeronauts had run out of breathing oxygen at 8,170 meters (26,804 feet).

The last observed altitude the men reached was 10,225 meters (33,547 feet), with an air temperature of -35.7 °C. (-32.3 °F.). Josef Berson saw Süring lose consciousness and pulled the emergency valve to vent gas from the balloon and start its descent. He too lost conciousness due to hypoxia.

“. . . dass der Ballon noch kurz nachdem auch der zweite Korbinsasse bei 10500 m das Bewussstein verloren hatte, um mindestens 300 weitere Meter stieg, sonit Maximalhöhe von sicherlich 10800 m (vielleicht 11000 m) erreicht und hierauf unfer Nachwirkung des Ventilzuges in ein jahes Fallen umbog.”

[Google English translation: “Shortly after the second basket occupant had lost the awareness stone at 10500 m, the balloon rose at least 300 meters further, reaching a maximum height of certainly 10800 m (perhaps 11000 m), and then reversed our after-effect of the valve train into a sudden fall.]

Both men regained consciousness at about 6,000 meters, but were unable to regain control of the ballon’s descent until 2,500 meters. Süring and Berson returned to Earth near Briesen, Kreis Cottbus, Germany, at 18:25 that evening. The total duration of their flight was 7 hours, 36 minutes.

© 2019, Bryan R. Swopes

30 July 1983

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Dago Red, Reno, 1988 (Wikimedia)

30 July 1983: Flying a modified World War II-era fighter, Frank Taylor set a  Fédération Aéronautique Internationale (FAI) World Record for Speed Over a 15-to-25 Kilometer Straight Course ¹ with an average speed of 832.12 kilometers per hour (517.056 miles per hour)—(0.686 Mach). The record flight took place at Mojave Airport (MHV) in the high desert of southern California. The runway elevation at MHV is 2,801 feet above Sea Level (853.8 meters). The airport is about 19 miles (30.6 kilometers) northwest of Edwards Air Force Base.

Flying magazine briefly commented the record run:

“. . . he ran the Mustang’s Merlin engine at 110 inches of manifold pressure [7.93 Bar] and 3,800 r.p.m. (it was designed for 61 inches and 3,000 r.p.m.) and fed it 110 gallons [416.4 liters] of 115/145-octane fuel with manganese additive, enough for only two passes.”

—Flying, Vol. 112, No. 1, January 1985, at Page 64.

Taylor’s air racer was Dago Red,² a North American Aviation P-51D-30-NA Mustang. The fighter had been built at Inglewood, California, in 1944 and assigned U.S. Army Air Corps serial number 44-74996. When the U.S. Air Force retired the last of its Mustangs from Air National Guard service in 1957, 44-74996 was sold as surplus.

Dago Red would have appeared like this F-51D when in U.S. Air Force markings. This fighter, 44-74998, was the second Mustang to be built by North American Aviation at Inglewood after Dago Red. (U.S. Air Force)

The airplane was issued the civil registration N5410V. The Mustang changed ownership many times before it crashed after an engine failure at Concorde, California, 16 August 1970. After a decade in storage, the wreck was rebuilt as an air racer.

North American Aviation P-51D-30-NA Mustang 44-74996, N5410V. (Unattributed)

The P-51D was modified for air racing. It’s wings were “clipped” (shortened) and the upper fuselage re-shaped, both intended to reduce aerodynamic drag. Approximately 2½ feet (0.76 meters) were removed from each wing tip. The Rolls-Royce Merlin V-12 engine also received many internal modifications to increase power output, and to survive that increase. The Merlin turned a Hamilton Standard “paddle blade” propeller. (Dago Red‘s current engine is based on the post-war Rolls-Royce Merlin 620-series commercial variant.)

On 21 August 1989, an Unlimited Class Grumman F8F-2 Bearcat, Rare Bear, exceeded Dago Red‘s record speed while setting its own FAI record,³ averaging 850.24 kilometers per hour (528.315 miles per hour) over a shorter 3 kilometer course. Both airplanes’ records stood until they were retired due to changes in the sporting code.

In addition to its world speed record, Dago Red has won the National Championship Air Races six times.

Dago Red (Dago Red LLC)
Carrari Dago Red

¹ FAI Record File Number 8434

² “Dago Red” is a derogatory American slang term referring to an Italian-style blended dark red wine. It was also the name of a commercial brand sold in the 1970s. Dago Red sold for about $2.00 per bottle ($13.29 in 2020). (Thanks to “Dr. Vinny” for the info).

³ FAI Record File Number 8437

© 2020, Bryan R. Swopes

 

30 July 1939

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A color transparency of the Boeing XB-15
A color transparency of the Boeing XB-15 in flight near Floyd Bennett Field, Long Island, New York, circa 1941. (Rudy Arnold Collection, National Air and Space Museum)

30 July 1939: Major Caleb Vance Haynes, Air Corps, United States Army, with Captain William D. Old, Master Sergeant Adolph Cattarius and Staff Sergeant William J. Heldt, flew the Boeing XB-15 experimental long range heavy bomber to a Fédération Aéronautique Internationale (FAI) World Record for Greatest Payload Carried to a Height of 2,000 meters. The XB-15 carried 14,135 kilograms (31,162 pounds) to an altitude of 2,000 meters (6,562 feet) over Fairfield, Ohio.¹ The flight set a second record by carrying 10,000 kilograms (22,046 pounds) to an altitude of 8,228 feet (2,508 meters).² Both records were certified by the National Aeronautic Association, the American organization representing the FAI.

Major Caleb V. Haynes, Captain William D. Old, Master Sergeant Adolph Cattarius and Staff Sergeant William J. Heldt, crew of the record-setting Boeing XB-15. (FAI)
Boeing XB-15 35-277 at NACA Langley Memorial Aeronautical Laboratory, 13 September 1938. (NASA)
Boeing XB-15 35-277
Boeing XB-15 35-277

The Boeing Model 294, designated XB-15 by the Air Corps, was an experimental airplane designed to determine if a bomber with a 5,000 mile range was possible. It was designed at the same time as the Model 299 (XB-17), which had the advantage of lessons learned by the XB-15 design team. The XB-15 was larger and more complex than the XB-17 and took longer to complete. It first flew more than two years after the prototype B-17.

Designers had planned to use an experimental 3,421.194-cubic-inch-displacement (56.063 liter) liquid-cooled, supercharged and turbosupercharged Allison V-3420 twenty-four cylinder, four-bank “double V” engine. It produced a maximum of  2,885 horsepower at 3,000 r.p.m. The engine was not available in time, however, and four air-cooled Pratt & Whitney R-1830 (Twin Wasp) engines were used instead. With one-third the horsepower, this substitution left the experimental bomber hopelessly underpowered as a combat aircraft. (The Douglas XB-19 was retrofitted with V-3420s in 1942, and re-designated XB-19A.)

Boeing XB-15 35-277, a prototype long-range heavy bomber. (U.S. Air Force)
Boeing XB-15 35-277, a prototype long-range heavy bomber. (U.S. Air Force)
Boeing XB-15 35-277. (U.S. Air Force)
Boeing XB-15 35-277. (U.S. Air Force)

The XB-15 was a very large four-engine mid-wing monoplane with retractable landing gear. It was of aluminum monocoque construction with fabric-covered flight control surfaces. The XB-15 had a ten-man crew which worked in shifts on long duration flights.

The prototype bomber was 87 feet, 7 inches (26.695 meters) long with a wingspan of 149 feet (45.415 meters) and overall height of 18 feet, 1 inch (5.512 meters). The airplane had an empty weight of 37,709 pounds (17,105 kilograms) and maximum takeoff weight of 70,706 pounds (32,072 kilograms)—later increased to 92,000 pounds (41,730 kilograms).

A ¼-scale model of the Boeing XB-15 inside the Full-Scale Wind Tunnel at the National Advisory Committee for Aeronautics (NACA) Langley Memorial Aeronautical Laboratory, Hampton, Virginia. The model has a wingspan of 37.3 feet (11.37 meters). (NASA)

The XB-15’s wings used a symmetrical airfoil and were very highly tapered (4:1 from root to tip). They had an angle of incidence of 4½° and 4½° dihedral. The total area was 2,780 square feet (258.271 square meters). A contemporary aeronautical publication wrote, “The airfoil provides constant center of pressure, minimum profile drag with flaps up and high maximum lift with flaps down.” The XB-15’s wings were adapted by Boeing for the Model 314 Clipper flying boat.

As built, the XB-15 was equipped with four air-cooled, supercharged, 1,829.39-cubic-inch-displacement (29.978 liter) Pratt & Whitney R-1830-11 (Twin Wasp S1B3-G) two-row 14-cylinder radial engines with a compression ratio of 6.7:1. The R-1830-11 was rated at 850 horsepower at 2,450 r.p.m. and 5,000 feet (1,524 meters), and 1,000 horsepower at 2,600 r.p.m. for take off. They turned three-bladed controllable-pitch propellers through a 3:2 gear reduction. The R-1830-11 was 4 feet, 8.66 inches (1.439 meters) long with a diameter of 4 feet, 0.00 inches (1.219 meters), and weighed 1,320 pounds (599 kilograms).

Boeing XB-15 35-277
Boeing XB-15 35-277

The experimental airplane had a cruise speed of 152 miles per hour (245 kilometers per hour) at 6,000 feet (1,829 meters), and a maximum speed of 200 miles per hour ( kilometers per hour) at 5,000 feet (1,524 meters). The service ceiling was 18,900 feet (5,761 meters) and maximum range was 5,130 miles (8,256 kilometers).

The bomber could carry a maximum of 12,000 pounds (5,443 kilograms) of bombs in its internal bomb bay, and was armed with three .30-caliber and three .50-caliber machine guns for defense .

Only one XB-15 was built. During World War II it was converted to a transport and re-designated XC-105. In 1945 35-277 was stripped and abandoned at Albrook Field, Territory of the Canal Zone, Panama.

Boeing XC-105 35-277 in Panama
Boeing B-15 35-277 arrives in Panama (49509 A.C.)

¹ FAI Record File Number 8739

² FAI Record File Number 8740

© 2018, Bryan R. Swopes

30 July 1935

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Northrop 3A. (Dan Shumaker Collection/1000aircraftphotos.com)
Lieutenant Arthur Henry Skaer, Jr. (David Schwind/Ancestry)

30 July 1935: The Northrop 3A was a prototype pursuit built to compete for the U.S. Army Air Corps’ fighter contract. It flew against the Curtiss-Wright Model 75 Hawk, X17Y, and the Seversky SEV-1XP, X18Y. During flight testing, the Northrop entry was found to have undesirable spin characteristics and was returned to the builder for further work.

On the afternoon of 30 July 1935, 1st Lieutenant Arthur Henry Skaer, Jr., Air Corps Reserve, who was employed by Northrop as a test pilot, took off from Mines Field (now Los Angeles International Airport, LAX) to conduct spin tests.

Skaer never returned. An extensive search was conducted of the nearby Palos Verdes Peninsula and the southern California coastal waters. An Air Corps search plane spotted what appeared to be fresh oil on the surface, but no other sign of Lieutenant Skaer or the Northrop 3A were ever found.

The United Press reported:

Mystery Airplane Of Army Missing; Hunt Under Way

Fear felt for Safety of Reserve Flier in Coast Hills

(By United Press)

     LOS ANGELES, July 30—Fear for the safety of Lieutenant Arthur Skaer, lost in a test flight in a new “mystery” pursuit plane—reportedly the fastest army plane in the world—deepened tonight when planes searching the desolate Palos Verdes hills, where he was last seen.

     Skaer, army reserve test flier, took off shortly afternoon from Mines field, and the plane has not been reported since.

Others to Search

     At dawn, planes from the sheriff’s air detail, national guard planes from the Long Beach, Cal., airport, and possibly planes from the army air base at March field, Riverside, Cal., will join the search, combing a 200-mile coastal strip from San Diego northward.

     The plane, latest weapon in army air warfare, reportedly was able to travel 300 miles an hour, and was a secret design, rigidly guarded by the U.S. army and officials of the Northrop factory, where it was built.

Last Report of Sighting

     Reports that his plane had been last seen over the Palos Verdes area between San Pedro and Venice, Cal., resulted in a search by a squad of army reserve planes from the Long Beach air base under Lieutenant John K. Nissley.

     The planes circled over the hills until after dark, but saw no sign of the Northrop. Meanwhile, Captain Claude Morgan of the sheriff’s air detail was preparing to join the search in the morning.

—The Salt Lake Tribune, Vol. 131, No. 108, Wednesday, 31 July 1935, Page 1, Column 3

—Los Angeles Times, Vol. LIV, Thursday, 1 August 1935, Page 1, Column 6 and 7

Arthur Henry Skaer, Jr., was born at Denver, Colorado, circa 1911. He was the son of Arthur Henry Skaer, Sr., purchasing agent for a manufacturing company, and Ada Jane Scott Skaer.

Skaer graduated from East High School in Denver in 1929. While there, he was a member of the student council, the track and wrestling teams, and the cooking club.

On 29 April 1935, Lieutenant Skaer married Miss Dorothy B. Firebaugh, a fellow student from East High School. They resided in Walnut Park, California.

Northrop 3A

The Northrop 3A was a single engine, single place, low wing monoplane with an enclosed cockpit and retractable landing gear. It was of all-metal monocoque construction. The airplane was 22 feet, 3 inches (6.782 meters) long with a wingspan of 34 feet, 6 inches (10.516 meters) and height of 9 feet, 1 inch (2.769 meters). It had an operational weight of 3,900 pounds (1,769 kilograms).

The Northrop 3A, photographed 30 July 1935, the day it disappeared off the coast of southern California. No trace was found of it or the pilot, 1st Lieutenant Arthur Henry Skaer, Jr. (Ray Wagner Collection, San Diego Air & Space Museum Archives, Catalog #: 16_005638)

The Northrop 3A was powered by an air-cooled, supercharged, 1,535.387-cubic-inch displacement (25.160 liters) Pratt & Whitney Twin Wasp Junior, two-row, 14-cylinder radial engine. The specific model is not known but most sources state that it was rated at 700 horsepower.

The prototype was unarmed, but was planned to carry a single .30-caliber or .50-caliber machine gun.

Northrop 3A

© 2023, Bryan R. Swopes