Tag Archives: Browning Aircraft Machine Gun Caliber .30 M2

19 August 1940

Vance Breese (SDA&SM)

19 August 1940: At Mines Field (now known as Los Angeles International Airport), the first North American Aviation B-25 twin-engine medium bomber, serial number 40-2165, took off on its first flight with test pilot Vance Breese at the controls and engineer Roy Ferren in the co-pilot’s position.

The airplane, North American model NA-62, serial number 62-2834, was developed from two earlier designs which had been evaluated by the U.S. Air Corps but rejected, and it was ordered into production without a prototype being built.

The first few B-25s built—sources vary, but 8–10 airplanes—were built with a constant dihedral wing. Testing at Wright Field showed that the airplane had a slight tendency to “Dutch roll” so all B-25s after those were built with a “cranked” wing, with the outer wing panels having very slight dihedral ¹ and giving it the bomber’s characteristic “gull wing” appearance. The two vertical stabilizers were also increased in size.

40-2165 was retained by North American for testing while the next several aircraft were sent to Wright Field.

Roy Ferren (SDA&SM)

The B-25 was named Mitchell in honor of early air power advocate Brigadier General Billy Mitchell. A total of 9,984 B-25s, F-10 reconnaissance variants and U.S. Navy and Marine Corps PBJ-1 patrol bombers were built by North American Aviation at Inglewood, California and Kansas City, Kansas. The last one, a TB-25J, remained in service with the U.S. Air Force until 1960.

Twenty-three B-25s were built before the B-25A Mitchell went into production. The B-25 was operated by a crew of five. It was 54 feet, 1 inch (16.485 meters) long with a wingspan of 67 feet, 6.7 inches (20.592 meters) and overall height of 16 feet, 4 inches (4.978 meters). The empty weight was 17,258 pounds (7,828 kilograms) and the maximum gross weight was 28,557 pounds (12,953 kilograms).

Scale model of a North American Aviation B-25 medium bomber being tested in a wind tunnel. (4″ × 5″ Kodachrome transparency by Alfred Palmer)

The B-25 was powered by two air-cooled, supercharged, 2,603.737-cubic-inch-displacement (42.688 liter) Wright Aeronautical Division Cyclone 14 GR2600B665 (R-2600-9) two-row 14-cylinder radial engines which were rated at 1,500 horsepower at 2,400 r.p.m., and 1,700 horsepower at 2,600 r.p.m. for takeoff. These engines (also commonly called “Twin Cyclone”) drove three-bladed Hamilton Standard Hydromatic variable-pitch propellers through 16:9 gear reduction. The R-2600-9 was 5 feet, 3.1 inches (1.603 meters) long and 4 feet, 6.26 inches (1.378 meters) in diameter. It weighed 1,980 pounds (898 kilograms).

The medium bomber had a maximum speed of 322 miles per hour (518 kilometers per hour) at 15,000 feet (4,572 meters) and a service ceiling of 30,000 feet (9,144 meters). It could carry a 3,000 pound bomb load 2,000 miles (3,219 kilometers).

Defensive armament consisted of three air-cooled Browning M2 .30-caliber aircraft machine guns and one Browning AN-M2 .50-caliber machine gun.

After testing was completed, B-25 40-2165 was retained by North American and modified as a company transport. On 8 January 1945, flown by Edgar A. Stewart, the airplane suffered an engine failure and made a forced landing at Mines Field—the location of its first flight. The prototype B-25 was damaged beyond repair.

Front view of the first North American B-25 Mitchell, 40-2165. The constant dihedral wing was used on the first nine airplanes built. (U.S. Air Force)
Front view of the first North American Aviation B-25 Mitchell medium bomber, 40-2165, at Mines Field, August 1940. The constant dihedral wing was used on the first nine airplanes built. (U.S. Air Force)
North American Aviation NA-62, B-25 Mitchell 40-2165, left front. (U.S. Air Force)
North American B-25 Mitchell 40-2165, left rear. (U.S. Air Force)
North American Aviation B-25 Mitchell 40-2165, left rear. (U.S. Air Force)
North American Aviation B-25A Mitchell twin-engine medium bomber in flight near Wright Field, Ohio, 1 May 1941. (Rudy Arnold Photo Collection, Smithsonian Institution National Air and Space Museum XRA-4945)
North American Aviation B-25A Mitchell twin-engine medium bomber in flight near Wright Field, Ohio, 1 May 1941. (Rudy Arnold Photo Collection, Smithsonian Institution National Air and Space Museum XRA-4946)

¹ The wing center section of the B-25H and B-25J has 4° 38′ 23″ dihedral. The outer sections have 0° 21′ 39″. The wing has 2° 29′ 37″ negative twist.

© 2019, Bryan R. Swopes

28 July 1935

Boeing Model 299, NX13372, photographed during its first flight, 28 July 1935. (The Boeing Company)
Boeing Model 299 X13372, photographed during its first flight, 28 July 1935. (The Boeing Company)
Boeing test pilot Les Tower. (Boeing)
Boeing’s Chief Test Pilot Leslie R. Tower.

28 July 1935, At Boeing Field, Seattle, Chief Test Pilot Leslie Ralph (“Les”) Tower and Louis Waite took off on the maiden flight of the Boeing Model 299, X13372,¹ a prototype four-engine long range heavy bomber. For approximately one-and-a-half hours, Tower flew back and forth between Tacoma and Fort Lewis. When he landed, he said, “It handles just like a little ship—a little bigger, of course.”

The Boeing Model 299 was a four-engine bomber operated by a crew of eight. It  was designed to meet a U.S. Army Air Corps proposal for a multi-engine bomber that could carry a 2,000 pound (907 kilogram) bomb load a distance of 2,000 miles (3,219 kilometers) at a speed greater than 200 miles per hour (322 kilometers per hour). Design of the prototype began in June 1934 and construction was started 16 August 1934. The Air Corps designated it B-299, and later, XB-17. It did not carry a military serial number, being marked with civil experimental registration X13372.

The Boeing Model 299 with Mount Rainier. (U.S. Air Force)
The Boeing Model 299 with Mount Rainier. (U.S. Air Force)

The Model 299 was 68 feet, 9 inches (20.955 meters) long with a wingspan of 103 feet, 9–3/8 inches (31.633 meters) and height of 14 feet, 11–5/16 inches (4.554 meters). Its empty weight was 21,657 pounds (9,823 kilograms). The maximum gross weight was 38,053 pounds (17,261 kilograms).

The prototype was powered by four air-cooled, supercharged, 1,690.537-cubic-inch-displacement (27.703 liter) Pratt & Whitney Hornet S1E-G nine-cylinder radial engines with a compression ratio of 6.5:1. The S1E-G was rated at 750 horsepower at 2,250 r.p.m., and 875 horsepower at 2,300 r.p.m. for takeoff, using 87-octane gasoline. They turned 11 foot, 6 inch (3.505 meters) diameter, three-bladed, Hamilton Standard Hydromatic constant-speed propellers through a 3:2 gear reduction. The S1E-G was 4 feet, 1.38 inches (1.254 meters) long, 4 feet, 6.44 inches (1.383 meters) in diameter and weighed 1,064 pounds (483 kilograms)

Boeing Model 299. (U.S.  Air Force)

In flight testing, the Model 299 had a cruise speed of 204 miles per hour (328 kilometers per hour) and a maximum speed of 236 miles per hour (380 kilometers per hour) at 10,000 feet (3,048 meters). The service ceiling was 24,620 feet (7,504.2 meters). Its maximum range was 3,101 miles (4,991 kilometers). Carrying a 2,573 pounds (1,167 kilograms) load of bombs, the range was 2,040 miles (3,283 kilometers).

Boeing 299 NX13372, all engines running.
Boeing 299 X13372, all engines running.

The XB-17 could carry eight 500 pound (226.8 kilogram) bombs in an internal bomb bay. Defensive armament consisted of five air-cooled Browning .30-caliber machine guns.

Nose turret of the Boeing Model 299, photographed 24 July 1935. (U.S. Air Force)
Nose turret of the Boeing Model 299, photographed 24 July 1935. (The Boeing Company)

X13372 was destroyed when it crashed on takeoff at Wright Field, Dayton, Ohio, 30 October 1935. An Army Air Corps pilot making his first familiarization flight neglected to remove the control locks. This incident led directly to the creation of the ”check list” which is used by all aircraft crew members.

Waist gun position of the Boeing 299. (U.S. Air force)
Waist gun position of the Boeing 299. (The Boeing Company)

Designated XB-17 by the Army Air Corps, this airplane and the YB-17 pre-production models that followed would undergo several years of testing and improvement before entering production as the B-17 Flying Fortress, a legendary airplane of World War II. By the end of the war 12,731 B-17s had been built by Boeing, Douglas and Lockheed Vega.

Boeing Model 299 NX13372, designated XB-17, at Wright Field, Ohio, 1935. (U.S. Air Force)
Boeing Model 299 X13372, designated XB-17, at Wright Field, Ohio, 1935. (U.S. Air Force)

Leslie Ralph Tower was born at Sisseton, South Dakota, 21 January 1903. He was the first of three children of Ralph R. Tower, a farmer who would later serve as a state senator for Montana, and Mayme Amanda Johnson Tower, a Swedish immigrant.

Les Tower attended high school at Polson, Montana, graduating in 1922. He then attended the University of Washington, where he studied engineering. He was a member of the Radio Club.

Tower enlisted in the United States Army as an aviation cadet, training at Brooks and Kelly airfields in Texas. He then served with the 2nd Bombardment Squadron at Langley Field, Virginia.

In 1925 Tower started working for Boeing as a draftsman, but soon began test flying new airplanes, which included the B-9 bomber and the Model 247 commercial airliner. He also demonstrated and delivered Boeing airplanes around the world.

On 20 August 1935, Tower and Louis Wait flew the Model 299 from Seattle to Dayton, approximately 2,100 miles, in 9 hours, 3 minutes, averaging 233 miles per hour (375 kilometers per hour).

Les Tower was aboard the XB-17 as an observer during the 30 October flight. He saw that the control locks had not been released and tried to reach them, but was unable. In the fire that followed the crash, Tower suffered severe burns to his face, right arm and both legs.

Leslie Ralph Tower died of his injuries 19 November 1935 at Miami Valley Hospital in Dayton. His remains were transported by train, escorted by Army airplanes, and were buried at Lakeview Cemetery, Polson, Montana.

¹ At that time, experimental and restricted category aircraft were prohibited from displaying the letter “N” at the beginning of their registration mark.

© 2020, Bryan R. Swopes

8 July 1941

Fortress Mark I, AN521 ‘WP-K’, of No. 90 Squadron RAF based at West Raynham, Norfolk, preparing for take off at Hatfield, Hertfordshire, during an inspection of newly-arrived American aircraft by the Chief of the Air Staff and the US Air Attache. (Photograph by Flight Lieutenant Bertrand John Henry Daventry, Royal Air Force/CH 2873, Imperial War Museum)
Boeing Fortress Mark I AN521, ‘WP-K’, (U.S.A.A.F. serial number 40-2052) of No. 90 Squadron R.A.F., based at West Raynham, Norfolk, preparing for take off at Hatfield, Hertfordshire, during an inspection of newly-arrived American aircraft by the Chief of the Air Staff and the U.S. Air Attache. Photograph by Flight Lieutenant Bertrand John Henry Daventry, Royal Air Force. © IWM (CH 2873)

00DD3437_5056_A318_A85F9DA3980B669B8 July 1941: Three Royal Air Force Boeing Fortress Mk.I heavy bombers departed from their base at RAF Watton to attack Wilhelmshaven, Germany. This was a daylight bombing mission, with the airplanes flying at 30,000 feet (9,144 meters). One bomber diverted to a secondary target because of engine trouble, while the remaining two Fortresses continued to the primary target.

At the very high altitudes flown, the defensive heavy machine guns that gave the airplane its name froze due to the low temperatures and could not be fired. (In standard atmospheric conditions, the temperature at 30,000 feet would be -45 °C., or -49 °F.)

"Vertical aerial reconnaissance of Wilhelmshaven." © IWM (HU 91201)
“Vertical aerial reconnaissance of Wilhelmshaven.” © IWM (HU 91201)

All three aircraft returned safely to their base. The mission was completely ineffective, however.

This was the very first use of the Boeing B-17 Flying Fortress in combat.

Fortress B.I WP-F
Fortress B.I AN530, WP-F (U.S.A.A.F. B-17C 40-2066) (Royal Air Force)

The Boeing Model 299H, designated B-17C, was the second production variant ordered by the U.S. Army Air Corps. 38 were built by Boeing for the U.S. Army Air Corps, but 20 were transferred to Great Britain’s Royal Air Force, designated Fortress Mk.I. (Boeing Model 299T.) They were initially assigned to No. 90 Squadron, Bomber Command. (A 1941 book, War Wings: Fighting Airplanes of the American and British Air Forces, by David C. Cooke, Robert M. McBride & Company, New York, refers to the B-17C in British service as the “Seattle,” which is in keeping with the R.A.F.’s system of naming bombers after cities.)

Of the 20 Fortress Mk.I bombers, 8 were lost in combat or in accidents.

Boeing Fortress Mk.I AN529 U.S.A.A.F. B-17C 40-2065) at Heathfield, Scotland, after arrival from United States, May 1941. © Imperial War Museum E(MOS) 276

The Boeing B-17C/Fortress Mk.I was 67 feet, 10-9/16 inches (20.690 meters long with a wingspan of 103 feet, 9 inches (31.633 meters) and the overall height was 15 feet, 4½ inches (4.686 meters). The B-17C had an empty weight of 30,900 pounds (14,016 kilograms). The maximum design gross weight was 47,500 pounds (21,546 kilograms).

The B-17C was powered by four air-cooled, supercharged, 1,823.129-cubic-inch-displacement (29.876 liters) Wright Cyclone G666A (R-1820-65)¹ nine-cylinder radial engines with a compression ratio of 6.70:1. The engines were equipped with remote General Electric turbochargers capable of 24,000 r.p.m. The R-1820-65 was rated at 1,000 horsepower at 2,300 r.p.m. at Sea Level, and 1,200 horsepower at 2,500 r.p.m. for takeoff. The engine could produce 1,380 horsepower at War Emergency Power. 100-octane aviation gasoline was required. The Cyclones turned three-bladed, constant-speed, Hamilton-Standard Hydromatic propellers with a diameter of 11 feet, 7 inches (3.835 meters) though a 0.5625:1 gear reduction. The R-1820-65 engine is 3 feet, 11.59 inches (1.209 meters) long and 4 feet, 7.12 inches (1.400 meters) in diameter. It weighs 1,315 pounds (596 kilograms).

Crew members of a No. 90 "RAF Fortress crew at RAF Polebrook July 19, 1941." (IWM CH 3090)
“RAF Fortress crew at RAF Polebrook July 19, 1941.” © IWM (CH 3090)

The B-17C had a maximum speed of 323 miles per hour (520 kilometers per hour) at 25,000 feet (7,620 meters). Its service ceiling was 37,000 feet (11,278 meters) and the maximum range was 3,400 miles (5,472 kilometers).

The Fortress Mk.I could carry 4,800 pounds (2,177 kilograms) of bombs in an internal bomb bay. Defensive armament consisted of one Browning AN-M2 .30-caliber air-cooled machine gun at the nose and four Browning AN-M2 .50-caliber heavy machine guns in dorsal, ventral and waist positions.

Fortress I AN528 (Getty Images/Three Lions)
Royal Air Force Fortress Mk.I AN528 (B-17C 40-2064) prior to being camouflaged. (Getty Images/Three Lions)

© 2018, Bryan R. Swopes

3 June 1942, 0900: First Contact

Consolidated PBY-5A Catalina
Consolidated PBY-5A Catalina, 1942. (U.S. Naval History and Heritage Command 80-G-K-14896)

3 June 1942: At dawn, twenty-two U.S. Navy PBY-5A Catalina patrol bombers launched from Midway Island to search for a Japanese fleet which was expected to be heading toward the American island base. One of them, 44-P-4, (Bu. No. 08031) commanded by Ensign Jewell Harmon (“Jack”) Reid of Patrol Squadron 44 (VP-44), sighted Admiral Raizo Tanaka’s Midway Occupation Force, 700 nautical miles (1,296 kilometers) west of the atoll, shortly before 9:00 a.m.

Chart of sightings, 3 June 1943. (U.S. Navy)

The Catalina scouted the enemy task force, which they believed to be the “main body” of the Japanese fleet and radioed information back to their base. The task force consisted of 1 light cruiser, 12 transports carrying 5,000 soldiers, 11 destroyers, 2 seaplane tenders, 1 fleet oiler and 4 patrol boats.

Standing, left to right: AMM2c R. Derouin, ACRM Francis Musser, Ens. Hardeman (co-pilot), Ens. J.H. “Jack” Reid (aircraft commander) and Ens. R.A. Swan (navigator). Kneeling, left to right: AMM1c J.F. Gammel, AMM3c J. Groovers and AMM3c P.A. Fitzpatrick. (U.S. Navy).

The Consolidated PBY Catalina made its first flight on 28 March 1935, with chief test pilot William B. Wheatley in command. It was a twin-engine flying boat produced from 1936 to 1945. It was utilized primarily as an anti-shipping and anti-submarine patrol bomber and for search and rescue operations.

Consolidated XPBY-5A Catalina, Bu. No. 1245, at NAS Anacostia, Washington, D.C., 18 December 1939. (Harris & Ewing/Library of Congress)

The PBY-5A was an amphibious variant equipped with retractable tricycle landing gear. It was 63 feet, 10-7/16 inches long (19.468 meters) with a wing span of 104 feet, 0 inches (31.699 meters) and overall height of 20 feet, 2 inches (6.147 meters). The parasol wing was mounted above the fuselage on a streamlined pylon and supported by four external braces. The wing has 6° incidence and the center section has no dihedral or sweep. The outer wing panels are tapered. There are no flaps. The total wing area is 1,400 square feet (130 square meters). The PBY-5A had an empty weight of 20,910 pounds (9,485 kilograms), and gross weight in patrol configuration of 33,975 pounds (15,411 kilograms). Its maximum takeoff weight (land) was 35,420 pounds (16,066 kilograms).

PBY-5A three-view with dimensions (U.S. Navy)

The PBY-5A was powered by two air-cooled, supercharged, 1,829.4-cubic-inch-displacement (29.978 liter) Pratt & Whitney Twin Wasp S1C3-G (R-1830-92) two-row 14-cylinder radial engines. These were rated at 1,200 horsepower at 2,700 r.p.m. at Sea Level for takeoff. The maximum continuous rating for normal operation was 1,060 horsepower at 2,550 r.pm., up to 7,500 feet (2,286 meters). The engines drove three-bladed Hamilton Standard controllable-pitch propellers with a 12 foot, 1 inch (3.683 meter) diameter through a 16:9 gear reduction. The R-1830-92 is 48.19 inches (1.224 meters) long, 61.67 inches (1.566 meters) in diameter, and weighs 1,465 pounds (665 kilograms).

The PBY-5A Catalina had a cruise speed of 124 miles per hour (200 kilometers per hour). Its maximum speed was 169 miles per hour (272 kilometers per hour) at Sea Level and 179 miles per hour (288 kilometers per hour) at 7,000 feet (2,134 meters). The service ceiling was 14,700 feet (4,481 meters) and maximum range was 2,545 miles (4.096 kilometers) at 117 miles per hour (188 kilometers per hour.).

The patrol bomber could carry 4,000 pounds (1,814 kilograms) of bombs or depth charges, or two torpedoes on hardpoints under its wing. Two Browning M2 .30-caliber air-cooled machine guns were mounted in a nose turret with 2,100 rounds of ammunition. A third .30-caliber machine gun was positioned in a ventral hatch with 500 rounds of ammunition. Two Browning AN-M2 .50-caliber heavy machine guns were mounted in the waist with 578 rounds of ammunition per gun.

3,305 Consolidated PBY Catalina’s were built, of which 802 were the PBY-5A variant. In addition to United States service, many other countries operated the Catalina during and after World War II. The last PBY in U.S. service was a PBY-6A which was retired 3 January 1957.

© 2019, Bryan R. Swopes

12 May 1938

U.S. Army Air Corps YB-17 Flying Fortresses numbers 80 and 82 fly alongside S.S. Rex, 620 nautical miles east of Sandy Hook, 12 May 1938. (Photograph by Major George W. Goddard, U.S. Army Air Corps)

12 May 1938: Three Boeing B-17 Flying Fortress four-engine heavy bombers of the 49th Bombardment Squadron, 2nd Bombardment Group, departed Mitchel Field, Long Island, New York, in heavy rain and headed eastward over the Atlantic Ocean. Their mission, assigned by Major General Frank M. Andrews, commanding General Headquarters, U.S. Army Air Corps, was to locate and photograph the Italian passenger liner, S.S. Rex, then on a transatlantic voyage to New York City. The purpose was to demonstrate the capabilities and effectiveness of long-range bombers.

Boeing YB-17 Flying Fortress 36-151, 42nd Bombardment Squadron, 2nd Bombardment Group, Number 80, in flight over New York City, 28 March 1937. The Art Deco skyscraper behind the bomber is the Chrysler Building, 1,046 feet (319 meters) tall. (American Air Museum in Britain)

The flight was led by Major Caleb Vance Haynes, commanding officer of the 49th Bombardment Squadron, flying B-17 number 80. The 2nd Bomb Group commanding officer, Lieutenant Colonel Robert Olds, was aboard Haynes’ B-17, along with an NBC radio crew to broadcast news of the interception live across the country. Reporters from the New York Times and the New York Herald Tribune were aboard the other airplanes.

1st Lieutenant Curtis Emerson LeMay, Air Corps, United States Army.

The planning of the interception and in-flight navigation was performed by First Lieutenant Curtis E. LeMay. Position reports from S.S. Rex were obtained and forwarded to LeMay as the aircraft were taxiing for takeoff.

The flight departed Mitchel Field at 8:45 a.m. They encountered heavy rain, hail, high winds and poor visibility, but at 12:23 p.m., the Flying Fortresses broke out of a squall line and the passenger liner was seen directly ahead. They flew alongside the ship at 12:25 p.m., 620 nautical miles (1,148.24 kilometers) east of Sandy Hook, New Jersey. They were exactly on the time calculated by Lieutenant LeMay.

The B-17s made several passes for still and motion picture photography while NBC broadcast the event on radio.

Colonel Olds would rise to the rank of Major General and command 2nd Air Force during World War II. He was the father of legendary fighter pilot Brigadier General Robin Olds. Major Hayes served in various combat commands and retired at the rank of Major General in 1953.

Curtis LeMay would be a major in command of the 305th Bombardment Group, a B-17 unit, at the beginning of World War II. He personally led many combat missions over Europe, and would command the 4th Bombardment Wing, then the 3rd Air Division. By the end of the war, he was in command of XXI Bomber Command based in the Marianas Islands. From 1948 to 1957, General LeMay commanded the Strategic Air Command. He served as Vice Chief of Staff of the Air Force., 1957–1961. General LeMay was Chief of Staff, United States Air Force, from 1961 to 1965.

At the time of the interception of the Rex, there were only 12 B-17s in the Air Corps inventory: the original Y1B-17 service development airplanes. By the end of production in 1945, 12,731 B-17 Flying Fortress bombers had been built by three aircraft manufacturers.

Boeing YB-17 Flying Fortress 36-149. (U.S. Air Force)
Boeing Y1B-17 Flying Fortress 36-149. (U.S. Air Force)

The Boeing B-17 (Model 299B, previously designated Y1B-17, and then YB-17) was a pre-production service test prototype. Thirteen had been ordered by the Air Corps. It was 68 feet, 4 inches (20.828 meters long with a wingspan of 103 feet, 9 inches (31.633 meters) and the overall height was 18 feet, 4 inches (5.588 meters).

Boeing YB-17 36-149. (U.S. Air Force)

The YB-17 was powered by four air-cooled, supercharged 1,823.129-cubic-inch-displacement (29.876 liter) Wright Aeronautical Division Cyclone G59 (R-1820-51) nine-cylinder radial engines with a compression ratio of 6.45:1. The R-1820-51 had a Normal Power rating of 800 horsepower at 2,100 r.p.m. at Sea Level, and 1,000 horsepower at 2,200 r.p.m. for Takeoff, burning 100-octane gasoline. A long carburetor intake on top of the engine nacelles visually distinguishes the YB-17 from the follow-on YB-17A. The engines drove three-bladed Hamilton Standard constant-speed propellers through a 0.6875:1 gear reduction. The R-1820-51 was 3 feet, 9.06 inches (1.145 meters) long and  4 feet, 6.12 inches (1.375 meters) in diameter. It weighed 1,200.50 pounds (544.54 kilograms).

Boeing YB-17 36-149. (U.S. Air Force)

The YB-17 had an empty weight of 24,465 pounds (11,097 kilograms), gross weight of 34,880 pounds (15,821 kilograms) and maximum takeoff weight of 42,600 pounds (19,323 kilograms). The maximum speed was 256 miles per hour (412 kilometers per hour) at 14,000 feet (4,267 meters). Its service ceiling was 30,600 feet (9,327 meters) and the maximum range was 3,320 miles (5,343 kilometers).

The YB-17 could carry 8,000 pounds (3,629 kilograms) of bombs. Defensive armament consisted of five air-cooled Browning .30-caliber machine guns.

Boeing YB-17 36-149. (U.S. Air Force)

© 2019, Bryan R. Swopes