Tag Archives: Torpedo Bomber

7 August 1941

A prototype Grumman XTBF-1 torpedo bomber. (Ray Crupi Collection)

7 August 1941: Grumman Aircraft Engineering Corporation chief engineer and test pilot, Robert Leicester (“Bob”) Hall took the XTBF-1, a prototype torpedo bomber, for its first flight. He quickly returned to the airfield. The airplane was seriously over-weight, its center of gravity was too far aft, and it was unstable in the yaw axis.

The first XTBF-1, U.S. Navy Bureau of Aeronautics serial number (“Bu. No.”) 00373, was modified to correct these faults. The engine mount was revised, moving the engine farther forward. A triangular fillet was added to the top of the fuselage in front of the vertical fin, and the weight was reduced.

Grumman XTBF-1 Bu.No. 00373. Note the dorsal fillet. (Northrop Grumman)

On 28 June 1941, 00373 caught fire during a test flight. Its crew safely bailed out but the prototype was destroyed.

The second prototype XTBF-1 was sent to the National Advisory Committee for Aeronautics Langley Memorial Aeronautical Laboratory at Hampton, Virginia, for testing in the 30- × 60-foot Full Scale Tunnel.

The second Grumman XTBF-1 prototype #2 in the NACA Full Scale Tunnel. (NASA)

Before the airplane’s first flight, the U.S. Navy had ordered 286 production aircraft. In October 1941, the type was officially named “Avenger.” The first production airplane, Bu. No. 000393, made its first flight on 15 December 1941.

A four-man flight crew boards a Grumman TBF-1 Avenger torpedo bomber, circa late 1941–early 1942. (Rudy Arnold Collection, Smithsonian Institution, National Air and Space Museum NASM-XRA-0780)

The Grumman Model 40, designated TBF-1 Avenger by the United States Navy, was a single engine torpedo bomber designed to operate from aircraft carriers. Initially it had a four-man crew: pilot, navigator, radio-operator/gunner and ball turret gunner. The TBF was 40 feet, 11½ inches (12.484 meters) long with a wingspan of 54 feet, 2 inches (16.510 meters) and height of 16 feet, 4¼ inches (4.991 meters).

Grumman TBF Avenger three-view illustration with dimensions. (U.S. Navy)

The XTBF-1 was powered by an air-cooled, supercharged, 2,603.943-cubic-inch-displacement (42.671 liters) Wright Cyclone 14 GR2600B698 (R-2600-8) two-row, fourteen-cylinder radial engine with a compression ratio of 6.9:1. The R-2600-8 was rated at 1,500 horsepower at 2,400 r.p.m., and 1,700 horsepower at 2,800 r.p.m. at Sea Level for Takeoff. The engine drove a 13 foot, 1 inch diameter ( meters), three-bladed Hamilton Standard constant speed propeller through a  0.5625:1 gear reduction unit. The R-2600-8 was 5 feet, 4.91 inches (1.649 meters) long, 4 feet, 6.26 inches (1.378 meters) in diameter, and weighed 1,995 pounds (904.9 kilograms).

A Grumman TBF-1 Avenger, mid-1942. (Hans Groenhoff Collection, Smithsonian Institution, National Air and Space Museum NASM-HGC-906)

© 2020, Bryan R. Swopes

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4 June 1942: Carrier vs. Carrier

USS Yorktown (CV-5) immediately after aerial torpedo hit, 4 June 1942. (U.S. Navy)

4 June 1942: The Battle of Midway: By the afternoon American planes had heavily damaged three Japanese Aircraft carriers. They would later sink. Planes from the fourth carrier, IJN Hiryu, were launched to attack the American aircraft carriers.

USS Yorktown (CV-5) was hit by two aerial torpedoes from Nakajima B5N torpedo bombers. She listed sharply, lost power and was out of action. She would later be sunk by the Japanese submarine I-168. Hiryu was attacked by U.S. Navy SBD Dauntless dive bombers and was badly damaged, set on fire, and sank later in the day.

The Battle of Midway was not over. It would go on until 7 June. However, the outcome was clear. Midway was a decisive American victory.

The Americans lost 1 aircraft carrier and 1 destroyer, about 150 aircraft, with 307 soldiers, sailors and airmen killed. The island outpost was saved and would never again be seriously threatened.

The Imperial Japanese Navy lost 4 aircraft carriers and one cruiser, with other warships, including battleships, so heavily damaged that they were out of the war for some time. Also lost were 248 aircraft and 3,057 sailors and airmen killed.

For the rest of the War, the Japanese Navy suffered from the loss of these highly experienced naval aviators. Though they could replace the men, they could not replace their years of combat experience. From this point forward, the Empire of Japan was on the defensive with its defeat inevitable.

The Battle of Midway was the most decisive naval battle in history. It was fought almost entirely by aircraft.

IJN Hiryu heavily damaged and on fire, shortly before sinking, 4 June 1942 (IJN photograph)

Very Highly Recommended: History of United States Naval Operations in World War II, Volume IV, Coral Sea, Midway and Submarine Actions, May 1942—August 1942, by Samuel Eliot Morison, Little, Brown and Company, Boston, September 1949. The entire 15-volume series has TDiA’s highest possible recommendation.

© 2018, Bryan R. Swopes

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