Two XTBF-l prototypes were ordered April 8, 1940, and 286 production TBF-ls purchased on December 23, for the need for a better torpedo-bomber could not await the prototype’s first flight by Bob Hall on August 7, 1941. Although the first XTBF-1 was destroyed November 28, the second flew December 20 with a new dorsal fin and extended engine mount.
Grumman flight delivered the first TBF-l to Anacostia on January 30, 1942, and 645 were accepted by the end of 1942. This production success at Bethpage contrasts with the only 50 Helldivers delivered by Curtiss that year.
A fat-bodied mid-wing monoplane with a 1,700-hp R-2600-8, the TBF had wheels retracting outwards into the wings, which the pilot could fold backwards to ease shipboard stowage. Instead of hand-held light guns, the gunner had a .50-caliber gun with 400 rounds in an electric-powered ball turret. The pilot had a single .30-caliber gun with 500 rounds on the cowl’s right side, and behind him the navigator could drop down behind the bomb bay to set the torpedo, use the bombsight, or fire the .30-caliber ventral gun with 500 rounds. Self-sealing fuel tanks and 331 pounds of armor were standard.
The capacious internal weapons bay contained the new Mod. 1 version of the Mk 13 torpedo, whose warhead was increased from 400 to 600 pounds. Total weight of the 22-inch diameter, 22.5-foot long Mk13-1 was 2,216 pounds. It could be launched from up to 300 feet high and as fast as the TBF could go, but careful attention to speed, height, and distance from target were required for success, since the water entry angle and underwater run had to be correct. Later Mods 13-2 and 13-3 improved launching.
Alternate loads included one 1,600 or 1,000-pound bomb, or four 500-pound bombs or 325-pound depth charges, or 12 100-pound bombs, or an auxiliary fuel tank. Combat experience soon favored low-level glide or skip bombing tactics, instead of the traditional horizontal run, making the Norden bombsight unnecessary.
The Avenger’s first combat deployment was the VT-8 detachment with 20 TBF-ls shipped to Pearl Harbor by May 29, 1942. On June 1, six of the VT-8 planes were flown to Midway Island and on June 4 these six, without fighter escort, attacked Japanese ships; none were hit and only one TBF returned.
Sustained TBF operations began with the squadrons aboard the three carriers (Saratoga, Enterprise, and Wasp) near Guadalcanal on August 7, and sank the carrier Ryuyo on August 24. The Navy’s first aerial mine-laying operation of the war was by 42 TBF-1s near Bougainville on March 20, 1943.
Even though Grumman had received another TBF order on January 2, 1942, the fighter programs had top priority, so the automobile industry’s resources were brought in on March 23, 1942, when General Motors contracted to build 1,200 Avengers. Designated TBM-1, they were assembled at the Eastern Aircraft Division in Trenton, New Jersey, where the first TBM-l was delivered on November 12, 1942.
Grumman completed one XTBF-2, flown May 1, 1942, with an XR-2600-10 Cyclone, but this two-stage engine was unnecessary for the low-altitude work of Navy attack planes. On July 2, Grumman was authorized to convert one TBF to a single-seat long-range fighter & torpedo configuration. First flown on July 26, it deleted all the guns and fittings for two crewmen and was armed with two .50-caliber wing guns, but was too slow for real fighter work.
The next production model, the TBF-lC introduced in July 1943, deleted the cowl gun, had two .50-caliber wing guns with 600 rounds and added bullet-proof glass in the turret. A 275-gallon auxiliary fuel tank could replace the bomb load, and two 58-gallon drop tanks could be attached below the wings. Eight 5-inch rockets could be launched from under the wings of the last ones built.
Search radar (ASB-3) was first installed on five TBF-ls and five SBD-4s in October 1942, and in January 1944, the first carrier-based night bombing attack were made by radar-equipped TBF-1Cs of the Enterprise’s VT-10 in the Pacific. By December 31, 1943, 1,524 TBF-l and 764 TBF-1C Avengers were completed at Bethpage, after which all Avenger production was at Trenton, so Grumman could concentrate on fighters.