Grumman TBM Avenger

The Battle of Midway, which began on 4 June 1942, was among the early and very vital actions of the Pacific war. In this savage encounter the Japanese fleet lost four aircraft carriers, the Akagi, Hiryu, Kaga and Soryu, these representing the spearhead of Admiral Yamamoto's naval strike force. Without them the Japanese fleet was deprived of its initiative and became a defensive rather than the innovative offence force which had brought chaos to Pearl Harbour less than seven months earlier. As in the Battle of the Coral Sea, fought rather less conclusively some four weeks earlier, the attack and defence of both the Japanese and United States naval forces had been almost entirely the prerogative of carrier-based aircraft. US Navy carriers involved in the Battle of Midway comprised the USS Hornet, Enterprise and Yorktown, the last being so severely damaged in the action that she became an easy target for a Japanese submarine two days later.

Forming a proportion of the naval aircraft which were involved in this action were the first of the US Navy's monoplane torpedo-bombers, the Douglas TBD Devastator, and the first operational examples of the newly developed torpedo-bomber intended to replace it, the Grumman TBF Avenger. For both of these aircraft types the operation was a disaster with two squadrons of Devastators almost completely destroyed, and of the six Avengers in action only one survived. The Devastators were no match for the Japanese aircraft against which they were ranged and were thereafter withdrawn from operational service. The Avengers, which had been intended to reinforce Squadron VT-8's TBD-1s aboard USS Hornet, arrived at Pearl Harbour after the carrier had sailed. Instead, they flew to Midway Island and went into action from there.

Clearly, the Devastator was obsolete and the Avenger's crews lacked adequate experience, for they had been equipped with these aircraft at Norfolk Naval Air Station only four weeks earlier. To highlight this latter point, it is necessary to point out that the Avenger continued in operational use without the need for any significant modifications as a result of their deployment at Midway, remaining in US Navy service for some 15 years.

The TBF had originated in early 1940 when the US Navy initiated a contest to procure a more modern torpedo-bomber to replace the Douglas TBD Devastator, ordering two XTBF-1 prototypes from Grumman on 8 April 1940, and two competing XTBU-1 prototypes from Vought a couple of weeks later. This latter aircraft was to enter production, built by Consolidated as the TBY Sea Wolf, but only about 180 of them were built. The XTBF-1 represented something of a challenge for the Grumman design team headed by Bill Schwendler, for although the company had produced a number of successful carrier-based fighters, this was the first attempt to evolve a torpedo-bomber.

First flown on 1 August 1941, the prototype was seen to be a hefty mid-wing monoplane of ail-metal construction, except for fabric-covered control surfaces. Leading-edge slots forward of the ailerons and split trailing-edge flaps were provided to ensure good low- speed handling characteristics, despite a comparatively high wing loading. On the Avenger the wing loading was to be as much as 37 lbs/sq ft (180 kg/m2) by comparison with 24 Ibs/sq ft (118 kg/m2) for the TBD Devastator. For carrier stowage the outer wing panels could be folded, or unfolded, with the locking pins actuated in correct sequence by hydraulic power, controlled from the pilot's cockpit. The fuselage and tail unit were of conventional construction, the retractable landing gear of the tailwheel type. Attachment points for catapult launch, and an electrically actuated arrester hook were standard. Later versions had RATO (rocket assisted-take off) provision. The powerplant consisted of a 1,700 hp (1268 kW) Wright R-2600-8 Cyclone 14 radial engine, driving a three bladed constant-speed propeller. Accommodation was for a crew of three (pilot, bomb-aimer and radio-operator/gunner) with a long transparent canopy covering all positions. All important, of course, was the armament which comprised of a 7.62 mm (0.30 in) machine gun firing forward through the propeller disc and controlled by the pilot; a ventral machine-gun of the same calibre under control of the bomb-aimer; an a 12.7 mm (0.50 in) gun in a power-operated dorsal turret controlled by the radio-operator as well a large fuselage weapon bay with hydraulically actuated doors to accommodate a 22 inch (559 mm) torpedo or up to 2,000 lbs (907 kg) of bombs.

Flight testing of the prototype by Grumman was followed by US Navy evaluation which ended satisfactorily in December 1941. But 12 months prior to that the us Navy had placed its first production order for 286 TBF-1s, and the first of these began to enter service on 30 January 1942. Despite the inauspicious start to the Avenger's career at Midway, the US Navy procured this aircraft in large numbers, and between first delivery at the end of January 1942 and December 1943, Grumman were to build a total of 2,293. These included TBF-1s, basically the same as the prototypes, and TBF-1Cs, which differed by having two additional 12.7 mm (0.50 in) machine-guns mounted in the wings, and provision for the carriage of drop tanks. Grumman also built XTBF-2 and XTBF-3 prototypes with XR-2600-10 and R-2600-20 engines respectively.

Of the above the Royal Navy received 402 aircraft under Lend-Lease, mostly procured as TBF-1Bs for this purpose, with No. 832 Squadron of the Fleet Air Arm being the first to be equipped on 1 January 1943, the aircraft being designated Tarpon I in British service until January 1944, when they became re-designated Avenger I. No. 832 Squadron took delivery of its aircraft at Norfolk Naval Air Station where their crews completed familiarisation with the type before embarking aboard the USS Saratoga in April 1943. Two months later they were deployed operationally in support of US Marine Corps landing in the middle of the Solomon Islands chain, and this is regarded as the first occasion that FAA (Fleet Air Arm) aircraft were flown into action from a US Navy carrier. Subsequent to the equipping of No. 832 Squadron, seven more FAA squadrons took delivery of their aircraft at US Navy air stations in the USA, completing training before embarking on escort carriers for the long journey to Britain. The TBF-1 version was also supplied to the Royal New Zealand Air Force, which received a total of 63 aircraft.

With the demand for Avengers considerably exceed- ing Grumman's productive capacity, the Eastern Division of General Motors, which had established production lines for the Grumman F4F Wildcat, was selected as a second source of supply. Avengers with the designations TBM-1 (equivalent to TBF-1) and TBM-1C (TBF-1C) began to flow from their lines in September 1942, and the company had produced a total of 7,546 of these and subsequent versions when its production lines closed down in June 1945. Of these early versions from General Motors, the Royal Navy received 334 TBM-1s, these duly being designated Avenger IIs.

General Motors had produced an XTBM-3 prototype with an R-2600-20 engine, generally similar to the XTBF-3 built by Grumman. It differed, however, by having strengthened wings to allow the carriage of rocket projectiles, drop tanks or radar pod, and many were supplied without the heavy power-operated dorsal turret. Designated TBM-3, delivery of this version began in April 1944, and of these the Royal Navy acquired 222 which were identified as Avenger III. These latter aircraft were particularly useful to the FAA which, despite the torpedo-bomber categorisation, had rarely deployed its Avengers in such a role. Instead they had been deployed on anti-submarine patrol, bombing missions, as rocket-firing strike aircraft and, occasionally, for mine-laying operations.

FAA Avengers thus saw a variety of action and proved a valuable and reliable addition to the Royal Navy's carrier-based forces. Avengers were involved in the Arctic convoys to supply the Russian ally, during which Avengers of No. 846 Squadron shared in the sinking of two German submarines (U-288 and U-355) and took part in D-Day preparation and operations, primarily in an anti-shipping strike role, but their major contribution came in the Far East, operating as a component of the East Indies ahd Pacific Fleets. Almost certainly their most important actions were the two attacks made by 48 aircraft of Nos. 820, 849, 854 and 857 Squadrons on the Japanese oil refineries at Palembang, Sumatra, on 24 and 29 January 1945, reducing the output of the two plants to the merest trickle at a moment when every drop of fuel was critical for both the Japanese army and navy. Many people are unaware of the co-operation and support which the FAA gave to the Americans in these closing stages of the Pacific War. Avengers from the carriers HMS Formidable, Illustrious, Indefatigable, Indomitable and Victorious gave intensive support in bombing operations against such targets as Formosa and the Japanese home islands. No. 820 Squadron actually launched an attack on Tokyo.

Apart from the main production stream of TBF-1/-1C and TBM-1C/-3 aircraft, there were also small numbers of special versions which resulted from modification programmes introduced during 1944-5. These included the TBF-1D with special radar equipment, the TBF-1E with electronics equipment, the TBF-1L which carried a searchlight in the bomb bay, and the TBF-1CP equipped with cameras for a reconnaissance role. More or less equivalent versions were modified from General Motors production aircraft under the designations TBM-3D, TBM-3E, TBM-3L and TBM-3P respectively. There was, in addition, a TBM-3H version equipped with search radar. General Motors also built the prototype of what had been anticipated as the next production version and this, designated XTBM-4, differed primarily by having a strengthened fuselage. No production aircraft were built, however, following contract cancellations after VJ-Day.

But the termination of production and the end of World War II did not bring to a halt the career of the Avenger, which still had valuable service to offer during the difficult postwar years. The major operational version in US Navy service was the TBM-3E, by then carrying even more advanced radar equipment for the search and location of submarines, and it is in this area of activity that the Avengers were used extensively until the introduction into service of newly developed and highly specialised aircraft. These were developed to cater for the growing threat from deep diving nuclear-powered submarines which, in the nuclear-weapons age, were then becoming regarded, somewhat prematurely, as the ultimate weapon. Thus TBM-3Ws and TBM-3W-2s carried APS-20 radar in a large underbelly radome and, in US Navy service, were paired eventually with TBM-3S and TBM-3S-2 strike aircraft to create submarine hunter-killer teams. Other postwar conversions included TBM-3Ns for night and all-weather operation, TBM-3Qs for electronic countermeasures against enemy radar emitters, TBM-3R seven-seat Avengers for COD (Carrier On-board Delivery) of priority personnel or urgently needed supplies, and target-towing TBM-3Us.

In Royal Navy service the wartime Avengers remained operational in only small numbers after the end of World War II, serving last with No.828 Squadron until 3 June 1946, but even that did not end the Royal Navy's operational use of Avengers. As in the USA, there was a growing awareness of the threat from new-generation submarines, leading to the acquisition from 1953 of TBM-3Es which entered service first with Nos. 815 and 824 Squadrons under the designation Avenger AS.4. These aircraft, supplied under the Mutual Defence Aid Program (MDAP) were followed by later examples, modified more specifically to Royal Navy requirements, which entered service as Avenger AS.4s or AS.5s, these remaining in first-line service until replaced by Fairey Gannets in 1955.

Also under the MDAP, Avenger variants were supplied after the war for service with the French Aeronavale, Japanese Maritime Self-Defence Force, Royal Canadian Navy, and the Royal Netherlands Navy. Many post-war Avengers saw continued civilian service as fire bombers. The Canadian province of New Brunswick used many of these aircraft (with the weapons bay converted over to carry a large water tank) until the year 2000, when finally replaced by more modern aircraft. It is one of these "retired" New Brunswick aircraft that the Canadian Warplane Heritage Museum in Hamilton, is trying to acquire to replace the one lost, ironically, in a hanger fire a number of years ago.

Nicknames: Chuff; Turkey; Pregnant Beast; Tarpon (RAF).

Specifications (TBM-3):
Engine: 1,900hp Wright R-2600-20 radial piston engine

Weight: Empty 10,545 lbs., Maximum Takeoff 17,895
Wing Span: 54ft. 2in.
Length: 40ft 11.5in.
Height: 15ft 5in.

Performance:
Maximum Speed at 16,500ft: 276mph
Climb Rate: 2060 feet per minute
Ceiling: 30,100ft
Range: 1000 miles

Armament:
Two 12.7mm (0.5 in.) forward-firing machine guns
One 12.7mm (0.5 in.) dorsal-mounted machine gun
One 7.62mm (0.3 in.) ventral-mounted machine gun
Up to 2,000lb of bombs in bomb-bay
Wing-mounted rockets / drop tanks / radar pod

Number Built: 9,836 (7,546 by General Motors)

Number Still Airworthy: 42