Considered the finest carrier-based torpedo bomber in the world after more than two years of grueling aerial warfare, Grumman's TBF Avenger is now one of the most widely used Naval aircraft. Designed to replace the Douglas TBD-1 Devastator, our standard prewar bomber of Torpedo Squadron 8 fame, the Avenger first went into action at Midway to revolutionize torpedo plane tactics. The low altitude attack. when the torpedo plane was vulnerable and needed complete fighter protection, was out. This new plane was equipped to move in with the dive bombers and at high altitudes under the same fighter coverage. When the enemy was sighted, it dove down to the torpedo release altitude at a speed greater than 300 mph. The torpedo was released and the airplane banked sharply to escape enemy ack-ack fire.
The versatility of the aircraft fits it for many purposes. It was the first American Navy plane to be equipped with rocket launching tubes. This model has underslung rocket tubes beneath each wing. Sometimes employed while carrying out torpedo attacks, the rockets lay down a terrific covering barrage for the bomber, which enables it to approach its objective with a minimum of resistance from enemy anti-aircraft gun units.
As a bomber carrying the full internal load of explosives, the Avenger has been employed for horizontal bombing against ground objectives. This method of attack has proven successful against enemy targets. Glide bombing, sometimes carried out on steep angles so as to approach the field of dive attack, is another attacking method of the Avenger which has been particularly successful. This is due to the heavy weight of explosives carried by the aircraft. The only other dive bombing machine capable of matching the Avenger's load capacity is the Curtiss Helldiver.
For extra long range missions, internal gas tanks may be carried in the bomb bays to increase appreciably the maximum operational range. In operation as a scout bomber, it carries a reduced load of explosives and with its excellent range characteristics. scouting duties may be carried out to the fullest extent.
The Avenger is also being employed in recent operations as a tactical ground cooperation machine. Employed in this category, the plane is sometimes equipped with special smoke screen launchers, carried beneath the wings of the aircraft. With this apparatus. plus the armament and bomb load, the aircraft is used to bomb and strafe enemy objectives while providing smoke screen cover for invasion troops launching attacks against enemy island positions.
During the fierce battles for Henderson field on Guadalcanal Island in the Solomons group, Avengers were used to bring vitally needed fuel onto the field. Gas tanks were loaded into the bomb bays and in this way precious time was saved and other planes were kept in the air.
In its debut in combat, the TBF-1 was mistaken by many Jap fighters as a Wildcat. which the Avenger closely resembles from many angles. Thus, many a Nipponese fighter fell victim to the dorsal armament of the big torpedo plane. The power-operated dorsal turret mounts one .50-caliber machine gun as standard practice, which fires freely.
A ventral hatch in the after-part of the Avenger's torpedo bay mounts a single flexible gun. Forward armament consists of one synchronized cowling gun of .30-caliber. In later Avenger TBF-1s a .50-calibre machine gun is installed in each outer wing panel.
Any one of the following loads may be carried inside the bomb bay: a Mark 13-1 or 13-2 torpedo, 100-pound bombs, 500-pound bombs, 1,000-pound or 1,600-pound bombs, a smoke screen tank, a droppable fuel tank or a tow target.
The airplane is powered with a Wright R-2600-8 or R-2600-8A two-speed-supercharged, 14-cylinder, air-cooled engine driving a three-blade Hamilton Hydromatic propeller. A Jack & Heintz hand electric inertia starter is installed. The power plant is designed to operate on 100-octane fuel with a take-off rating at sea level of 1,700 bhp at 2,600 rpm. Its service ceiling is over 20,000 feet. Cruising speeds range from 180 to 200 mph, depending upon the load carried. The range with load is 905 miles, and 1,000 miles can be reached with the aircraft in overloaded condition.
The fuselage is of stressed-skin semi-monocoque construction consisting essentially of angle type frames and stamped bulkheads, covered with a smooth aluminum alloy skin. The skin is stiffened longitudinally by aluminum alloy Z and channel type stringers which extend the entire length of the fuselage. Special stiffeners and fittings are used to distribute concentrated stresses at the engine mount, wing center section attachment, cockpit cutouts. stringer splices, gun turret, tail wheel and arresting hook. The overturn structure, designed to protect the pilot in case of a complete turn over, extends to the top of the cockpit enclosure.
The wings are of the full-cantilever type with a single beam and consist of one center section and two folding outer panels. The wings are folded and spread hydraulically, the locking pins operated in the proper sequence by one motion of the wing folding hydraulic control lever. Three fuel tanks are integral with the center section of the wing.
Statically and dynamically balanced elevators and rudder are of aluminum-alloy-frame construction with fabric covering; fin and stabilizers are of all-metal construction. The elevators are provided with controllable trimming tabs and the rudder with both servo and trimming tabs
The landing gear is extended and retracted hydraulically and locked mechanically in the up and down positions. A hand operated emergency release control for lowering the wheels in the event of complete hydraulic system failure, is installed in the pilot's cockpit. The tail wheel is hydraulically operated, extending or retracting simultaneously with the landing gear, and is secured in the trailing position by a lock controlled from the cockpit.
The airplane is designed to carry a crew of three, with the pilot in the front cockpit. a bomber in the lower fuselage aft of the bomb bay, and a radio operator who also serves as a gunner in the rotating turret. The hydraulically operated bomb bay doors may be opened and closed by either the pilot or the bomber, however, the bomber does not control release of the torpedo, fuel tank or the smoke tank.
Investigation of carrier approaches and arrested landings on the landing platform at the Naval Aircraft Factory has indicated favorable characteristics for these functions. It was found that variations in power or speed during the approach have less adverse effect than in other types. A slow condition could be corrected by a large application of throttle without undue probability of excessive over-correction. The arresting hook assembly is located inside the after end of the fuselage on a track The action of an electric motor extends the hook out through an opening in the tail cone into position for carrier landing.
The Avenger can be catapulted as a scout, bomber or torpedo plane. A catapult hook is provided on the inboard side of each landing gear strut and a hold back fitting on the tail wheel assembly.
Last December, the General Motors Corporation started exclusive production of this torpedo bomber, permitting the Grumman Corporation to concentrate its productive capabilities on other Naval airplanes. Designated the TBM, the ship differs little from the Grumman-built TBF. Greater speed has been attained in the newer TBM-3 with a larger engine giving it increased horsepower. A favorite with pilots who can appreciate its stable characteristics, this bomber is formidable evidence of the manufacturers designing and engineering ability.
The Avengers nave been death on wings to the Japs since the Battle of Midway, have flown off British carriers against the Axis, and have been the world's outstanding torpedo bombers since their first day on active service and will continue to be so until there is no longer a use for their deadly sting.
This article was originally published in the November, 1944, issue of Air Tech magazine, vol 5, no 5, pp 19-25.
The original article includes 6 photos, a three-view drawing and 5 diagrams.
Photos credited to Rudy Arnold, Grumman Aircraft Engineering Corp, US Navy.