Saturday, January 4, 2020
Douglas TBD Devastator
Length: 35 ft.Wingspan: 50 ft.Height: 15 ft. 1 in.Wing Area: 422 sq. ft.Empty Weight: 6,182 lbs.Loaded Weight: 9,862 lbs.Crew: 3Number Built: 129 Performance Power Plant: 1 Ãâ" Pratt Whitney R-1830-64 Twin Wasp radial engine, 850 hpRange: 435-716 milesMax Speed: 206 mphCeiling: 19,700 ft. Armament Power Plant: 1 Ãâ" Pratt Whitney R-1830-64 Twin Wasp radial engine, 850 hpRange: 435-716 milesMax Speed: 206 mphCeiling: 19,700 ft.Guns: 1 Ãâ" forward-firing 0.30 in. or 0.50 in. machine gun. 1 Ãâ" 0.30 in. machine gun in rear cockpit (later increased to two)Bombs/Torpedo: 1 x Mark 13 torpedo or 1 x 1,000 lb. bomb or 3 x 500 lb. bombs or 12 x 100 lb. bombs Design Development On June 30, 1934, the US Navy Bureau of Aeronautics (BuAir) issued a request for proposals for a new torpedo and level bomber to replace their existing Martin BM-1s and Great Lakes TG-2s. Hall, Great Lakes, and Douglas all submitted designs for the competition. While Halls design, a high-wing seaplane, failed to meet BuAirs carrier suitability requirement both Great Lakes and Douglas pressed on. The Great Lakes design, the XTBG-1, was a three-place biplane that quickly proved to possess poor handling and instability during flight. The failure of the Hall and Great Lakes designs opened the way for the advancement of the Douglas XTBD-1. A low-wing monoplane, it was of all-metal construction and included power wing folding. All three of these traits were firsts for a US Navy aircraft making the XTBD-1 design somewhat revolutionary. The XTBD-1 also featured a long, low greenhouse canopy that fully enclosed the aircrafts crew of three (pilot, bombardier, radio operator/gunner). Power was initially provided by a Pratt Whitney XR-1830-60 Twin Wasp radial engine (800 hp). The XTBD-1 carried its payload externally and could deliver a Mark 13 torpedo or 1,200 lbs. of bombs to a range of 435 miles. Cruising speed varied between 100-120 mph depending on payload. Though slow, short-ranged, and under-powered by World War II standards, the aircraft marked a dramatic advance in capabilities over its biplane predecessors. For defense, the XTBD-1 mounted a single .30 cal. (later .50 cal.) machine gun in the cowling and a single rear-facing .30 cal. (later twin) machine gun. For bombing missions, the bombardier aimed through a Norden bombsight under the pilots seat. Acceptance Production First flying on April 15, 1935, Douglas quickly delivered the prototype to Naval Air Station, Anacostia for the beginning of performance trials. Extensively tested by the US Navy through the remainder of the year, the X-TBD performed well with the only requested alteration being an enlargement of the canopy to increase visibility. On February 3, 1936, BuAir placed an order for 114 TBD-1s. An additional 15 aircraft were later added to the contract. The first production aircraft was retained for testing purposes and later became the types only variant when it was fitted with floats and dubbed TBD-1A. Operational History The TBD-1 entered service in late 1937 when USS Saratogas VT-3 transitioned off TG-2s. Other US Navy torpedo squadrons also switched to the TBD-1 as aircraft became available. Though revolutionary at introduction, aircraft development in the 1930s progressed at a dramatic rate. Aware that the TBD-1 was already being eclipsed by new fighters in 1939, BuAer issued a request for proposals for the aircrafts replacement. This competition resulted in the selection of the Grumman TBF Avenger. While TBF development progressed, the TBD remained in place as the US Navys frontline torpedo bomber. In 1941, the TBD-1 officially received the nickname Devastator. With the Japanese attack on Pearl Harbor that December, the Devastator began to see combat action. Taking part in attacks on Japanese shipping in the Gilbert Islands in February 1942, TBDs from USS Enterprise had little success. This was largely due to problems associated with the Mark 13 torpedo. A delicate weapon, the Mark 13 required the pilot to drop it from no higher than 120 ft. and no faster than 150 mph making the aircraft extremely vulnerable during its attack. Once dropped, the Mark 13 had issues with running too deep or simply failing to explode on impact. For torpedo attacks, the bombardier was typically left on the carrier and the Devastator flew with a crew of two. Additional raids that spring saw TBDs attack Wake and Marcus Islands, as well as targets off New Guinea with mixed results. The highlight of the Devastators career came during the Battle of the Coral Sea when the type aided in sinking the light carrier Shoho. Subsequent attacks against the larger Japanese carriers the next day proved fruitless. The TBDs final engagement came the following month at the Battle of Midway. By this time attrition had become an issue with the US Navys TBD force and Rear Admirals Frank J. Fletcher and Raymond Spruance possessed only 41 Devastators aboard their three careers when the battle began on June 4. Locating the Japanese fleet, Spruance ordered strikes to begin immediately and dispatched 39 TBDs against the enemy. Becoming separated from their escorting fighters, the three American torpedo squadrons were the first to arrive over the Japanese. Attacking without cover, they suffered horrific losses to Japanese A6M Zero fighters and anti-aircraft fire. Though failing to score any hits, their attack pulled the Japanese combat air patrol out of position, leaving the fleet vulnerable. At 10:22 AM, American SBD Dauntless dive bombers approaching from the southwest and northeast struck the carriers Kaga, Soryu, and Akagi. In less than six minutes they reduced the Japanese ships to burning wrecks. Of the 39 TBDs sent against the Japanese, only 5 returned. In the attack, USS Hornets VT-8 lost all 15 aircraft with Ensign George Gay being the only survivor. In the wake of Midway, the US Navy withdrew its remaining TBDs and squadrons transitioned to the newly arriving Avenger. The 39 TBDs remaining in the inventory were assigned to training roles in the United States and by 1944 the type was no longer in the US Navys inventory. Often believed to have been a failure, the TBD Devastators principal fault was simply being old and obsolete. BuAir was aware of this fact and the aircrafts replacement was en route when the Devastators career ingloriously ended.