Savoia-Marchetti SM.84
The Savoia-Marchetti SM.84 was an Italian three-engined bomber and torpedo bomber of the Second World War, built as a modernised successor to the SM.79 Sparviero: it kept the SM.79's wing and three-engine layout but added a new fuselage, a twin tail and more powerful Piaggio P.XI engines. First flown on 5 June 1940, it entered service in February 1941. Production is unsettled between the accounts: 309 delivered in the Italian accounting, 329 in the English Wikipedia's total. The type disappointed in service, with handling markedly poorer than the SM.79's; its best-known action was the torpedo hit on HMS Nelson in September 1941, bought with heavy losses, and it fought through the Malta convoy battles of 1942 before being phased out in favour of the CANT Z.1007bis and the SM.79 itself. A few flew on as transports after the armistice of September 1943, and the post-war Italian Air Force kept survivors flying until 1949.
Why It Mattered
The SM.84 was Savoia-Marchetti's attempt to replace its own SM.79 Sparviero, which was fast but already obsolescent when the design work began. It kept the SM.79's three-engine layout and a similar wing, and promised more powerful engines, much improved armour and a new fuselage. In service, the promise failed: the Italian account records handling markedly inferior to its predecessor's and only slightly higher speed. It never entirely replaced the Sparviero and was retired from service before it; Francesco Pricolo called it a "wrong aircraft", and its crews never liked it. Against that verdict stands one famous action: the torpedo hit on the battleship HMS Nelson in September 1941.
Design Notes
Designed under Alessandro Marchetti, the SM.84 kept only the SM.79's wings and main landing gear, mated to a new fuselage of rectangular section. The SM.79's single fin and dorsal hump gave way to a twin tail, fitted for stability and to clear the dorsal gun's field of fire, and that gun now sat in a rotating Caproni-Lanciani turret. Three Piaggio P.XI RC.40 radials of 1,000 hp each drove the aircraft, and a roomier bomb bay stowed its bombs horizontally, where earlier Savoia-Marchetti designs had carried them vertically at a cost to accuracy. Defensive armament was four 12.7 mm Scotti machine guns, but the Italian account notes the Scottis jammed easily, unlike the robust Breda-SAFATs of the SM.79. Production figures remain unsettled between the accounts: an original order of 246 aircraft, 309 delivered in all versions in the Italian accounting, and 329 in the English Wikipedia's total. A revised SM.84bis, with a modified wing and improved torpedo release gear, changed details rather than the aircraft's character.
Operational History
The prototype first flew on 5 June 1940, five days before Italy entered the Second World War, and series production began at the end of that year. The first unit to operate it was 41° Gruppo, from 2 February 1941. On 27 September 1941, aircraft of 36° Stormo from Sardinia attacked the Malta-bound Operation Halberd convoy; Arduino Buri torpedoed the battleship HMS Nelson and put her out of action for six months, but six of the eleven aircraft sent were shot down, and almost all their crews were lost. The type's war over Malta continued into 1942: 4° Gruppo bombed targets on the island through the spring and summer, and in June its bombers joined 36° Stormo torpedo aircraft against the Operation Harpoon convoy. In August 1942, during Operation Pedestal, ten SM.84s attacked the convoy with special circling torpedoes and lost two aircraft to fighters. Losses and limits then told: two wings had stopped flying the type by October 1942, and it was gradually phased out as a bomber, replaced by the CANT Z.1007bis and even by the SM.79. By 10 July 1943, 43° Wing was the only unit still flying the SM.84. The complaints were not only from the top: Ettore Muti complained in 1941 about its awful handling and take-off.
Afterlife
At the armistice of September 1943 some 150 SM.84s remained, over 100 of them serviceable, and almost all were captured by the Germans, who rarely used them. Ten aircraft stayed with the Italian Social Republic's Aeronautica Nazionale Repubblicana but were not used, while the Co-Belligerent Air Force flew a few as transports — seven in the English account, six in the Italian, which places them in a transport squadron formed after the armistice. Slovakia had also received a small batch during the war: six aircraft in the Italian account, ten in the English. The post-war Italian Air Force operated some surviving aircraft until 1949, and the type was phased out shortly after the war ended. The last of the line, the single SM.84ter with 1,500 hp Piaggio P.XII engines, was destroyed by fire in a landing accident in 1946.