Aviation USK 1/72 Savoia Marchetti SM.84
Torpedo Bomber
by Enrico Calanchini


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This airplane was designed to replace the SM.79, but it was not quite able to match the earlier aircraft. Although the SM.84 was modern and generally a better airplane it was not an ideal combat aircraft like its predecessor. Its chief weakness was that it was not highly maneuverable. This became evident when it was used as a torpedo bomber. Nevertheless the 309 aircraft manufactured put in a good showing in the Mediterranean until the 1943 armistice. Some SM.84s were used in transport units after the war and remained in service until 1948.

The SM.84 was designed by Alessandro Marchetti who had designed SIAI’s earlier tri-motor aircraft. The new plane kept the main plane of the SM.79 however the fuselage was more modern, the tailpane had twin-rudders for improved directional stability and a wider scope of fire for the rear gunner and engines that were more powerful. The SM.84 was a low wing monoplane with a frame of wood and steel tubing and skin of fabric, plywood and aluminum. The undercarriage was retractable and partially enclosed in the engine nacelles. Power was provided by three 1,000 hp Piaggio P.XI radial engines which drove three blade metal propellers with variable pitch. Defensive armament consisted of 4 x 12.7 mm MGs. Bombs could be carried inside the fuselage or under the wings. A maximum of 1 ton of bombs could be carried internally. Outside, the airplane could carry four rockets, various accommodations of bombs up to a maximum of 3,500 pounds or two torpedoes.

The prototype made its first flight on June 5, 1940. Earlier tests had already been carried out on a modified SM.79 with twin rudders and 860 hp Alfa Romeo engines. The new aeroplane, however, experienced various difficulties, especially in take-off, and the Piaggio P.XI engines did not prove to be very reliable. Nevertheless the SIAI-Marchetti SM.84 was ordered at once in large quantity, a first order for 246 aircraft being placed while the prototype was beginning test flights.

The first unit to receive the new tri-motor aeroplane was the 41st Bomber Group in February 1941. Several months later the 36th Torpedo Bomber Group received the aeroplane. The SM.84 served as a torpedo carrier until the autumn of 1942, when it was reassigned to bomber groups. Meanwhile the 84bis model had gone into production. This model had a modified wing, with positive dihedral, changes in the cockpit and in the ventilation of the engines and torpedo-launching controls.

After the 1943 armistice some of the SM.84s fell into German hands, but they saw little duty in the north. Ten aeroplanes were used by the Allies in the south in a transport group and these aircraft remained in service until the end of the war.







Unit Operational History - 108 Gruppo BT (256, 257 Sq., 36 St.)

108 Gruppo BT was formed on 4 February 1938 at Bologna Borgo Panigale with crews and aircraft from 8 Stormo. It participated with SM 81s and SM 79s in the occupation of Albania. Its main war began over Bizerte, Tunisia, followed by attacks on Malta. It also joined in the Battaglia de Punta Stilo on 9 July, losing an SM 79 from 257 Sq.

The unit returned to Italy for retraining and fresh equipment receiving its first SM 84s on 7 May 1941. With this new aircraft the unit changed role, and on 1 September became a Gruppo Aerosilurante. Three days later, with fourteen SM 84s, it went to Sardinia for operations against shipping from Gibraltar.

Operating jointly with 109 Gruppo on the 27th September 1941, eleven SM 84s (six from 108, five from 109 Gruppo) took off from Sardinia to attack the convoy off La Galite. Their main targets were the battleship HMS Nelson and the carrier HMS Ark Royal. At first escorting fighters kept interceptors engaged, then the unit split in two for its attack. The escorts, from 161 and 24 Gruppi, were at the limit of their range and had difficulty following the torpedo-bombers all the way in. Indeed, one CR 42 was downed by Italian naval anti-aircraft fire in error, and the Royal Navy also shot down two Fulmars amid the massive barrage set up to protect the warships. Sergente Maggiore Valotti of 354 Sq flew aerobatics to the amazement and distraction of the naval crews, but it was not enough to prevent the torpedo-bomber losses, and he was also shot down. Six SM 84s were lost, including the Stormo commander, Colonello Riccardo Seidl, and three of his squadriglia commanders. For the first time a whole command section, 36 Stormo, was awarded the Medaglia d'Oro alle Bandiere for its dedication and sacrifice to its nation. Thirty-eight crew members were lost and six wounded out of seventy. HMS Nelson was put out of action for six months. Sottotenente Del Vento of 287 Sq kept watch on the convoy throughout the battle, then landed his Z506B to pick up torpedo crews in the water. Enemy fighters attacked, setting fire to the Cant, and Del Vento had to land on the water again. When the enemy had left, his observer, Sottotenente Majorana, although mortally wounded and unable to speak, guided the crew to land. Both he and Del Vento were awarded the Medaglia d'Oro.

On 23 October 1941 four SM 84s of 256 and 258 Sq took off from Decimomannu to attack ships west of La Galite. Vichy French anti-aircraft fire from neighbouring ships hit one of the SM 84s. Detachments of S.84s were sent to Sicily and Pantelleria as needed in the anti-shipping role. On 7 March 1942 three aircraft from 257 Sq carried out armed reconnaissance flights, one force-landing at Maison Blanche. On the 20th fourteen Stormo aircraft moved to Sciacca in anticipation of approaching convoys for Malta. Two days later nine of them attacked a convoy in the bay of Sollum.

By April 1942 both 108 and its sister Gruppo, 109, were temporarily out of action because their remaining twelve airworthy aircraft were grounded with engine problems. They spent the next few weeks on training sorties and convoy escorts, while the engines were all gradually replaced. On 14 June six out of fourteen Stormo aircraft were lost in a mission south of Sardinia, including two senior crews, despite an escort of nineteen CR 42s and twenty MC 200s. On 13 September some of the SM 84s were passed to 32 Stormo at Gioia del Col le. Two days later the Gruppo exchanged the remainder for S79s.

Returning to Sardinia the unit carried out convoy escorts, reconnaissance missions and anti-shipping strikes. After five weeks it went to Pisa for training in night attacks on shipping. By 28 November 1942 the Stormo had sixteen aircraft at Pisa and nine had returned to Decimomannu. They were all returned to action in May 1943. Gerbini was also used about this time. In June the Gruppo moved to Lecce to join the newly formed Raggruppamento Aerosilurante and became Autonomo on 15 July. This unit followed the same operational history as 108 Gruppo, its sister unit in 36 Stormo. It carried out its first night missions on 12 August 1940, over Malta.

On 20 September 1941, with fifteen SM 84s, the unit followed 108 Gruppo to Sardinia for operations against shipping from Gibraltar, beginning on the 27th near La Galite. Five aircraft were temporarily transferred to Pantelleria on 29 November, making armed reconnaissances. The next day they land at Castelbenito, one being accidentally shot down by German anti-aircraft fire near Zanzur.

On 18 December 1941 three aircraft from 259 Sq attacked ships south of Malta, Maggiore Gastaldi receiving a posthumous Medaglia d'Oro for his leadership during the attack. Three days later six aircraft from 259 Sq moved to Comiso via Pantelleria, five returning to Decimomannu shortly after.

On 14 June 1942 one aircraft from 256 Sq and one from 259 Sq guided eight CR42 fighter bombers against the HARPOON convoy, claiming a near miss on a cruiser. Two Fiats were downed by Fulmars, as well as the 259 Sq aircraft. The other SM 84 claimed two of the intercepting fighters.

On 13 August 1942 three aircraft were detached Chinisia via Castelvetrano, joining two from 3 NAS and ten from 130 Gruppo for attacks on the PEDESTAL convoy. After intensive operations the unit reorganised in Italy, returning to Sardinia with fifteen SM 79s in November, together with ten from 1, 2 and 3 NAS.

Joint operations continued with its sister unit until July 1943. By 9 July the unit had no serviceable aircraft. 36 Stormo was disbanded on the 15th, followed by the Gruppo on 9 August.

Source: Courage Alone: The Italian Airforce 1940-1943 Hardcover, 2009



Construction

This is the Aviation USK 1/72 SM.84. The kit suffers from a number of dimensional mistakes that will visibly compromise the appearance if not remedied. Unfortunately, describing them all would make the description dull, so I limited myself to highlight the most important points (indicated in image captions), starting from the fuselage that is reduced by section and length, the wings should be reduced in the chord and camber lines, the engine covers and the replaced propellers taken from a SM 81 Supermodel kit, the numerous minor changes can be deduced from the Nomenclature Catalog (CMPR) and Ali d'Italia No.21. WIP photos with captions provide some additional clarification on the exact work done. The plane depicts MM.22462, 256a Sq.,108o Gr., 36o Stormo, Decimomannu, June 1942.





Technical Data

Aircraft: SIAI-Marchetti SM.84
Manufacturer: SIAI-Marchetti
Type: Bomber
Year: 1941
Engine: Three Piaggio P.XI RC 40, 14 cylinder radial, air-cooled, 1,000 hp each
Wingspan: 69 ft 7 in (21.20 m)
Length: 58 ft 10 in (17.93 m)
Height: 15 ft 1 in (4.59 m)
Weight: 29,330 lb (13,288 kg) (Loaded)
Maximum Speed: 268 mph (432 km/h) at 15,000 ft (4,600 m)
Ceiling: 25,900 ft (7,900 m)
Range: 1,137 miles (1,830 km)
Armament: 4 machine guns; 4,400 lb (2,000 kg) of bombs
Crew: 5

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