Savoia-Marchetti SM.84

Savoia-Marchetti

Company type	Aircraft manufacturer
Industry	Aerospace
Founded	1915
Headquarters	Italy
Products	Aircraft, including the SM.84 bomber

Template:Infobox aircraft

The Savoia-Marchetti SM.84 was an Italian bomber employed during World War II, distinct from the similarly named Savoia-Marchetti S.84 airliner prototype. Conceived by Savoia-Marchetti to succeed the acclaimed SM.79, it retained the tri-motor configuration of its predecessor. Although it entered operational service with the Regia Aeronautica in 1941, it never fully supplanted the SM.79 and was withdrawn before it.

Development

Work on a successor to the SM.79 began in 1938, with Savoia-Marchetti opting to enhance the existing design by incorporating a similar wing structure but introducing a redesigned fuselage, a twin-tail assembly, and more powerful powerplants. Two prototypes, initially designated SM.89 or SM.79bis, were commissioned on 21 September 1939, followed by a production contract for 183 units in December of that year. The first prototype took to the skies on 5 June 1940, just days prior to Italy's entry into World War II.

The intention was to replace the aging SM.79 fleet, which, despite their speed, were becoming outdated and had yet to be fully adapted for use as torpedo bombers. The principal upgrade involved installing new engines delivering a combined output of 2,237 kW (3,000 hp). Series production commenced late in 1940.

Design

Essentially an advanced iteration of the SM.79, this model incorporated contemporary technologies and systems. It maintained the three-engine mixed-construction monoplane layout characteristic of its predecessor. The wings were constructed from wood and reinforced by three spars, while the fuselage framework consisted of steel tubing covered forward by metal and aft by fabric and wood.

The crew complement ranged from five to six personnel seated within the new fuselage design; pilots occupied side-by-side positions with a radio operator and flight engineer located behind them. Visibility was enhanced by a large windscreen and eight side windows.

Protection was significantly upgraded compared to the minimal armor on the SM.79, reportedly totaling around 700 kg (1,540 lb), although whether this included self-sealing fuel tanks—capable of resisting up to 12.7 mm (.50 in) rounds—is uncertain. The twin-tail configuration improved dorsal gun coverage and helped manage the increased power and weight relative to the SM.79.

Armament resembled that of the CANT Z.1007 rather than the SM.79’s setup. A Caproni-Lanciani Delta turret mounted dorsally housed a 12.7 mm (.50 in) Scotti machine gun with 350 rounds available; another Scotti gun was installed in the ventral gondola, while two additional Scotti guns were positioned on each flank with six belts of 120 rounds each. Despite theoretical advantages, Scotti guns were less reliable than Breda models despite a marginally higher rate of fire. A notable limitation was that the turret could not fire forward through the propeller arc, leaving the aircraft vulnerable to frontal assaults.

The bomb bay was centrally located within the fuselage and designed for horizontal bomb carriage: configurations included two 500 kg (1,100 lb), three 250 kg (550 lb), ten 100 kg (220 lb), or ten 50 kg (110 lb) bombs. External mounts allowed for two bombs weighing either 500 kg (1,102 lb) or 800 kg (1,760 lb), or alternatively two torpedoes or multiple smaller bombs. Typically, missions involved carrying either one torpedo or approximately 1,000 kg (2,200 lb) of bombs.

Bomb aiming utilized a retractable Jozza U3 sight located in the bombardier’s nacelle beneath the cockpit to minimize drag when not deployed.

Photographic reconnaissance capability included an OMI camera installed in the fuselage and provision for one of three camera types—such as AGR.90 or AGR.91—in the tail section.

Powerplant consisted of three Piaggio P.XI RC.40 engines rated at 746 kW (1,000 hp) each at an altitude of 4,000 m (13,120 ft). Fuel was stored in sixteen self-sealing tanks distributed between wings and fuselage: six tanks for the central engine holding 1,070 L (283 US gal), and five tanks per wing engine containing 1,095 L (289 US gal) each—totaling 3,260 L (860 US gal). This fuel capacity was lower than earlier Italian bombers despite increased engine power but could be augmented with three additional tanks: two fuselage tanks of 415 L (110 US gal) each and one bomb bay tank holding 2,500 L (661 US gal).

Performance at full load included:

• Maximum speeds ranging from 400 km/h (250 mph) at 1,000 m (3,280 ft) up to 467 km/h (290 mph) at 5,000 m (16,400 ft).
• Climb times reaching altitudes between 1,000 m and 6,000 m varied from approximately two and a half minutes up to nineteen minutes.
• Operational ceiling extended to about 8,200 m (26,900 ft).
• At an altitude of 5,500 m (18,050 ft) and speed of 397 km/h (247 mph), endurance was recorded at just over five hours with a range near 2,040 km (1,270 mi).

As anticipated during development phases, these specifications surpassed those of its predecessor SM.79 in terms of overall performance.

Operational history

The initial operator of this aircraft was the 12° Stormo (Wing), specifically the 41° Gruppo (Group), commencing service on 2 February 1941. Stationed at Rodi, this Group’s early missions were unsuccessful, with two aircraft forced to land in Turkey and consequently lost, although their crews eventually returned to Rodi.

The 36° Stormo (108 and 109 Groups) received its SM.84s on 7 May 1941 and was stationed at the Decimomannu airbase in Sardinia starting September 1941. On 27 September 1941, twelve aircraft from the 36° Stormo launched an attack against a British convoy bound for Malta during Operation Halberd. One aircraft aborted the mission due to mechanical issues, but the others proceeded with the assault. The first wave, led by Arduino Buri, targeted British vessels, successfully torpedoing HMS Nelson, which was incapacitated for six months. From this initial group, one aircraft was lost to enemy fire; in the second wave, two of three aircraft were shot down. When Seidl led his five aircraft into action, he and two others were also downed. Although damaging Nelson marked a rare success for Italian torpedo bombers, it came at a severe cost: six aircraft destroyed and nearly all crew members lost—over thirty personnel. The following day, SM.79s sank the merchant ship Empire Pelican, suffering only one loss, allowing the rest of the convoy to deliver supplies to Malta.

Following these heavy casualties, the 36° Stormo persisted in targeting enemy shipping, sinking the merchant vessel Empire Defender in November and severely damaging HMS Penelope with nine SM.84s on 9 April 1942. The 282^a Squadriglia also participated in such operations with moderate success.

The 7° Stormo (4° and 5° Gruppo), operating from Sicily, employed SM.84s for bombing raids on Malta in July 1941. By mid-October that year, the 32° Stormo received SM.84s, organizing one group as torpedo bombers and another as conventional bombers to optimize maritime strike capabilities. This Wing engaged in assaults during Operation Torch, but by late December had lost twenty aircraft and was withdrawn from active duty.

Throughout spring and summer of 1942, the 4° Gruppo Autonomo Bombardamento Terrestre conducted bombing missions against targets on Malta, incurring significant losses. On 12 May, three SM.84s from the 14^a Squadriglia, accompanied by four Junkers Ju 88 bombers and escorted by Italian and German fighters, attacked the Ta' Qali airfield. The Savoia-Marchetti bombers suffered heavy damage from Spitfires and Hurricanes defending the island. RAF pilots claimed two SM.84s destroyed (mistakenly identified as CANT Z.1007s). In reality, only one Savoia-Marchetti piloted by Tenente Vinicio Vego Scocco was shot down; three Italian crew members bailed out but none survived—one drowned while two were killed upon landing near a cliff.

In June 1942, nine bombers from the same 4° Gruppo, along with fourteen torpedo bombers from the 36° Stormo, attacked a Malta convoy during Operation Harpoon (1942). They suffered at least two losses to Spitfire fighters and one to ground-based anti-aircraft fire.

On 4 July 1942, further losses occurred when three SM.84s returned to Malta to bomb Luqa airport. These Italian trimotors were escorted by numerous Messerschmitt Bf 109s, Macchi C.202s, and Reggiane Re.2001 fighters. Spitfires from No. 249 Squadron RAF, diving from above and out of sunlight, penetrated the dense Axis fighter escort and inflicted severe damage on the Savoia-Marchettis (again misidentified as CANT Z.1007s), claiming all three aircraft shot down. During this sortie, two SM.84s were lost: one crashed offshore possibly piloted by Tenente Raffaele Notari of the 15^a Squadriglia, while another flown by Sergente Maggiore Romolo Cristiani of the 14^a Squadriglia crashed near Ta' Garda. The third damaged SM.84 managed to return safely to Sicily.

During August's Operation Pedestal, ten SM.84s equipped with specialized circling torpedoes (Motobomba) attacked the convoy but lost two planes to enemy fighters. Aircraft from both the 32° and 36° Wings also participated in these attacks. Despite intense German and Italian efforts—including attacks by SM.82s—only five out of fourteen ships reached Malta; however, their cargo was vital for sustaining the garrison after previous operations had largely failed.

While some units continued receiving SM.84s, both the 36° and 7° Wings ceased flying them by October 1942; meanwhile, the 32° Wing engaged North African targets but suffered twenty losses before returning to Apulia for reorganization in December that year. Early in 1943, the new SM.84bis variant was introduced to the 38° Group and later delivered to the 8° Stormo (27° and 28° Groups). However, decline had already set in—the use of SM.84s by the 8° Stormo for resupplying North African forces proved unsuccessful: although faster than the SM.82, its payload capacity was insufficient. Consequently, it was gradually phased out in favor of both the CANT Z.1007bis and even older SM.79 models. By mid-July 1943, only the 43° Wing based at Gioia del Colle in Apulia remained operational with SM.84s.

In September 1943, despite bomber units being nearly depleted, around 150 SM.84s were still available—over one hundred deemed serviceable—but most were seized by German forces who seldom utilized them. Some units were transferred to the Slovak Air Force, while ten remained with the RSI’s Aeronautica Nazionale Repubblicana but saw no active use; seven were operated by the Italian Co-Belligerent Air Force as transports before being retired shortly after World War II ended.

Overall, the SM.84 proved an unsuccessful design—Francesco Pricolo described it as a 'wrong aircraft', while Ettore Muti criticized its poor handling and takeoff characteristics as early as 1941. It never gained favor among crews nor managed to replace the SM.79 effectively. When the final version of its predecessor—the SM.79bis—became available, production of the SM.84 ceased entirely for bomber roles due to its inferiority compared to models like the CANT Z.1007 ter especially at higher altitudes; flying above approximately five thousand meters was nearly impossible for the SM.84.

Torpedo bombers demanded agility and speed for effective target engagement; many designs struggled with increased weight and wing loading beyond their original specifications. The SM.84 was considerably heavier than its predecessor—the SM.79—and once improved versions like the SM.79bis appeared featuring enhanced engines yet lower weight and wing loading alongside better power-to-weight ratios—it became clearly preferable.

An official report from command of the 43° Stormo B.T., documented critical evaluations of this bomber wing’s performance beginning with bombing operations from Gioia del Colle on 13 July 1943. The commander of the 41° Stormo lamented that their limited attack force was insufficient to overwhelm enemy defenses—even during nighttime raids—and noted a shortage of pilots trained for nocturnal missions combined with low sortie numbers alongside poor operational performance of the SM.84 itself.

Variants

SM.84bis

Incorporated multiple adjustments without representing a major redesign.

SM.84ter

A sole unit finalized in 1944, equipped with 1,119 kW (1,500 hp) Piaggio P.XII engines, reaching speeds exceeding 500 km/h (310 mph). It was lost to fire following a landing mishap in 1946.

Operators

Template:Country data Kingdom of Italy

Regia Aeronautica:

• • 7° Stormo, active from 29 July 1941 until October 1942:
    • 4° Gruppo (Squadriglie 14^a and 15^a) alongside 25° Gruppo (Squadriglie 8^a and 9^a)
  • 8° Stormo, operational since 1943:
    • 27° Gruppo (Squadriglie 18^a and 52^a) and 28° Gruppo (Squadriglie 10^a and 19^a)
  • 10° Stormo, from November 1942 onward:
    • comprising solely the 30° Gruppo
  • 12° Stormo BT, starting from 2 February 1941:
    • 41° Gruppo (Squadriglie 204^a and 205^a) plus the 42° Gruppo
  • 32° Stormo, between October 1941 and 1943:
    • 38° Gruppo (Squadriglie 49^a and 50^a) as well as the 89° Gruppo (Squadriglie 228^a and 229^a)
  • 36° Stormo, active from 7 May 1941 until October 1942:
    • 108° Gruppo (Squadriglie 256^a and 257^a) together with the 109° Gruppo (Squadriglie 258^a and 259^a)
  • 43° Stormo: from late July 1942 through summer of 1943:
    • 98° Gruppo (Squadriglie 240^a and 241^a) alongside the 99° Gruppo (Squadriglie 242^a and 243^a)
  • 282^a Squadriglia AS
• Italian Co-Belligerent Air Force

Template:ITA

• Italian Air Force operated remaining aircraft until approximately 1949.

Germany

• Luftwaffe

Slovakia Slovakia received a total of ten units

• Slovak Air Force (1939–1945)
• Slovak Insurgent Air Force

Bibliography

• Angelucci, Enzo, editor. World Encyclopedia of Military Aircraft. London: Jane's Publishing, 1981. ISBN 0-7106-0148-4.
• Donald, David, editor. The Encyclopedia of World Aircraft. Aerospace Publishing, 1997. ISBN 1-85605-375-X.
• Gori, Cesare. SIAI SM.84 Ali d'Italia No. 21. Turin: La Bancarella Aeronautica, 2006.
• Rogers, Anthony. Battle over Malta - Aircraft Losses & Crash Sites 1940-42. Phoenix Mill Thrupp - Strout, Gloucestershire: Sutton Publishing, 2000. ISBN 0-7509-2392-X.
• Lembo, Daniele. S.84, il fratello stupido dello Sparviero, Aerei nella storia magazine, Westward editions, no. 24, pp. 10–32.