On the whole, Italy’s aviation industry was badly organized and inefficient, producing a wide variety of aircraft types in small numbers. The various companies involved resisted manufacturing each other’s more successful designs, and the almost artisan production methods resulted in production times that were more than 50 percent longer than for comparable German aircraft. The Italian air force largely depended on radial engines, but these low-powered machines seldom exceeded 1,000 hp. Adoption of the bulkier but much more powerful German-designed Daimler-Benz in-line engine helped solve that problem.
The fact that the CR-42, a wood-and-canvas biplane fighter with nonretractable landing gear, was still in production in 1944 (and a serious candidate for the Daimler-Benz engine) reveals the sad state of Italian aircraft production. Italian fighters were almost all underarmed, due to financial considerations and poorly designed, weak wings. Radios were not installed in all aircraft until 1942; fuel was stored in thinly lined, leaking tanks; most airfields were dirt runways; and pilots were slow to adapt to closed canopies. On any given day, operational efficiency was rarely higher than 70 percent. Ground-support aircraft, based on precepts developed by General Amadeo Mecozzi, were so poorly designed that early in the war, Italy simply retired its ground-attack planes and purchased 159 Ju-87 Stuka dive-bombers from Germany.
One area in which the Italian air force excelled was the torpedo-bomber. Although use of this plane was hindered by interservice rivalry before the war, the torpedo-bomber was deployed to units by late 1940. German air units later successfully emulated Italian torpedo-bombing tactics and purchased torpedoes from Italy. Yet the Italians chose simply to adapt a three-engine SM-79 level bomber for torpedo bombing rather than design a true torpedo-bomber.
The Sparviero began its torpedo bomber (Aerosilurante in Italian) career on 25 July 1940 when a new unit was established after several years of experiments. The "Special Aerotorpedoes Unit" was led by Colonel Moioli. After having ordered the first 50 torpedoes from Whitehead Torpedo Works, on 10 August 1940 the first aircraft landed at T5 airfield, near Tobruk. Despite the lack of an aiming system and a specific doctrine for tactics, an attack on shipping in Alexandria was quickly organized. There had been experiments for many years but still, no service, no gear (except hardpoints) and no tactics were developed for the new speciality. This was despite previous Italian experiments into the practice of aerial torpedoing in 1914, 26 years earlier.
The first sortie under way on 15 August 1940 saw five SM.79s that had been modified and prepared for the task sent to El Adem airfield. Among their pilots were Buscaglia, Dequal and other pilots destined to become "aces." The journey was made at an altitude of 1,500 m (4,920 ft) and after two hours, at 21:30, they arrived over Alexandria and began attacking ships, but unsuccessfully. The departure airport had only 1,000 m (3,280 ft) of runway for takeoff, so two of the fuel tanks were left empty to reduce weight, giving an endurance of five hours for a 4.33 hour journey. Only Buscaglia and Dequal returned, both aircraft damaged by anti-aircraft fire. Buscaglia landed on only one wheel, with some other damage. The other three SM.79s, attacking after the first two, were hindered by a fierce anti-aircraft defence and low clouds and returned to their base without releasing their torpedoes. However, all three ran out of fuel and were forced to jettison the torpedoes which exploded in the desert, and then force-landed three hours after the attack. Two crews were rescued later, but the third (Fusco's) was still in Egypt when they force-landed. The crew set light to their aircraft the next morning, which alerted the British who then captured them. These failures were experienced within a combat radius of only about 650 km (400 mi), in clear contrast with the glamorous performances of the racer Sparvieros just a few years before.
Many missions followed, on 22–23 August (Alexandria), 26 August (against ships never found), and 27 August (Buscaglia against a cruiser). The special unit became known as the 278th Squadriglia, and from September 1940 carried out many shipping attacks, including on 4 September (when Buscaglia had his aircraft damaged by fighters) and 10 September, when Robone claimed a merchant ship sunk. On 17 September, after an unsuccessful day attack, Buscaglia and Robone returned at night, attacking the British ships that shelled Bardia. One torpedo hit HMS Kent, damaging the heavy cruiser to the extent that the ship remained under repair until September 1941. After almost a month of attacks, this was the first success officially acknowledged and proven. After almost a month of further attacks, a newcomer, Erasi, flew with Robone on 14 October 1940 against a British formation and hit HMS Liverpool, a modern cruiser that lost her bow and needed 13 months of repair. After several months, and despite the losses and the first unfortunate mission, the core of the 278th was still operating the same four aircraft. The last success of this squadron was at Souda Bay, Crete, when Buscaglia damaged another cruiser, HMS Glasgow, despite the anti-torpedo netting surrounding the ship, sending it out of commission for nine months while repairs were made. The aircraft continued in service until a British bomb struck them, setting off a torpedo and a "chain reaction" which destroyed them all.
The year started out badly, but improved in April when many successes were recorded by SM.79s of the 281st and 280th . They sank two merchant ships, heavily damaged the British cruiser HMS Manchester (sending it out of service for nine months) and later also sank the F class destroyer HMS Fearless. However, one SM.79 was shot down 25 nmi (46 km) north west of Gozo on 3 June, landing in the sea and staying afloat for some time. Further Italian successes came in August, when the light cruiser HMS Phoebe was damaged. The large merchant ship SS Imperial Star (10,886 tonnes/12,000 tons) was sunk by an SM.79 in September. The 130th and 132nd Gruppi were also active during the autumn. On 24 October, they sank the Empire Pelican and Empire Defender, on 23 November they sank the Glenearn and Xhakdina, and on 11 December they heavily damaged the Jackal.
The year ended with a total of nine Allied ships sunk and several damaged. The Italians had lost fourteen torpedo bombers and sustained several damaged in action. This was the best year for the Italian torpedo bombers and also the year when the SM.84, the SM.79's successor was introduced. Overall, these numbers meant little in the war, and almost no other results were recorded by Italian bombers. Horizontal bombing proved to be a failure and only dive bombers and torpedo-bombers achieved some results. The damaging of the British cruisers was the most important result, but without German help, the Italians would have been unable to maintain a presence in the Mediterranean theatre. The 25 Italian bomber wings were unable to trouble the British forces, as the Battle of Calabria demonstrated. Almost all of the major British ships lost were due to U-Boat attacks, with the damaging of HMS Warspite, and the sinking of HMS Barham and Ark Royal. The British fleet was left without major ships in their Mediterranean fleet leaving the Axis better situated to control the sea.
The Axis' fortunes started to decline steadily during 1942. Over 100 SM.79s were in service in different Italian torpedo squadrons. In addition to its wide-scale deployment in its intended bomber-torpedo bomber role, the Sparviero was also used for close support, reconnaissance and transport missions. In the first six months of 1942, all the Italo-German efforts to hit Allied ships had only resulted in the sinking of the merchant ship Thermopilae by an aircraft flown by Carlo Faggioni.
The Allies aimed to provide Malta with vital supplies and fuel through major convoy operations at all costs. Almost all Axis air potential was used against the first Allied convoy, Harpoon. 14 June saw the second torpedoing of Liverpool, by a 132nd Gruppo SM.79, putting it out of action for another 13 months. Regardless of where the torpedo struck, (amidships in the case of Liverpool, aft as for Kent, or forward as happened to Glasgow) the cruisers remained highly vulnerable to torpedoes, but no Italian air attack managed to hit them with more than one torpedo at once. On the same day the merchant ship Tanimbar was sunk by SM.79s of the 132nd, and finally the day after HMS Bedouin, a Tribal-class destroyer, already damaged by two Italian cruisers, was sunk by pilot M. Aichner, also of 132nd Gruppo. For years this victory was contested by the Italian Navy, who claimed to have sunk Bedouin with gunfire.
August saw heavy attacks on the 14 merchant ships and 44 major warships of the Operation Pedestal convoy, the second Allied attempt to resupply Malta past Axis bombers, minefields and U-boats. Nine of the merchant ships and four of the warships were sunk, and others were damaged, but only the destroyer HMS Foresight and the merchant ship MV Deucalion were sunk by Italian torpedo bombers. Although damaged, the tanker SS Ohio, a key part of the convoy, was towed into Grand Harbour to deliver the vital fuel on 15 August 1942 to enable Malta to continue functioning as an important Allied base, a major Allied strategic success.
By winter 1942, in contrast to Operation Torch, 9 December was a successful day when four SM.79s sank a Flower class corvette and a merchant ship, with the loss of one aircraft. Carlo Emanuele Buscaglia, another prominent member of the Italian torpedo-airforce who was credited with over 90,718 tonnes (100,000 tons) of enemy shipping sunk, was shot down the day after saying "We will probably all be dead before Christmas". The risks of attempting to overcome the effective defences of allied ships were too great to expect much chance of long-term survival, but he was later rescued from the water, badly wounded.
Despite the increased activity in 1942, the results were considerably poorer than those of the previous year. The efforts made by the bombers were heavily criticized as being insufficient. Many debated the possibilities of torpedo manufacturing defects or even sabotage: the first 30 used in 1940 had excellent reliability, but a number of later torpedoes were found to be defective, especially those made at the Naples factory. During Operation Harpoon, over 100 torpedoes were launched with only three hitting their targets.
The year opened with attacks against Allied shipping off North Africa, but still without much success. In July, the Allies invaded Sicily with an immense fleet. The Sparvieri were already obsolete and phased out of service in bomber Wings and its intended successors, the SM.84 and Z.1007, were a failure, while the latter were not produced in enough numbers. As a consequence, the latest version of the Sparviero was retained for torpedo attacks, being considerably faster than its predecessors.
Before the invasion, there was a large force of torpedo aircraft: 7 Gruppi (groups), 41, 89, 104, 108, 130, 131 and 132nd equipped with dozens of aircraft, but this was nevertheless an underpowered force. Except 104th, based around the Aegean Sea, the other six Gruppi comprised just 61 aircraft, with only 22 serviceable. Almost all the available machines were sent to the Raggruppamento Aerosiluranti. But, of the 44 aircraft, only a third were considered flight-worthy by 9 July 1943.
Production of new SM.79s continued to fall behind and up to the end of July only 37 SM.79s and 39 SM.84s were delivered. Despite the use of an improved engine, capable of a maximum speed of 475 km/h (295 mph), these machines were unable to cope with the difficult task of resisting the invasion. The size of these aircraft was too large to allow them to evade detection by enemy defences, and the need for large crews resulted in heavy human losses. In the first five days, SM.79s performed 57 missions at night time only and failed to achieve any results, with the loss of seven aircraft. Another three aircraft were lost on 16 July 1943 in a co-ordinated attack with German forces on HMS Indomitable. that was eventually hit and put out of combat for many months.
SM.79s were not equipped with radar, so the attacks had to be performed visually, hopefully aided by moonlight, while the Allies had ship-borne radar and interceptor aircraft. Despite their depleted state, the Regia Aeronautica attempted a strategic attack on Gibraltar on 19 July with 10 SM.79GAs, but only two managed to reach their target, again without achieving any result.
The last operation was in September 1943, and resulted in the damaging of the LST 417, on 7 September 1943. On 8 September, when the Armistice with Italy was announced, the Regia Aeronautica had no fewer than 61 SM.79s, of which 36 were operational.
Following the Armistice, the SM.79s based in southern Italy (34 altogether) were used by the Italian Co-Belligerent Air Force as transports in support of the Allies; those that remained in the North (36) continued to fight along German forces as part of the Aeronautica Nazionale Repubblicana or were incorporated into the Luftwaffe. A small number of SM.79s remained in service in the post-war Aeronautica Militare, where they served as passenger transports into the early 1950s.