The Savoia-Marchetti SM.86 was a derivative of the earlier SM.85.
Along with the radial equipped SM.85, the engineers of the company designed a version with liquid-cooled engines. The continuity of the design remains, but the modernization of the bomber was by no means superficial. Almost all components of the aircraft were refined: the fuselage, cockpit, tail, flaps. The design specification provided for the installation of several engine types to determine the most optimal configuration. The Italian Air Force specification of September 22, 1937 required the installation 12-cylinder V-type engines Walter "Sagitta" ICSR (600 hp), which had good weight characteristics with sufficient thrust-weight ratio. Six months later, on February 2, 1938, the specification was changed towards Piaggio P.VII C.16, but ultimately the first option was selected. The prototype SM.86W (registration number MM.397) entered trials in 1940. These were conducted by test pilot Scarpino, who was pleased with the aircraft, although there were some marked disadvantages. The tests lasted for several months, and were completed in August 1940 at the research center in the Guidon, where the dive-bomber had been delivered to assess it's suitability as a fighting machine.
The second prototype, registered MM.398 was built soon afterwards, receiving a similar SM.86W designation, but fitted with 515 hp Isotta Frascini "Gamma" engines. On August 7, 1941 the first flight, performed by a pilot named Nobili, generally confirmed the data previously obtained from testing the first prototype.
Both versions of the dive bomber were almost the same, with the only difference being that "eighty-six" had a slightly higher speed. The decision to launch SM.86W into production was quite controversial, because the already built SM.85 dive bombers SM.85 had a lot of problems. In 1940 an order was issued for 97 aircraft, and the first prototype SM.86W decided to send to the front-line for trials by the 96 Gr. Aut. BT. This group recently received a German Ju 87B, so that its pilots had to decide how good or bad the two dive-bombers were. The only example of the Italian dive bomber was placed at the disposal of Scarpino at Comiso airfield on September 10, 1940. On September 15 he made his first combat mission by participating in a raid on an airfield at Al-Far (Malta). The exact number of flights made using SM.86W remains unknown, but the use of aircraft caused almost no complaints. Suddenly, the progress in the case allowed the Italian commanders to conclude that this dive bomber could also be used in the Greek campaign, which began in late October. Scarpino flew it to the airfield at Lecce and from November 4, also participated in the bombing of the Greek troops at G.Yanina.
The combat experience of the SM.86 should be recognized as being more successful than the earlier SM.85, but the Air Force has already made a major stake in the Ju.87B. Prototypes were left for a while in the hangar until August 17, 1941. 
- Model: SM.86
- Wing span: 14.9 m
- Length: 10.9 m
- Height:3.30 m
- Wing area:28 m2
- Weight: Empty 3820 kg, Normal take-off 5077 kg
- Engine Type: Two 600 hp PD Walter Sagitta ICSR
- Maximum speed: 412 km/h
- Cruising speed: 368 km/h
- Range: 980 km
- Service ceiling: 7000 m
- Crew 1
- Armament: two 12.7-mm machine gun plus 800 kg bombload