The prototype for the SF.260 series, known as the F.250, was designed by Dott Ing Stelio Frati and built by Aviamilano. Flown for the first time on 15 July 1964, it was powered by a 186.5 kW (250 hp) Avco Lycoming engine and was certificated for aerobatic flying. A description appeared in the 1965-66 Jane's.
The version developed initially, for civil production, was manufactured, at first under licence from Aviamilano, by SIAI-Marchetti, and is designated SF.260. It received FAA type approval on 1 April 1966. Subsequently SIAI-Marchetti became the official holder of the type certificate and of all manufacturing rights in the SF.260.
Descriptions of the civil SF.260A and SF.260B can be found in the 1980-81 and earlier editions of Jane's, and of the SF.260C in the 1985-86 edition. Current models are as follows:
SF.260D. Improved and updated civil version, replacing SF.260C, with aerodynamic and structural improvements developed for military SF.260M. Certificated by RAI on 14 December 1985 and by FAA in October 1986.
SF.260M. Two/three-seat military trainer, developed from civil SF.260A and first flown on 10 October 1970. Introduced a number of important structural and aerodynamic improvements, many of which were subsequently applied to later models. Meets requirements for basic flying training; instrument flying; aerobatics, including deliberate spinning and recovery; night flying; navigation flying; and formation flying. Detailed customer list in 1984-85 and earlier editions of Jane's.
SF.260W Warrior. Trainer/tactical support version of SF.260M, first flown (I-SJAV) in May 1972. Two or four underwing pylons, for up to 300 kg (661 lb) of external stores, and cockpit stores selection panel. Able to undertake a wide variety of roles, including low-level strike; forward air control; forward air support; armed reconnaissance; and liaison. Also meets same requirements as SF.260M for use as a trainer. Customers as listed in 1984-85 and earlier Jane's. One aircraft (described in 1980-81 and earlier editions) completed as SF.260SW Sea Warrior surveillance/SAR/supply version.
SF.260TP. Turboprop powered development. Described separately.
By early 1987 more than 800 SF.260s of all models had been delivered, mainly for export, and production of the piston engined models was continuing. Military trainer variants are operated by more than 20 armed forces worldwide.
The following description is generally applicable to all piston engined models unless otherwise stated:

TYPE: Two/three-seat fully aerobatic military light aircraft.

WINGS: Cantilever low-wing monoplane. Wing section NACA 641-212 (modified) at root, NACA 641-210 (modified) at tip. Dihedral 6° 20' from roots (5° on SF.260D). Incidence 2° 45' at root, 0° at tip. No sweepback. All-metal light alloy safe-life structure, with single main spar and auxiliary rear spar, built in two portions bolted together at centreline and attached to fuselage by six bolts. Press-formed ribs, with dimpled stiffening holes. Skin, which is butt joined and flush riveted, stiffened by stringers between main and rear spars. Differentially operating Frise light alloy mass balanced ailerons, and electrically actuated light alloy single-slotted flaps. Flaps operated by torque tube and mechanical linkage, ailerons by pushrods and cables. Servo tab in each aileron.

FUSELAGE: Semi-monocoque safe-life structure of frames, stringers and flush riveted skin, exclusively of light alloy except for welded steel tube engine mounting, glassfibre front panel of engine cowling, stainless steel firewall and detachable glassfibre tailcone.

TAIL UNIT: Cantilever light alloy safe-life structure, with sweptback vertical surfaces, fixed incidence tailplane and one-piece elevator. Two-spar fin and one-piece tailplane, bolted to fuselage; single-spar elevator, statically and aerodynamically balanced, and balanced rudder. Rudder and elevator operated by cables. Controllable trim tab in starboard half of elevator; ground adjustable tab on rudder.

LANDING GEAR: Electrically retractable tricycle type, with manual emergency actuation. Inward retracting main gear, of trailing arm type, and rearward retracting nose unit, each embodying Magnaghi oleo-pneumatic shock absorber (type 2/22028 in main units). Each welded steel tube main leg is hinged to the main and rear spars. Nose unit is of leg and fork type, with coaxial shock absorber and torque strut. Cleveland P/N 3080A mainwheels, with size 6.00-6 tube and tyre (6-ply rating), pressure 2.45 bars (35.5 Ib/sq in). Cleveland P/N 40-77A nosewheel, with size 5.00-5 tube and tyre (6-ply rating), pressure 1.96 bars (28.4 Ib/sq in). Cleveland P/N 3000-500 independent hydraulic single-disc brake and parking brake on each mainwheel. Nosewheel steering (20° to left or right) is operated directly by the rudder pedals, to which it is linked by pushrods. Up-lock secures main gear in retracted position during flight; anti-retraction system prevents main gear from retracting whenever strut is compressed by weight of aircraft.

POWER PLANT: One 194 kW (260 hp) Avco Lycoming O-540-E4A5 flat-six engine, driving a Hartzell HC-C2YK-1BF/8477-8R two-blade constant-speed metal propeller with spinner. AEIO-540-D4A5 engine available optionally. Fuel in two light alloy tanks in wings, capacity of each 49.5 litres (13.1 US gallons; 10.9 Imp gallons); and two permanent wingtip tanks, capacity of each 72 litres (19 US gallons; 15.85 Imp gallons). Total internal fuel capacity 243 litres (64.2 US gallons; 53.5 Imp gallons), of which 235 litres (62.1 US gallons; 51.7 Imp gallons) are usable. Individual refuelling point on top of each tank. In addition, SF.260W may be fitted with two 80 litre (21.1 US gallon; 17.5 Imp gallon) auxiliary tanks on underwing pylons. Oil capacity (all models) 11.4 litres (3.0 US gallons; 2.5 Imp gallons).

ACCOMMODATION (SF.260D): Three seats in enclosed cockpit, two side by side in front, one at rear. Two children with a combined weight not exceeding 113 kg (250 lb) may occupy rear seat. One-piece fully transparent rearward sliding Plexiglas canopy, with rubber cord canopy release. Baggage compartment, capacity 40 kg (88 lb), behind rear seat. Cabin carpeted, heated and ventilated; walls thermally insulated and soundproofed by a glass-fibre lining. Slots at base of windscreen admit air for windscreen defrosting.

ACCOMMODATION (SF.260M; W similar): Side by side front seats (for instructor and pupil in SF.260M), with third seat centrally at rear. Front seats individually adjustable fore and aft, with forward folding backs and provision for back type parachute packs. Dual controls standard. All three seats equipped with lap belts and shoulder harnesses. Baggage compartment aft of rear seat. Upper portion of canopy tinted. Emergency canopy release handle for each front seat occupant. Steel tube windscreen frame for protection in the event of an overturn.

SYSTEMS (SF.260M; other models generally similar): Hydraulic equipment for mainwheel brakes only. No pneumatic system. 24V DC electrical system of single-conductor negative earth type, including 70A Prestolite engine mounted alternator/rectifier and 24V 24Ah Varley battery, for engine starting, flap and landing gear actuation, fuel booster pumps, electronics and lighting. Sealed battery compartment in rear of fuselage on port side. Connection of an external power source automatically disconnects the battery. Heating system for carburettor air intake. Emergency electrical system for extending landing gear if normal electrical actuation fails; provision for mechanical extension in the event of total electrical failure. Cabin heating, and windscreen de-icing and demisting, by heat exchanger using engine exhaust air. Additional manually controlled warm air outlets for general cabin heating. Oxygen system optional.

AVIONICS AND EQUIPMENT (SF.260M; W generally similar): Basic instrumentation and military equipment to customer’s requirements. Blind-flying instrumentation and communications equipment optional: typical selection includes dual Collins 20B VHF com; Collins VIR-31A VHF nav; Collins ADF-60A; Collins TDR-90 ATC transponder; Collins PN-101 compass; ID-90-000 RMI; and Gemelli AG04-1 intercom. Landing light in nose, below spinner. Instrument panel can be slid rearward to provide access to rear of instruments.

ARMAMENT (SF.260W): Two or four underwing hardpoints, able to carry external stores on NATO standard pylons up to a maximum of 300 kg (661 lb) when flown as a single-seater. Typical alternative loads can include one or two SIAI gun pods, each with one or two 7.62 mm FN machine-guns and 500 rds; two Aerea AL-8-70 launchers each with eight 2.75 in rockets; two LAU-32 launchers each with seven 2.75 in rockets; two Aerea AL-18-50 launchers each with eighteen 2 in rockets; two Aerea AL-8-68 launchers each with eight 68 mm rockets; two Aerea AL-6-80 launchers each with six 81 mm rockets; two LUU-2/B parachute flares; two SAMP EU 32 125 kg general purpose bombs or EU 13 120 kg fragmentation bombs; two SAMP EU 70 50 kg general purpose bombs; Mk 76 11 kg practice bombs; two cartridge throwers for 70 mm multi-purpose cartridges, F 725 flares, or F 130 smoke cartridges; one or two photo-reconnaissance pods with two 70 mm automatic cameras; two supply containers; or two 80 litre (21.1 US gallon; 17.5 Imp gallon) auxiliary fuel tanks.