n October 1963 Silvercraft SpA flew the XY prototype light helicopter further developed with financial and technical assistance of shareholder SIAI-Marchetti as the all-metal three-seat SH-4, the prototype of which (I-SILX) made its first flight in March 1965.
The SH-4 had a skid undercarriage and a high-set tubular corrugated tailboom with a small fin and tailplane and a two-blade tail rotor and powered by a 235hp (derated to 170hp) Franklin 6A-350-D1B piston engine. The main rotor had two blades and a transverse mass-balanced stabiliser bar.
A pre-production model was displayed at the 1967 Paris Air Show, certification was achieved in September 1968. The first helicopter of all-Italian design and construction to receive both Italian and U.S. certification. The SH-4 went into production at Silvercraft’s works at Sesto Calende in basic form. Variations were the SH-4/A for agricultural use and as the SH-4/C with a supercharged Franklin 6AS-350-D1 engine.
Serious production had begun as SIAI-Marchetti/Silvercraft SH-4, but under name Silvercraft alone deliveries began 1970. Production ceased 1977. Production of a batch of about 50 SH-4s was started at the Sesto Calende works with the aid of Fiat Aviazione (Motori), who manufactured mechanical parts for the rotor transmission, but the firm ran into difficulties over the Franklin engine, which had gone out of production.
A total of 21 SH-4s were completed with individual examples being exported to Brazil, South Africa, France and Holland. One aircraft was delivered to the Italian Air Force.
The company ceased operations in the late 1970s.
SH-4 / SH-4A
Engine: Franklin 6AS-350-S1, 235 hp de-rated to 170 hp
Main rotor diameter: 29 ft 7.5 in / 9.03 m
Fuselage length: 25 ft 1.25 in / 7.65 m
Empty weight: 1142 lb / 518 kg
MTOW norm: 1900 lb / 862 kg
Max cruise: 70 kt / 81 mph / 130 kph
ROC: 1180 fpm / 360 m/min
Service ceiling: 15,100 ft / 4600 m
Range max fuel: 173 nm / 200 mi / 320 km
Seats: 3
SH-4A ag capacity: 54 USG / 200 lt / 441 lb / 200 kg
External cargo hook: 441 lb / 200 kg
Cabin length: 4 ft 9.75 in / 1.47 m
Cabin height: 4 ft 0.25 in / 1.24 m
All Aero 