Silvercraft Italiana and SIAI-Marchetti jointly designed an all-metal three-seat helicopter, the SH-4, the prototype of which (I-SILX) made its first flight in March 1965. It was a robust little machine with a skid undercarriage and a high-set tubular corrugated tailboom with a small fin and tailplane and a two-blade tail rotor. The SH-4 was powered by a 235hp Franklin 6A-350-D piston engine and the main rotor had two blades and a transverse mass-balanced stabiliser bar similar to that on a Bell 47. Certification was achieved in September 1968, and the SH-4 went into production at Silvercraft's works at Sesto Calende in basic form, and as the SH-4/A for agricultural use and as the SH-4/C with a supercharged Franklin 6AS-350-D1 engine. 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.
R.Simpson "Airlife's Helicopter and Rotorcraft", 1998
First flown in March 1965, the SH-4 is a three-seat light general-purpose helicopter powered by a 235hp Franklin 6A-350-D1B engine (derated to 170hp). The standard version is suitable for pilot training, utility, survey, police, ambulance, military liason and observation duties. An agricultural version was also produced as the SH-4A. The SH-4/4A is no longer in production. A replacement for the SH-4 was built as the SH-200, first flown in April 1977.
M.Taylor "Jane's Encyclopedia of Aviation", 1989
Silvercraft and SIAI Marchetti were aiming to produce a highly economical aircraft. The SH-4 had some original features such as the semirigid rotor and simplified mechanics, with parts which could easily be inspected from the outside and were quick to replace. The prototype flew in March 1965 with a six-cylinder Franklin engine. A pre-production model was displayed at the 1967 Paris Air Show, and a year later the SH-4 was certified by the American FAA and the Italian Aeronautical Register.
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. An agricultural version of the SH-4 was developed, designated SH-4A. The company ceased operations in the late 1970s.
G.Apostolo "The Illustrated Encyclopedia of Helicopters", 1984
Silvercraft SpA, formed in Italy in 1962, designed and built the prototype of a three-seat light helicopter which it flew for the first time in October 1963. Its development was continued with financial and technical assistance from SIAI-Marchetti, the resulting Silvercraft SH-4 being the first helicopter of all-Italian design and construction to gain Italian and FAA certification. Of conventional configuration, with two-bladed main and tail' rotors, and powered by optional 149- or 175kW Franklin 6A-350 series engines that in both cases were flat-rated at 127kW, the type was available in SH-4 utility and SH-4A agricultural versions. A total of about 50 is believed to have been completed, plus prototypes of an improved two-seat SH-200, before the company terminated aircraft production in the late 1970s.
D.Donald "The Complete Encyclopedia of World Aircraft", 1997
Technical data for SH-4
Engine: 1 x Franklin GA-350D, 175kW, main rotor diameter: 9.0m, length: 7.50m, height: 2.7m, take-off weight: 862kg, empty weight: 510kg, max speed: 161km/h, cruising speed: 140km/h, ceiling: 4000m, range with max fuel: 360km