The S-4 was first created in 1922 as an intended successor to the SPAD S.VII and S.XIII, For service with the newly created Czechoslovak Air Force.
It first flew in 1922, with fabric-covered wooden wings and a metal fuselage and tail.
The Czechoslovak Air Force ordered 20 Š-4s in 1922 and these were delivered in early 1923.
The plane lived out the 1920s as a fighter and trainer, but by 1927 difficulties were being experienced due to the low manufacturing quality of the SH-4.
As a result, all remaining SH-4s were upgraded to SH-4a trainer aircraft in 1928.
20 aircraft were built.
Specifications
Crew
1
Length
6.58 m (21 ft 7 in)
Wingspan
8 m (26 ft 3 in)
Height
2.62 m (8 ft 7 in)
Wing area
15.9 m2 (171 sq ft)
Empty weight
673 kg (1,484 lb)
Gross weight
980 kg (2,161 lb)
Powerplant
1 × Hispano-Suiza 8Ba,
V-8 water-cooled piston engine,
160 kW (220 hp)
Propellers
2-bladed wooden fixed pitch propeller
Performance
Maximum speed
232 km/h (144 mph, 125 kn)
Service ceiling
6,200 m (20,300 ft)
Time to altitude
3,000 m (9,800 ft) in 9.3 minutes
Wing loading
61.5 kg/m2 (12.6 lb/sq ft)
Power/mass
0.16 kW/kg (0.1 hp/lb)
Armament
Guns
2 x synchronized 7.7 mm (0.303 in) Vickers machine-guns.