Letov Š-20

The Letov Š-20 was a conventional, single-bay biplane with unstaggered wings, braced by N-struts. In overall appearance, it greatly resembled contemporary SPAD fighters. The fuselage and empennage were of welded steel tube construction and covered in fabric. The wings had a tubular metal spar but were otherwise wooden, and also fabric-covered.[1]

The Czechoslovakian Air Force bought 105 machines, and ten examples were produced for Lithuania under the designation Š-20L. These remained in service until 1936 and 1935 respectively.

An Š-20 placed second in the single-engine category of the national President of the Republic air race in 1925, but fared better the following year. In the 1926 race, an Š-20 not only won this category, but also set a new national airspeed record of 234 km/h (146 mph). This record was short-lived, however, since the prize for the fastest circuit was also won in an Š-20, and this raised the record to 245 km/h (153 mph).[2]

A single prototype of an unarmed advanced trainer version was built as the Š-21, but this did not sell.

• Š-20 – initial production version
  • Š-20M – revised version with slimmed down rear fuselage (main production version for Czechoslovakia)
  • Š-20L – export version for Lithuania (eight built)

A side view of the Š-21 prototype

• • Š-20R – version with further revisions to fuselage (one built)
  • Š-20J – version with Walter-built Bristol Jupiter engine
• Š-21 – trainer version with Hispano-Suiza 8Aa engine (one built)

Letov S-20 3-view drawing from Les Ailes January 13, 1927

Data from Jane's all the World's Aircraft 1928[3]

General characteristics

• Crew: 1
• Length: 7.44 m (24 ft 5 in)
• Wingspan: 9.6 m (31 ft 6 in)
• Height: 2.56 m (8 ft 5 in)
• Wing area: 18.4 m² (198 sq ft)
• Empty weight: 740 kg (1,631 lb)
• Gross weight: 1,050 kg (2,315 lb)
• Powerplant: 1 × Škoda-built Hispano-Suiza 8Fb V-8 water-cooled piston engine, 221 kW (296 hp)
• Propellers: 2-bladed wooden fixed-pitch propeller

Performance

• Maximum speed: 257.5 km/h (160.0 mph, 139.0 kn)
• Range: 528 km (328 mi, 285 nmi)
• Endurance: 2 hours 10 minutes
• Service ceiling: 7,250 m (23,790 ft)
• Rate of climb: 6 m/s (1,200 ft/min)
• Time to altitude: 5,000 m (16,000 ft) in 13 minutes 40 seconds
• Wing loading: 57 kg/m² (12 lb/sq ft)
• Power/mass: 0.2163 kW/kg (0.1316 hp/lb)

Armament

• Guns: 2x fixed, forward-firing, synchronised 7.7 mm (0.303 in) Vickers machine-guns (ZB vz.09) in the forward fuselage upper decking

Related lists

• List of Interwar military aircraft

Wikimedia Commons has media related to Letov Š-20.

Notes

• Němeček, Václav (1968). Československá letadla (in Czech). Prague: Naše Vojsko.
• Taylor, John W. R.; Alexander, Jean; et al. (1969). Combat aircraft of the world. London: Ebury P.; Michael Joseph. p. 65. ISBN 0-71810-564-8.
• Taylor, Michael J.H.; Gunston, Bill; et al. (1989). Jane's encyclopedia of aviation. New York: Portland House. ISBN 0-517-69186-8.