Letov S-28

The Letov Š-28 was a Czechoslovak single-engined, two-seat reconnaissance aircraft. It was manufactured by Letov Kbely in a number of versions with different powerplants. Most important version was Š-328, which was produced in relatively high quantities (412 planes produced).

Letov S-28
Class Aircraft
Type Reconnaissance
Manufacturer Letov Kbely
Origin Czechoslovakia
Country Name Origin Year
Czechoslovakia 1929
Country Name Operational Year Retirement Year
Bulgaria View
Czechoslovakia 1934 1944 View
Estonia View
Germany View
Slovakia View
ManufacturerName Production From Production To Quantity
Letov Kbely 470 View

Variants

  •     Š-28 - prototype with Walter Castor engine (1 built)
  •     Š-128 - production version with Gnome et Rhone-built Bristol Mercury VII engine (12 built)
  •     Š-228 - production version for Estonia with Walter-built Bristol Mercury VII (4 built)
  •         Š-328F - prototype for Finland, powered by 580 hp (433 kW) Bristol Pegasus IIM-2 radial engine (1 built).
  •     Š-328 - main production version. Approx 412 built in total, including:
  •         Š-328N- night fighter, armed with four forward firing and two flexibly mounted machine guns.
  •         Š-328V - floatplane target tug (4 built)
  •     Š-428 - close ground support aircraft covering armies on the battlefield. The engine was an Avia VR-36 545 kW, V-12 liquid-cooled inline piston engine of 740 hp (1 built)
  •     Š-528 - planned replacement for Š-328 developed in 1935, powered by 800 hp (597 kW) Gnome-Rhône Mistral Major (6 built).


Design work started in 1932 to meet a requirement from the Finnish Air Force although they never accepted the type. It first flew in 1934 and began equipping the Czechoslovak Air Force the following year. The machine was made in two versions—with wheeled undercarriage for land use and with floats for water operations. Although Czechoslovakia was a land locked nation, a floatplane variant was necessary for a Czechoslovak anti-aircraft artillery training depot in the Bay of Kotor (now in Montenegro) and four were built as the Š-328v. (v stood for vodní or water). It was used as a reconnaissance aircraft, light bomber and ground-attack aircraft for the Czechoslovakia Air Force during the mid and late 1930s and in that same role during the early months of World War II, when the Slovak Air Force came under German control following its occupation of Czechoslovakia in March 1939. 13 planes from first production batch was tested as night fighters armed with 4 7,92 mm vz.30 machine guns in the wings and 2 movable vz.30 for the observer. These were later modified for normal use because without radar their effectiveness was minimal. At the time of the Munich agreement, which ended the Sudeten crisis the Czechoslovak Air Force had 227 planes in operational units and 87 in training schools and mobilisation depots. Production continued even after German occupation of Czechoslovakia until 1940, the last planes being 30 Š-328 produced for Bulgaria, and 50 planes of that type ordered by Slovakia in July 1938. Altogether, 412 Letov Š-328 were produced.

The Letov Š-328's combat record is vague but some sources suggest that some Š-328 landplanes may have been used during the Spanish Civil War however there is no evidence to confirm this and is likely a misidentification of another type. The Germans used captured Š-328s both as trainers and in the night attack role on the Eastern Front in the Winter of 1942-43. The Germans handed over some of these machines to their allies, Bulgaria, and Slovakia.

The Slovak Š-328s carried out reconnaissance and bombing sorties in support of the Slovak participation in the Invasion of Poland in September 1939. Following Slovakia's participation in the German Invasion of the Soviet Union in 1941, Slovak Š-328s were used for patrol and reconnaissance flights and few of them also attacked soviet trucks and cars. They were again used in anti-partisan operations in western Ukraine in the summer of 1942. At least 11 Slovakian aircraft were seized by Slovak insurgents and flown against the Germans in late 1944 during the Slovak National Uprising in September to October 1944. The unit never had more than 3 planes operational at time, but they were an important asset. On 7 September 1944 this aircraft achieved the last shoot-down of an enemy aircraft achieved by biplane, when a patrolling Š-328 was attacked by a reconnaissance Focke-Wulf Fw 189. The Fw 189 was damaged by machine gun fire and forced to land in an area controlled by the insurgents.

Role Reconnaissance aircraft
Manufacturer Letov Kbely in Prague
First flight 1929
Introduction 1934
Retired 1944
Primary user Czechoslovakian Air Force
Number built 470 (all variants Š-28, -128, -228, -328 and -528)


General characteristics

  • Crew: 2
  • Length: 10.34 m (33 ft 11 in)
  • Wingspan: 13.69 m (44 ft 11 in)
  • Height: 3.38 m (11 ft 1 in)
  • Wing area: 424 sq ft (39.40 m² - 20,4 top wing, 19 lower wing)
  • Empty weight: 1,680 kg (3,704 lb)
  • Loaded weight: 2,750 kg (6,062 lb)
  • Powerplant: 1 × Walter-built Bristol Pegasus II.M-2 , 9-cylinder, air-cooled radial piston engine, 485 kW (650 hp)

Performance

  • Maximum speed: 280 km/h (0 m), 328 km/h in 2000 m. (174 mph (0 m), 204 mph in 6561 ft.)
  • Cruise speed: 250 km/h (155 mph)
  • Range: 1,280 km (795 miles)
  • Service ceiling: 7,200 m (23,620 ft)

Armament

  • 2× fixed forward-firing 7.92 mm (0.31 inch) machine gun vz.30 in lower wing (400 rpg)
  • 2× 7.92 mm machine gun in flexible mount in rear cockpit (420 rpg in 6 drums)
  • 500 kg (1,102 lb) of bombs. 5 x 100 kg bombs (4 in pairs under the wing, 1 under the fuselage). Usually 6 x 20 kg bombs under wing and 2 x 50 kg under the fuselage.

Avionics

  • complete for night actions (as standard 1938)

End notes