SV.5 Tornado
A Latvian Air Force SV.5
Role Military trainer
National origin Belgium
Manufacturer Stampe et Vertongen
Designer George Ivanow[1]
First flight September 1933[2]
Primary user Belgian Air Force[3]
Number built 31, plus one SV.9[3]

The Stampe et Vertongen SV.5 Tornado was a military trainer aircraft designed and built in Belgium in the 1930s.[4][5] It saw service with the Belgian Air Force[6] and Latvian Air Force,[7] and Latvian firm VEF purchased a production license, although it is uncertain whether it built any examples.[6]

Design and development

The SV.5 was Stampe et Vertongen's response to a 1933 requirement by the Belgian Air Force for a two-seat training biplane with aerobatic capabilities.[1] Jean Stampe directed designer George Ivanow to update the company's RSV.22 to meet the new specifications, but the resulting design was an entirely new aircraft with only a superficial resemblance to its predecessor.[1] It was a conventional, single-bay biplane with staggered wings of unequal span.[8] The pilot and instructor sat in open cockpits in tandem[8] and the aircraft was powered by an Armstrong Siddeley Serval radial engine[9] in the nose, enclosed in a Townend ring.[7] The main units of the fixed undercarriage were divided and the tail was supported by a tailwheel.[8] It could be equipped for bombing or gunnery training.[5] Unlike earlier Stampe et Vertongen products, which had wooden structures, the SV.5 airframe was riveted together from steel tube in a method inspired by Hawker in the United Kingdom.[1]

The prototype first flew in September 1933,[2] and on 16 October 1934, the Belgian Air Force evaluated it against five competitors: the Avro 626, Breda Ba.25, Fairey Fox III, LACAB T-7, and the Renard R.34.[7] A sixth competitor, the Caproni Ca.113, suffered an accident on arrival and was disqualified.[7] The SV.5 outclassed all its rivals in the maintainability trials, and was less expensive than any of them.[7] However, the Avro 626 was selected for political reasons.[7]

The SV.5 nevertheless found a customer in the Latvian Air Force, which was seeking a similar aircraft.[7] When a study mission to Belgium confirmed the type's suitability, the Latvian government negotiated the purchase of ten examples in exchange for 5,700 tonnes of wheat.[7] These machines were slightly different from the prototype, with a NACA cowl in place of the Townend ring, a redesigned horizontal stabiliser, and simplified main undercarriage.[7] Germany would not permit the overflight of the aircraft, so in September 1936 they were shipped disassembled to Riga, where Jean Stampe oversaw their assembly by VEF.[6]

In the meantime, the Belgian Air Force finally placed an order for twenty SV.5s.[6] Stampe et Vertongen delivered these between October 1936 and mid 1937.[6]

Variants

Ivanow used the SV.5 as the basis for a family of follow-on designs with only minor variations:[6]

SV.6
version with 260-kW (350-hp) Armstrong Siddeley Cheetah IX
SV.7
version with 378-kW (507-hp) Pratt & Whitney Wasp Junior, also with spoilers under the upper wing
SV.8
version with 180-kW (240-hp) Armstrong Siddeley Lynx IV
SV.9
SV.5 with metal, variable-pitch propeller, and upper wings moved 2 cm (1 in) rearward to improve centre of gravity

Of these, only a single SV.9 was built. This aircraft was exported to Latvia, together with a license for production by VEF. Although rumours exist that VEF built examples of the type, this cannot be confirmed.[6]

Operators

 Belgium
 Latvia

Specifications (SV.5)

Data from Jouhaud 1999, p.86

General characteristics

Performance

Notes

  1. ^ a b c d Jouhaud 1999, p.82
  2. ^ a b Jouhaud 1999, p.88
  3. ^ a b Jouhaud 1999, p.82–85
  4. ^ a b Taylor 1989, p.839
  5. ^ a b The Illustrated Encyclopedia of Aircraft, p.2955
  6. ^ a b c d e f g h Jouhaud 1999, p.85
  7. ^ a b c d e f g h i j Jouhaud 1999, p.84
  8. ^ a b c Jouhaud 1999, p.87
  9. ^ Jouhaud 1999, p.83

References

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