Valmet Vihuri (Cold Wind) is a Finnish two-seat advanced trainer produced by Valmet between 1951 and 1957, and used by the Finnish Air Force from 1953 to 1959.
Development[]
Vihuri was designed in the early 1950s to replace the old and troublesome VL Pyrys. Most of the design work had been done by Lauri Hämäläinen and T. Mäntysalo already in 1948-1949. The wing profile was borrowed from the VL Pyörremyrsky fighter project. Due to the shortage of aircraft engines in post-war Finland, Vihuris had to be equipped with worn-down wartime Bristol Mercury engines taken from Bristol Blenheim bombers. The control columns and oxygen systems were from Messerschmitt Me 109s, the pedals from VL Myrskys and some of the gauges from several other retired aircraft, as new aircraft parts were in short supply.
The first prototype, coded VH-1, flew for the first time on 6 February 1951. The Finnish Air Force ordered 30 aircraft on 27 April 1951, and 20 more in fall 1954. These were known as Vihuri II and Vihuri III, respectively. Last of the total of 51 Vihuris was delivered on 15 January 1957. Their registration codes were VH-1–VH-51.
Service[]
Vihuri suffered a string of accidents and built up a stark reputation as a dangerous aircraft. The accidents received significant media attention over time, especially after Risto Kuuskoski, the son of future Prime Minister Reino Kuuskoski, was killed in a Vihuri crash on 14 December 1957. Vihuri was speculated to be severely flawed, with even the Finnish Parliament discussing about the type's safety. In 1958 a British Gloster test pilot was invited to Finland to test the type, but the only significant issue he found was in the way the engine was installed.
Vihuris were grounded and withdrawn in April 1959 after two fatal crashes in 16 days. The attempt to sell them to Tunisia failed, and all but one were scrapped.
Vihuri had been the most-flown aircraft in service, and although it seemed to be exceptionally prone to accidents, the accident rate actually wasn't all that high, bearing in mind how much the type flew. However, the elderly engines certainly caused some accidents.
Survivors[]
- VH-18 is at the Finnish Air Force Museum in Tikkakoski. It is the only intact example.
- The forward part of VH-25's fuselage is at the Finnish Aviation Museum in Vantaa.
Specifications[]
- Crew: 2
- Length: 8.8 m (28 ft 10 in)
- Wingspan: 10.4 m (34 ft 1 in)
- Height: 3.86 m (12 ft 8 in)
- Wing area: 18.86 m2 (203.0 sq ft)
- Aspect ratio: 5.7:1
- Airfoil: NACA 0019-64 (root), NACA 23009 (tip)
- Gross weight: 2,678 kg (5,904 lb)
- Max takeoff weight: 2,884 kg (6,358 lb)
- Fuel capacity: 195 L (52 US gal; 43 imp gal) normal fuel, 260 L (69 US gal; 57 imp gal) auxiliary tanks
- Powerplant: 1 × Bristol Mercury VIII 9-cylinder air-cooled radial engine, 610 kW (820 hp)
- Maximum speed: 432 km/h (268 mph, 233 kn) at 3,700 m (12,100 ft)
- Cruise speed: 327 km/h (203 mph, 177 kn) at 1,000 m (3,300 ft) (econ. cruise)
- Service ceiling: 8,900 m (29,200 ft)
- Rate of climb: 11.50 m/s (2,263 ft/min)
- Armament: 2 × 7.7 mm Browning machine guns, in Vihuri III also a provision for carrying four 25 kg bombs