Photograph:
Monnett Sonerai IIILS VH-NDS (c/n N.54) at Luskintyre, NSW in 2002 (David C Eyre)
Country of origin:
United States of America
Description:
Two-seat light amateur-built sport monoplane
Power Plant:
One 52 kw (70 hp) modified Volkswagen (2,180-cc) four-cylinder horizontally-opposed air-cooled engine
Specifications:
- Wingspan: 5.69 m (18 ft 8 in)
- Length: 5.74 m (18 ft 10 in)
- Wing area: 7.8 m² (84 sq ft)
- Max speed at sea level: 266 km/h (165 mph)
- Max cruising speed: 225 km/h (140 mph)
- Max rate of climb at sea level: 229 m/min (750 ft/min)
- Stalling speed: 72 km/h (45 mph)
- Service ceiling: 3,048 m (10,000 ft)
- Range with max fuel and 30 mins reserves: 676 km (420 miles)
- Fuel capacity: 38 litres (8.3 Imp gals)
- Take-off run: 274 m (900 ft)
- Landing run: 244 m (800 ft)
- Empty weight: 236 kg (520 lb)
- Payload weight: 195 kg (430 lb)
- Loaded weight: 431 kg (950 lb)
History:
In 1970 Mr John T Monnett began construction of a single-seat Formula V racing aircraft to enter in the USA Air Race circuit in that class of racing. The prototype was flown for the first time in July 1971. Known as the Monnett Sonerai, it was of all-metal construction, fabric covering, and a non-retractable undercarriage. This design won the ‘Best in Class’ award at the 1971 Oshkosh fly-in, and since then it has been offered for amateur construction in a number of models, with plans and some components being made available by the designer. In more recent years it has been marketed by Great Plains Aircraft.
The success of the single-seat machine led to the design of the Sonerai II, a two-seat version generally similar in appearance but slightly larger, and with an up-rated engine. Stressed to + or – 6G in the single-seat aerobatic category, the prototype of this model was flown for the first time in July 1973. Since then quite a number have been built around the world.
As with the Sonerai single-seater, which became known as the Sonerai I, plans were made available for amateur construction. Other variants included the Sonerai II-L with a low-wing rather than a mid-wing configuration, and three-degrees of dihedral; Sonerai II-LT, first flown in January 1983, similar to the II-L with a tricycle undercarriage and a larger front cockpit; Sonerai II-LTS, first flown in June 1984 with a fuselage length of 6.2 m (20 ft 4 in) and all-aluminium folding wings.
At least 22 examples have been built and registered in this region over the years, including model I, II, IIL, IILS. A number are operated on the Recreation Aviation Australia (RAA) register. A number of FAI records for aircaft in the C-1a/O category, landplanes with a max take-off weight of less than 300 kg (661 lb) were set by Robin Austin, these being: Aero Efficiency at Jacobs Well, QLD on 5 June 2008 – 29.79 km/kg and speed record over a recognised course at St George, QLD on 17 May 2008 – 404.3 km/h (251.22 mph).