Viking SF-2A Cygnet

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SF-2A Cygnet
G-BXCA Sisler SF-2A Cygnet (9679406621).jpg
Role Amateur-built aircraft
National origin United States
Manufacturer Viking Aircraft LLC
Designer Bert Sisler
First flight 1973
Introduction 1973
Status Plans available (2003)
Number built 100 (2003)
Unit cost
US$150 (plans only, 1998)[1]
Developed from Sisler SF-2 Whistler

The Viking SF-2A Cygnet, also called the Sisler SF-2A Cygnet and the HAPI SF-2A Cygnet, is an American STOL amateur-built aircraft, designed by Bert Sisler and produced by Viking Aircraft LLC. The aircraft is supplied in the form of plans for amateur construction. The Cygnet first flew in 1973.[1][2]

The Cygnet plans were originally marketed by the designer through his company Sisler Aircraft of Bloomington, Minnesota and later by HAPI Engines, a supplier of Volkswagen air-cooled engines. By the 1990s Viking Aircraft of Elkhorn, Wisconsin took over supplying the aircraft plans.[1][2][3][4]

Design and development[edit]

The SF-2A Cygnet is a development of the earlier Sisler SF-2 Whistler introduced in 1973. The design features a strut-braced shoulder-wing, a two-seats-in-side-by-side configuration enclosed cockpit under a bubble canopy, fixed conventional landing gear and a single engine in tractor configuration.[1][2][3]

The aircraft is made from wood, 4130 steel tubing and covered in doped aircraft fabric. Its 30 ft (9.1 m) span wing employs a NACA 3413 airfoil, has an area of 125 sq ft (11.6 m2) and is supported by a single strut with a jury strut. The cockpit is 39 in (99 cm) wide and has a baggage compartment with a limit of 70 lb (32 kg), located behind the seats. The aircraft's recommended engine power range is 60 to 82 hp (45 to 61 kW) and standard engines used include the 82 hp (61 kW) Volkswagen four-stroke powerplant. Construction time from the supplied kit is estimated as 1700–1800 hours.[1][2][4]

The Cygnet won a design award at the EAA Annual Convention and Fly-In in 1973.[1]

Operational history[edit]

By January 2003, 100 examples had been reported as completed and flown.[2]

In July 2016 a total of 19 SF-2A Cygnets were registered in the United States with the Federal Aviation Administration, four with Transport Canada and seven with the Civil Aviation Authority in the United Kingdom.[5][6][7]

Specifications (SF-2A Cygnet)[edit]

SF-2A Cygnet

Data from Kitplanes and Purdy[1][2]

General characteristics

  • Crew: one
  • Capacity: one passenger
  • Length: 19 ft (5.8 m)
  • Wingspan: 30 ft (9.1 m)
  • Height: 5.8 ft (1.8 m)
  • Wing area: 125 sq ft (11.6 m2)
  • Airfoil: NACA 3413
  • Empty weight: 585 lb (265 kg)
  • Gross weight: 1,100 lb (499 kg)
  • Fuel capacity: 15 U.S. gallons (57 L; 12 imp gal)
  • Powerplant: 1 × Volkswagen air-cooled engine four cylinder, 1835 cc, four stroke automotive conversion, 82 hp (61 kW)


  • Maximum speed: 108 mph (174 km/h, 94 kn)
  • Cruise speed: 100 mph (160 km/h, 87 kn)
  • Stall speed: 48 mph (77 km/h, 42 kn)
  • Range: 390 mi (630 km, 340 nmi)
  • Rate of climb: 580 ft/min (2.9 m/s)


  1. ^ a b c d e f g Purdy, Don: AeroCrafter - Homebuilt Aircraft Sourcebook, page 285. BAI Communications, 15 July 1998. ISBN 0-9636409-4-1
  2. ^ a b c d e f Downey, Julia: 2003 Plans Aircraft Directory, Kitplanes, Volume 20, Number 1, January 2003, page 29. Primedia Publications. ISSN 0891-1851
  3. ^ a b Aerofiles (7 April 2009). "Aircraft from Saalfield SEE Skyskootor". Retrieved 4 December 2012.
  4. ^ a b Lednicer, David (2010). "The Incomplete Guide to Airfoil Usage". Retrieved 3 November 2012.
  5. ^ Federal Aviation Administration (21 July 2016). "Make / Model Inquiry Results". Retrieved 21 July 2016.
  6. ^ Transport Canada (21 July 2016). "Canadian Civil Aircraft Register". Retrieved 21 July 2016.
  7. ^ Civil Aviation Authority (United Kingdom) (21 July 2016). "GINFO Search Results Summary". Retrieved 21 July 2016.

External links[edit]