Czech ultralight aircraft
The Letov ST-4 Aztek (English: Aztec) is a Czech microlight aircraft that was designed and produced by Letov Kbely of Prague - Letňany, in the 1990s. When it was available, the aircraft was supplied as a complete ready-to-fly aircraft, or as a kit for amateur construction.[1]
In January 2014, the ST-4 was no longer listed as a product of the company.[2]
Design and development
The aircraft was designed to comply with the Fédération Aéronautique Internationale microlight category, including the category's maximum gross weight of 450 kg (992 lb). The ST-4 Aztek features a strut-braced high-wing, a two-seats-in-side-by-side configuration enclosed cockpit, fixed tricycle landing gear with wheel pants, a small tailskid and a single engine in tractor configuration.[1]
The aircraft is made from aluminum tubing with fairings made from fibreglass and its flying surfaces are covered in Dacron sailcloth. Its 10.40 m (34.1 ft) span wing mounts flaps and has a wing area of 15.21 m2 (163.7 sq ft). The wings are supported by V-struts with jury struts and the empennage is cable-braced. The acceptable power range is 45 to 50 hp (34 to 37 kW) and the standard engine used is the 50 hp (37 kW) Rotax 503 two-stroke powerplant. The engine is mounted high above the cockpit on the front end of the aluminum tube that acts as the tailboom.[1]
The ST-4 Aztek has a typical empty weight of 220 kg (490 lb) and a gross weight of 450 kg (990 lb), giving a useful load of 230 kg (510 lb). With full fuel of 57 litres (13 imp gal; 15 US gal) the payload for pilot, passenger and baggage is 189 kg (417 lb).[1]
The manufacturer estimated the construction time from the supplied kit as 80 hours.[1]
Operational history
By 1998 the company reported that 26 kits had been sold, and that 15 aircraft were completed and flying.[1]
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