Harman Patil (Editor)

SZD 20X Wampir II

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Wingspan
  
15 m

First flight
  
September 9, 1959

Length
  
6.2 m

Manufacturer
  
PZL

SZD-20X Wampir II wwwscalesoaringcoukVINTAGEDocumentationSZD20

The SZD-20x Wampir II (Szybowcowy Zakład Doświadczalny - Glider Experimental Works) was a single-seat tail-less research glider designed and built in Poland from 1959.

Contents

Development

The SZD-20X Wampir II (vampire II) was designed to compare a flying wing designed to Standard class rules with a more conventional standard class glider. Main designer was Jan Dyrek. Based on experience with the earlier SZD-6X Nietoperz and SZD-13 Wampir tail-less gliders, the SZD-20X was an all wood flying wing, with the pilot sitting in a pod extending aft of the trailing edge on the centreline, and large swept fins & rudders at approx 2/3 span on each wing.

The SZD-20X was associated with the number 15, having a 15m span, aspect ratio of 15 and wing area of 15m², whether this was by design or accident is not known. Early flight trials commenced with hops towed behind a car to test control responses, followed by an aero-tow launch on 9 September 1959, piloted by Adam Zientek. Flight trials revealed a marked sensitivity to turbulence resulting in flutter, and during trials at stalling speed, the SZD-20X entered a spin, which the rudders were unable to recover the aircraft from, only when the pilot shifted his weight as far forward as he could, did the SZD-20X recover from the spin. Flying in the SZD-20X continued until 6 October 1959, when turbulence-induced flutter tore the aircraft apart, the pilot escaping with parachute.

Specifications (Standard Austria)

Data from The World's Sailplanes:Die Segelflugzeuge der Welt:Les Planeurs du Monde Volume II

General characteristics

  • Crew: 1
  • Length: 6.2 m (20 ft 4 in)
  • Wingspan: 15 m (49 ft 3 in)
  • Height: 1.7 m (5 ft 7 in)
  • Wing area: 15 m2 (160 sq ft)
  • Aspect ratio: 15
  • Airfoil: NACA 23112
  • Empty weight: 171 kg (377 lb) equipped
  • Gross weight: 268 kg (591 lb)

    • Performance

  • Stall speed: 50 km/h (31 mph; 27 kn)
  • Never exceed speed: 200 km/h (124 mph; 108 kn)
  • Aerotow speed: 120 km/h (74.6 mph; 64.8 kn)
  • g limits: +4.5 -2 at 91 km/h (56.5 mph; 49.1 kn)
  • Maximum glide ratio: 24.4 at 82 km/h (51.0 mph; 44.3 kn)
  • Rate of sink: 0.84 m/s (165 ft/min) at 72 km/h (44.7 mph; 38.9 kn)
  • Wing loading: 17.8 kg/m2 (3.6 lb/sq ft)

    • References

    SZD-20X Wampir II Wikipedia
    (Text) CC BY-SA