Schleicher Ka-4 Rhönlerche II

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Ka-4 Rhönlerche II
Aussenlandung KA 4 25062010089.jpg
Role Glider
National origin West Germany
Manufacturer Alexander Schleicher GmbH & Co
Designer Rudolf Kaiser
First flight 1955
Introduction 1955
Status Production completed
Number built several hundred

The Schleicher Ka-4 Rhönlerche II (English: Rhön Lark), sometimes called the KA-4 or even K 4, is a West German high-wing, strut-braced, two-seat glider that was designed by Rudolf Kaiser and produced by Alexander Schleicher GmbH & Co.[1][2][3]

Design and development[edit]

The Rhönlerche II was first flown in 1955. Its design goals were to produce a simple, inexpensive and robust two-seat trainer for school and club use. The design was a success and several hundred were constructed.[1][2]

Rhönlerche fuselage showing underlying welded steel tube structure

The Rhönlerche II is constructed with a welded steel tube fuselage and a wooden wing and tail surfaces, all finished in doped aircraft fabric covering. The 13.0 m (42.7 ft) span wing is supported by single lift struts and employs a Goettingen 533 airfoil. The aircraft's landing gear is a fixed monowheel, with a nose skid.[1][2][4]

The aircraft was issued a US type certificate on 28 September 1960.[3]

Operational history[edit]

The Ka-4 was widely used by clubs and schools in West Germany and also by Canadian military gliding clubs stationed in West Germany, including the Lahr Gliding Club at CFB Lahr. One of these aircraft was later shipped to Canada and operated by the Cold Lake Gliding Club at CFB Cold Lake and in July 2011 was owned by the Gravelbourg Gliding And Soaring Club, Gravelbourg, Saskatchewan.[2][5]

In July 2011 there were still five Ka-4s on the United States Federal Aviation Administration aircraft registry.[6]

Aircraft on display[edit]

Rhönlerche on display in the Technikmuseum Speyer
Museum Rhönlerche display

Specifications (Ka-4)[edit]

Data from Sailplane Directory, Soaring and Type Certificate 7G6,[1][2][3] The World's Sailplanes:Die Segelflugzeuge der Welt:Les Planeurs du Monde[9]

General characteristics

  • Crew: one
  • Capacity: one passenger
  • Length: 7.3 m (23 ft 11 in)
  • Wingspan: 13 m (42 ft 8 in)
  • Wing area: 16.34 m2 (175.9 sq ft)
  • Aspect ratio: 10.3:1
  • Airfoil: root: Göttingen 533 15.7%, mid: Göttingen 533 15.7%, tip: Göttingen 533 12.5%
  • Empty weight: 107.5 kg (237 lb)
  • Max takeoff weight: 400 kg (882 lb)

Performance

  • Stall speed: 56 km/h (35 mph; 30 kn)
  • Never exceed speed: 170 km/h (106 mph; 92 kn)
  • Rough air speed max: 120 km/h (74.6 mph; 64.8 kn)
  • Aerotow speed: 120 km/h (74.6 mph; 64.8 kn)
  • Winch launch speed: 90 km/h (55.9 mph; 48.6 kn)
  • g limits: +4.7 -2.3 at 170 km/h (106 mph)
  • Maximum glide ratio: 17.5:1 at 78 km/h (48 mph)
  • Rate of sink: 1.1 m/s (220 ft/min) at 62 km/h (39 mph)
  • Wing loading: 24.5 kg/m2 (5.0 lb/sq ft)

See also[edit]

Aircraft of comparable role, configuration and era
Related lists

Notes[edit]

  1. ^ a b c d Activate Media (2006). "Ka-4 Rhonlerche Schleicher". Retrieved 22 July 2011. 
  2. ^ a b c d e Said, Bob (November 1983). "1983 Sailplane Directory". Soaring Magazine (Soaring Society of America). USPS 499-920. 
  3. ^ a b c Federal Aviation Administration (October 1960). "Type Certificate Data Sheet No. 7G6" (PDF). Retrieved 22 July 2011. 
  4. ^ Lednicer, David (2010). "The Incomplete Guide to Airfoil Usage". Retrieved 22 July 2011. 
  5. ^ Transport Canada (July 2011). "Canadian Civil Aircraft Register". Retrieved 22 July 2011. 
  6. ^ Federal Aviation Administration (July 2011). "Make / Model Inquiry Results". Retrieved 22 July 2011. 
  7. ^ Nationaal Luchtvaart-Themapark Aviodrome (n.d.). "Collectiestuk" (PDF). Retrieved 22 July 2011. 
  8. ^ US Southwest Soaring Museum (2010). "Sailplanes, Hang Gliders & Motor Gliders". Retrieved 22 July 2011. 
  9. ^ Shenstone, B.S.; K.G. Wilkinson & Peter Brooks (1958). The World's Sailplanes:Die Segelflugzeuge der Welt:Les Planeurs dans Le Monde (in Primarily English with French and German) (1st ed.). Zurich: Organisation Scientifique et Technique Internationale du Vol a Voile (OSTIV) and Schweizer Aero-Revue. pp. 9–13. 

References[edit]

External links[edit]

Media related to Schleicher Ka-4 at Wikimedia Commons