The LAK-17 is a Lithuanian single-seat sailplane that was designed at the Lithuanian Aero Club (Lithuanian: Lietuviškos aviacinės konstrukcijos or LAK), and is manufactured by Sportinė Aviacija.

LAK-17
Role 15 metre-class and 18 metre-class sailplane
National origin Lithuania
Manufacturer Sportinė Aviacija
Status In production (2015)

Design and development

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LAK-17bt fuselage and engine

The LAK-17 is designed to meet the requirements of the utility category of JAR-22.[1] It is a single-seat mid-wing sailplane of composite construction with a T-tail and flaps, it has a retractable single-wheel main landing gear and has airbrakes on the upper wing surface.[1] The airfoil is a combination of the LAP92-130/15, at its roots, and the LAP-92-150/15, at its tips.[2] The LAK-17 holds water ballast in tanks in the wing and fin.[1] The LAK-17A was certified in November 1994 by the Lithuanian Civil Aviation Authority.[1] A new variant with an improved wing was designated the LAK-17B.[3] All variants have a 15.00 m (49.21 ft) wingspan but a wing with span increased to 18.00 m (59.06 ft) is available as an option; powered self-sustaining versions are also produced.[1][3]

An optional front electric sustainer engine variant was developed for the LAK-17 by Slovenian engineers at LZ Design. It originally had a 0.9 metre propeller, and the latest versions have a 1.0 metre propeller in the nose driven by an electric motor.[4][5]

Variants

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LAK-17A
Production flapped 15- or 18-metre wingspan sailplane.[2][6]
LAK-17AT
Powered self-sustaining sailplane variant of the LAK-17A with a Solo 2350 two-cylinder air-cooled two-stroke retractable engine.[1][7]
LAK-17A FES
A LAK-17A with a front electric sustainer.[4]
LAK-17B
Improved variant with new wing profile and modified geometry.[3]
LAK-17BT
Powered self-sustaining sailplane variant of the LAK-17B with a Solo 2350 retractable engine.[3]
LAK-17B FES
A LAK-17B with a front electric sustainer.[5]
LAK-17C FES
Improved variant with aerodynamic changes as well as a raised undercarriage to provide increased ground clearance for the folding propeller and increased battery capacity for self launching.[8]

Specifications (LAK-17A with 15 metre wingspan)

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Data from [3]

General characteristics

  • Crew: one
  • Capacity: 188 kg (414 lb) water ballast
  • Length: 6.53 m (21 ft 5 in)
  • Wingspan: 15.00 m (49 ft 2 in)
  • Height: 1.29 m (4 ft 3 in)
  • Wing area: 9.06 m2 (97 sq ft)
  • Aspect ratio: 24.63
  • Empty weight: 245 kg (540 lb)
  • Gross weight: 500 kg (1,102 lb)

Performance

  • Maximum speed: 275 km/h (171 mph, 149 kn)
  • Maximum glide ratio: 45
  • Rate of sink: 0.53 m/s (104 ft/min)

References

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