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Sailplane · JS4

JS4 Rengeti

The most modern Standard Class sailplane: best value for money, optionally with the MD-TJ-42 jet sustainer — built to make world champions.

The JS4 shares the low-drag fuselage and large cockpit of the JS3, combined with newly optimised airfoils and fifth-generation winglets. As the official JS partner in Switzerland we configure it personally.

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Why the JS4

The JS4 is designed for all pilots — from a first Standard Class glider to competition. Its standard options have been carefully selected, making it the best value-for-money new glider on the market.

The cockpit carried over from the JS3 offers exceptional forward visibility — 12-o'clock traffic stays visible even slightly below the horizon. Available as a pure glider or with a jet sustainer for the security to get home.

46.5 : 1
Best glide ratio
15 m
Standard Class
JET optional
Sustainer
9 G
Cockpit crash resistance
Studio side view of the JS4 Rengeti sailplane

Technical data

15-metre configuration.

Best glide ratio (L/D)46.5 : 1
Wing area10.0 m²
Aspect ratio22.6
Empty weight280 kg
Max. take-off weight525 kg
Water ballast174.7 l
Minimum sink0.64 m/s
Max. wing loading52.5 kg/m²
Never-exceed speed (VNE)280 km/h
Manoeuvring speed (VA)208 km/h
Max. aerotow speed180 km/h
Max. pilot height1.95 m

Cockpit & comfort

  • Cockpit carried over from the JS3 with exceptional forward visibility
  • Electrically in-flight adjustable pedals, adjustable seatback with headrest
  • Forward-opening canopy, green-tinted for extra UV protection
  • Leather interior with storage pockets, 525 mm shoulder width

Performance & safety

  • Safety cockpit in carbon and aramid fibre with integrated crumple zones
  • Airfoils optimised by PSO algorithm, fifth-generation winglets
  • Teflon/Mylar control-surface gap sealing, integrated bug-wiper garages
  • Dynafoam seat cushion, Flarm antenna and hydraulic disc brake

Propulsion options

Pure glider

The JS4 is available as a pure sailplane — light, simple and uncompromisingly focused on Standard Class performance.

MD-TJ-42 jet sustainer

Optionally with the MD-TJ-42 jet sustainer for climb support and the security to get home. Operation is as simple as it gets: one switch, one throttle dial. Not self-launch; no RES or combustion variant planned.

Class & certification

Standard Class single-seater with a fixed 15-metre span, designed for competition and cross-country flying. Certified under EASA CS-22.

Complete technical data, manuals and brochures from the manufacturer Jonker Sailplanes.

Full specifications & downloads

Request an Offer

Interested in this aircraft? Request a no-obligation offer — we will get back to you personally.

Propulsion