Schleicher ASK 21 (Laminar Research)

The Schleicher ASK 21 (widely recognized across soaring clubs and flight simulation as the ASK 21, ASK21, K21, Schleicher Glider, and Laminar ASK 21) is the global benchmark for dual-seat soaring instruction. Designed by Rudolf Kaiser and built by Alexander Schleicher GmbH & Co, this rugged fiberglass sailplane has introduced more pilots to motorless flight than nearly any other modern glider. Thanks to its glass-reinforced plastic (GRP) construction, forgiving spin characteristics, and certified +6.5G / -4.0G aerobatic load limits, the ASK 21 excels in roles ranging from first-time student hops to advanced aerobatic routines. Laminar Research updated this classic sailplane for X-Plane 12, taking full advantage of the platform's reworked volumetric atmospheric modeling, thermal physics, and blade-element aerodynamics.

The flight deck focuses strictly on essential soaring instrumentation. Simmers sit beneath a large bubble canopy offering expansive panoramic visibility, with an animated physical yaw string taped to the outer windscreen to visually indicate slip and skid. The panel is anchored by both a mechanical total energy-compensated (TE) variometer and a modern electric audio variometer. The electric variometer features an adjustable MacCready speed ring and dual-tone acoustic audio—delivering high-frequency chirps when climbing through core lift and low-pitched groans when encountering sink, allowing pilots to keep their eyes outside the cockpit while centering thermals. Laminar also models functional wing water ballast dump valves and a center-console yellow tow-release knob.

In X-Plane 12, soaring in the ASK 21 provides a genuine workout in atmospheric energy management. Without an engine, pilots rely on X-Plane 12’s dynamic weather engine to sustain flight—working localized cumulus cloud thermals, windward mountain ridge lift, and high-altitude mountain wave rotors. Launch options are built directly into the simulator, allowing pilots to choose between a high-acceleration ground winch launch or an AI-driven aerotow behind a towplane. With an effective glide ratio of 34 to 1, cross-country gliding requires balancing speed-to-fly tactics with careful descent planning, deploying the powerful two-tier Schempp-Hirth airbrakes to control touchdown points during runway or off-field farm strip outlandings.

Primary Missions & Operational Roles

• Ab-Initio Sailplane Flight Training: Practicing primary glider takeoffs, winch launches, aerotows, coordinated thermaling turns, and spot landings.

• Glider Aerobatic Certification & Practice: Executing certified aerobatic maneuvers including inside loops, chandelles, lazy eights, stall turns, and spins within its +6.5G / -4.0G structural envelope.

• Cross-Country Thermal & Ridge Soaring: Working rising air currents along mountain ridges, valley passes, and thermal corridors to complete cross-country distance tasks without motor power.

• Simulated Emergency Outlanding Drills: Practicing off-field forced landings in remote fields and pastures when lift decays, relying on Schempp-Hirth dive brakes to control steep descent paths.