Sailplanes

Sailplanes, or gliders, are aircraft designed to fly without an on-board engine. They are optimized for high lift-to-drag ratios, allowing efficient ascent and long-duration flight by exploiting atmospheric lift such as thermals, ridge, or wave lift.

Most sailplanes feature a slender, high-aspect-ratio wing and a streamlined fuselage. The wing often carries airbrakes or spoilers to control descent, and the undercarriage is typically a wheel or retractable gear with a single-seat or two-seat cockpit enclosed by a canopy. Modern designs use composite materials to reduce weight and improve rigidity.

Sailplane flight relies on managing altitude and exploiting lift sources. Pilots circle in thermals to gain height, fly along ridges to stay aloft, or use wave lift in mountainous areas. The best sailplanes achieve glide ratios well above conventional aircraft, enabling cross-country and distance records and extended flight durations.

Launches are accomplished by aerotow or ground-based winch, and some sailplanes, called motorgliders, carry a small engine for self-launching and flight to the tow point. After reaching altitude, engine power is shut off and flight proceeds as pure gliding.

The aviation world classifies sailplanes into several competition classes, such as Open, Standard (or 15-meter), 18-meter, and 20-meter or Ultra-light classes, defined by wingspan and other design rules by the international federation. Training and competition are common uses.

Sailplanes developed from early wood-and-fabric designs in the first half of the 20th century, with rapid improvements during the mid-century era. Postwar advances introduced fiberglass, carbon fiber, and other composites, enabling longer wings, lighter construction, and better performance. Today, modern sailplanes are highly optimized for efficiency, maneuverability, and endurance.