Soaring is the art of flying without an engine. It
is one of the most peaceful sports in
existence. Gliders stay aloft by using lift. Lift comes in many forms. Wind rises when it hits a ridge, rises when it is heated, and oscillates when going over a mountain range. Gliders use this to stay aloft for as much as 10 hours at a time.
History
One Otto Lilienthal made flights in the hills of Germany in 1891. His bird-like cloth and softwood hang-gliders were flown by running down a steep hill until takeoff velocity was reached. He flew about 100 meters in his more successful flights. Otto discovered many of the aircraft design fundamentals still in use today. One must also mention the Wright brother's efforts. They used some interesting design techniques, but are pretty much considered hobbyists among glider pioneers. Their real contribution was combining gliders and engines. Soaring as a sport started in the 1920's with planes made of wood in Germany.
The materials used in gliders has changed quite a
bit in the last 75 years. Sail planes were first made
of wood frames with cloth covering the wings and
fuselage. Designers then used metal framing as metalurgy became advanced enough to support light tubular steel. Planes like the SGS 2-33 and the SGS 1-35 used tubular steel construction. The steel was still covered with cloth. All metal sailplanes, like the Ross RJ-5, were briefly
experimented with. Next, in the late 1970s, fiberglass
came into use. This led to a whole new breed of sailplanes. The majority of sailplanes flying today are fiberglass birds. Fiberglass allowed for larger aspect ratios, lighter designs, and more aerodynamic shapes. Fiberglass resin is badly degraded by ultraviolet rays. Gel coats help, but not enough to stop the problem completely.
Current carbon fiber marked an improvment
over fiberglass. Ultraviolet light does not affect carbon fiber. Carbon fiber is allowing extremely high performance planes such as the eta glider and entirely new designs, such as the SparrowHawk.
Gliders have also changed aerodynamically, mainly
due to the fiber revolution. Wings experienced
longation. 50:1 aspect ratios became common. This is
because near the edge of the wing, air curls over and causes downward forces on the wing. These
improvements led to 60:1 glide ratios. Gliders have
forever been drifting in and out of similarity with
power planes.
Modern planes, such as the Nimbus II have made
1000 Km flights possible, which is quite a stretch
from Otto's 100 meter flight 80 years ago.
Topics:
Flying
Soaring
Glider Design Concepts
Glider Parts
Gliders
FIA 15 meter racing class/Standard Class/World Class
18 meter class
Self launching/auto recovery
Multi place gliders
Companies
The Soaring World
People
History and Random Stuff
This is intended to be a clearing
house for glider and soaring information. I have used
many sources for this, such as the 3rd edition of
Fundamentals of Sailplane Design and
Cross Country Soaring. I would appreciate
any help in filling out the many nodes linked here and
anything else having to do with gliders. For the noding format of gliders, please see Eta or SparrowHawk. Links to sort:March 8, 2001.