Sailplanes/Gliders
As sailplanes or gliders are built to generate the least amounth of drag for any amounth of lift, they are made in a very streamlined shape fittet with long, thin wings. Gliders often use winglets or similar features for better aerodynamics. Modern sportgliders are built in composite materials as fiberglass and carbonfiber. Some older sportsgliders also sometimes contain some wooden parts.
In glider racing, pilots depend on beeing able to change the gliders weight in-flight. Modern gliders are built in very light materials. However, the wings contain large watertanks which can take 1-3 hundred liters of water. Water makes the glider heavy, which then again makes it go faster. The downside is that the pilot will have to spend longer time stopping in rising air to gain height as the glider will climb slower. It can be difficult to find the balance between speed and climb before takeoff. Gliders also have to be as light as possible when landing as gliders often need to land on short runways and sometimes, not even on a runway at all! Because of all this, the gliders are fitted with valves to dump the water in-flight when needed.
The capabilities of the different gliders are often meashured by it's "glide ratio". This ratio defines how much lift the drag of the glider spends while it's flying trough dead(still) air. A typical, modern sport glider might have a glide ratio of 1:40. This means that the glider travels 40 meters forward for every meter it drops in silent air. Glide ratio may also be refeered to as L/D ratio (Lift over Drag). The glide ratio depends on the speed of the glider. Higher speed means more drag and a lower L/D. Gliders are often meashured by their "L/D at best glide speed". This is basicly the maximum glide ratio the glider can have in silent air.
The pilot can controll the glider directly via the cockpit. The cockpit is usually a bit narrow and flat but long. To make good space for the pilot, the seat offers a laydown position for the pilot. Because gliderpilots need a good overview of what's going on around their glider, the cockpit is fitted with a large canopy (plexiglas) often making out almost half the cockpit.
The cockpit controls are linked to the ailerons, rudder, elevator, flaps, airspoilers, landing gear and brakes directly via light metal rods and wires. The cockpit controls features levers for flap and spoilers, a stick and rudders for direction control. To increase a gliders speed, the pilot have to point the front of the glider more downwards, and more upwards to slow down. Many modern gliders have flaps to increase the gliders good ability and control in very low and very high speeds. Spoilers can be deployed to destroy the lift over the gliders wings which is mandatory for the pilot to have good control when landing. The pilot can control the glideslope when landing by increasing or decreasing the amounth of lift generated by the wings in the same sence a motorplane uses his engine to control the glideslope when landing.
The cockpit of modern gliders are very well instrumented. The standard instrumentation contains an airspeed indicator, altimeter, a VHF radio for communications, variometers showing the vertical speed and direction of the air around the glider, compass, anti collision system and a yaw-string to indicate wether the glider flies coordinated or not. Typical sport gliders used for racing also contains one or several computers and GPS systems for navigation, wind information and some tools for glide calculations. Gliders with on-board engines also have some engine controls and monitors. The instruments are usually setup in tidy order making them easy for the pilot to read and use. The most important instrument though, is in the minds of the pilots. Gliderpilots should be able to fly the gliders even witout instruments, and even during normal operations relay more on the feeling of the glider and the enviornment around it to fly and navigate than the instruments.
Because of the constant need to reduce air drag on a glider, the glider usually have only two wheels. Both mounted on the longitudinal axis of the glider. During takeoff, the wing of the glider is usually supported by groundcrew the first few meters. Afterwards the pilot will use aileron control to balance the gliders wings until it's off the ground.
Photo of glider cockpit with instrument panel. Glider is a Duo Discus XT.
ASW 20 - 15m class flapped glider
