gliders

no need for propulsion or engine 

all aircraft, including gliders, can glide for a bit with no propulsion but then due to weight all will climb down and lose altitude 

gliders designed to take full advantage of force balance 

weight is distributed at strategic points to better air penetration 

wing configuration means more lift than drag

glide ratio one of the most efficient amongst all aircraft

glide ratio - distance an aircraft can travel in respect to the lost altitude. modern gliders can have between 40:1 to 70:1 (meaning can fly 7000 m horizontally with the loss of 100 m vertically)

impossible to aircraft to gain altitude without any propulsion in a static environment, but gliders use atmospheric phenomena 

  1. ridge lift - ascending currents of air over mountain slope, can take advantage of current. the closer to the slope the stronger the current is 

  2. thermals - most common way to gain altitude, columns of hot air generated by a surface heated by sun, air becomes less dense than surrounding air and rises rapidly, glider can fly in a circular motion around this air and gain altitude until thermal disappears or weakens (this is what birds do)

  3. wave lift - air waves after air passes through mountains, similar to sea waves, gliders can gain altitude  

totally clean and free energy allowing gliders to fly for hours

need a airplane to tow it to take off or a tow winch on the ground (altitude gained not as much as from plain)

also from mountain take offs using retractable propulsion system inside the glider or system of elastic ropes on a hillside 

thin wings less aerodynamic drag, obtaining same lift and losing less lift than other planes 

fuselage design - as smooth and aerodynamic possible, pilot almost lying down as you would in an f1 car

high aspect ratio - not necessary to make quick manoeuvrability

large wing area required, restriction of reduced chord wing to minimise drag 

built to be very light but strong 

gliders have to have water ballast filled on the wings to make them heavier for better air penetration abilities, can be trained during flight in case thermals are not too strong and must be drained before landing. can sometimes be heavier than the pilot 

used to be made of wood and fabric, and now fiberglass, carbon fibre, and Kevlar 

basic instruments apart from any relating to an engine 

yaw string, generally red, placed above the pilot which indicates wind direction, cuz if the glider is not facing air flow then drag induced 

important to be away of glider speed at all times cuz it can lose control and stall if going too small

some gliders have a particular speed for max performance 

air s