A shuttlecock (also called a birdie or shuttle) is a high-drag projectile used in the sport of badminton. It has an open conical shape formed by feathers or plastic (or a synthetic alternative) embedded into a rounded cork (or rubber) base. The shuttlecock’s shape makes it extremely aerodynamically stable. Regardless of initial orientation, it will turn to fly cork first, and remain in the cork-first orientation.
The feathers are brittle; shuttlecocks break easily and often need to be replaced several times during a game. For this reason, synthetic shuttlecocks have been developed that replace the feathers with a plastic skirt. Players often refer to synthetic shuttlecocks as plastics and feathered shuttlecocks as feathers’. Feather shuttles need to be properly humidified for at least 4 hours prior to play in order to fly the correct distance at the proper speed and to last longer. Properly humidified feathers flex during play, enhancing the shuttle’s speed change and durability. Dry feathers are brittle and break easily, causing the shuttle to wobble.
Saturated feathers are ‘mushy’, making the feather cone narrow too much when strongly hit, which causes the shuttle to fly overly far and fast. Typically a humidification box is used, or a small moist sponge is inserted in the feather end of the closed shuttle tube container, avoiding any water contact with the cork of the shuttle. Shuttles are tested prior to play to make sure they fly true and at the proper speed, and cover the proper distance. Different weights of shuttles are used to compensate for local atmospheric conditions. Both humidity and height above sea level affect shuttle flight. World badminton federation rules say the shuttle should reach the far doubles service line plus or minus half the width of the tram. According to manufacturers proper shuttle will generally travel from the back line of the court to just short of the long doubles service line on the opposite side of the net, with a full underhand hit from an average player.