The yaw string, also known as a slip string, is a simple device for indicating a
slip or
skid in an
aircraft
An aircraft is a vehicle that is able to fly by gaining support from the air. It counters the force of gravity by using either static lift or by using the dynamic lift of an airfoil, or in a few cases the downward thrust from jet engines. ...
in flight. It performs the same function as the
slip-skid indicator
In aviation, the turn and slip indicator (T/S, a.k.a. turn and bank indicator) and the turn coordinator (TC) variant are essentially two aircraft flight instruments in one device. One indicates the rate of turn, or the rate of change in the airc ...
ball, but is more sensitive, and does not require the pilot to look down at the instrument panel. Technically, it measures sideslip angle, not
yaw angle, but this indicates how the aircraft must be yawed to return the sideslip angle to zero.
It is typically constructed from a short piece or
tuft of yarn placed in the free air stream where it is visible to the pilot. In closed-cockpit aircraft, it is usually taped to the aircraft
canopy
Canopy may refer to:
Plants
* Canopy (biology), aboveground portion of plant community or crop (including forests)
* Canopy (grape), aboveground portion of grapes
Religion and ceremonies
* Baldachin or canopy of state, typically placed over an ...
. It may also be mounted on the aircraft's nose, either directly on the skin, or elevated on a mast, in which case it may also be fitted with a small paper cone at the trailing end. They are commonly used on gliders, but may also be found on
jet aircraft
A jet aircraft (or simply jet) is an aircraft (nearly always a fixed-wing aircraft) propelled by jet engines.
Whereas the engines in propeller-powered aircraft generally achieve their maximum efficiency at much lower speeds and altitudes, jet ...
(especially
fighters),
ultralight aircraft
Ultralight aviation (called microlight aviation in some countries) is the flying of lightweight, 1- or 2-seat fixed-wing aircraft. Some countries differentiate between weight-shift control and conventional three-axis control aircraft with aile ...
,
light-sport aircraft
A light-sport aircraft (LSA), or light sport aircraft, is a fairly new category of small, lightweight aircraft that are simple to fly. LSAs tend to be heavier and more sophisticated than ultralight (aka "microlight") aircraft, but LSA restrictio ...
,