yaw string
telltale

Yaw strings are also used on some (especially smaller) helicopters.

The yaw string dates from the earliest days of aviation, and actually was the first flight instrument.

Besides, the yaw string never lied to him.

Yaw strings are also fitted to the Lockheed U-2 high-altitude surveillance aircraft.

Start to circle in a normal turn with about 20 of bank, keeping the yaw string exactly in the middle while you reduce speed very gradually.

Even the most sophisticated modern racing sailplanes are fitted with yaw strings by their pilots, who reference them constantly throughout the flight.

The yaw string is the only flight instrument that will directly tell the pilot the flight conditions for zero sideslip.

You should be able to go into turns and make centring movements without having to refer to the slip ball, yaw string, or ASI.

Gliders usually have a piece of string mounted in the pilot's vision which indicates airflow over the glider, and is called the yaw string.

The Wright Brothers used a yaw string on their 1902 glider tied on their front mounted elevator.

The yaw string, also known as a slip string, is a simple device for indicating a slip or skid in an aircraft in flight.

A simple alternative to the balance indicator is a yaw string, which allows the pilot to simply view the string's movements as rudimentary indication of aircraft balance.

The yaw string is considered a primary flight reference instrument on gliders, which must be flown with near zero sideslip angle to reduce drag as much as possible.

The yaw string serves the same purpose as the ball in the turn and slip indicator except that it is more sensitive and removes the need to look at the instrument panel.

Some light twin-engine airplane pilots place yaw strings on their aircraft to help maintain control in the event of an engine failure, because the slip-skid indicator ball is not accurate in this case.