Where does the term “throttle quadrant” come from?

Question

The area of many flight decks that contains throttles or thrust levers is often referred to as the “throttle quadrant” or “thrust lever quadrant” even if it’s not one of four parts of the panels.

Where does the term come from?

I guess I figured it was because the levers move through approximately 90 degrees. — Fred Larson, Nov 27 '17 at 19:23
Just a guess, but maybe some early designs used a quadrant gear to drive the cables. That's how a ship's wheel works. The rudder cables are attached to a quadrant driven by the wheel. A ship's wheel itself is also sometimes called a quadrant for a different reason. Aviation borrows nautical terms — TomMcW, Nov 27 '17 at 20:46

score 6 · Accepted Answer · answered Nov 28 '17 at 01:17

The term quadrant refers to the panel containing the levers and is derived the circular arc in which the throttles are placed:

throttle quadrant

The recess in which the throttle is located and moves. ... It derives its name from the circular arc in which the throttle is placed.

Looks like the term entered aviation from the rudder controls in a ship:

quadrant

A frame fixed to the head of a ship's rudder, to which the steering mechanism is attached.

3.1 A panel with slots through which a lever is moved to orient or otherwise control a mechanism.

Here's a rudder quadrant

Rudder quadrant; image from titanic-model.com

score 4 · Answer 2 · answered Nov 28 '17 at 02:02

A quadrant is a generic name for part of a circle with an angle of 90°. From Wikipedia:

A sector with the central angle of 180° is called a half-disk and is bounded by a diameter and a semicircle. Sectors with other central angles are sometimes given special names, these include quadrants (90°), sextants (60°) and octants (45°), which come from the sector being one 4th or 6th or 8th part of a full circle, respectively.

The throttle quadrant is the circular segment that houses the thrust levers. The B737 thrust lever has a stroke of roughly 90°.

Image source

Other quadrants found in aircraft are for instance the cable quadrants for the interconnect cables between flight controls and control surfaces.

Image source

Where does the term “throttle quadrant” come from?

2 Answers2