rivet cutter (mechanic’s hand tool). A special type of cutter used to cut aircraft solid rivets to the required length. The jaws of the cutter are ground so the cut end of the rivet shank is flat.
rivet gage. The distance between rows of rivets in a riveted aircraft structure.

rivet gun (aircraft sheet metalworking tool). A hand-held air hammer that drives a rivet set with a series of sharp blows. A rivet set, with a recess the shape and size of the head of the rivet being driven, is held in the rivet gun with a spring-type retainer. The rivet set is pressed against the head of the rivet, and a heavy polished-steel bucking bar is held against the end of the rivet shank. The blows on the head of the rivet upset the shank and cause it to swell out and form the bucked, or shop, head.
rivet pitch. The distance between the center of adjacent rivets in the same row in a riveted aircraft structure. See illustration for rivet gage.

rivet set. A tool used to drive aircraft rivets. A rivet set is a piece of hardened steel with a recess the shape of the rivet head in one end. The other end of the rivet set fits into the rivet gun. The rivet gun vibrates the rivet set and hammers the rivet against a heavy steel bucking bar held against the end of the rivet shank.

Rivnut. A patented fastener used to install threads in thin sheet metal. A Rivnut is a blind rivet with an internally threaded hollow shank. The Rivnut is slipped through a hole drilled in the thin sheet metal, and its shank is collapsed by pulling it with a special pulling tool screwed into the threads.
Rivnuts were developed by the B. F. Goodrich Company to install deicer boots on airplane wings.

RL circuit (electrical circuit). An electrical circuit that contains both resistance and inductance.
RLC circuit (electrical circuit). An electrical circuit that contains resistance, inductance, and capacitance.
RMI (radio magnetic indicator). An electronic navigation instrument that combines a magnetic compass

with an automatic direction finder (ADF). The card of the RMI acts as gyro-stabilized magnetic compass, and shows the magnetic heading the aircraft is flying. A pointer gives the relative bearing between the nose of the aircraft and the radio station being received on the navigation radio.

rms (root mean square). See root mean square.
RNAV. See area navigation.
RNAV waypoint. 14 CFR Part 1: “A predetermined geographical position used for route or instrument approach definition or progress reporting purposes that is defined relative to a VORTAC station position.”
robot. A form of automated machine, used to replace a human operator in some tasks that are dangerous or highly repetitive. Robots can be programmed to sense certain conditions and act in the correct way for the conditions that exist.
robotics. The branch of science or technology that deals with the design, application, construction, and maintenance of robots.