Engine Setup

TIP

This page covers the engine parameters in ArduPilot — petrol or hybrid — for unmanned systems that run on an engine rather than batteries alone.

Overview

On petrol fixed-wing aircraft, VTOLs and some large multirotors, the engine provides thrust or charges the battery. This page is about setting the engine parameters in ArduPilot and the adjustments people usually make.

Warm-up and idle

• Warm the engine up before starting; a cold start is how engines stall.
• Adjust RCMAP_THROTTLE / THR_MIN to match the engine's idle band, so it idles steadily and does not stall.

Engine parameters

• THR_MIN: minimum throttle, which sets the idle point — too low and the engine stalls.
• THR_MAX: maximum throttle, which caps engine output.
• THR_MID: the middle throttle for hover or cruise; used as a reference for launch and recovery.
• THR_SLEW: limits how fast the throttle can change, so engine speed never jumps.

NOTE

On engine-powered aircraft, set a sensible throttle mapping against the engine's actual RPM feedback, and run a ground test at idle and at full throttle before the first flight.

More tutorials

• ArduPilot multirotor tutorial
• ArduPilot fixed-wing tutorial
• ArduPilot VTOL tutorial