Internal Combustion Engines (ICE)

Canberra UAV’s petrol powered tricopter. See blog post here

Internal combustion engines can increase flight times but care must be taken to handle the extra complexity and increased vibration.

What to Buy

Connection and Configuration

The engine’s ignition power switch and (optional) starter should be connected to the autopilot’s servo outputs, Ignition and Starter (see ICE section in Autopilot Output Functions).

To allow the pilot to directly control the ignition and (optional) starter from the transmitter, RC pass through should be set-up:

  • Set SERVOx_FUNCTION (where “x” is the autopilot’s output channel connected to the ignition or starter) to RCINy (where “y” is the transmitter channel). For example set SERVO8_FUNCTION = 59/”RCIN9” to allow the transmitter’s channel 9 to control the autopilot Output 8

Be sure to check the engine’s behavior when the transmitter is turned off to simulate what will happen during an RC failsafe.

Note

The engine can be started and stopped in autonomous missions by using the DO_ENGINE_CONTROL mission command. This useful preceding NAV_VTOL_TAKEOFF or NAV_VTOL_LAND to start or stop the engine to prevent prop strikes while landing in wind with a low clearance prop. See Mission Commands section.

Vibration isolation

The high vibration from internal combustion engines means that vibration dampening is critical. It is often necessary to mount the autopilot on an plate with self adhesive lead weights added to increase its mass.