Inverted Flight

Plane supports inverted flight. Inverted flight is initiated by setting an RC channel via RCx_OPTION parameter.

Details

The RCx_OPTION parameter allows you to configure a transmitter switch to enable inverted flight for fixed wing aircraft. To enable it, choose a RC input channel which is not being used for anything else, and setup your transmitter to give a PWM value larger than 1750 when a previously unused 2 position switch is enabled, and a value below 1200 when it is not enabled.

For example, if channel 7 is currently unused, and you set RC7_OPTION to InvertedFlight (which has value 43) then if your transmitter sends 1900 on channel 7 the plane will flip upside down and continue flying in whatever mode it is in, but with the plane inverted.

Transmitter Setup

Enabling inverted flight only changes how ArduPilot stabilises the plane. It will stabilise it with a roll of 180 degrees from normal whenever inverted flight is enabled.

To get the most out of inverted flight it can be useful to also invert your transmitter elevator and rudder controls while your inverted flight switch is enabled. This should be possible with any good transmitter.

Interaction with flight modes

Inverted flight can be used with any of the non-quadplane stabilized flight modes (which means anything but manual mode). That means you can switch on inverted flight during a mission and the plane will continue the mission inverted. Make sure you disable it before trying to land!

Tips

Here are some general tips about inverted flight

  • Try it out in simulation first to get used to it, and ensure your transmitter is setup right.
  • make sure you have plenty of height before engaging or disengaging inverted flight. Depending on your airframe, you could lose a lot of height while flipping over, and it may be that your airframe struggles to maintain height while inverted
  • make sure your PTCH2SRV_I value and PTCH2SRV_IMAX is high enough. Planes commonly need more pitch trim while inverted to hold height.