After my first time using Ardupilot on a plane, I decided that perfecting the autonomous part should be done on a plane which is proven to fly well. I decided to bring back the Photon motorglider which had been rotting away in the top of my closet. Why didn’t I use it earlier? Honestly, I have no idea. Poopy memory I guess. Anyways, I replaced the old wing with the new, larger one and installed the flight controller in the plane.
On 2nd February 2025, I went out with the intention of performing the first autonomous tests: Autolaunch & RTH (Return-To-Home). In an autolaunch, the plane is thrown during which the flight controller detects the sudden acceleration and throttles up the motor before autonomously flying itself up and into a circling pattern above the launch point, also known as “loitering“. The same is the case with RTH, where the plane autonomously flies to the launch point (also called the home point) and loiters above it. RTH and RTL (Return-To-Launch) are used interchangebly but mean the same thing.
The first autolaunch attempt clearly didn’t go well. I threw it at a high angle which meant that the speed of the plane quickly diminished. The motor started up but wasn’t able to recover the lost speed, sending the plane into the ground. Luckily it was more of an “unexpected landing” than a crash, so the plane was picked up and ready to go for a second autolaunch attempt.
The second attempt was a success! While the plane nearly met the same fate as the first attempt, the motor was able to recover from the dive and pull itself up just in time before smoothly flying away. It then turned by itself and starting flying in circles directly above us. I was ecstatic! This was the first time I had a plane flying completely by itself with no manual input from me. I asked my dad to record a video which is shown below.
My battery soon fell below 20% shortly after recording the video seen above, so I took manual control and brought the plane down for a successful landing. And that concluded the first autonomous flight test! My next success was getting autonomous waypoint missions (in which the plane follows a given flight path by itself) to work, which I will talk about in my next post.
Thanks for reading!