Today I had my first ever flight with Ardupilot on a fixed wing, with the Arduplane firmware. And I’m really not sure what to say. As an INAV pilot with some experience collected over the last 2 1/2 years. Working with 7 Generations of INAV Firmware, having built and flown 10 different INAV Planes of many shapes and sizes, and helped with possibly 100 more to get issues solved and tune them in. It was really strange to look at the other side of the fence.
My feelings are mixed. They range from marvel to confusion and disappointment. This was done on my Long-Range AR Wing that was perfectly dialled in with INAV before.
What Amazed Me
It just flies! And damn it flies good! After I found my way through that nightmare of a configurator, which put my brain into stupid mode. I just followed what some good tutorials showed, and what 2 people told me without question, I was sceptical.
The Servo throw in ANGLE mode and ACRO mode was massive. An INAV plane with so much throw on the bench, would freak out as soon as it is in the air. But, nothing. I accidently launched in ACRO mode instead of FBWA, with pitch back on the stick.
A friend of mine threw the plane. I launched LOS in ACRO. I then switched into FBWA and turned around. Did a few circuits and then switched to my goggles. And it was amazing how well it already flew. A bit bumpy and wiggly but I have seen worse INAV maidens before. Immediately I did the Autotune for around 5minutes. After that, the plane just flew like butter.
FBWA was rock steady, CRUISE was smooth, and ACRO was like flying a quad. I had no attitude lock turned on. But, the stabilization did an awesome job of reacting to commands. LOITER was very stable, only slight altitude fluctuations and nice circles. RTH worked too. I flew around for about half an hour with my Li-Ion pack and thought about what I was experiencing.
Then the confusion kicked in.
What Confused Me?
The flight was with an AR Wing, as mentioned before. A low power, high efficiency setup; that is still capable to do some nice manoeuvres. But something did not feel right. It felt less like I’m flying the plane, but more like a video game. And that is the point of how Arduplane works.
From my feeling, I’m not flying the plane anymore. As soon as any stabilization is active, even in ACRO mode, it feels remote. There is no difference if I fly fast or slow. It always behaves the same. My guess is, that any plane will fly the same and feel the same in the air. I totally lost the feeling that I have with my INAV setup, where every plane has its characteristics. In INAV I can feel the speed by the stick responsiveness. I can feel when I get too slow when the plane gets sloppy. I do not have that on Arduplane at this point.
Of course, this is a thing that depends on the pilot, if you like that or not. But it clearly shows to me that Arduplane is built in a way, that it wants to make every plane fly the same, to make everything as consistent as possible. This is a fantastic thing for cruisers, slow planes, long range builds. But, in my opinion, this is not what I want from an agile plane I also want to have fun with. But this is just my opinion. And speaking of manual control, that leads me to the disappointments.
What Disappointed Me with Ardupilot?
!!! DISCLAIMER !!! It was my first flight with Ardupilot, and I just scratched on the surface, so I have no idea what of these points can be changed and how!!!
A lot of people said to me that Ardupilot defaults are simply perfect for most planes. But I must disagree here.
- The maximum bank angle was way too low. It took me forever to make a turn in FBWA.
- The loiter radius was huge! Around 90m radius on average with some +/- 10m fluctuations at absolutely no wind. Even for a big plane like a mini talon that is just too much.
- I cannot change the altitude in LOITER mode by default. When I pitch down it sinks like in FBWA mode but climbs back when I release the stick. What! That makes no sense to me.
- RTL or LOITER takes sometimes about 2s before it kicks in when I set the switch. This can kill my plane in a video loss emergency.
- The OSD Possibilities for on board OSDs in a F405 Wing FC are way too limited and still hard to set up. No comparison to the huge possibilities of INAV.
Ardupilot is a huge piece of software, with tons of possibilities. But for some reason it just feels like a golden cage. Tons of settings on one side, but a lot of limitations and restrictions on the other side. Being limited to 6 main flight modes (I use 7 on INAV) and then only one additional flight mode or modifier per RX channel is annoying. But the most disappointing thing is, as mentioned before, the complete loss of flight feeling. I just cannot feel the plane. It is all pure fly by wire. An AR Wing feels like an airliner instead of an agile and fast RC Plane.
These are just my first thoughts. I will for sure do some further work with that. Maybe on that AR Wing or maybe on my new test platform I am just getting ready. We will see how that goes but I really want to learn Ardupilot too, although my heart belongs to INAV.