I am in doubt about whether I should keep the flight controller (Pixhawk 1) active or passive for the initial flights of a naturally stable, CTOL fixed wing plane that is my own design.
I am perfectly aware that Arduplane is designed to simplify things, avoid problems and not to create them. However, in the hands of an inexperienced user, perhaps it is easy to shoot your own foot with so many parameters that may be set wrong triggering failsafe in the wrong moment or power systems misconnections that may lead to a brown out and a crash.
Alternatives I am considering for the maiden flight:
Keep Pixhawk as a passive vehicle flight data collection tool and connect all the servos directly to an independently powered RX
Set all servos to pass through or redirected to RCIN# channels through Pixhawk, but this will not protect me against a Pixhawk brown out
Use ArduPlane / Pixhawk as how they are intended to be used and drive the plane through Pixhawk with the benefits of the auto- stabilization, failsafe and autotune functions it provides. (Eventually, I will have to use them, so what not use them from day one?)
Any opinions and recommendations to minimize the risks of the maiden flight would he welcome?
I just used a normal rx for initial flight, (to get an idea of c of g etc) then i went to flight controller in full manual mode for entire flight, which allows you to view logs after, then on later flights i tried manual takeoff and then switching to rtl during flight, then tried fbwa and fbwb which is where im upto now.
I now take off in fbwa because i had three crashes in a row doing hand launches in manual by myself. An overweight model full of long endurance batteries and gear can be hard to hand launch in manual because by the time you throw it you have just a split second to get both hands to the transmitter and correct the ugly attitude you have thrown the model into, and with a high wing loading, low airspeed and really small control surfaces its easy to end up holding in full corrective throws and the model hits the ground before it straightens up.
With fbwa the control surfaces are already correcting before you have even let go of the model.
Hand launch in Auto works well. I have a Takeoff command and a Loiter_unlim command in the Mission plan so it flies out a bit and circles until another mode is chosen. Some use RTL after Takeoff but I often have trees at my back where I fly. Takeoff mode I think is still a work in progress. I experienced the “switch to Circle Mode after launch” issue some others have reported. It’s entirely possible this was a pilot (my) error in configuration but I haven’t yet repeated the attempt.
you mean takeoff and loiter unlim waypoints or do you manually punch these in MP in real time? I fly solo in FPV so it’s too hectic to switch between the laptop and the transmitter. what I do now is simply to set up a mission with a takeoff wp and a loiter unlimited wp. I haven’t got it to work yet, too high power loading.
Thank you very much for your replies. i am convinced that going with direct control through the RX is the way to go for the first flight indeed My key issue was disassembling the wiring of the pixhawk and all its servo rail outputs just for the first flight. As I have a dongle of servo extensions going into the Pixhawk’s servo rail, I left them where they are and connected the servos directly to the RX. This way Pixhawk still remains online to collect and transmit flight data through the FrySky pass through telemetry, but it does not interfere with the flight controls and power to the RX. The swap between the 2 modes of control takes about 2-3 minutes which I can live with.