So I have some vacations coming up and already have some quads and a hex I figured I needed a fixed wing to round out my aerial camera fleet. (for now) heh. So I took the plunge and picked myself up an X8 to fill up with electronics.
I'm running an ArduPilot Purple, with a Castle 75 esc waiting for Hobbyking to drop of my new Scorpion motor until then I have a 700W max 50Amp local hobby store motor to power the bird. I'm running 1.2 video feeding through MinimOSD with a Sony 720 line mini cam. I have a roll and tilt GoPro mount in the works that I'll post up some pics when I can get some play time on the router this weekend. Communication is done through a Futaba 10C 72Mhz and some 900Mhz XBees.
I've only made a few mods for now like adding a second motor mount plate that bolt through the foam to the outer plate.
I made some electronics trays and filled in the lower camera cut out with some foam and Gorilla glue.
I ended up bringing the control linkage up through the wing, leaving it on the bottom seemed like a bad idea for a belly lander. I have never flown a or built a fixed wing, but I said the same about the multirotors and DIYDrone's gear and community made it simple, awesome and enjoyable. Only crashes were ah-hem user error. So I'm hoping for the same luck with this bird. I do have tons of hours now on RealFlight sim just to make sure I feel comfortable with the controls. That being said any input from from you guys will be greatly appreciated. I'll update this blog as things progress and as I get the camera mount going. But for now heres some more eye candy. Be happy and safe all!
Comments
Hi Gustav, yes sure, I understand the limitation.
Its just that with other airframes it has not been as big an issue as what it seems to be on the X8.
I actually have an airspeed sensor there I could use if it cannot be resolved.
Most of my flights are generally in no or low winds so I feel it should be able to be tuned without the airspeed sensor in these conditions.
Hi Toby,
The APM tries to maintain a fixed speed.
If you use GPS only, that will be groundspeed.
Worst case example, your APM/plane is setup to fly at 50Km/h.
Now you have a headwind of 50 K, APM thinks you are standing still, which you actually are, refering to ground.
You have perfect airspeed, but APM tries to increase, and you end up with 100Km/h airspeed.
Bang goes all your perfectly tuned PIDs.
Turn downwind, and APM tries to get the groundspeed down to 50, and your plane falls out the sky.
I used to fly hanggliders, weird sometimes to see a groundspeed of over 100Km/h or more during downwind runs, yet only 60Km/h airspeed.
No way you can fly a real aircraft on GPS.
In the meantime, here is a collection of X8 with APM2 flights in almost every type of weather condition.
I'm not using an airspeed sensor, but I never have with any of my models and this is the first one that has done this.
I'm using a Xtrack Gain of 80 and 35 degrees.
Hi Gustav Kuhn.
Yes, i`m using airspeed sensor.
Toby Mills, what is the value of Xtrack Gain and Xtrack Angle you are using?
Ok, I'm getting a X 8 soon, I hope :-)
Only have a APM 1 though...
We were definitely using airspeed.
Hi guys, are you using an airspeed sensor, or relying on GPS speed?
Because if you only use GPS speed, your true airspeed is going vary tremendously.
I saw similar results on my Discovery, I forgot to connect the Pitot tube once, :-(
Hi Alexandre,
Yes I get exactly the same results as you. lots of roll into the wind and pitch problems with the wind.
I`m playing with the PIDs of X8 too. Saturday we had a flight with really strong wind and APM managed to navigate the X8 through a 35km flight path. But I`ve noticed a lot of variation in Roll when flying against wind (snaking). In other hand when flying in favor of the wind the roll was ok but the Pitch had a lot of variation.
Anyone had similar results or have a hint about it?
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