I finally got around to the X-8 maiden flight. Nice day, gentle breeze, batteries charged and ready to go. Things went as well as they could for a first flight. The plan was to take off in manual, trim things out, then try stabilize and maybe even RTL. Unfortunately when I switched to Stabilize the plane leveled then seemed unresponsive to my control inputs. I quickly switched back to Manual before it flew into the ground and continued to fly. I also had a few radio glitches for some reason which caused the APM to Failsafe to "Circle" mode. Is that normal? I should probably change that to RTL.
Here comes the bad news. My "helper" was to film the ground to air footage for this video. After the 6-7 minute 1st flight, I landed and he hit "Record", the whole flight the camera was on pause. WHAT! @*%$! Now my dilemma, the wind is picking up but I want some nice footage from the ground. It's getting too windy to hand hold both the radio and X-8 with one hand each so how about this, I'll have my helper hand launch the plane while I man the radio? After some brief instructions and a wind check, it was time for flight #2. As you will see from the beginning of the video, things did not go as planned. When he went to toss the plane he left his hand up and in the way and it was struck by the prop causing it to nose over into an uncontrollable dive.
So far the only damage I can find is both plywood wing flanges where the little screw goes through broke and I got a pitot tube full of mud. I didn't like the wing attachment set-up anyway so now I have a reason to fix them. By the way, he's alright and he only suffered a couple small scratches on his fingers. Very lucky!
Moral of the story is, don't be rushed to make a flight if ANY of the conditions aren't right, always make sure the cameras are rolling and don't put un-trained personnel on the end of expensive equipment.
Hope you enjoy and if anyone has any comments on the Stabilize non-control issue please let me know.
Google Earth file-2013-05-01%2009-46-24.tlog.kml
T-Log- 2013-05-01%2009-46-24.tlog
Comments
@Adam
No changes were made to the setting other than checking the RTL altiude which was set at 0 feet! now set to 100'
That was a surprise, It came at me like an arrow as I was standing at the home position. . now it behaves OK. this is a X5 not an X8 so you may neeed some pid adjustments. ? I dont know.
@Dwgsparky- I'll give that a try. Did you have to change any of the max-min PID settings for auto modes like someone mentioned earlier?
I had the same issue with my X5, the solution is to fly staright and level at about cruise speed and note the angle that the HUD is showing. this is the +ve angle the wing needs to fly. Then set up the wing on a table and use blocks or books to set the plane to the same angle you saw in the HUD then perform a manual level . next flight the HUD will show roll and pitch at zero as the plane is flying correctly.
@Lloyd- Good tip on the leveling, I'll give that a try. I figured the Circle mode thing out when I watched the mission planner video back. My radio was going into Failsafe in a certian part of the field. I've also re-routed the way the antenna was layed out inside the plane better.
Also the latest version switches to circle for a short while as part of RTL I think.
That may explain the seemingly random elevon deflections as well as the attitude problem.
On my X8 initially stabilize would lose altitude very quickly and even loiter would too.
I had to level the plane in a fairly pronounced nose up attitude to overcome these problems.
I think what looks like level to the X8 on the ground is really quite a nose down attitude in flight.
I went through the radio calibration again yesterday after repositioning some equipment inside the plane. One thing I noticed is that on the ground, after initial power up with a good 3D GPS signal, the servos twitch all over when I switch into RTL mode. I even walked out always away from "Home" and tried it again to see if it would move the correct direction and take me home but nothing. Just random aileron deflections. Manual mode seems to work correct as does Stabilize although I probably need to adjust my max pitch and roll angles like U4eak stated above. In the video I try Stabilize 2 times and while it seems to level the plane, the plane just starts a slow desent into the ground causing me to swich back to Manual mode ASAP.
Any ideas on the twitching servos?
Good Luck !!
@Alex- Yes, this is the one I like and want to build.
This is one of the best and easy to do catapult for X8
http://www.rcgroups.com/forums/showthread.php?t=1806237
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