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
The switch to circle is normal failsafe behaviour if you select RTL as failsafe action. It will first switch to circle for 20s and if signal is not regained after that, it will switch to RTL.
Now watching you GCS in the video I find your airspeed kinda strange. I'm guessing it is in m/s, right? Cause else the values really don't make sens, but I regulary see your groundspeed at 22 or something and your airspeed at 5-10. That seems like an awefully low airspeed to me (18-36 km/h) so maybe your pitot is not calibrated right, or you have some leakage ?
I've seen a report somewhere of a batch of bad pitot tubes, that all had leakages. Blow into the tube while holding it shut at the rear to find out.
Also, I find that in stabilise the plane is much less responsive then in manual. In manual you control the deflection of the controlsurfaces. In stabilise you control the pitch and roll angle of the plane. So full roll stick in stablise is only 45° bank with standard settings, while in manual you'll roll at max rolspeed. I'm not sure that stabilise mode also respects max pitch angles, but I would assume so. In that case you may have a fairly low max pitch up (15° standard) which will make the plane rather sluggish on climbing.
About the handlaunching : I always launch myself and my hand goes down to my tx immediately after the plane leaves my hand. Ofcourse a helper doesn't have a tx and so does not have any motivation to lower his hand after launch (other then fatigue ;-) )
BTW, what prop and motor do you have on ?
Thank you for posting and +1 to Gary's comment on the opening shot. It made for a much more entertaining presentation.
Why was the mode switching from Manual to Simple and back so quickly at times?
Why would you need Simple with a fixed wing?
-=Doug
That has to be one of the best opening shots on a YouTube video I have ever seen. We have all had moments like that. I have used a simple glider bungee with big wings, only starting the motor once its off the end, must save a couple of maH as well ;-)
Every time I screw up its because I am having just one more flight or the line I'm sure it will be alright runs through my head. I am mindful of the other phrase that causes most incidents. "Watch this"
@ Thon, +1. That is not a dirty setup process.Is quite clean IMHO..
@ Adam,
BTW in-spite of few successful flights in all modes, Mine wanted to fly away to the only direction that would have been dangerous( a oil refinery few miles away !! I was flying in barren desert where you could land a 747 and no body would know. Before I could react with in few minutes ( gave the auto pilot few minutes to figure out which way was home) , it was almost a mile or more away :(( and my inputs while in AP mode did not do much. Fortunately I did not jump to manual( as it was too far for me to see it clearly) and but tried stabilized mode and tried all sorts of fancy turns and finally it started turning home after I insisted a lot. Pew.. To this day I don't know why it happened!!. I guess it was one of those Murphy's Law. Tune down the setting so that plane does not do aggressive turns in any mode and keep your fingers glued to mode switch :)). Good luck.
So remember , In AP and stab mode , auto pilots usually fights any manual inputs, :). Good luck
"Lawn dart" I like that terminology. Definitely done that a few times.
That's a horrifying way to launch.
Just curious, is it possible to toss it by the tip like a smaller wing? Or is it too heavy?
I'm impressed you flew so close to water on a maiden!
@Thon- Great Start up list. The only thing I diid not do was test fly without the APM but I followed everything else almost exactly. Seperate BEC on output side, manual mode all worked ok, stabilize mode on ground worked and reacted as it should when I moved plane around its axis. When I first switched to stabilize in the video, you see it quickly level, then I noticed that it seemed to be headed on a downward path so I pulled back on the stick and it was not responding so I quickly switched back to manual. I tried a second time but again as soon as I went into stabilize the plane would not react to my control inputs so I abandoned any auto or stabilize modes for the rest of the flight.
From the lessons I have learned from setting up a few airplanes with apm 2.5
1. without the APM installed, fly the aircraft and trim it so that it flys straight and level, tweak your linkages if needed to reduce trim. Fly multiple times to ensure you have a steady and well trimmed aircraft.
2. Install the APM. Make sure you have extra power going to the output side to power the servos, the APM 2.5 alone can not provide enough power to the servos.
3. Connect the APM to your computer and power the radio. Go through the settings to match your airplane. Go through the radio calibration process, do not adjust the trims. Complete the setup.
4. Power your radio and aircraft. Make sure your controls work correctly in normal mode. Switch to stabilize mode and verify the control surfaces move in the correct direction to correct roll, pitch and yaw as you move the aircraft. (This step is also part of my preflight process)
5. You are now ready to fly.
That was the quick and dirty setup process.
The big part is making sure the aircraft is flying well and is trimmed properly before setting up the APM
@criro1999- CG was on and I don't know exact weight but flew fine the first time. Did you watch the whole video? Basic set-up is-
2x 3300 4s Batteries
APM 2.5 w/power module
Castle 5amp BEC
Aurora 9 7Ch Rx
Stock power set-up
GoPro3 on nose
Looks heavy for me. Usually when I test a motor glider or wing (model without landing gears), I launch it by hand, with motor off and needs to glide and land normal after few meters. This gives me the certitude all controls are well setup and GC is well located. Then next time I do the same with motor on on FULL.
Which video editor did you user for PIP or video in video and which video effect are you using?
Nice to hear both sounds, when I am doing the same, only one sound is available.
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