After having some desync issues you guys helped me troubleshoot I replaced the 4-in-1 ESC and so far so good for that, flies beautifully. However during the test flight, almost 2 minutes in, I got a failsafe about 20m away from myself, no more than 10m high. I'm a little frustrated, it's my first full build and I love the damn thing but at this rate I'll never be able to fly it with confidence...

Video
Blackbox: 
  LOG00009.BFL.zip (Size: 1.25 MB / Downloads: 74)

Radio: FrSky Taranis QX7
Receiver: FrSky R-XSR

I'm pretty confident my QX7 is ok as I used it without issue in the last few days on my old Arris X220. I haven't done a range check yet, I need to go see how to do one properly first, while the quad dries out... (yay for conformal coating)

Was wondering if you guys see anything, other than the fact that I'm not using Crossfire (-_-), that jumps out as a probably cause.

Here's my receiver antenna setup:









Antenna tips don't seem bent, I pressed on both antenna connectors to the board and they're nice and snug. No contact with the carbon fibre and I'm using standard forever-tubes I got from pyrodrone. I've also flown here multiple times, much further, without issue.

In the blackbox info it's worth noting that my RSSI channel isn't scaled (200) and offset (-100), I'm using the ImpulseRC OSD which expects 0-1000. I think I also made the mistake of setting the RSSI aux to 0 during failsafe stage 1 instead of holding the last received value, but I'm not 100% sure I left it that way.

I've only got two leads so far:



It looks like I may have damaged the ground wire where it meets the plug when my tweezers slipped last time I disconnected it. I doubt this is the reason but it's worth replacing regardless.

My best guess is I didn't have my TX antenna positioned correctly. It's pointed up and away from me at 45deg, a habit I carried over from when I used a monitor on my TX instead of goggles. Like this:



So the TX antenna tip would have been pointing at the quad (I know, bad) and when the failsafe happened, one RX antenna would have been pointing away from me and the other at about 90deg. If I hold my quad out in front of me with the same orientation I can see in the DVR the 90deg antenna tip may have been behind the arm/motor. 

Anyone got a clue?

Edit: I was right, Tx antenna was not positioned properly. For academic purposes: doing the range checks seemed to indicate that, with my Rx antenna setup, having the Tx antenna folded to 90deg with the tip pointing to either side yields the best results when the quad is level.

Looks like you lost power before you hit the ground.

(04-Apr-2020, 07:25 AM)voodoo614 Wrote: Looks like you lost power before you hit the ground.

Looking frame by frame I'm still a few feet off the ground when the static comes in, but you can still make out the standoffs for a few more frames. My ImpulseRC OSD is set to switch to 25mw when disarmed. When I found the quad it was still powered on, only the front right arm was sticking out of the snow a bit. FPV antenna was deep under there.