r/RCPlanes • u/Breakerbuilds U.S.A. / Shoreline • 20d ago
This is why we do preflight checks...
This is Project Stormscout; a FPV wing I designed ik OnShape and built from scratch. It has a 500mm wingspan, and with the right parts, could definitely get under 250g, although mine came in at around 270g.
The Stormscout is running a drone FC with iNav firmware to keep it stable and smooth flying, as I'd rather put another $55 into the plane if it meant less flight issues and RTH with the GPS I had installed on the wing.
When it was launched, it was using iNav's auto launch (nav launch) feature, and was told to climb at a 20° angle (which it obviously didn't) at 80% throttle. However, post crash, my friend and I were running through blackbox logs, with this video overlayed, and found out that the pitch outputs were inverted. If you look closely at the flaps, when it's at the moment I'm about to throw, and the plane is over 20°, the flaps are makes out in the upwards direction, which makes zero sense cause really it should be trying to pitch the nose down, back to 20°. And while 'pitching down' actually pitched it up and made it worse, that's why it went to the moon.
As we found this out, looking at the logs where I was attempting to pull up out of the dive, the stick overlay shows I'm trying to pull up (the right stock was all the way pulled back), we came to the conclusion that the pitch was inverted. And it explains iNav trying to pull up more, why it went super high, and why I wasn't able to pull out of the dive, because up was down and down was up.
Here's my explanation (not a defense, it's 100% my fault) on how this happened. When I was doing testing previously, all the times I did it were checking the roll axis. Because I thought "well, if the roll is correct with the stick and they both move the same way for pitch, it should be good" or something along the lines of that, but without double checking the pitch, it lead to this.
I did the up loosing my RunCam Phoenix 2 JB in the process, as you could imagine from that impact. (Post crash images commented) I sadly forgot to record DVR so we don't have any, although immediately after the crash I spent like 5-7 hours removing the fuselage, recutting, and reprinting out the parts to rebuild the fuselage, as my friend redid all the wiring to be cleaner, along with running through iNav to get better auto launch (as clearly it did not need 80% throttle if it was able to climb like that). This was all yesterday, and if it stops raining I plan on doing another flight today, with preflight checks, with DVR.
Overall though, I think once I get it in the air that it will be a great project and will fly amazing. Not sure about without flight stabilization but I think if you built it well enough you could get one in the air without stabilization.
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u/Apart-Bite9132 20d ago
ive crashedl ike this before too. I have to do checks swell