Well it flies.
Kind of hard to get a photo of by myself. Took these while running dRonin's autotune:
Gotta love being able to snap photos while tuning
But this was the 3rd tune on the pack and it was getting low so not touching throttle was risky. Almost hit the ground at one point and had to quickly get back on the stick.
Tune results weren't bad:
http://dronin-autotown.appspot.com/...hdXRvdG93bnIYCxILVHVuZVJlc3VsdHMYgICAkJa2xAoM
First tune I got a 25ms tau - fairly respectable for something this small. Last go it sagged to 34ms but I wasn't surprised since my hover throttle went from just under 50% to a bit over 50% due to the pack sagging, so a loss of performance was expected.
It's by no means done yet though. I made a few little tweaks to the frame and re-printed it. I shrank the FC mounting posts by .5mm and raised them .5mm taller to clear the DSM port. Which I may go ahead and just remove anyway since all my DSM sats have the connectors removed so I just soldered to the back of the port anyway
Additionally I added a small gap to the motor pods for motor wires to pass through:
And finally I lengthened the arms 5mm each so it's now 100mm motor to motor
This was to give room for the ESC's to fit on top of the arms...but...I ended up mounting them underneath anyway
Mainly because I decided I really need to switch to a 4 in 1 esc for this guy and didn't want to cut my motor wires. So...the way my ESC's are laid out is pretty goofy. Basically the ESC for each motor is on it's opposing arm. This caused me a little bit of confusion when I wired up the motors and they were responding in the wrong location - but thankfully dRonin makes it super easy to remap those.
The build is super ugly right now, I was really rushed because I desperately wanted to "just get it in the air" last night but we did a family trip to the county fair after work, then I had to wait for the new frame to print so it wasn't until 10PM that I even got to plug in my soldering iron.
Doesn't look THAT bad from the top...other than not having the FPV cam on yet. I got a mount printed for my TX02 cam but need some spacers before I can install it.
From the bottom though:
The ugliness really shows. The RX is just shoved in there with wires that are really too short. If I remove the connectors from the RX and the FC I can probably make the RX fit under the FC for a final build.
Also, all that extra wire. I need to shorten the signal wires on the ESC's, shorten the power wires on the ESC's, and remove the signal ground wires (they're not connected right now and the pico doesn't have an obvious good way to connect them.) That will probably shed a few grams.
And I may as well go back to my original 90mm frame if I'm going to assemble it like this.
But...I want to add some tabs on the side of the frame for the battery rubber band so going to print one more frame anyway. And if I'm going to go with the ESC's underslung like this I may just shink down to a 80mm frame while I'm at it...depends on what mood I'm in.
Even as a 100mm it's a little sketchy with high rates. Feels nice and locked in, but easy to get into trouble fast LOS on something this small!
I'm also already using it as a test bed. As already mentioned I'm running dRonin on it - and pico blx support isn't yet official on dRonin so this is an experimental build right off the start. I started with a recent nightly but pico blx doesn't have the new autotune code enabled due to a memory constraint one of the early testers ran into. Since that test though some tweaks were made to the new autotune code to make it less memory intensive due to Brain RE1 having the same issue. The lead developer suggested that I try enabling that and seeing how it does. The change was super simple, just two lines to adjust in a header file:
https://github.com/d-ronin/dRonin/pull/1701
This morning before work I quickly gave it a go...and got back results.
Those are the most interesting bits of the new autotune code results. Y is pitch X is roll. The green line is what autotune commands the quad to do - the blue line is what the gyros read out in response. The better the two lines match up the more accurate the tune is. And the smoother the blue line - the less noisy the quad is. This is by far the smoothest result I've got.
Which honestly surprised me because I'm not overly impressed with these 1103 motors. When I setup my neutral points on them the first one spun up nice and smooth and quiet at a lower input than I expected - I was hyped. Then the second one...needed more input than I expected and I could see it wasn't perfect - the shaft is apparently very slightly bent as I can see a tiny wobble in it
I did drop one of the motors once or twice so that's probably my fault. But...the next two motors fresh from the packages and un-dropped also took more power and were louder and rougher sounding than the first two. So...not overly consistent. But can't argue with the end results, I was doing flips in the office this morning - which wasn't a great idea since I can barely tell the from from the back flying LOS on this thing!
Oh yeah, AUW with battery but no FPV yet ready to fly came in at 79g. Bit heavier than I was hoping, but still a lot of weight I can ditch.
And also - managed to have a few decent crashes already. Into the bricks in my yard, into the wall of our office, off the floor of our office...so far the PLA frame has held up better than I expected with no damage!
So tonight hopefully I'll have time to move this to a slightly smaller frame, clean up the wires and RX, then get some packs charged, add the FPV gear and rip up my backyard if all goes well! Guess I should try and get my DVR working too now....