So this didn’t go down exactly how I planned. I still have some maiden flight footage to work on, but I sorta fast-forwarded to problem resolution. While I will consider my maiden flight a success, I wasn’t totally out of the woods yet on this build.
My first flight went okay. Battery didn’t last long. It was cold outside. It did what it was built to do. All stock settings, and it hovered just perfect. Touched it down, went again. Okay…that’s strange. I just had a brown out of some sort. Lost all power, and the tricopter dropped to the pavement from about 6 feet. Bouncy landing gear came in handy there (see that snippet in the second video). Flew again…this time taking it up in elevation, flying around the yard…then after a couple of minutes… lost all power to the motors and she dropped like a brick…from about 30-40 feet high. There was damage.
The damage was not bad at all. I had to replace an arm and some zip ties. Everything else survived. But I definitely have a problem. One brown-out, could be a fluke. Two is a problem. I was fairly certain it wasn’t receiver-related, but I wasn’t going to rule anything out. Was it power? Was the .5A BEC powering the KK2.1 board and RX not powerful enough? Was something wrong with my motors, or ESCs? Where do I start?
Well…I started with the motors. I noticed that they were really stiff when I brought the tricopter in after the last crash. Maybe they were tightening up when they got warm, and sucking a bunch of amps and killing the FC power. Welcome to rabbit trail #1.
It turns out that what I was seeing with the motors was normal…for my ESCs. You see, when the power is removed, there is still a little energy stored in the FETs, and it basically creates a brake situation. After the power drains (in a couple of minutes) everything returns to normal. I also found that in all cases, as long as the battery was hooked up to the ESCs, everything was normal. BTW, I learned that if you just short all three of your motor wires (just touch them together) you get the same braking action you get when your ESC does braking. Cool, huh? So that wasn’t the issue. What next? That lead to a question of whether there was a problem with my Afro ESCs being able to handle high pole motors like my DT750s. Welcome to rabbit trail #2.
Some testing indoors this time, and I got a wonderful uncommanded backflip. What is an uncommanded backflip? It’s a backflip that I didn’t ask for. I sent out feelers for help by posting this video while I was still running down ideas on the side.
Troubleshooting some gremlins. Take a look and see if you see something I may be missing. Right now, I am rebuilding the body to remove the ESCs from the inside. My thoughts are that they are overheating in their current location (between the body panels). I’ll test them outside of the body, and if the problem disappears, then well, I’ll know.
So, it wasn’t long after posting that video that I finally figured out what was going on. Before, I seemed to loose all three motors at once. This last time, I only lost one…the center one. My ESC for that motor was in the very middle of the body. Was it a problem with my ESCs overheating, and this time the middle one went first? The only way to know for sure was to get them out of the body and test again.
So I did. Making no other changes than attaching the ESCs to the arms, and she flies perfect now! This last video sorta wraps it up, and shows off the new look.
Well…super short and sweet. BLUF: I relocated the ESCs to the arms, and she flies great now. Several batteries through, without any hiccups. This is all stock settings on the Steveis 2.1V1.11S2 firmware. Tuning to come soon…
Oh…and the coolest part… I played “pass the transmitter” with my son and the new tricopter. He really liked it. I controlled the left stick, and I let him take over the right. With self level…he could just move it around and there was no worry about it tipping!
I really liked the clean look with the ESCs hidden in the body, but in the end it didn’t work out for me. That’s the risk you take when you try something new. Remember, this design started from 2D and 3D modeling. I didn’t want to build someone else’s tricopter. Sure, I used design ideas from those before me. I would be stupid not to. But, the body design was 100% original. I was really hoping to hide those ESCs. Oh well. Now that it is changed, I like that the wiring harness is in there. Actually, I have come to prefer this new look. The octopus of wires that is the harness was unsightly before. I never figured out how to hide it. That was going to be my next project. Problem solved.
Anyway…thanks to those of you who stuck with me, offered me help and advice, or even just your condolences as I was working through this. I now can safely say the CPO 135° Tricopter is a reality!
Now I need to get the GoPro mounted, and get her all tuned up!
Until next time….