**UPDATE/CRAZY EXPERIENCE***
I wish these flight controllers weren't sold out/back-ordered everywhere... I want to order a couple more for some backup builds.
Key Word:
Backup.
Yes, something happened to the quad already.
I want to first recap on the build, outline the general scope of what was going on before the incident, and still trying to figure out what caused the issue, and what I can do to prevent every pilot's nightmare from happening again.
BUILD SUMMARY
Betaflight F3 Flight Controller
First off, I absolutely love this board over anything I've used before. In chronological order, each step up having more features I've gone from
one 250 quad w/ KK2.1.5,
two 250 quads w/ CC3D running OpenPilot, then recently i was flying a 180 and a 250 quad both w/ Naze32 Rev. 5 running CleanFlight.
Since the Naze32 Rev. 5 i bought around September '16, I wasn't quite keeping up with the newest tech in the hobby, as I wasn't able to afford a pretty decent build at the time. After some research, and luckily getting my hands on one before they sold out, this
Betaflight F3 Flight Controller pretty much takes everything I used before, and kicks it to the curb. Having so much packed into the form factor of a small FC is such a huge plus, time saver, packing an amazing amount of benefits over any other boards I've used in the past.
I haven't messed with Kiss or any others yet, I'm still looking into them and doing research before I bounce on them.
Flight Characteristics
With the F3, I ran
Lumenier Silk 32bit 30A ESC's running
BLHeli_S, their own exclusive firmware, and
Dshot600 (which is also a game-changer, since last September, OneShot125 was the latest protocol I knew about) felt way more locked in compared to anything I've flown before, and and the response was way faster.
However, I gambled on the PIDs before I even flew it, which is kind of risky... but the results were surprising:
Liftoff, an FPV simulator that I practice on ~2-4 hrs/day (2nd shift woes... and no daylight only fly on weekends), now utilizes Betaflight's PID loops, and now has updated physics, dynamic changes in flight characteristics based on weight calculation of your model from the components you choose, motors, props, etc... The best it can get for any multirotor simulator out there right now, especially since I also use my DX6 as a controller through the trainer port to my Pc's microphone jack (ask if you need any tips, pretty easy)... so the muscle memory and practice translates to the field very well in my opinion, and I'm not sugar coating that one bit.
I created a model that used a damn near identical setup to what I built... frame style and size, weight, props, motors, battery... I fine-tuned my PIDs in the simulator for HOURS until it flew perfect, flew it about 25 hours or so...THEN copied all the PIDS to my "real-life" quad in Betaflight, and took it for a maiden.
Butter smooth, and very responsive, almost identical accuracy in maneuvers, except that this new build was WAY more locked in. Blew my mind...
...for the whopping
1m 39s it flew. I landed it at 3.7v per cell, after seeing ~15.1v on my OSD. Way too short of a flight time for my liking. I started looking into ways to cut down on the weight, or increase efficiency without sacrificing too much performance.
What led to a near-heart attack...
For more efficiency, I couldn't really shave much weight off the quad even with different components, I'd only save maybe in the 25g ballpark, as it was already built as tidy as I could.
I was running
HQ 5x4.5 Bullnose two bladed props to start out, but really wanted to run some decent tri-blades, as I liked how they powered out of corners, and they had a lot more low end torque. However, i wasn't sure that my motors would be the right application for that setup, with an already abysmal flight time.
Maybe I'm chasing a false hope for this setup, but is that flight time to be expected? What flight times do you guys usually expect for a high performance or aggresive 210 quad with a GoPro?
I ended up swapping the
Emax RS2205s 2600kv motors for the
Lumenier RX2205 2400kv, as those motors have multiple advantages in this situation. They weighed about 5g less per motor, which helps...and the lower kv would help in the low end, and also handle a heavier prop. While they aren't slouchy motors by the test results, and not near as powerful as the new Emax red bottoms, they are a lot more efficient. I figured I could offset the decreased power by putting on some tri-blades...which is what I wanted to run anyways. I was hoping that the Lumenier's could put me somewhere around the 3-4min flight times.
Upon switching out the motors, I also swapped my Lemon DSMX Satellite RX (which worked perfectly fine) for a new Spektrum SPM4849 Quad Serial Race Receiver w/ Diversity, making use of the dual antennas in the DX6, for better protection against a loss of signal, which i had never experienced...
Until I went to test it out.
I mounted up the new RX with the antennae at a 90* angle from each other, out the top frame piece. Went in to Betaflight CLI:
set spek_sat_bind=9
save
bound successfully at DSMX 11ms, solid orange light as per usual
Then, back to Betaflight CLI:
set spek_sat_bind=0
save
*to my understanding, this RX has a feature called "AutoBind"... while I wasn't sure if setting the RX to bind in Betaflight was necessary or not, i figured it wouldn't hurt at the least.
Double checked all my inputs in the Receiver tab, and honestly, no placebo effect, the response and update times seemed significantly faster than with the Lemon DSMX sattelite RX. I was feeling like this was a worthy upgrade, and was getting hyped!
I drove out to my spot, doing my typical pre-flight checks... turned on the radio TX, made sure I was disarmed (aux switch) Air Mode (as per usual), correct model, everything looked good. Checked the battery voltage, then plugged it in, everything A-OK. Looked for any signs of aircraft, all clear.
Hit the arm switch, and
immediately the thing just shot up at full throttle like an Estes rocket.
I had absolutely no control whatsoever. Disarm switch did not work, and I chased after it with the radio on making sure it stayed in Disarm mode (like it helped already -___-), while trying to maintain a visual...and also trying not to $#!+ myself. I would have gotten in the car and set up my FPV goggles to track it, but I felt it was best to maintain a line of sight at this point, whileI could still see and hear it.
Soon, I couldn't hear the motors any more, from being too far away, and I thought it was a goner. It was
almost out of sight after flying for about 25 seconds or so, which seemed more like an hour... then I saw the quad change it's trajectory...it stoped climbing, slowed, and then it started falling back, as it looked like the motors seemed to have stopped.
It barreled back from "God-knows-how-far-up", and I saw it land ~700 yards away from where it took off. running quickly, and hoping that the thing didn't catch fire. As I ran, i began wondering how much of the quad is still going to be left, what all was fried, etc.
I finally recovered it. It had landed in some talll-ish grass, and just missed a set of metal bleachers at a local football stadium by about 20 feet.
-Landed almost completely flat on all four arms, right side up.
-Didn't Break a single prop.
-Flight Controller LED's still on and looked normal.
-Motors weren't hot.
-ESC's weren't hot.
-Battery was lukewarm at best, no damage.
-FPV camera was fine.
The impact from the fall and weight of the battery did however break the top plate inward on one corner, just behind the second row of standoffs from the front. It also bent all the bolts that were threaded into the aluminum standoffs on the frame about 15 degrees forward meaning it had hit at a slight angle. Barely missing the lens of the RunCam Owl Plus. The new angle actually looked kind of cool
Checked the GoPro...I I had forgot to start recording. GAHHH!!!
I'm most thankful that no one got hurt or no property was damaged. Besides that signature X Mark in the ground from the point of impact. Sorry about the grass!
I have no words for how I managed to not destroy anything but the frame...which luckily is also a limited-lifetime warrantied frame by MQC, so I filled out a warranty replacement form, 20 bucks. If that's all the damage it got, they sure have a believer, they make one hell of a frame, and they use the good hardware for sure! Any run-of-the-mill stuff would have broke for sure. No Loctite was used on any of the threads.
First thing I'm doing is setting up Failsafe before I go out again, and may as well strap the thing to a brick before I take off! Hoping it doesn't fly away with it....
However, I'm still concerned as to why this loss of signal occurred, and I would very much rather this never happen again.
Any ideas?
Thanks for spending your Saturday morning reading my story.