I just got my CX20 yesterday, I have been reading up on all the details and quirks so I was ready for it's arrival. I did a complete inspection of the interior components (ensuring I had disconnected the magnetometer in the mast). Everything is secure and in it's proper position. all solder connections seem sound. APM and GPS are in place and secure (they are mounting the GPS on the opposite side from the USB now). I reassembled everything and reconnected the Mag. Checked the propellers for balance. By this tiem the stock battery on the stock charger was completely charged. I updated the firmware and made sure it knew where home is in the Mission Planner software, as well as did a full calibration of accelerometers, Mag and transmitter. Propellers on their proper arms. All set to go.
Ok time to fly. I take the unit outside. connect the battery, switch on the TX. The system binds as it should. Everything seems good. I have a solid green (Sats visible). I unlock the motors and try to take off. the moment the throttle leaves the full off position, the motors kick in at moderate revs, not enough for liftoff but flattening the grass. The unit leans forward so i pull back on the cyclic (right stick) to compensate.
As i rev to max throttle, there is not difference in the RPM of the motors. At 0 throttle it is off, at 1% and up it is at a fast idle, not enough to take off. If i move the cyclic, i can rock it side to side and front to back, but it doesn't have the power to liftoff. similar to and ICE with the choke applied.
I have gone through every permutation of the calibration routines from the incorrect factory ones to the ones used by people who fly this unit successfully many times over.
I tried the all at once ESC calibration but this seems to not be the APM that works with that method. The only thing I can think of is doing a manual 'one at a time' ESC calibration but at this moment I am waiting for word back from the supplier.
I have been waiting for a while for this to show up and now I am waiting with the thing right in front of me. it's pretty frustrating as you can imagine. Great weather and I can't fly it. FPV and telemetry gear on the way for it. ARG!
If anyone has some good suggestions, i am VERY eager to try them. Flying the little Walkera and the Syma is getting old.
Replies
Hi,
I know it is a very old post, but I appreciate if you could shed a little light on the fix. I have tried so many different methods but I could not fix it! When you are saying to use "USB" , "Without Plugging the battery" for "full calibration and setup", What do you mean by the "full calibration and setup"? Do you mean the "Mission planner Wizard" calibration and setup? If that is the case, How can I connect it to mission planner when the battery is not plugged, it does not allow that! Should I open the cover and connect the USB directly to the flight controller chip? (unplug the USB already there and connect mine directly?)
Or there is another calibration you are talking about, like the esc calibration?
I really appreciate your help.
Rob Nielsen said:
I just used whatever was most current on the Mission Planner software. I actually sold my 2 CX-20s off. a little while ago. I have been running a home built 550mm running AMP Mega, and I am preparing to build a really big (1500mm) offset coaxial octo with a Pixhawk FC and full sensor array.
Back to the CX20's though. I had a problem once with 'position hold' of as i called it the "Stay' Command. I tried it from a fairly stable hover and it made a mad dash for the roof of my house. I have not trusted the automated systems much since then and almost exclusively flew in manual mode. One of the few times I tempted fate with the automatic systems was when I negligently let it get a little too far and high for me to keep orientation. I flipped to headless mode but was still not sure it was doing what I wanted so I switched to 'Heel' mode (RTL) and when it was close enough that I could determine it's direction, I flipped back to manual.
On my 550 (and WILL be also on my BIG build) I have of course a 3D gimbal for HD filming, but I also like a basic fixed FPV camera (I have the telemetry on that one's display. If I lose orientation of if i accidentally lose visual contact....I can see where I am going and recover)
My ground station has 2 screens PLUS my laptop so multiple redundancy.
FYI, I was having an issued with my 550 going into LOC and then RTL after 3-5 minutes (unfortunately a tree was in it's path before RTL engaged) and after much testing, yes, motors were turning props that were a little too big for them (only a problem when all the toys are added) but the power sensor moduleseemed to have developed a flaw and was gravely overheating. upon landing, it barely touched the back of my finger for a split second and I had a huge blister/burn. It was almost glowing. THAT was causing the LOC and RTL. So the automated systems DO work, I am just not 100% on trusting them on the CX 20 in particular.
I hope that helps a bit at least somewhat.
Interesting. Thanks for posting the fix. I had the same problem but found a throttle limit sitting at 100 that should have been at 1000.
I do have a copy of the factory params that I found online. Not sure how current they are but they fixed my unlocking problem.
Can you tell me which version of firmware you're running and if you're having any trouble with hover, alt-hold or RTL? I'm dying to try a planned mission but at the moment I can't get past some erratic behavior in those modes and it if can't even hover properly I sure as hell aren't sending it on an away mission.
Yes, the problem is amazingly simple yet annoying. Do a full calibration and setup WITHOUT plugging in the battery. It will beep at you and you will be on the verge of wanting to fling it. After the full initial setup, power down and disconnect, after that do it all over again and you should be fine. The batter plugged in apparently hold some old data and prevents it from getting configged
yes, through the USB, it should be the ONLY think plugged in for the first pass at calibration.