Hey guys,
I just wanted to share with you a little about my most recent project. I've been into RC for about 20 years, and have flown everything from helicopters (gas and electric), high wing trainers, 3D, pattern, pylon racers, EPP, SPAD (who remembers that craze!), gliders, giant gas....
More recently I've really got into multi-rotors (as a platform for autopilots). My first was an AR Drone made by Parrot. Whilst this does everything you want, it's not very satisfying as it came complete (at least for me, I can fully see the appeal to others).
I started looking around for a suitable platform and that's when I stumbled across the latest 3DR offerings. It was reassuring to find a company that had been created from an opensource community and was flourishing. It was also great to see the development of the kits and the quality offered.
I ordered the kit a little over 2 weeks ago and consistently followed my order status to see when it would ship. It did say "ready" for a number of days, so I decided to follow up with 3DR to see when they expected it to be dispatched. A very polite gentleman helped me with my enquiry and I was told that it would ship in 3 days. At this point I'd already seen some of the poor reviews that some have been posting about 3DRs service so I was a little skeptical.
To my surprise (and delight), 3 days later I received a shipping notification that the kit was on its way! This came complete with the FedEx tracking number (which I would be sure to immediately punch into the tracking app on my phone and continue to look at every couple of hours for the next 2 days) :)
The kit came in a very small box and I figured there would be something missing. I was reassured to see that it was just packed extremely well and everything was intact and accounted for. Then came the build. Initially I had feared that it would take days and that I wouldn't have everything I'd need. To the compliment of 3DR, the build only took 4 hours (from opening the box to firing up the motors etc). The instructions were extensive and the website was invaluable.
On a side note to anyone looking at purchasing one of these. Make sure you read through the website pages on the building etc before starting on the kit. There are some great tips (like not fixing down the ESCs until you test the motor direction) that if you don't follow; you may end up taking a few steps back to go forward.
All in all I've been really happy with the build (although routing the wires and mounting the ESCs were a pain). It all worked well. I'm sure there is a better way to route/attach the ESCs so if anyone has any suggestions I would love to hear them.
The copter is ready to go and I just need to wait for my battery to arrive and it will be good to fly. I've set it all up on an old 2.2Ah 3s but it doesn't have enough punch to get it off the ground (it's a really old abused battery). I have a 4.5Ah A-Spec Turnigy NanoTech battery on the way that should do the trick :)
I did try with the old 3s but at max throttle, the battery voltage dropped to 9.9V @40A and it was going no where!
I'm using a Hitec Aurora 9 as it is the most flexible when it comes to channel assignment. Getting the 6 modes was a little bit of a pain but a small science experiment soon resolved that issue. I also have a lightweight CF roll/tilt camera mount with a 900Mhz video transmitter to fit. I want to take it step by step so once I'm comfortable with the flying characteristics and modes, I'll strap on the camera really have some fun :)
There's a few more photos in the album below if anyone is interested.
On a final note, I've been playing with autopilots for the last 9 years and I have to say that the maturity and quality of the ArduPilot (including the excellent ground station), is the best I have found so far. I have a background in electronics and software and understand just how much work has gone into a product like this.
So... A big thanks to the community, keep it up guys! I'm really hoping to get some more free time soon and begin to contribute.
Comments
OK so that still could be the case. Basically. If it is a dry solder joint (which looks likely) on one of the output connections, only two of the channels will be driving (as opposed to all 3). If this happens, the two channels will be pulling the additional current (and a bit more) to generate the same lift as if all 3 channels were working. The result is additional heat generated by these two channels which eventually kicks in the thermal overload protection... at least that is my theory.
Not Sure I understand what you mean by that?
The problem with the bullet connectors is related to the fact that in modern, PC society , we cannot use Lead based solder anymore. The tin alloy solder used in the industry has to be done RIGHT, or you will end up with dry (bad contact) joints. I have seen many bad solder joints, and being old-school, I have re-soldered all my connections with good old fashioned mil-spec Resin core lead solder.
Glad (hope so) that you have got to the bottom of your problem tho. Test it thoroughly just to make sure before attempting anything big.
Quick update. This morning I swapped over the ESCs that were driving the motors (top ESC connected to bottom and vice-versa). I tested the motors again... hey presto! Everything is now working as expected. I've not reversed the servo connections on the AMP and as soon as I can I will test stabalise mode again.
I did this to try and narrow down the issue. Just in-case it was a faulty ESC as opposed to a faulty motor. The other reason for doing this was that I had read somewhere on here that there have been a few issues with the bullet connectors and it was recommended to solder them once you had the orientation correct for the motor. Not entirely sure what the problem was (as the connectors had a solid connection), but it's great to see it working.
On another note - It looks like that previously; the reason for the Y6 dropping out of the sky after a few seconds; looked to be caused by the ESC in question thermally tripping due to the additional current the 2 sets of FETs were having to drive (as opposed to the normal 3). To make sure there were no thermal issues, I ran the copter on the ground for 5-6 minutes and measured the temperature of each motor and ESC after the run. They were all withing 5 deg F of each other. This is only a theory at present as looking through all of the telemetry logs, the ESC with the issue had the highest PWM input at the time of the failure and was still being driven as the copter descended.
After the test, one thing to note is the 2xESCs mounted at the front (on each side) were a little warmer than the rear ESCs. I supposed this is to be expected as they are stacked on top of each other. I did wonder if they would interfere with one another and had expected a little temp rise.
As I'm using a Hitec Rx/Tx, I plan to wire up the telemetry station and use the supplied thermal probes to monitor these ESCs on the next flight. Hopefully there will be no issues but we shall see.
Thank you for all of the help which aided in narrowing down where the problem was. It will provide me with subsequent checks on future builds to ensure the motors and speed controllers are working as expected before the maiden flight :)
EXACTLY what I had, and strangely enough same arm, same motor. LOL
Here's a video:
OK that was it. I managed to get access to the servo connectors so I could test each individually. That motor definitely has a start up issue which looks to be a phase down... I can't believe I didn't see it before!
I just had to re-calibrate all the throttles where I was setting up my rig (go the polarity wrong at first and messed one of the cals up). After the cal I slowly advanced the throttle and you could see plain as day that the motor is bad! I'll see if I can upload a video.
you can, but its risky, so be careful.
1. Put the copter into pass-through mode (esc calibration).
2. Hold the copter down by hand
3. Punch the throttle a few times from standstill, and see if the motor misbehaves. (Motors need to be loaded, so unfortunately the props need to stay on) (REPEAT : BE CAREFUL)
As for the paprameter file, that is a good start, you may need to do some dynamic tunig just to get it that last bit 100%. Good Luck
Love the video by the way :)
Where do I find the parameter file?
Gecko, I had Really similar symptoms that caused me MANY headaches and many props. Connect that motor & esc to a servo tester or directly into the throttle channel of an RX, and "punch" it. IOW, raise the throttle suddenly.
If it behaves anything like THIS, the motor is faulty, there is more than likely one phase down in the windings.
Have you loaded the Y6 Param file yet? night and day stability wise. Also add 25% exponential to the ELE and AIL channels on your radio.
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