Hey guys - Kind of a newbie to the whole MK and flying thing. I have a standard CS8 (from Quadrocopter) with a 2-axis gimbal with a GoPro mounted and 2 Quadropower 6200 batteries that I fly around. I have been flying it around twice a day for about a month now, and (knock on wood) haven't had a crash yet. I am slowly learning to read the GPX file, but I'm far from understanding it all. Could someone please take a look at this attached GPX file and tell me what's wrong and what I should do to improve? It's from a short flight I did today, nothing special, used both manual and assisted flying (AH, PH). Personally, I prefer manual mode over assisted. I only place it in AH and PH if I plan on doing a 360 panorama or something of that nature (I'm not good enough at flying to where I would feel comfortable rotating the bird all in manual). The one thing that worries me is obviously the temperature of the motors and BLs. And some of them are much higher than the others, which I assume is a balancing issue. Thank you in advance for your comments.
A few comments. It looks like you're flying in a residential neighborhood. I strongly suggest that you find a park or other open space. It's far too dangerous to fly in areas like that. It looks like you did a lot of hovering and just "hanging around". Motor temps will be wonky in situations like that. Yours don't look too bad, considering. Your current draws look ok, but with nothing but a GoPro, I wouldn't expect anything out of band. So get out of your backyard and go find a place to do some "nose-in" and other maneuvering practice where you don't have to worry about landing in your neighbor's swimming pool.
Steve - Thank you for your response. I'm glad to hear that from that little test nothing looks out of the ordinary. As for getting out of my back yard, I'm working on it. Been trying to find a place nearby, but the closest flying park I found is about half hour away. Thank you again.
I'd avoid flying parks. Any neighborhood park will work. I prefer baseball fields, as they're typically empty during the day as the youngins are in school. Or, conversely, a school yard is often a good place on the weekends.
By the looks of the current draws, your copter seems well balanced. My concern is with the BL temps on motors 3 and 5 are slightly higher for such a low current draw. Normal day about 75F outside I do not get to 190 on BL's unless I am carrying a heavy camera and running 12 to 14 amps per motor. If it was a hot day high 80's or 90's that would explain it, but if you are only flying a gopro now, you might expect over temping of the BL's if you are carrying a larger camera. I would suspect though that you might have some cold solder joints on the BL's causing them to heat up. Shaun
Shaun, That's kinda what I figured. I'm supposed to get the parts for an FPV system tomorrow, so while installing that I plan on re-soldering all the motors nice and clean, and also check for anything else that may look out of whack. I also plan on installing aluminum coolers on the BLs, that should keep the temperature down a bit. I also did another flight today in which I experimented with the CH mode for the first time. I'm attaching the GPX file for today's flight, in case anyone has time to take a look and see any other anomalies. (Steve, I took your advice and went far away from the back yard this time)
Important thing is to keep the heat on the wire long enough to allow it to flow then release by precisely holding down. Another mistake I have seen is people unsheathe too much of the motor leads on the BL allowing for exposed wire which can potentially lead to shorts, and have completely damaged an entire BL and lost a motor in flight. I like to pre-tin all of my wires to bind the frays together as well as allow for a better electrical bond to the board.
Hey Guys, wondering if you could take a quick look at this and comment. Not sure about the compass interference, and BL 6 seems a bit hot, but not sure if it's anything to worry about: MK Version: FC HW:2.1 SW:0.88n + NC HW:2.0 SW:0.28n Flight date: 07/05/2013 1:42:34 PM Flight time: 1:42:34 PM - 1:45:15 PM (161 secs, 00:02:41) Batt. time : 162 secs, 00:02:42 Elevation(GPS) : 0.424 8.66 20.41 m (min/avg/max) Altitude(Barom.): -1.55 6.74 17.6 m Vertical speed : -1.9 -0.01 1.3 m/s Max speed : 27.4 km/h Max target dist.: 0 m Sats : 9 9 10 Voltage : min. 14.2, max. 15.5 V Current : 36.1 61 75.5 A Wattage : 531 902 1072.1 W Capacity: 2783 mAh Motor1: 4.5 6.8 10.6 A Temp: 32 43 53 °C Motor2: 3.4 5.7 8.8 A Temp: 31 41 50 °C Motor3: 0.5 4.8 7.5 A Temp: 26 38 43 °C Motor4: 0.7 8.1 12.2 A Temp: 30 46 53 °C Motor5: 0.8 7.9 10.5 A Temp: 33 55 67 °C Motor6: 1.3 10.9 13.8 A Temp: 37 66 79 °C Motor7: 2.5 7.2 9.7 A Temp: 27 51 60 °C Motor8: 3.6 7.7 12.4 A Temp: 25 47 58 °C Magnet Field: 116 119 123 % <- check! Magnet Inclination: 60 67 72 deg Errors / warnings: Compass is disturbed by magnetic fields!
Andrew: 1. Can you confirm that you have done a compass calibration for the location at which you were flying? That it is the usual cause of the compass errors. 2. Motor 6 is probably working a bit harder to compensate for a motor out of alignment -- check that all the motors are indeed vertical with respect to the posts holding up the battery plate (close one eye, look at the side of the motor casing from about two feet away and verify that the side of the motor casing is parallel to the battery post -- you may have to move your head left/right a bit two bring the side of the motor casing almost into overlap with the post). This is a "quick and dirty" method of checking motor alignment that I use. Hope this helps. Andy.
Hey Andy, Thanks for this. So can I get it clear, you're doing a compass calibration for every new location you fly? Also, would a small level across the two front motor clamp screws work to level it out?
Andrew yes you could use a level but would need to level the copter first, like you do for the ACC calibration with a bubble level in the center of the battery plate. Can you send a photo of the center section of your copter showing location of the NAVI/GPS and any other antennas like video or XBee? You might also want to check on the MK screens, assuming you are using the MX20, what the declination deviation is while sitting on the ground. This is the screen. From the normal screen press the SET button for a second and the bottom line will change. The incl reading should not be more than a 10 value difference. If it is then there is metal in the ground interfering with the compass. Try moving the copter to another spot.
Andrew: Yes -- If I move more than two or three hundred yards, I would re-calibrate -- primarily because the Earth's magnetic field is so easily influenced by metal pipes, phone/power lines, metal railings, you name it. It never hurts to re-calibrate -- but it can hurt if you don't. The idea behind the leveling procedure I described is that all of the motors' thrust lines (the line that ideal runs down the centre of the prop shaft) should be pointing vertical when the battery plate is horizontal. Of course, if you're out in the field then the odds are that the battery plate will not actually be horizontal -- which is why I use the visual approach I describe -- you at least get the motors at 90 degrees (aka "normal") to the battery plate by using the battery plate posts as a visual guide. The other thing I'll also do is hover the Cinestar about six feet away from me, and bring it to eye-line, so I'm looking at the disks formed by the rotating props absolutely edge on -- you can easily see if one or more prop disks are out of alignment as the disk for a misaligned motor is canted over. Hope this helps. Andy.
Every time I fly in a new location that's more than, oh, 500 yards/meters from where I've flow before. The Earth's magnetic field is so variable given all the man-made stuff around. Andy.
No not really. All your motors look fairly nominal. The temperature looks consistent with the current draw. 6 is running a little higher than the rest, but nothing to send alarm bells off at the moment. You will want to monitor it and see how it is doing under heavy loads. The BL's will heat up if the copter is in a stagnant hover. Nothing looks too out of the ordinary. I get alarm bell if I see one motor running significantly different than the rest, i.e 7 motors have an average current of 12A and on motor is only pulling 5 for example. Or if an entire set is such as the ODDS are running higher than the evens. In your case they all seem to be fine, but again keep an eye on it. Shaun
What do you consider as your max OK temp for the ESC then? ... like on a hot day with a heavy load - the temp where you call it quits.
Tyler: When the BL-Ctrl hits 100C it starts to throttle back the amount of power it outputs to the motor. There's no hard and fast rule for when a BL-Ctrl will hit 100C -- it's a combination of ambient temperature, payload, and how much time the bird is spending in a hover (which has minimal airflow across the MOSFETs (power transistors) on the BL-Ctril). You might want to install heat sinks to increase the amount of heat the MOSFETs can dissipate. http://www.quadrocopter.com/Aluminum-ESC-Cooler-for-MK_p_324.html Hope this helps Andy.
Thanks for the thoughts. My board already has heat sinks actually (Aerodrive). The guy I bought it from (the dealer here) suggested a max temp of 80degrees. I'll stick to that for now. That is why I was questioning the temps written above and what other's use as their limit (and why). I suppose it depends on the board and how it is cooled as well.
There are several factors, such as OAT, payload weight and whether the copter is in a constant hover in one spot. If you climb to a high altitude you will expect the temps to be higher while in the climb. Just some things to consider.