Hey Guys, First I want to say this doesn't really have much to do with anything FreeFly builds so if it gets removed I understand. It's mainly to inform people of the awesome products from KDE and Herkules for their electronics in this build. Recently I started rebuilding our SynDrones X8HL frame into a bigger heavylift rig. I had built it once already with the A2 FC, KDE 4014-380KV motors, and KDE 55+Amp ESCs but the A2 failed and caused a crash. I decided to rebuild without using the A2 and went back to the trusted MikroKopter FC which I have been flying on our smaller Cinestar 8 frame for over 2 years without an issue. Here are the specs for the new build: -SynDrones X8HL Frame (best frame out there honestly)! -Mikrokopter 2.5FC w/Navi Ctrl and GPS -Herkules III Quadro XL (x2) ESC system -KDE 5215-435KV motors -T-Motor 18x6.1 CF Props Here are some pictures from the build. These motors are HUGE! I had to modify the motor mount slightly so the hole on the bottom would clear the screw that helps hold the shaft collar on. I don't have the large motor mounts for the frame since originally I was just using the 4014s. Because I am using 2 of the Herkules boards I have 4 power leads coming out of them. I only am flying with 2 batteries so I merged them together so I have the each battery power both boards. To do this I used 2x 5mm bullet connectors and soldered a power lead from each board into the LONG end. Then I soldered them together with a single wire coming out from the connectors and heatshrank it all together. I stacked the boards ontop of each other and the way they are wired to the motors the top board powers all the top motors and the bottom powers the bottom motors. With the mixer setup If I loose one board inflight I loose the top or bottom motors and not 2 motors on one boom. I think with the total weight I will be flying it should fly on 4 motors! I will be testing this soon. **Side note, Herkules does offer a Octo XL board which has 2 quad power boards mounted to one heatsink. Because I live in Phoenix and have to fly in really hot weather I opted for 2 Quadro XL boards so I had 2 heatsinks which will keep things cooler. Here it is completed just before the maiden. I love how clean of a setup this is with the Herkules boards! During my initial motor tests I was getting a very strange sound coming from the motors. Here is a video to show what it was doing: [video=youtube_share;_uHIrGDqU8g] This concerned me as I had never heard this before. I sent an email to both Andreas from Herkules and Patrick from KDE to get their opinion. Andreas emailed me back first saying this was normal and was because of the "Active Freewheeling" feature of the Herkules boards. He noted that once you add the props to the motors so there is a load on them it would go away. I added the props and sure enough it sounds normal again. For those of you who are not familiar with the "Active Freewheeling" here is the description from Herkules website: "This is a method to dramatically reduce the power loss of the power MOSFETs. Another positive is that the ESC can decelerate the motor actively by directing current back to the battery (regenerative braking). With AFW ON, the motor reaction time to setpoint changes is reduced and the multicopter flight control loop gets faster and more stable." Today I received an email from Patrick at KDE and he wasn't sure of the sound. Once I explained to him what it was he said it made sense. By default the Herkules ESC system comes with the timing set to 18*. Because of the high-pole count of the 5215 motors I changed it to 24*. I also had to program the ESCs so they had the correct motor address that the Mikrokopter FC could understand. After that it was time for the maiden. The first flight I did without any payload. It was just the copter and 2x 10,000mAh 6s batteries from Tattu. Ambient outside temp was 100*F and around 50% humidity. I hovered around for a few minutes to ensure how it was flying. With the initial PID settings on the MK FC (P110, I120, D10, Gyro-Comp: 55, Gyro Stability 5) the copter was flying beautifully! I flew around for 15 1/2 minutes and used 17,000mAh out of the 20,000 total. Motors weren't any warmer then what they were just sitting in the sun before the flight and the Herkules boards never went above 50*C. This was mostly hovering around with a few, almost full throttle, climbs. This thing climbs like CRAZY! After that test I decided to load it up with more weight then I would probably be flying. I added 16.5lbs of payload and took off. Total AUW was 34lbs with the 2x 10,000mAh 6s lipos. The way the payload was strapped on made the copter unbalanced, as you can see in the picture, and wasn't supported well so it swung around a lot. Because of this I only hovered and didn't do any movements. I stayed in a hover about 10ft off the ground for 5 1/2 minutes. There was no wind and no airflow over the motors or Herkules boards. Even at this weight and with the ambient temperature now around 105*F the Herkules boards didn't go above 80*C. This was only on 2 motors since it was off balance. The rest of them were around the 65*C mark with an average for all at 68*C! This made me VERY HAPPY as I haven't been able to fly anything heavy before without risking them overheating. Total current draw was 146-150amps. I have full telemetry just like I would if I was using the MK BLs. I'll post up a log file for you guys to see. I'm using the Graupner MZ-24 which also allows me to receive all the data back to my transmitter. I will be doing more tests in the next few days. We just had a crazy storm come through so I couldn't fly today but I will be flying tomorrow and doing more tests. Overall I am EXTREMELY happy with how the rig is performing. I will update this thread with more info as I test. Josh
Super interesting, Josh. Do you have any sense of the power consumption from the heavy configuration? It'd be good to know that in relation to the stated capacity of those ESCs.
Hmm. I'm still not seeing them. I'm on a MacBook air using Chrome. Is anyone else seeing just small rectangles in place of the images? Andy.
Data Log from the 16lb payload test: Flight date: 9/6/2014 12:20:21 PM Flight time: 12:20:21 PM.8 - 12:25:58 PM.2 Duration : 336 secs, 00:05:36 Batt. time : 334 secs, 00:05:34 Start Location : +33.3126244 / -111.8922990 @354.8m Elevation(GPS) : -0.006 4.42 6.895 m (min/avg/max) GPS alt. (raw) : 354.811 358 361.712 m Altitude(Barom.): -0.15 4.52 6.9 m Vertical speed : -0.69 -0.01 0.85 m/s Max speed : 5 km/h Max target dist.: 0 m Max distance/LOS: 9.8 m / 11 m Sats : 10 10 11 Voltage : min. 21.4, max. 24.9 V Current : 0.5 127 169.3 A Wattage : 11 2846 3809.55 W Capacity: 11658 mAh Motor1: 0.0 18.0 25.1 A Temp: 41 61 71 °C Motor2: 1.2 16.9 24.1 A Temp: 42 63 69 °C Motor3: 1.4 13.9 23.6 A Temp: 40 61 69 °C Motor4: 0.5 15.4 24.9 A Temp: 42 61 69 °C Motor5: 0.0 16.0 24.1 A Temp: 40 68 80 °C Motor6: 1.4 14.4 23.6 A Temp: 40 66 76 °C Motor7: 0.0 15.8 25.3 A Temp: 40 69 81 °C Motor8: 0.0 14.5 25.1 A Temp: 41 69 81 °C Magnet Field: 99 105 114 % (ok) Magnet Inclination: 42 45 59 deg Errors / warnings: Error "no MK3Mag communication" (4) occured 5 times! FC-Flag "LowBat" (5) occured 387 times! That Mag Error only happened right at the end when I unplugged the batteries. It didn't occur during flight. Josh
Josh, that's of some concern. Those current numbers are awfully close to the stated max for the ESCs (30A continuous/60A burst). I'm not sure that inspires confidence with the kind of payload you're targeting. Wouldn't you be better off with something like the new KDE 55A or 75A ESCs? I know you lose the nice data reporting, but you gain a considerably higher current ceiling, as well as having the security of discrete, separated ESCs. If one fails, it can be replaced. The Herkules III Quadro XL (x2) ESC system has some of the same liabilities of the MikroKopter all-in-one BL-CTRL 3.0 boards. The KDE 75A ESCs quote a 75A continuous/135A max current rating (3300W continuous per motor!). Oh, and a max RPM of 240,000. That's super helpful... http://www.kdedirect.com/KDEXFUAS75HV.html
I really am not worried about it since the average is 1/2 of what the continuous is rated for. The Max Amps are when I punched it slightly and they are still under the 30A continuous and way under the 60 amp max. This was with a lot more payload than I normally will be flying anyway. I just did a flight with my camera setup and it was way below that data file in terms of amps and temp. I unfortunately forgot to put the SD card back in so I don't have a log. I'll go out and do another flight this afternoon though and see what it says. Temp wise on this last flight I was only seeing mid to high 50's. Josh
I see a max amp of 169.3 in Josh's log file. That's 21.25amps per motor. Average was 15.87amps. Can you better explain your concern Steve?
I see max current draws of 25A on a couple motors, and if the copter were to lose a motor, it might push one or more ESCs over the edge. But I'm paranoid.
Steve that's the max current which is still under the 60 amp max. Also talking with Andreas from Herkules he says it can handle the 60 amps for up to 20 seconds. I am not worried at all about overloading the controllers. Temperature wise it's still well within limits too. I've also never heard of a herkules board catching fire. Josh
HI Josh Thanks for taking the time for the detailed writeup. You always seem to be on the leading edge of heavy lifters. I'll be curious to see how everything turns out after about 20 flights. I know Ozkan Erden was having issues with a very similar setup as you as he was reporting shaking problems. This could issue could be unrelated to the hercules setup but please keep us up to date. I do have a couple questions for you. What camera do you normally fly? Why do you think the Syndrones frame is that much better? I have not been able to see one in person. Dave
Steve Interesting comment, are you asking why not use the I2C converter? I have thought about switching to that setup a lot over the past year and every time I revisit it I find reasons not to. I have talked to a few people that have used this setup (including some people that worked at QC) and some have experienced intermittant yaw issues as well as it being less efficient with a loss in overall power which kind of puts you back to square one trying to make a system work around its flaws (higher powered motors for the needed payload) which results in lower flight times. On the other hand I think Howard swears by the setup which kind of makes you wonder.
Thanks for the detailed report Josh. Since I'm building exactly the same system, except the frame, we should come up with the same results. I tried Herkules III with KDE 4014XF, for those who are interesed, can read my report here: http://forum.freeflysystems.com/ind...fc-2-5me-kde-4014xf-18-props.5046/#post-52019 Initially the bird was flying perfectly but then something I can't explain happened, it started to shake. I will test the copter with new motors again this weekend.
Hey Dave, I have done flights now without any payload and it flew perfectly. I then did the 16lb payload test and it also flew perfectly (no retuning), then yesterday I did the first flight with the copter setup exactly how I would on a shoot, M5 with camera and it still flew perfectly. Today I will be going to a buddies and testing it with the EPIC. I'll report back on that. Here are a few pictures from yesterday's test: Since it was the first test with the gimbal I didn't raise the landing gear... just incase. I'll post the video up later today (which has the landing gear in there the entire time but oh well. As for your question to why the SynDrones frame is so much better, without going into too much detail since I'm not here to bash anything FreeFly makes, it's just stronger. Like ridiculously stronger. With full load, batteries, gimbal, and camera, you can pick it up from two arms way out to the motors and literally shake it up and down as hard as you possibly can and it doesn't flex AT ALL! The booms are twice as thick as the ones on the CS frames and the way they are mounted makes them virtually impossible to move no matter what you do. I'll post some detailed pictures of the frame if you want. My normal day-to-day camera is the Canon 1D-C w/Rokinon Cine-Glass. I will never use the I2C converter again. It worked ok in calm wind but as soon as it got windy the delay in the conversion process becomes very apparent. I spent days trying to tune the copter to fly well in the wind with no luck. It was very shaky and felt slow to respond. Also there is the issue of power loss. You had to set the max throttle in MK to 247 and even then I was flying around 60-65% throttle to get it in the air. There is also an issue with MK firmware messing with the I2C converter. I had mine flying ok for 2 years on the 1.90J firmware. Decided to update it to the latest 2.6 firmware and did a test flight. Flew fine on that one. Went and did 5 more flights than on the 6th it just started spinning like crazy. Virtually no YAW response. I had this happen on one other copter that I was working on for someone. I thought theirs was due something else but now I'm not so sure because their's too started spinning about 5-6 flights after a firmware upgrade. I have a video of that somewhere which I can post. Josh