I am jumping ship from the MK stuff, in order to do a heavy lift on new Cinestar Frame. I am building a Coax X8 with MN4014's, freely motor distro system. I have an idea where to put all of the DJI components. Looking for DJI setup pictures on the CS frame to see if someone has done something better than what I am thinking. My thought is to put a 40x40mm a carbon-fiber plate above the FF PDB in the place where the MK FC would have gone. This is where I will mount the IMU to the A/C. I plan on mounting the GPS/Compass dome on a small boom that would have been where the tail boom that would have been motor 5 boom on a flat8+ config. I will need to find some arbitrary place to put the Main controller that is convenient, probably adjacent to the IMU somewhere. One question for the WKM folks. Will the rubber standoffs be sufficient for vibe isolation? Or will I need to use the mounting block for vibration isolation on the IMU. I have the parts on there way sans motors since QC only has 4 in stock. If anyone sees any issues or has a better way to do it, please chime in. Shaun
Shaun according to the DJI site the new IMU in the A2 system can be directly attached to the frame. Take a look at the specs and manual. For mounting try one of these or similar from AGL Hobbies http://www.shop.aglhobbiesllc.com/Frame-Spare-Parts/UAP1-Standard-FC-Plate.html
I build a HL quad, 10lb bird with 30lbs of thrust, using a wookong and I mounted the FC right to the bird with no dampening at all. Work perfectly, you just need to make sure your props and motors are balanced and there's no vibes coming from them, which you should do anyway. If you need to out vibration dampening for the wookong to make it work properly you have bigger issues to fix.
Gary Thanks for the link I was looking for something like that it will help put all the pieces together without looking like a hogepodge mess. I decided not to go with the A2, which sucks. But standard DJI fashion looks like they released another "beta" with a bunch of bugs in it. So I am going with the good ole WKM board, since this one been vetted for a while. In fact the manual looks incomplete for the A2. You are correct it can be mounted to the frame with just standard 3M type tape. For some reason I was thinking it needed a foam block like what APM uses. Shaun
Paul Thanks for the info. I understand the standard Multi-rotor 101 stuff like balancing props etc, and center of gravity. I do have a question. How fickle is this autopilot to CG changes. I read that you have dial in changes to weight configurations is this only made if a major change is done? Shaun
Hey Shaun, No need for the foam or dampener for the IMU... actually that's a huge mistake. Just 3M tape is perfect. The thin stuff not the big thick stuff. The IMU doesn't like to move or it'll make your copter crazy. We used a thin lexan sheet to mount over the big hole of the CS frame. Taller stand offs for the battery plate and you're good to go. As far as weight and CG. We use a few different 6s battery combinations.... sometimes 2 x 5400 or 2 x 4000 and never worry about the CG. Now if you're going from 2 x 4000 to 2 x 8000... then you got to worry. Good luck, brandon
Thanks for that info. I guess DJI must use a smoothing algorithm to ignore spikes in the ACC. It seems like every other autopilot I have dealt with needed foam or rubber dampers, especially my APM 2.5 on my hex thing. As for the batteries looks like I will have to see how the 4 6S quadropower 10,000s that I ordered work. My hope was to put those in parallel when carrying the GH2 that I have, to see if I can get some awesome flight times. With larger cameras like RED's I will most likely have to go with a single battery for weight. I am doing a Coax with the standard 450 booms (4 off of the current aircraft, its going to be a coax also) and 16 inch props to start. My order cant come soon enough Shaun
Shaun you may find that a single battery with the heavier load will put hear stress on the battery, connectors and cables.
Thats possible for sure, I cant imagine the stress being anywhere near the stress on a single 4S battery carrying a heavy camera on the standard rig. Of course I will be doing some tests to see what the best results are. I may go with twin 5000's for heavier loads. I noticed that with my current rig, the batteries that seemed to not like flying as a single one were the 6200's. because 155A was the continuous discharge rate. With these 10K's I should in theory have 250A continuous so I should be no where that current draw with the higher torque motors.
I run dual 8000 6s with my coax octa and get 10 min flight time with the red, also have dual 5000 i fly sometimes which also work great.
What motors and props are you using? I purchased 8 Tiger Mn4014-11's and I am thinking on Xoar 16X8's.
Thanks, Looking at the comparisons looks like yours might be a little bit more efficient than mine. 4014's have an internal resistance of 85mOhm yours are 35 mOhm, so I can probably expect to loose some energy in the motor winding's. I guess I will have to see as soon as my motor mounts and props come in.