hey again all! I thought it would be cool to have a dedicated thread for guys who build bigger hex and octocopters with apm where we can share tips and advice regarding tech specs, builds, code, firmware and whatever else comes up.
Firstly, how many of you are building bigger AP rigs with APM? We've been building all our commercial SteadiDrone RTF kits with APM with great results.
so, who else is out there, lets get chatting.
I've just built an Octo using APM 2.5. After calibrations, i did a PID setting test (fastening a pole along one axis). The Octo is fairly stable. But i have no control over the perpendicular axis (be it roll or pitch). Can anyone please advice on what could be the possible errors? Thanks.
Has anyone had success programming waypoint routes into their heavy copters? I'm flying a 3kg Octo which stays in the air for 20 minutes, and it isn't navigating well. I mean it follows the waypoints roughly, but it builds up too much speed and sometimes overshoots waypoints, making crazy banked turns to get back on track.
This is my heavy custom octo, don't fly yet, but I will do soon.
It have a width of 100cm shaft to shaft and I will use 6s lipos with 400 kv motors.
What do you thing about it? Any suggestions?
P.D. Sorry for my english.
Our SteadiDrone octos are also failry over powered and most of our clients shoot tvcs and commercial stuff with SLRs which give us at least 10min flying time and as mentioned before, I've flown our octo without a motor perfectly and when we get a gap would love to test mid air motor failure. You might have also seen us flip/loop our big octo :) Soon I will do this with fully loaded camera gimbal :)
We've just gotten the new sony cx760 and are speechless, the video stab is just something else, here is the vry first flight outside our building with hour smaller SteadiDrone H6X, av200 gimbal and the Sony CX760, this is NOT post stabilized and straigt out of camera. We are doing a bit of a roadtrip this weekend and will have plenty of stuff to post when we get back next week, keep your eyes on our SteadiDrone website and also our Facebook page, https://www.facebook.com/SteadiDrone
Heres that video
First Flight - SteadiDrone H6X with Sony CX760 from Motion Pixel on Vimeo.
Now trying to get back on track of my desired Octo machine:
For me, the only reason to build an Octo is to gain the advantage of redundancy. I want something that will not fall from the sky if it loses a motor. I think part of the problem here is as I say, people are building Octos with the theoretical benefit of redundancy, but then they also take advantage of the payload, and install massive cameras and gimbals. The result is that, regardless of who's flight controller they use, if you lose one motor, you effectively lose 25% of your thrust, not just 12%. I think the design MUST plan for this, and ensure that you have sufficient reserve thrust that the flight controller has a reasonable chance of controlling it.
So, I think the power specification must result in an "overpowered" octo. This isn't great for efficiency, but it's necessary for redundancy. You're going to have to chose here. In my case, I choose redundancy. I simply can't consciously put an expensive camera up in the sky if the darn thing will fall because one of 16 single points of failure can cause it to crash.
I prefer an X8 platform over a flat Octo, because I have heard that they simply do better in the wind. I find my quad is bad enough in even a light wind, I don't want to make it worse by going with a flat Octo. And of the frames I've looked at, I prefer the CarbonCore X8 650. Simply put, I think square arms are better, because it avoids all the complexity of round tubing adaptors. Weight is 650g.
I also know I want to use 4S 5000 batteries, because I already have a lot for my heli.
And obviously I'm going to use an APM. ;)
I want to lift cameras ranging from a lightweight P&S such as the Sony WX10, which is only 162g. Up to a Nex5N which weighs 465g. I'm not sure how much weight to add for the gimbal, I'm assuming the whole thing will come to 1kg with the camera. I'm not sure this is enough, realistically, for the Nex5 though? A Photohigher AV130 is 410g without pan, which I'm undecided on wanting pan at this point.
But the power system I'm not sure about. I'm using Ecalc, and looking at something like the Turnigy Propdrive 2830-750 with 12x4.5 props. Ecalc says that with an empty frame weight of 1800g, it will fly with only 49% throttle. Good. Now I do a check, and reduce it to 6 motors, but add the weight of the dead motors back in. It says 64% throttle. That sounds great. Too good to be true. Am I missing something?
Realistically, I'd probably get the 2836 motors and have even more power. Very little cost/weight penalty.
But I just can't get past the idea that these motors just "seem" too small for what I want to do. So any input would be appreciated.
Interestingly, I just watched that video about National Geographic's camera systems they use. They have an Octo they've spent a lot of time and money on. But, they showed a video clip where they lost a motor and... it crashed. I wonder what their system specs are? Which FC? Etc.
To me, if your Octo is going to crash anyway, you might as well just build a quad with BIG motors, so you have half as many failure points.
two words, 'APC props' they are by far the most reliable and strong props, we've never ever broken a single prop or had any trouble mid air (apart from the odd prop broken due to HUGE crashes)
APC, the best.
Bumping this back up...
So I was looking at getting an Octocopter because of the redundancy, being able to stay in the air and not crash if a motor or ESC failed. For aerial photography obviously.
But then I recently heard that staying alive with a lost motor is not guaranteed. Apparently the DJI units crash anyway. But Mikrokopter can survive.
Does anybody have any example of Arducopter Octos being able to fly with a motor failure?
Hey again all you BIG drone fliers :) Just a quick update on our SteadiDrone airframes and full RTF kits, our airframe range is now available on CANADA DRONES as well! if there are other stores interested in reselling these really high-end but affordable frames let us know, any time.
Here are a few pics of the latest tweaks we;ve made as follows:
New quick release motor arm system, we got rid of the 3 pin bullet plug system and have developed a great new mount system that allows the arms to still very quicly and easily be removed and then dropped down to fit in a carry case, ( we use the pelican 0340 and 0350 cube cases. It takes maybe two minutes from in the case to setup and ready to flyl!
We've also made a new bottom plate (and removed the top plate) and all the ESC controllers now sit under the airframe, covered by the ESC plate, this gives up better staillity with the weight sitting lower, it shortens the + and ground power lines from each ESC A LOT but most importantly it gets the APM/GPS much further away from the EMI from the esc, our rsults are amazing, the smoothest raft I've ever flown.
Oh and it still looks AMAZING! :)
Here are some images. Please go check out the SteadiDrone wbsite www.steadidrone.com
Any feedback and comments welcome, i would also like to se other frame designs you guys are building.
oh yes, the landing gear for the H6X also simply pulls out for very quick setup and remove for traveling.
You mentioned that you use an APM2 as a standalone gimbal controller. Are you getting good results with it? Do you happen to know that the output rate is from the controller to the servos? I have found that there aren't many tuning options with the gimbal controls. Have you modified the code at all?