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.
Cool, I am one!
4.1kg (with dummy weight) hexa, Avroto 2814 770kv, 12x3.8SF, DYS flashed ESCs, 4s, APM2. Frame is Rusty's frame (G10, alum booms), which is pretty great.
I am using my APM2 that I have had since they first came out. V2.6 is amazing, but i am still tuning it up. Unfortunately, my GPS functionality is not working currently (another story), but stabilize is looking great.
My goal is to have stabilized video from the T2i, GH2 sized cameras. I am looking at a few different gimbal choices out there. And i will probably add a gimbal controller at some point as well. I definitely at the 'hobby' level ,but want pro-grade performance :)
Great! We have 1! lol, must be more out there ??
Post some pics of your build! I will do as well. What gimbals are you looking at ? Also how do you do your power distrobution ?
I'm actually just getting into the quad building world, but probably a little bit rushed with time. I need (probably) an octacopter. I have a friend who came to me (because im about the most computer literate person he knows) and wants me to build a copter for him soon to use for videography for his fishing addiction. He wants super stable and smooth shots and also needs it reliable because I will be flying it over salt water bays to film him. Any expertise greatly appreciated (or pointers to threads that could help) I've found the RTF Arduino shield/board for about $299 online. I think i want to go with this since its pre programmed (I can learn the programming later but I'm already a little experienced with c++ so I'm not too worried about having to modify code). I want to build my own aluminum square tubing frame but as far as props/esc's/motors I'm not too sure how to go about choosing these.
Can someone explain why with the Mega 1 hardware it looks like it requires two boards, but with the Mega 2 hardware it seems to be able to work just fine stand alone?
Basically because the APM2 is designed with a "clean sheet" to be as compact as possible, whereas the APM1 was closer to an Arduino architecture. The APM1 has a few features that the APM2 does not, such as built in voltage dividers, the relay, plus a bunch of space was required just to be able to mount the second board in the first place.
Duran, are you going to provide some details about your multicopter systems? There's really not much info on your website. I'm potentially going to get some money to invest in an Octo soon, so I might be in the market. I'm sort of getting tired of monkeying around with Trad Helis without any success. I've been wanting to try starting an AP business, but it's been 9 months now with not much to show for it. I'm starting to think TradHelis are just too complicated.
Anyway, just looking for more details on your system.
I made my own power harness for the 6 ESCs, sizing the wires appropiately. It's a bit hefty, but does the job. i am not a big fan of PDBs.
Hey again, sorry been pretty busy!
@ R Lefebvre, we are still slowing adding images and more info on the systems, what other info would you like to know ? Most the basic specs are there under each product, we will have videos of each system and more info images as we go.
Here are some images of our builds, I will try give some more info along with each image :)
Here's a quick shot of the octo 'ei8ht' with APM2 mounted on a soft foam, next to the Aurora 9 receiver, underneath we have the 8 40A esc controllers (we find the top sheet of carbon fibre helps with EMI)
above you can see our 'quick release' removable arms system, where the motor arms pop out easily and with only one screw, making it very fast to pack/unpack. The bullets are held by a custom plastic part and fit very well and securely with the pins from the arms.
bottom of the main airframe, you can see the esc wires that go to the bullet pin quick release mounts, very neat and also all esc wires are twisted. We have two main power cables for the two lipos and also function as a double up failsafe if one battery/connector fails.
another shot of our octo ei8ht ultra with photohigher AV200 pro 360 with retractable landing gear. The APM and rx all fit on the large and customizable control plate covered by a strong flat dome, which also helps with airflow to both APM and ESCs.
Motors we use are the T-Motor 2814-11 for our standard octo, and the 3515-15 for our bigger octos. Motor mounts we've designed to be very light weight but super strong, and very neat with a hole for the motor wires and fits directly snuglly into the 20mm carbon fibre tube and is glued in place.
Ok, all looks nice and professional.
The things I'm interested in knowing about are:
1) Serviceability - How easy it is to build and maintain, and how much maintenance it will require in service.
2) Crash Durability - How/What is going to break in a crash.
3) Vibration Damping - I do think that vibration isolating of the motors is a good idea
4) Performance - Payload, flight responsiveness and stability, flight times
So in regards to yours:
1) Looks pretty good. Very simple construction. Arms pop out for transport. I assume those are gold plated connectors? What state of assembly does it come in if we buy just a kit? Are we going to have to solder all the terminals and install them into the recepticals, etc? It looks like it would be very easy to have a few "spare" assembled arm/motor units which could be quickly changed in the field. That's great.
But the ESC access is very tight, requiring, basically full disassembly? What about airflow?
The screws which secure the arms from rotation, do they just pass through drilled holes in the tube? How will that hold up over time? I've got an airplane that uses a CF tube as a main spar, and for disassembly the two wings halves can just come out. But it is not very robust. The screw holes get bigger and bigger every time. This would be better if there was an aluminum collar in/on the tube.
2) CF is a winner here. Not only is the strength/weight high, but it also really benefits from "If it's not broken, it's not bent". Aluminum has big problem where it can bend on a light hit, but not be seen easily. But I wonder how the center hub will hold up. I'd prefer if the arms were "sacrificial" and would break before the center hub or mounting blocks. Then you just need to pop the arms out, and put a new one in. Of course, this is probably not a big issue with something like this, because hopefully you won't be crashing much.
But what are the mounting blocks made of? Plastic? I'd prefer aluminum there.
How thick are the center plates?
3) Looks like no vibration damping at all, and no ability to easily add it. I would really like to see something there.
4) Well, it doesn't look like it can get much lighter. That's for sure. Should be high performance. I do worry that you have placed the APM2 too close to the ESC/power wires. What is the mag interference like there? It's basically right on top of everything with almost zero distance.
Obviously the bullet connectors in the hub are contrary to the "no bullet connectors" idea. Any problems with them, motors falling out of sync, etc? I guess this would be less of a problem on an Octo as it won't crash necessarily.
Hey again, I will try best I can to reply to your questions :)
1) Serviceability - With the kind of shooting we do, which is mostlu film/tv we travel a lot and pack/unpack a lot as well, and the ease of use and putting this thing together is really a must for us, we just can't spend an hour or two everytime for setup, it's just pop in the arms, and fly. The only servicing we try and do is to keep it clean and dry, other that that, or a crash, there is nothing that really needs servicing.
2) Crash Durability - With ANY copter out there, if it falls from any realy hight, it's goind to break, the idea here is to not crash ;) We've tried to use lightweight yet strong parts, and after months of testing and building have found that there is no real practical need for stronger parts if they are not needed. As you mentioned aluminium tube holders would be great, but they are heavy and bend, and if you crash, they too will break, so there we might as well use a very strong but much lighter 3D printed ABS part, it's cheaper to replace but still more than strong enough for everyday use and high performance flying.
3) Vibration Damping - Again, we shoot video mostly, for film and tv and have never had any issues with vibration, by the time any vibration reaches the camera mount it's not visible at all. The APM is placed on soft foam which we find also does the best for vibriation. With the Photohigher camera gimbals we currently use they laso have vibration isolation mounts, so we\ve not yet had the need to solve this, as it's not a problem, but we are looking at a foam/rubber isolation pad under each motor on the motor mounts.
4) Performance - As our frames are pretty light and strong they perform very well, not sure if you've seen our video where we flip the octo ? Stability is super solid and there machines are very fast if you want them to be! Payloads for our normal octo ei8ht is around 2-4kg, and with our bigger motors setup, up to 8kg.
Bullets are gold plated yes, never had any issues with this, the way we have the arm fit into the bullet connector holder it can't go anywhere.
As you mention, the point is to keep things fairly modular, you can simply replace a reayd made motor arm with motor and prop already installed, or replace a ESC with the bullet mount as well. Replacing the ESC will obvioulsy entail removing the camera mount and getting under into the frame, this all depends how people setup their kits, or if you get a full RTF. You also have the option of using motors wires soldered direclty to the esc, and just lossen the motor arm and let it 'dangle' loose for transport.
There is plenty of airflow to each ESC, they have holes under each esc in the plate specifically for this and also the open flate dome helps get them lots of cool air.
An aluminium collar in the tube might be a good idea, but again, will cost more and we've not had any issues with this either, the hole is clean cut and when the screw it tightened virtually no movement for the wear to happen.
In terms of having 'sacraficial arms' a motor tube costs more than replacing one of the tube holders, the weakest link here would be the plastic tube holders, if we'd used aluminium it would rip the frame apart, currently the small and cheap plastic parts break first, simply replace and fly. I'd rather replace a small part than a whole motor arm tube.
Centre plates are just under 2mm thick, custom carbon fibre with a tight strong weave. We've used APM1 with most of our past octos and starting to build them now with APM2 only, we will monitor EMI with the APM and might move the boards up slightly, but again, currently no issues.
hope this all helps :)
Soft/dampened motor mounts might actually not be a good idea. Just like if the arms are to soft (DJI F550) the motors/propellers can start to self oscillate from even tiny vibrations in the system. And if those oscillations are bad enough, one of your propellers might lose a blade in the air from the strain. Resulting in one of those slow motion moments where you watch as $$$ worth of frame, gimbal and camera is heading towards the ground. :)
:) yip. had a very similar thing on a quad frame once, it came with these crappy little motor mounts that had a lot fo flex in them, caused such bad vibrations in the motor the props just snapped off, replaced motor mounts with our own and issue gone. Will need to do some testing with different materials.