AOS-5 build and BetaFlight tune / Best 5 inch drone I've ever built and tuned / PIDs and Rate tuning
So let me explain hello and welcome to the worldly bloke channel. This aos frame is designed by chris rosser. Now hes an aerothermal engineer who specializes in computational modelling and he uses a completely scientific quantitative approach to frame design and tuning, and i really like this – this approach is what i sort of thought i did anyway, but after watching his channel, i realized i needed a Bit of a rethink now theres a lot of test and analysis gone into the design of this frame, and i dont plan to repeat what chris so eloquently covers on his channel. But what ill try to do is summarize. The standout points on the frame, design and tuning approach that convince me this was the way to go, and i encourage you to visit chriss channel and ill leave a link in the description anyway today ill show you how i built this fantastic quad, the components i Used and my experience tuning it the chris ross away, this build is based around the aos 5 frame, its just arrived from canada and ive screwed it together already and, as you can see, it uses six millimeter thick arms with this arrangement of bracing sort of like An x frame, but with additional bracing on these long arms at the front and its so mega mega stiff everything about this design is deliberate, nothing is guessed and its all scientifically calculated, tested and analyzed. Even the way the camera plates are designed are to help reduce any frame resonances.
It really is a fantastic frame and its beautifully produced ill, be building this with the dji air unit mounted in here at the back, and these plates are designed to take the dji camera at the front and in my opinion this is a much better camera than Any of the other compatible cameras like the cadex polar, for example. The flight controller that im going to be using is the speedy b f7v2 stack that ive reviewed before and its going to fit at the front here, and the motors which havent turned up yet will be the iflight zing, 2207 1855 kv so lets get on. With this build well, there we go as if by magic. Its all made up – and i have to say this frame – is a pleasure to put together its beautifully cut. Everything fits just tightly and uh its perfect, as you can see here, were using the ethics. S3 props – these are very low, mass lightweight props and i have got some other props. I want to try, but these were the recommended ones. Ive got one of my gopro session mounts on the top heres, a suspension mount, which works quite nicely, and the antennas for the dji air unit are mounted across this way to stop them flapping about to stop it introducing sort of additional resonances. If you like one other thing i had to do when i did my first data collection flight, i was getting a lot of noise in the pitch axis this way it was fairly well quiet.
That way – and i realized it – was this air unit flapping up and down, so i put an additional cable tie on there, just to hold it in place and underneath one of the really clever things is, you would think with this type of arrangement of arm that Replacing it would be difficult, but in fact its only two screws so to take that arm out there. You just undo that screw that screw and it will just pull straight out and you can slot a new one in and yeah as you can see, these arms six millimeter is yeah. This is unbelievably stiff and everything fits in tightly but beautifully. The nice thing is that you can get the motor wires to come in the back, which ill show in a second, so youve got no cable sticking out here anyway. Lets get the top off this and ill. Give you a quick rundown of whats inside with the top off. You can see its a reasonably tight fit, but everything just fits inside the frame neatly im using a speedy b tx 600 flight stack, which is basically the f7 v2 and weve, got a 65 amp. Four in one esc on the bottom: this is all soft mounted very nicely and the beauty of this flight controller is, i dont need to use a laptop. I can talk to this with bluetooth or wi fi, and i can set up everything. I have reviewed this on the channel before its a really good flight stack when youre out in the field trying to do some tuning and up the front weve got the dji full size camera.
These are the best cameras, all the other, smaller alternatives that have come from cad x, theyre pretty good, but you know this is the best. In my opinion, ive got a full size, dji air unit on the back here, as i said, ive mounted this. It was just a nice fit in there quite tight. I had one piece of tape holding on, but it was just vibrating about and i was seeing a lot of noise on the logs, so ive just held that down with an additional tie, wrap out the back antennas come outside here and theyre strapped onto the arms. So that we dont get any additional residences or unwanted resonances anyway and then, as i showed in the opener, were using the zing 2207 1855 kv, because this is running on 6s. The batteries im using are these gmb um 1050 milliamp hour 6s. These are rated 120c, which is pretty good. They are quite small and quite light, and it gives me some degree of movement to get the cfg about right. I have tried it. One of these is a little bit heavy anyway, so weve got the flight controller and the stack here in the center there. There is a thousand microfarad 35 volt low, esr capacitor, and just underneath it in that piece of heating, shriek theres, a spike suppressor and ill leave links to all those. In the description. Just on this side, ive got a wi fi finder 2, which fits in nicely just solders on the top there and other than the motor wires and that theres hard theres no soldering.
This is all just sort of plugging connectors in to get it together and talking of soldering im not going to take this apart, but the way that the motor wires ive got them running down here, you can run them in the front and round the back. So you can back solder them. That means youve got nothing, sticking out this side and you can just solder them in quite neatly, and i like that way of doing things, and that is about it. The only thing i was a little bit concerned about is this camera cable running so near to the gyro, but i think im going to pull that out of the way, because i have seen some additional noise, which im not quite sure, whats, causing that i think It might be this, but i have been out and done. The first data run with this and collect some data, but even just on stock beta flight tune is really good. This is set up with rpm filtering, so everythings, nice and simple. I had to reverse the motors because one was okay, two three and four all running the wrong way around ill show that um in a later video, but you can change the motor direction without having to use bl, heli suite or anything like that. You can just use the speedy b app on your phone to change them, its almost a real breeze again ive covered this in the review of the tx 600 stack and ive used this on a couple of builds.
Now it is really very good building this, as you can see, was pretty straightforward and its one of the benefits of using the air unit or the kx vista. With the dji fpv controller. You dont need to solder in a receiver and worry about where youre going to mount the antennas, plus the only soldering on this was the motors and the finder ii buzzer. Everything else is just plugs and i find im doing more and more of that on. My builds these days because the air unit i found is very reliable and gives me excellent range so on to the setup and tuning now. The way i normally do, things is to get the motor rpm filtering, set up first and then use the default betaflight pids and i dial in the rates that i know work for me and i just go and fly it generally. The default betaflight settings work great for five inch quads and then what ill do is start out by tuning the p term. Just keep winding it up until it performs quite nicely then dial in a d term. Until i get the nice pd balance that works and its flying nicely with no nasty wobbles bounce back hot motors or nasty sounding motors, that sort of thing and then ill generally flail about tweaking things to see. If i can make it better and not being able to decide if the change i just made was any better or any worse, sometimes ill use the black box logs and sometimes not.
I just do it by feel the chris rosser approach is a much more organized analytical way to tune, which means theres simply no guessing, and i was keen to give it a try now, as ive said before, i wont just repeat what chris describes so well on His videos, but the summary sort of goes like this first thing, is to check the mechanicals of the quad, so theres no loose bolts that your flight come up. Your flight controller is soft mounted and so on then get the rpm filter set up then go and fly the quad on beta flight default pids and filters and rates completely stock and remember to turn on your black box logging then adjust the filters to get rid Of the motor and the frame noise and then you need to find the maximum d gain, so you do that first, then, you find the right pd balance and then tune the feed forward for the best set point tracking how quickly the quad follows: the stick, movements And then you set your rates to suit personal, feel and set the throttle resolution and then do any fine tuning thats needed now. I only had a couple of problems along the way when i followed this approach. When i looked at the black box logs after the first flight, all using this betaflight defaults filters and rates, i noticed there was much more frame noise in pitch than there was in roll heres.
The roll noise, which is okay but look how much bigger the pitch noise is, and it looks like theres some motor noise mixed in as well, but its mainly frame noise. And when i looked at the quad, i noticed the air unit could move up and down. In the frame now its quite a snug fit in there, so i just put some tape round to hold it in place, but i put it near the front of the unit, so i could get to the usb plug, but it was flapping up and down. Quite a bit, so i just fixed it in place with some 3m vhb pads and that brought the pitch noise down to about the same as the roll noise theres still a bit more pitch noise. But i put that down to my flex suspended gopro mount that id made. I can live with that, though. The other problem i had was motor desyncs ive covered how i fixed this in another video and, to be honest, i never used to get these, but ive found theyre appearing more often with low kv motors running on 6s and its a pretty easy thing to fix. So with that sorted, i got on with the tune following chriss steps, and this is what i ended up with, with the final tune. Heres a snap roll viewed in the black box, analyzer bear in mind my old man fingers arent. That quick, but this looks pretty good to me – the set point and thats the green trace is very closely followed by the gyro, the grey trace theres a slight delay, but if i wound the feed forward up any higher to bring it back in line, there was Much more overshoot at the end of the maneuver and the motors were getting saturated for too long.
So im happy with this and to me it feels very good indeed. These are the settings that i ended up with. The master multiplier ended right up on its end, stop which has pushed the detail much higher than i would normally set it to pd balance and p and d gain. Didnt need changing and the feed forward was cranked up to 1.8 id taken up a little bit higher. But, as i said before, i was getting some overshoot on the end of the maneuver and the motors were saturating. I gradually wound up these values, checking motor temperatures and black box logs, as i went, and during the tuning i had d min turned off. If youve got it on, while you tuning it sort of masks the effects of the true devalue, most of the filters were turned off. Apart from the gyro rpm filter and a bi quad or second order, low pass filter set to 105 hertz because the frames got such low resonance, i could just gradually keep turning off the filters again, keeping a closer eye on the motor temps. Looking out for weird noises and so on in the logs, remember that filters do a great job of removing noise, but they have a side effect that they introduce phase delay. So the less filters there are the better response from the quad to stick inputs. And surprisingly, i was even able to turn off the dynamic notch. Gyro filter, something id never normally do after four minutes of hard flying well as hard as i can fly anyway.
With these particular settings, the motors are barely warm and thats fantastic. This level of tune with these filters is something i would never attempt normally and is a testament to the aos frame design. So over to the rates, i always tune using actual rates, because they just make sense to my brain ive scaled. The throttle and added some expo again. Something ive never done before and found that i didnt need to set the rates and expo as high as i normally would, and this feels really nice to me. I cant stress enough that you shouldnt just try and copy these settings if id seen this setup on a quad without knowing the frame id have predicted that the motors or the esc would fry pretty quickly. I worked up to those values and this is the nicest five inch quad off flow, its fast, its responsive, theres, no prop wash no bounce back or any sort of weird behavior and other than the obvious benefits to tuning this way. Theres a few big takeaways. For me, leave the setting of your rates until the quad is properly tuned and calibrate your throttle and add some throttle expo. You wont believe how this makes modulating the throttle movements when youre trying to come out of a dive or something smoother and more accurate, give it a try now. The other thing was the air unit. Antennas are fixed to the frame like this to prevent any additional resonance you get if theyre hanging out the back initially, i was really worried.
This would affect the range, but as part of this flight, i flew diagonally across this field, which is almost 400 meters, and i had no problems at all ill. Do a proper test at some point, but with the air unit and these antennas ive seen 500 meters with no issues in a clean environment and im sure it will go an awful lot further. Also chris recommends the first data gathering flight should be on beta flight heads filters and rates, the stock default values and theres, nothing wrong with that for five inch quads, because thats what the defaults are geared up for on beta flight. But in my experience, especially with any ducted cine whoops, the motors can get very hot, very quickly on the defaults, so id recommend trying a quick flight hover around in the garden for about 30 seconds land and check the motors and, if theyre, anything but stone cold. Somethings wrong check the build check the mechanicals and, if thats, all okay dial the roll on the pitch d term right down before you. Take it out on a day to gathering flight, and apart from the good news that this is a fantastic quad theres. Even better news, the aos 3.5, a sub 250 gram version of this has just been released and mine has been ordered. Im really looking forward to reviewing that and if that wasnt enough, theres a seven inch version in development, and you know how much i like seven inch, quads theyre, just so relaxing to fly as always thanks for watching and if you found that useful.