School me on latest DIY RC planes, drones, and their modules... - Page 1
Forum section: electronics / projects

author: metrologist
author_rank: Super Contributor
timestamp: February 07, 2019, 05:12:59 pm
content: I recently saw a video of a lad testing a Musk style vertical landing rocket. He used a single propeller in the base with 4 independent fins, and then 4 more motors higher up for lateral stability. He mentioned a couple of flight controllers and the ESC he was using, which I think came out of a DJI drone or other commercial product.Anyway, I was thinking of trying some sort of 4 motor drone and was looking at flight controllers and radio controls. I looked on ebay and have no idea what is what. Maybe Hobby King stuff?I bought a couple of shrink wrapped 30A ESC with I think K-MANN code or similar. That code supposedly meant something good for drones and that is the sort of info that takes involved intimacy with the hobby to learn. I am just aware it is/was a thing, but know nothing else about it, for example.What should I be looking for in very inexpensive modules and controller?

author: linux-works
author_rank: Super Contributor
timestamp: February 07, 2019, 05:28:25 pm
content: I would first start with a 'bnf' (bind and fly) pre-built drone.my first one was a small (but powerful, scary, even, for a newbie who only flew 'toys' before):https://www.amazon.com/EMAX-Babyhawk-R-136mm-Magnum-Racing/dp/B079TR312N/its all worked out for you and you can learn how to configure betaflight software, add more options (led strips, etc).then, next step is to build one from parts; buy CF frame, 4in1 ESC, f4 controller, motors, props, etc.I'm in that phase right now; built a few of the 3" CF ones, now building 5" versions with 22xx motors.quite a lot of reading needed, of course.

author: linux-works
author_rank: Super Contributor
timestamp: February 07, 2019, 05:31:46 pm
content: I suggest the blheli_32 ESC's. they are flashable and quite good.f4 controller (hackrc is good, for one brand).one thing I'm finding is the 'bec' (what we call 'voltage regulator') is always ALWAYS under-heatsinked and they often blow up after X amount of flights. you should avoid putting too much current load on the flight controller and defer it to some PDB board or outboard 'bec' regulator. that will help a lot.clean wiring is also important. location of modules can matter; if you put the rf receiver too close to the f4 controller, it can cause noise issues and make the quad unstable at times. running wires also can matter (keep things away from the IMU chip, for example).

author: netdudeuk
author_rank: Frequent Contributor
timestamp: February 07, 2019, 06:02:10 pm
content: Hopefully Dave won't mind if I refer you to RC Groups. They have a massive, busy forum dedicated to this stuff.

author: james_s
author_rank: Super Contributor
timestamp: February 07, 2019, 06:09:38 pm
content: Yes RCGroups is a great forum for this stuff. Spend the time researching first before you go out and buy anything and you'll save a lot of time and money. I will also second the advice to start with something ready to go, a kit or at least a documented build. There are a LOT of variables, not the least of which is learning to fly. If you aren't skilled at the flying part it's almost impossible to know how well tuned your craft is.Oh and don't forget safety. In addition to the hazards of improperly used LiPo batteries, those little plastic props may not look like much but spinning at 10k+ RPM they can slice a finger clean off or take out an eye. I've already seen too many gory pictures of prop lacerations.

author: NorthGuy
author_rank: Super Contributor
timestamp: February 07, 2019, 06:53:14 pm
content: Quote from: linux-works on February 07, 2019, 05:28:25 pmA capacitor sticking out of the body is a nice touch.

author: metrologist
author_rank: Super Contributor
timestamp: February 07, 2019, 08:40:58 pm
content: LoL, I didn't see the cap...I flew and built a lot of gas planes as a kid, and I have a small toyish 4-prop drone that I can fly around and do flips. It has some stabilization but nothing fancy. It's about the size of my hand. I also have a couple CP 3D helicopters that I got to hover, but not spent the time to actually learn to fly it (Szabo style). There is a gyro but no fancy stabilization. I might even want to add something to that if it exists...I really became intrigued with the single prop and 4 independent rudders being able to keep a rocket shape in a stable vertical hover, and wanted to try and duplicate something similar as a compact aircraft.I dug out the video, this is his second one.I will reluctantly check out RC Groups but I feel the encyclopedia of everything RC is going to land on my head...For me it's more about building unique and learning a few things than having a toy I can fly around.

author: rstofer
author_rank: Super Contributor
timestamp: February 07, 2019, 10:41:04 pm
content: I would think one of the pre-built or kit models would be the way to get started. Definitely, the rocket is an advanced topic.One think we demonstrate in controls class: Try to balance a pencil upright on your palm. Won't happen, ever! Now add a lump of clay to the top of the pencil (away from your palm). Technically, you would expect the system to be more unstable, and it is, but inertia prevents the top of the pencil from moving very fast so the system is easier to control.I haven't played with drones but if I wanted to get started, I would probably wander over towww.lynxmotion.comThey have been doing robotics for a very long time and their products are first rate.It's probably worth buying quality components because they are serially reusable.

author: linux-works
author_rank: Super Contributor
timestamp: February 08, 2019, 04:49:31 am
content: Quote from: NorthGuy on February 07, 2019, 06:53:14 pmit was easily moved to the back where its not seen. why the factory didn't do that, I have no idea. yeah, its stoopid hanging out like that.

author: linux-works
author_rank: Super Contributor
timestamp: February 08, 2019, 04:56:23 am
content: Quote from: rstofer on February 07, 2019, 10:41:04 pmnot at first, thoughyou'll break your carbon fiber frame, of course break many props and maybe break a motor and blow some ESC sections. if you don't, you are not having enough fun, lol.for a small 3" build, this was a neat strong frame (not CF, all metal):https://www.amazon.com/Rakonheli-CNC-Aluminum-3inch-Silver/dp/B07D6NLNG4its not much heavier and it won't fracture and splinter like CF does.anyway, don't overspend on your first few drones. damage will happen as you learn and that's normal.

author: MarkF
author_rank: Super Contributor
timestamp: February 08, 2019, 05:38:03 am
content: RC Model Reviews has a lot of infohttps://www.youtube.com/user/RCModelReviews/featured?disable_polymer=1

author: james_s
author_rank: Super Contributor
timestamp: February 08, 2019, 09:28:25 pm
content: Quote from: metrologist on February 07, 2019, 08:40:58 pmThis was not indicated in your initial post, so most people probably assumed like I did that you were a complete noob who saw a video of a cool "drone" and decided you wanted to build one of your own. RC forums tend to be filled with noob posts like that so it's understandable that would be the assumption if it is not said otherwise.

author: metrologist
author_rank: Super Contributor
timestamp: February 08, 2019, 10:22:53 pm
content: Quote from: james_s on February 08, 2019, 09:28:25 pmWell, I'm not sure if newb isn't still appropriate. The RC planes were 20 years ago. I'm sure tech is much different now. Also, the drone I have was a $19 toy, so I do not think that has given me any knowledge of anything significant. It's a palm sized indoor flyer.I was just looking at my Helios, they are the Honey Bee King 2 models. I flew one of them a few times to get a hover a few feet off the ground. I read a bit and it seems the gyro only affects the tail rotor speed or pitch to help prevent weather veining.So, yeah, I saw a cool video and wanted to build something.Here is what I'm thinking.A2212 2200 kV motors with 30A SimonK ESC and 7x4E props for $6 each.There are a couple inexpensive F4 FCs - either the $14 or a $30 one (I almost went for CC3D, and that is a newb mistake).I might rip the radio out of one of my helios (72 MHz AM), but I have an inkling it does some kind of mixing that I wont be able to work around...or buy an inexpensive radio set. Any suggestions?I'd run a 3S pack and the body size is looking like 250 to 300, which I would make either 3d print or just flat fibre board.Is that coming in about right?Now I think I should go play with betaflight software and see what it does... Can an F4 controller do anything for my helios, like replace the gyro and hover the helo automatically so I'd have to actually fly it into something to crash? I think I would do that first! I'm too scared to fly them because I know it will crash. That little drone is easy to fly.

author: metrologist
author_rank: Super Contributor
timestamp: February 10, 2019, 02:21:33 pm
content: I found a video showing basically what I was thinking of building, and for $100 minus a controller and goggles, which was beyond what I was thinking initially. It looks too fun, but something I realize and now I'm completely discouraged.For one, I burned out my power supply by testing my $5 hobby motor and ESC for a few seconds. I'm surprised because the supply can put out 15 amps @ 50V and I was running 12V @ 10A, for about 15 seconds. I am puzzled. I might be able to fix the supply if I get lucky and shotgun a few components, but it made me realize something.When I flew gas RC planes a few things that happened. Crashing is part of the hobby and I hit a light pole and a metal statue, besides the ground a dozen times. A friend folded his wing and crashed on a car, through windshield and through instrument cluster - totalling car. He also crashed on a house and made a hole through the roof! It's a dangerous hobby and I live in a very populated area.Look, if I don't know enough about what I'm doing not to burn out my power supply maybe I should not consider doing something that could kill someone else. Besides, I think there are now drone laws and insurance requirements. I know you had to buy a million dollar insurance policy around here to be a member of any RC flying club, and that was 20 years ago.I flew my little toy drones around the house and crashed a few times. It's out of my system now. And, since I have no power supply, I have time to evaluate whether electronics is for me at all. I've not been able to make anything work in a long time. years. I'm good at taking things apart and breaking them, and making half finished projects and messes. I could completely fill the back of a pickup truck with all the gear and crap. I should haul it all off to the trash.

author: hlavac
author_rank: Frequent Contributor
timestamp: March 03, 2019, 11:05:25 am
content: Quote from: metrologist on February 10, 2019, 02:21:33 pmThe joy of the BLDC motors + controllers: they back feed current when turnning off the phase winding.Most power supplies are not ready for that, having regulation only when sourcing the current.The whole thing can pump energy back into the power supply flyback style during each turn-off transient, you need massive caps to capture this with low enough rise in voltage.Try calculating the energy in your winding with given inductance and current, then calculate the voltage rise on your capacitor with given capacitance for that energy. You will get scaredBatteries don't mind being chargedI have even seen a RC battery being used on BLDC controller (o-drive) to capture the transients instead of a brake resistor, and provide boost for the srart up current

author: metrologist
author_rank: Super Contributor
timestamp: March 04, 2019, 06:54:33 pm
content: I wonder if this is where you'd stick in those big diodes? Yeah, I was ramping the throttle up and down a few times. Wow, look at this power...wait!