China is such a magical place… among all those affordable things you can buy there, there are those not so useful, but still affordable things that, for sure, you do not need. Just like DIY Assemble 2204 2-3S Brushless Motor 0.42*2.8 Copper Wire with Motor Cap Banana Plug.
As you can see on a picture above, it is a motor that you have to assemble by yourself. Wind the coils, install bearings, learn the difference between Delta and Star configuration, and so on and so on… Oh, and there is absolutely no manual. So even number of wire turns is a mystery. I suspect something around 10, but who knows.
Tomorrow will be the first attempt to assemble it. I hope magic smoke will not appear…
You finished your build, you connect LiPo, power up flight controller, apply throttle (no propellers of course) and you see that one or motors are spinning in wrong direction. How to fix that? You can not do it, for example in Cleanflight Configurator. ESC communication protocol does not allow to change BLC motor direction.
There are 4 ways of dealing with this problem:
- Hardware way that works all the time: swap any two motor wires. Does not matter which, just take any two and swap them between motor and ESC: A with B, B with C or A with C. If you have bullet connectors, it's simple. If you soldered wires to ESC pads, you would have to resolder them.
- If you have BLHeli ESC software, BLHeliSuite allows to change motor direction without swapping any wires. Connect to ESC with BLHeliSuite, and change Motor Direction option. This works only with BLHeli enabled ESC, and only on Windows.
- Most of ESC allows to change options like motor direction via transmitter. Exact procedure differs from manufacturer to manufacturer, but usually it looks like below. For exact procedure and possible options refer to ESC user manual!
- Connect ESC to radio receiver throttle channel or use flight controller configurator software Live mode. Remember to remove propellers!
- Throttle UP
- Power ESC, it will start to beep signaling number of cells
- Keep throttle up until you hear a sequence that confirms programming mode has been entered
- Wait to hear beeping sequence indicating Motor Direction option
- Throttle DOWN
- Wait until you hear beeping sequence indicating desired rotation direction (normal or reversed)
- Throttle UP
- Setting will be changed and after next power cycle rotation direction will be changed
- Sometimes special programming cards for ESC can be acquired. They somehow automate procedure from point 3 but work on the same principle. For exact programming procedure refer to programming card user manual.
EMAX programming card photo 
One of the things that can happen to brushless motors, specially outrunners, is broken off magnet. Stronger crash, or even extensive vibrations, can cause one one small magnets located in motors bell to tear off. After all, they are only glued to rotating part of motor.
- If magnet stays inside motor, it will either rattle, or more probably block motor completely. It will stop spinning, and will not start again. Do not try to force it, it will only get worse,
- If magnet will somehow leave motor interior, motor will usually continue to spin. More, multirotor or a fixed wing plane will be flyable. Of course, motor will loose some power, there might be some jerkiness, excess vibrations, but it will keep to rotate.
When case one happens, you can easily see it happened: motor blocked completely or very rattly. Immediately disconnect power, magical smoke is very near. In case two, motor when pushed with finger will spin, but jumpy, like this:
Plus, due to weight imbalance, motor will be a source of huge vibrations.
Can I fix a motor with broken off magnet?
Yes, if you have a magnet, it can be glued in place. If it stayed inside motor, you already have it. Just remove shaft clip and pull motor bell. If you have lost broken off magnet, you could get a new one. Maybe to buy it, but better option will be different damaged motor as a donor. The same type of course.
Continue reading Damaged motor: broken off magnet
I’ve bought first Turnigy 2730 1500KV brushless motor by accident. I needed something small and cheap for Depron airboat. Then I needed something similar for a Depron airplane. At the end, in 6 months, I owned 3 T2730 1500KV motors. Not all of them survived the experience. One got lost in the middle of a lake with the rest of airboat it powered. Second got burned what I forced it to power too big propeller. Third one still lives and this type is my first choice for anything up too 400g of weight.
Continue reading Quick review: Turnigy 2730 1500KV brushless motor
Since I was lacking some power in my Reptile 500 quadcopter, I was considering switching my Turnigy MT2213 935KV motors to something more powerful. Last previous weekend kind of forced me to make that switch: I destroyed one motor while trying to replace bearings. Being forced with lack of motors I’ve decided to stay with 3S LiPo, AfroESC and 10″ APC propellers and buy motors that would deliver more power while being compatible with rest of my setup. So I have chosen EMAX GT2218/09 1100KV.
Why them? Mainly because they were meeting my requirements and being actually available and within reasonable price.
- Weight: 80g,
- KV: 1100,
- Max power: 312W,
- Max thrust:
- 1380g on APC 11×3.8,
- 1290 on APC 10×4.7
- With long shaft at the bottom, so can be mounted in front and behind an firewall,
- GT series (Grand Turbo, woot woot) for “hi-tec” and “pro” models (such a nice name…),
- Black (!),
- Mounting holes: 16x19mm.
Continue reading Quick Review: EMAX GT2218/08 1100KV motors
My 250 class quadcopter project is slowly coming to a successful (hopefully) end. Finally had some time to assemble motors and ESC.
Since I wanted to have rather standard setup with 5×3 propellers, I had no super high demand on ESC, I’ve decided to use Turnigy Multistar 10A V2 ESC preflashed with BLHeli software available at Hobby King. Why them? Cheap, already flashed with BLHeli so no need to to flash at home and 10A is enough to drive 5×3 props. And it’s also enough for 6×3. Just in case.
Motors are also Turnigy bought at Hobby King with 50% discount few months ago: Turnigy Multistar V2 2206 2150KV “Baby Beast”. After discount they were super cheap: $7.5 apiece. And they are green, what goes nicely with carbon fiber ZMR250 frame.
Right now motors are not soldered directly to ESC, I’ve only removed 2mm bullet connectors from both motors and ESC. Waster on space. I’m still thinking about where to put those ESC, so for first few weeks there will be some extra cable between them. Later we will see.
Hitting the ground with a drone is not healthy. For pilot’s self esteem and UAV both. Specially when impact’s force will be taken by one of the motors. Most probably it will survive, they are quite tough little devices, but delicate bearing will take punishment and might wear off. Luckilly, signals of damaged bearings are easy to notice: motor starts to make strange noises and you can hear oscillations during maneuvers. At this point you have two options: replace whole motor, or replace bearings.
I faced this situation last weekend when one of my MT2213 935KV BLDC motors stated to rattle in flight. It was very hard to notice in hover, but audible in turns. So I had no other option and decided to replace damaged bearings. Continue reading Turnigy MT2213 935KV bearing replacement
Work on wooden quadcopter from this post continues. This weeken I’ve been able to almost finish. Almost. Frame itself is done, motors and ESC are in place, electric cables soldered, but this wooden multirotor is grounded. The reason is flight controller Thunder QQ Super. Why? Because it is crap. Really. The first unit was broken and 2 motor channels were not working. Fine, it happens. Seller has sent me second unit. It arrived few weeks ago, but I never had time to check it.
Yesterday I finally connected second Thunder QQ Super to radio receiver and motors. And what? One of the motors is not spinning. ESC is only beeping and this is all. After connecting this ESC to radio RX directly, motor spins just fine. There are also no problems with this ESC when used with different flight controller (OpenPilot CC3D). It only does not work with QQ Super. Why? No idea.
OK, this time it’s not 100% Thunder QQ Super fault. It is more like incompability. But very frustrating incompability. Either way, new flight controller should be on its way and in 2 weeks my quadcopter from wood should be fully operational.
I must say I’m happy with results. Frame is lighter than I expected and itself it weights only 256g. With motors and propellers, weight goes up to 615g and 1100g with ESC and battery. So, it’s not light, but not so heavy after all. And it’s very rigid.
- motor to motor diagonal: 500mm,
- motor to motor front arms: 370mm,
- motor to motor rear arms: 300mm,
- frame weight: 256g
And it finally has an official name: DeadRat.Why DeadRat? Because it’s a dead cat frame type and we have a pet rat. And my older daughter likes the name very much.
You want to fly, you need a motor. Electric, internal combustion, jet, ion, gravity. It does not matter. And since gravity engines are not invented yet, ion has no place in atmosphere and jet or internal combustion are kind of non-practical for multirotors usage, we have to stick with electric motors.
In RC world there are two types of DC motors we can choose from: brushed and brushless. The brushed ones are wth us for decades. Cheap and proven, but with a few downsides. First of all, they have brushes and brushes wears off because of friction. After time, they stop to conduict electricity and has to be replaced. Plus, they cause sparks, lowers efficiency, make noise, are sensitive to dust and so on… This is why, we do not use brushed DC motors any more.
Continue reading Brushed or brushless – RC motor dilemma
Good motor-propeller combo is a key for building stable and reliable multirotor platform. Since many amateur RC builders does not feel qualified enough for choosing motor and propeller separately, many producers offer brushless motors and matching propellers as sets. One of them is Turnigy with their budget, entry level set of 935KV motor and matching 10×45 CW and CCW propellers.
- one MT2213 935KV brushless motor with dual mount for both standard and DJI style sloted propellers with male 3mm “gold” connectors,
- one CW 10×45 DJI style sloted prop,
- one CCW 10×45 DJI style sloted prop,
- 3 female 3mm “gold” connectors,
First, the motors. They are rated at 935KV and are suited for both 3S and 4S batteries. Unfortunately, not too high power limit (200W in surge) does not allow to use 10″ props with 4 cell batteries. Manufacturer suggests 10″ prop with 3S and 8″ props with 4S. Too bad, since from my experience, their effective lift limit is around 250g per motor. Going above that value causes multicopter to behave little sluggish due to not enough power on more aggresive maneuvers. One the other hand, my current bulid uses four of those motors and weights 1400g with camera, FPV set and 5000mAh 3S battery. And it flies like a charm. I would not mind to have more power, but it’s fast and agile enough to have a lot of fun. Of course, one can forget about aggressive acrobations, but flips and rolls are doable as long and one remembers about alitude loss.
Very nice feature of those motors is possibility to use both DJI props and standard, not-sloted propellers. Short M6 shaft helps to eliminate extensive vibrations for running propellers. And a drop of anaerobic glue secures shaft’s nut tight enough not to let it unscrew in midflight.
Second, the propellers. To be frank, those props are crap. Sorry guys, but that is true. They are not rigid and reliable enough. At about 60% throttle they were going into audible oscillation that even my neighbor that had never any experince with RC recognized as something strange. And he was right, since one of those props actually broke during flip. And I think everybody knows what happens to a quadcopter when one of propellers stops to exists then machine is in the air. Crash. And although it fell into high grass grass that softened the fell, all four propellers were broken after that. So I replaced them with APC 10×4.5MR without any regrets.
To sum things up: motors yes, propellers absolutely not! If you are looking for a good 900~1000KV motor then consider Turnigy MT2213-935KV bought separately. And match them with, for example, APC 10×4.5MR like I have.
All photos are from HobbyKing.com website