Quick Review: EMAX GT2218/08 1100KV motors

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.

EMAX GT2218/08 1100KV

Why them? Mainly because they were meeting my requirements and being actually available and within reasonable price.

Specs:

  • 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.

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Let’s build 250 class quadcopter: motors and electronics

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.

Almost assembled ZMR250 with Turnigy Multistar 10A V2 ESC BLHeli

Turnigy Multistar 10A V2 ESC BLHeli

Turnigy Multistar V2 2206-2150KV Motor The "Baby Beast" with Turnigy Multistar 10A V2 ESC BLHeli

Turnigy Multistar V2 2206-2150KV Motor The "Baby Beast" with Turnigy Multistar 10A V2 ESC BLHeli

250 class ZMR250 carbon fiber

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Turnigy MT2213 935KV bearing replacement

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” »

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Wooden quadcopter, work continues

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.

Wooded quadcopter almost done

wooden quad frame on scale

wooden quad frame on scale

wooden frame

plywood central platform

ESC on wooden arm

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.

Dimensions:

  • 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.

 

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Brushed or brushless – RC motor dilemma

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.

Brushed DC 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.

Brushless BLDC motors and ESC

 

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Turnigy MT2213-935KV MultiStar Motor & Propeller Combo 10-4.5 Review

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.

MT2213-935KV motor propeller set

It contains:

  • 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,
  • screws

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.

Turnigy MT2213-935KV

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

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