RCX ZMR 1804 2400KV Brushless Motors

To my first review it’s fair to beggin with the very first motor that I use in my first DIY drone, RCX ZMR 1804 2400KV. I set it in f250 glass fiber quad.

In fist lookup RCX are small and light motors but powerfull anyway. Exactly 13.4g, so perfect to set and don’t be worried about the weight. Furthermore, it’s diameter only 23mm, 5mm in axis.

Theoretically, provide 2400KV and may set with 2S (7.4V) or 3S (11.1V) batteries so discard mounting with 4S batteries, are not allowed, looking in datasheets.

Package include M2 screws to fix the motors in the frame. Also, one nut per motor to set the propellers.

Could be found in CW (Clock Wise) and CCW (Counter Clock Wise) but, to be honest, I have never found CW model. It’s could a problem using nut provided in the package, because tend to unscrew. Also, screws are quite short and should be re-screw almost before every flight.

Both issues could be easily solved. Setting few larger M2 screws, cheap and common, let you flight securely. On the other hand, aluminum auto-tapping nuts will hold your props very strongly to motors.  

Finally, in this moment you could find RCX motors less than 10€ each one.

Who are they for?

As I told you previously are the one which I used in my very first quad settings so destination user is, mainly, beginners.

Why? Easy to explain, they are very cheap brushless motors and easy to find out so you wouldn’t suffer so much if your first crashes break a couple of these.

Furthermore, are very light and small motors that make easier the quad build. It wouldn’t affect your flight weight.

I like

Cheap

Very light

Easy to find out (very common)

Good thrust keeping in mind weight and price

I don’t like

- M2 screws are very short to set the motors firmly, provoking motor jumps if you don’t tight it every time you are going to fly.

Solution: Buy M2 screw pack little longer and set it with rings to set it firmly. Please, be careful to not set a too long one in order to avoid screws block the motor rotating movement.

- Provided nuts are low quality and will deteriorate by use. Taking into account will be focused to beginners, you surely must change usually propellers. 

Solution: Easy as I said before. Buy aluminum auto-tapping nuts to hold the props. You could find it out for a little money.

- After intense shock these motors may decrease his performance considerably so you should swap it. The main problem is the rotation will be affected so shocked one will rotate slowly and your quad control will be affected. Very easy to notice because the quadcopter will tend to fly always in same direction.

Solution: You should buy at least two or three spare motors.

- Mounted wires are very tiny. It will affect the moment you solder it to ESC and, mainly, could be pull out if your motors get loose by the screw problem. In that case will be very difficult to repair.

Soultion:  You should fasten it with plastic bridle to the frame to prevent the pull out and ensure the solder with shrinkable pieces.

Features

RCX ZMR 1804 2400KV

Motor diameter = 23 mm.

Axis diameter = 5 mm.

Nuts diameter = 2mm (M2)

Weight = 13.4 g.

Voltage = 2-3 S (6v–12v)

Revolutions per minute per applied volt = 2400 KV.

Thrust tests:

Test were done with two propeller sizes 6030 and 5030.

5030 = Thrust is close to 300g

6030 = Thrust get over 300g (very close to 350g)

In summary

Even there is several unfavourable features I strongly recommend these motors to beginners mainly based in three characteristics: are powerful, light and cheap. Maybe you could find find better motor to begin with but I am pretty sure it would be more expensive that RCX.

Do not hesitate to get it, performance it’s better than good.

My recommendation

If you finally decide to set these motors to your multicopters notice that behaviour depends mainly on the size of the propellers. I have test with my quad with f250 frame where the proper ones are 5030 size. So, I have checked this one and also 6030, which are significant bigger. There is a big difference between each.

In case of beginners I highly recommend 6030 because make the quads much more stables and easy to control. On the other hand, you must be very careful due the props are so big that will be rotating so close to frame and could cut any part as esc wires for instance. Not in all frames will fit. Furthermore, make the rotors get higher temperatures, so you would take it into account. In my tests, I was flying for more than 15 minutes uninterrupted and there was no problems.

Regards.