ZMR 250 Mini Quad Build

[iwan_canobi]

So I have succumbed to the mini quad craze, and ordered myself up the bits to build myself a 250 sized quad for blasting about on.

Parts List:

DYS 1806 2300kV Motors
Afro 12A Super Lite ESC's
Naze32 Acro
Diatone 5030 props
Mobius camera
A few 1300mah 3S Batteries

GOODIES!:



I was originally going to try and build a frame myself, but a colleague offered me a ZMR250 Blackout clone for a price I couldn't turn down, so I took that off his hands! :)

Starting the build

I had looked at some power distribution boards for mini's but most were coming from the US and I didnt want to wait. I noticed when the ESC's arrived that they were pre-bulleted for the motor connections. I was planning on direct soldering the motors so I cut off the bullets and knocked up a 4-way power distro connector:









I then set about the ESC's, cutting the heatshrink off and removing the remains of the motor wires, cut down the wires from the motor (they are really long out of the box!) and soldered directly on. Putting them straight on aligned with the ESC gives CCW rotation, swap one round and its CW. I put on some new heatshrink and job done! I ran out of black heatshrink so used some clear on one :(.



Test fitted on the frame and screwed the bottom 2 plates together, sandwiching all the wires in between, ends up quite neat! I put the latest firmware onto the naze and soldered up the pin headers, and stuck it on using some foam double sided tape folded up a few times then cut into 4 squares.



Today I went back to it on my lunch break and realised that to fit the top section with the standoffs you need to put the screws through the top plate of the bottom 2 first, before screwing the arms on! D'oh! So I took apart the sandwiched section and took the opportunity to replace the clear heatshrink with black. Uniformity restored! :D

Screwed on the spacers then put it all back together including the top plate, then clipped on the little landing gear standoffs.





The frame is pretty sturdy, as has been said before in many reviews the machining isn't the most accurate in the world, but things line up well enough.

Now I need to figure out where to put the remaining stuff - LC filter, Rx, VTx and camera. I've overspent this month already so will just use the mobius as FPV cam to begin with, but a board cam will be on its way soon for the low/proximity stuff!

[Coyote]

Nice neat build, looks pretty strong :)

[iwan_canobi]

And its finished...pretty much:





Still got to finish the LC filter, which I've made as a bit of a general purpose power supply for VTx and camera + OSD. Just need to do a bit more soldering and heatshrink it together and it will sit in the back!

Gave it a quick test hover and everything seems ok, will need some tuning as it was wobbling a bit but I'll wait for some better weather to start that! I also may need to re-think the Rx antenna placement, as those will get damaged as soon as I crash (which wont take long I imagine). They are just drinking straws so will crumple. What does everyone else do with their antennas on these?

[lordchris]

Hey Iwan_canobi nice clean build.
How does it handle? I have a ZMR250 built but for the life of me can't understand setting up the naze32 or my Taranis for that matter.
Your question about antennas. Mine are just zip ties in the frame in a V shape, and the antenna wire is heat shrunk to them.

[iwan_canobi]

Well, had its first flights and it didn't go to well...

ZMR250 Mini Quad Maiden and Crash

Air crash investigation underway...

[Coyote]

You did get lucky ! :)

[Billy_boy_2010]

Is there any benefit to keeping the C of G low on a quad? Largely by putting the battery on the bottom?

Would it act as a kind of ballast like a boat and keep it more upright?

[ezroller]

Is there any benefit to keeping the C of G low on a quad? Largely by putting the battery on the bottom?

Would it act as a kind of ballast like a boat and keep it more upright?

If you want a stable multirotor for filming or steady flying then weight at the bottom is beneficial, whereas these acrobatic quads suit having the weight spread a bit more evenly for rolls etc.

Also having the battery on the bottom makes it a lot more vulnerable when you twat the floor :D

[marcin]

Is there any benefit to keeping the C of G low on a quad? Largely by putting the battery on the bottom?

Would it act as a kind of ballast like a boat and keep it more upright?

yes ,but then any multirotor will take more amps to stabilise itself having low CoG in Z axis.