Wizz's ZMR250SS (slim/short) mod

By WizzX on Jun 04, 2019

6  390  4

This is my first build and my second quad (I started with toy SYMA X5C) and Im still in a "begginer" level.

My goal was to build universal freestile quad with better range for some mountine downhill ower threes.

video:

my YT channel:
https://www.youtube.com/channel/UCNuXT1gGvqYWVAVrnR4uC2Q

Frame:
I started as many begginers with cheap ZMR250 / QAV250 bought as set with motors,esc, pdb and FC from aliexpress. It wasn't great deal, as I most of the components was crap and I already replaced PDB MATEK XT60 clone to MATEK PDB XPW and FC ominibus F3 to Matek F722STD, motors (red bottom) still works correct as well as ESC on DSHOT600.

As original ZMR250 assembly looks uggly with lot of useles free space, i take saw and modify it acording my needs.
I made it "upside down" to correct centre of gravity with battery / gopro on top
First version was with 1200TVL camera on tilting servo, but there was only problem with that, and servos burned everityme, I replace it to fiexd one - Runcam micro eagle.

ESC/capactiors
I'm using ESC from bottom to protect from props and as I build this frame "upside down" ESCs are protected by frame size from bottom, anyway in first version of build I had even 470uF capacitors under the ESC, but than I found out that is not a good idea because I shorted one of them during crash.
Now im using one 2200uF capacitor inside frame for Lipo and separate 1000uF/6.3V for 5V (camera) and 1000uF/25V for 12V (VTX) so voltage is stale enough.
ESC are without heatsing, but i put thermal silicone pad between carbon arm and cover with heatshrink.

PDB
XT60 socked is fixed on rear side of frame, I have also "charging" wires with 100ohm resistor to prevent sparks on XT60 which I connect as firts to balancing connector and than connect battery to XT60. works pretty well, no sparks even with big capacitors, also It keeping balance lead in safe place.

VTX
as cheapo HLV VTX is crazy heater, i losing picture during first flight and get 90°C on static test, I made cooler as part of the frame.
as Fist I put thermal pad inside shielding plate (and also replace bigger shielding plate from wifi dongle) and than i made part of the frame from aluminium plate (SSD drive spacer) and screw some small heatsink on them. Ofcourse paint all to black. It sits exactly inside frame, Just VTX button was to high so I desolder it out as I fly alone only and no need to switch channels on place :).

Big Crash:
Lo qualityt VTX antenna which disconnect itself by vibration cause lost video - crash from around 100m to field and hits the rock.

  • All the main frame plates broken (No arm broken)
    Alt Tag

  • Runcam Micro eagle broken, PCB damaged, frame broken, lens lost
    Alt Tag

Alt Tag

  • Gopro Session 5 broken, Lens OK but can not control it, reacts on buttons but to late, make whatever it wants, not record, no connection to PC.
    Alt Tag

Corrective action an repair.
New frame concept for next build with using 3d Prints (still use ZMR250).
Tried to repair micro eagle with resolder broken chip but not helps - new runcam ordered.
Gopro dissasembled and did not find a failure, reflow not helps, so bought gopro with broken lens from ebay (30euro) and replaced PCB.
Total cost 90 eur.

Photos

Part List

Frame

ZMR250 V2 Carbon Fiber Frame Kit 4.0mm Arm Thickness Support 1806 2204 2206 Power (14 builds)
Banggood.com
$24.99

Flight Controller

Matek F722-STD F7 30x30 Flight Controller w/ 32K Gyro, BFOSD, Barometer (36 builds)
Racedayquads.com
$39.99

ESCs

4pcs TTSRC BLHeli-S 30A ESC 2-4S Speed Controller for Racing QAV210 QAV250 F450 S500 Quadcopter
Aliexpress.com
$23.99

Motors

4X Emax RS2205-2300 2205 2300KV Racing Edition CW/CCW Motor For RC FPV Racing Drone (86 builds)
Banggood.com
$50.99

Propellers

US $4.69 20% OFF|8pairs/lot 5 Inch 5065 3 Blade Propeller CW CCW Prop Blades for Wizard X220 X220S QAV250 Quadcopter-in Parts &
Aliexpress.com
See Site

FPV Camera

RunCam Micro Eagle 800TVL WDR 16:9/4:3 CMOS FPV Camera (323 builds)
Getfpv.com
See Site

FPV Transmitter

5.8G 48CH 5V 25MW/600MW Switchable AV Wireless Transmitter for FPV Multicopter High Quality Parts & Accs
Aliexpress.com
$13.75

Antenna

TBS Triumph 5.8GHz RHCP FPV Antenna Set (SMA Male) (191 builds)
Getfpv.com
See Site

Receiver

Radiolink R12DSM 2.4G 12CH DSSS FHSS Receiver for AT9 AT9S AT10 AT10II Transmitter (7 builds)
Banggood.com
$15.99

Batteries

US $35.71 32% OFF|2UNITS GOLDBAT 14.8V Lipo Battery 1500mAh 4S Lipo Battery 14.8V lipo 4s 100C with XT60 Plug for FPV RC Car Tru
Aliexpress.com
See Site

Power Distribution

Realacc/Matek PDB-XPW 5V 12V Dual BEC PDB Built-in 140A Current Sensor with XT60PW Socket (15 builds)
Banggood.com
$6.99

Misc Parts

Matek M8Q-5883 GPS Module w/ Compass (53 builds)
Racedayquads.com
$33.99

Misc Parts

4pcs CNC XT60 XT90 Plug Holder Connector Installation Bracket for RC Multicopters Drone Spare Part
Aliexpress.com
$3.49

Misc Parts

HGLRC 2-in-1 WS2812B 5V LED with Alarm Buzzer Motor base light for Naze32 F3 CC3D Flight Control FPV RC Drone Helicopter
Aliexpress.com
$1.71

Misc Parts

12/20PCS M3 Flight controller Anti-Vibration standoff Fixed Screw Damper/Mounting Hardware Spacer for F3 F4 Matek F405
Aliexpress.com
See Site

Misc Parts

RC 3M LiPo Battery silicone non-slip mat 3s 4s lipo Battery Protect Guard fixed and protected against skid/back glue
Aliexpress.com
See Site

Battery Charger

Battery Charger D6 Dual Channel Intelligent Model Charger 2 in 1 For Phone RC Plane Wireless Charger
Aliexpress.com
$103.00

Backpack

Protector Plus 25L Outdoor Bag Multifunctional Waterproof Military Backpack for Hiking Camping Climbing Travel Sport Travel Bags
Aliexpress.com
$32.75
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Discussion

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IcarusIX   Jun 20, 2019  
1

this is well put together, especially like the heat sink, shame about the terrible zmr arms. if this build still exists, it might be worth cutting custom arms for it, the rest is just so good

WizzX   Jun 23, 2019 
1

yes, this build still flyes. its my first and only build. You mean that arms are to wide= to much air resistance? thats really bad, but so far i did not break any of them and the spare ones are really cheap if i will. As I´m still rockie, theres no build to compare, so i can´t feel the air redistance. anyway i feel great to fly that :) already collecting parts for my next build- that will be 7" light one

WizzX   Jun 23, 2019 

on 7" I will use F2 Mito frame with 8/6mm arms so hope they will be much better

IcarusIX   Jun 23, 2019 
1

the zmr arms are defo chunky and block some thrust no doubt but that's not much of an issue really, I mean their strength kinda sucks. a redesigned arm which is simpler with far less holes will fare a lot better. and nice, good luck on that 7 inch (defo better aero arms yh)!

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