Greetings all.
It has been a while since I built a copter for myself.
The RcMumbai competition could not come at a better time as I had all the parts ready for a 250 which I was gonna build in December.

I had enough parts for two copters, but I'm afraid that I can only build one in time for Game Changers.

This one uses mostly old parts I salvaged from my completely 3D printed ZMR I built a while ago.
I decided to not go for a standard ZMR, and instead cut down the chassis to make it smaller/lighter and go for an X arrangement for consistent control on all axes.
The build was inspired from http://www.hacksmods.com/2015/10/zmr-x-custom-zmr-build/

This was also a build where I fully took advantage of my 3D Printer.

This is my meticulous build log with pictures of all the steps.

Parts used and source -
1. ZMR250 Carbon Fiber Chassis - Quadkopters
2. Flip32+ Flight Controller - Banggood (Salvaged)
3. DYS BE1806 2300kv - Banggood (Salvaged)
4. Sunrise Slim 20A ESCs - Banggood (Salvaged)
5. Gemfan and KingKong 5040 Propellers - Hobbyking
6. Tattu 4S 1300/1800mah 45C Batteries - RcMumbai
7. Mini Power Distribution Board w/ 5V and 12V Regulator - Quadkopters

8. Frsky D4R-II Receiver - Hobbyking

9. Sony 480TVL FPV Camera - RcIndia Classifieds Waiting for a new one
10. TS5823 200mW 5.8G Transmitter - RcIndia Classifieds
11. MinimOSD - Banggood

12. WS2812 LED Bar - Quadkopters


First things first, it was time to cut down the frame. This is what came with the original frame.



Gloves, a handkerchief to cover your nose, a hacksaw and a file. Plus an open space like the roof and a few hours later, this is the result.



A close look at the cut plates.



The next step was to dry fit the frame to see how it would look.





Installed the motors.



ESCs installed and motor wires trimmed.



The Flight Controller and the PDB will be stacked one top of the other using nylon standoffs. I dry fitted them to trim the ESC servo wires to length.



Okay, so this is the fun part, I wanted to do something cool with the ESCs, I ended up insulating them with thin red tape, and then covering them up with wire mesh. Really like the end result.



Also trimmed and soldered the ESC power wires to the PDB.



Next I set the MinimOSD up.



Problem was, I didn't have a FTDI cable at the moment, so couldn't program the OSD. That meant I would have to either delay the build, or install the OSD in a way that the FTDI pins would be accessible even after the build is complete for easy programming. I found the perfect place to mount it.





The vtx connector is at the back, the camera connector is at the front. Also, the minim is almost hidden under the PDB. Perfect.

At this point I realised a few things.
I need to way to mount the vtx and the frsky antennas - a 3D printable part was provided in the blog which was perfect.

Second, I wanted a way to mount my camera, and also wanted it at an angle. Thought of a mount, loaded Sketchup, designed it and printed it. Came out perfect.

Third, I wanted a way to mount the LEDs, again, thought of a simple mount, designed it and printed it. Perfect again.



Mounted the LEDs, they look great!



Time for the XT60. I didn't want it hanging with a cable, I again designed and printed a small part which will hold the XT60 snug, vertically on the top plate (you will see it at the end).



I soldered the wires to the XT60. I couldn't find proper gauge wires so just installed two wires each. It was probably overkill, but meh!
This is my own trick I use to solder connectors without using a helping hand.





Next, I soldered the pins to the flip. The PPM and LED connectors have been soldered minimally. I soon had to change that as they were interfering with the XT60.



I actually missed a few images after that.
In short, the flip goes over the PDB.
All the wires are plugged in.

I just double taped the camera to the mount and the mount slides over the front standoffs.
Screwed the top plate in, and the vtx is just held by the SMA connector at the back.

Here is the showcase.








There are a few changes I made later, which I will post in the comment.
I apologize if I missed any step.
If anyone wants the STL files,, you may contact me.
I have a couple of videos which I am in the process of uploading, will post when done.

Please share your views about the build. I would really appreciate it.

At the end, I'd like to thank RcMumbai for hosting the competition. It was really fun!

Okay. So after flying it a bit, I can say that I am really happy at how it flies.
I am starting my next build, and will install the fpv gear in that one as it is more spacious.
So I removed the fpv gear from this and rebuilt it.

I don't have a weighing machine, but with 5040 on a 4S, it is insanely powerful even when the battery is close to depleted.

I desoldered all the pins from the flip and went for a really clean and minimal pin layout.





I also removed the PDB as I didn't need a 12v regulator now. I used a small 7805 based BEC I made myself.
Plus, to mount the XT60, I cut a small piece of perfboard, soldered the XT60 on it, and soldered all the power wires underneath. Smallest, cheapest and simplest PDB. :p





Even the receiver is under the Flight Controller and the Bind/Failsafe button is accessible from the underside.
This makes the whole copter really slim, and it looks even better.





Videos coming up soon.
Stay tuned.

awesome work there 

Quote from: madaquif on December 23, 2015, 09:09:58 PM
awesome work there 

Thanks a lot buddy!

This sets a milestone in the 250 copters, hats off Pushpreet!
Great Job !

Quote from: sanjiv1994 on December 23, 2015, 10:24:02 PM
This sets a milestone in the 250 copters, hats off Pushpreet!
Great Job !

Thanks a lot buddy!

Here are a couple of videos.
It flies smooth as butter.

Terrific.

Quote from: charlie9165 on December 26, 2015, 08:15:15 PM
Terrific.

Thanks bro!

Looks amazing! Great build. I'm inspired to try this on my ZMR

Looks Amazing great build

Liked the work... Professional build.

Hi Pushpreet
Great going with the build.
Was wondering if you could please post how you updated the firmware on minim osd. And how you burned the bootloader etc.
Having a tough time with minim osd. Getting errors like failed to talk to bootloader.
Thanks