Hi guys. Feeling unsatisfied with the performance of my Reptile 500 (too big and slow), I decided it was about time I got in on the racer scene. I planned out this build over a while, and it is intended to be very fast and powerful. I will try to make this a complete build log.

This is my parts list:

• ZMR250 V2 frame (without PDB)
• Overcraft PDB version 4
• Acro Naze32 rev. 6
• ZMR250 premium CF arms
• RCX H2205 2633kv motors and FVT Little Bee ESCs
• FrSky D4R-II receiver (with upgraded firmware}
• King Kong 5040 props (for bashing)
• GemFan 5040 Carbon blend props (for performance)
• FCModel 5040 triblade props

And my planned FPV setup (future upgrade):

• HS1177 camera
• Aomway 200mW VTx
• FR632 Diversity VRx
• Aomway Helical antenna
• Aomway RHCP cloverleaf
• MinimOSD (with KV team mod)

If you are planning to buy any of these products, please do me a favour and use the links above. I have added my referral code to some of these links. I am still waiting for the frame and FC so I will take some time to complete this build

 welcome to the world of 250's bro.. now u will get real thrill soo be ready and best of luck 

Mods please add the prefix GC - to the topic title. I can no longer edit my first post.

Hey you have naze32 rev6 board in the list
Have you got it
If yes,then please send me a pm about the shipping price from fpvmodel
And also if you had not ordered anything yest then try the new Emax cooling series 2204/2300 kv
They are ultimate. They are available on Bangood
And there is kit which has zmr250v2, these motors and little bee escs but it also has skyline32 Fc,again on  Bangood
But at any rate I haven't used the motors you have mentioned

The naze32 rev. 6 and frame currently show "Send item to customs" so I am expecting to receive them some time next week so I will be starting the build. FPV Model offered free shipping by registered airmail.
What is the advantage of those Emax motors? I don't particularly like the look of those motors- the thrust is terrible! 620 grams on 6045 at 4S? With my motors I should be getting ~850g with 5040 on 4S. I already have the motors and ESCs anyway. I don't know how that Eachine ZMR250 V2 compares to the actual FPV Model ZMR250 V2. Theya re selling it 10$ cheaper. I have also decided to stay away from kits. I find that for maximum performance and to save money in the long run, it is better to choose good parts at the onset.

I will  try to explain why I chose each of these parts. I went with this frame since the standard ZMR250 is a popular first time racer frame. Without costing too much more, this V2 frame from FPV Model comes with better quality, thicker carbon fiber and is supposed to be better machined. This power distribution board fits above the bottom plate and will help make this a neat build, as it integrates the OSD and routes the signal lines for the ESCs apart from providing various options to power all the components. However, I have heard it has issues with electrical noise apart from being a weak point in the frame, so I will have to see how it holds up.

These motors seem to be excellent performers and I've heard they are on par with the famous Cobras. The V2 motors come with set screws to fix the issue of bells flying off or the shafts loosening. Also spare parts such as circlips, shafts, bearings and even entire bells are available so the motor is easily serviceable. The FVT Little Bee ESCs are also supposed to be excellent performers since they come with dedicated FET drivers and a SiLabs F330 that far outperforms Atmel based ESCs. They are supposed to be similar in terms of performance to Rotorgeeks RG20A. However, the F330 may have trouble coping with high kv motors on LiHV packs, limiting the thrust available. Also, they may not do as well with next-gen protocols such as MultiShot so an F39x based ESC may be a better choice. Options include the new DYS XM20A, and XRotor ESCs. The Xrotors are big, heavy and difficult to flash however, so it is well worth keeping an eye out for a light, pre-flashed version that is coming out on ggracers.com. I believe that ZTW is coming out with an F39x offering as well.

The Naze32 is coming close to obsolescence with its STM32F1 processor. Although there are F3 boards available at twice the price, the naze should do fine with Betaflight until Raceflight for the STM32F4 is stable. The F3 boards do not have that much of an edge over the Naze as the F3 is just the F1 with a floating point coprocessor. The additional UART may be useful for some but i will hold off until I can buy an F4. Some would suggest that most pilots can't even feel the difference but I am mentioning this for people looking to be at the cutting edge of racer tech.

I chose the D4R as I have a FrSky DJT module in my Turnigy 9XR. For those with an XJT or internal XJT in their Taranis, the X4R-SB is a better choice as SBus has significantly lower latency and better error handling than CPPM.

I bought the PAL, IR Blocked version of the camera with a 2.8mm lens. PAL is the standard ihere and since I don't plan to do any low-light flying, IR block will offer more vivid colours. 2.8mm should be good for general flying but some may prefer the narrower field of view of the 3.6mm lens for proximity flying.

The frame, FC and LiPos came in today so I got started with the build. Here are a few pics of all the parts. I will post some more details soon. I really need a better camera 

Step 1: Preparing the electronics.

This is a pretty straightforward step. I removed the heat shrink from the ESCs so that I can solder the motor wires directly to the ESC pads. I then soldered everything to the Overcraft PDB. i really love this PDB since it makes provides power and signal routing for the ESCs, FPV gear, and even the OSD, Vbat and a buzzer. Servo leads are used on all the signal pads of the Overcraft to plug into the Naze.
On the Naze32, I soldered a servo lead to the 5V, GND, and PPM input pin (number 1). I soldered straight pins on the ESCs output as well as the VBat and Buzzer pins. I put right angles pins on Tx and Rx (for the OSD) so I can disconnect it when I need to work by USB. I also added another right angle pin on the bottom of the Naze for RSSI input (pin 2). The RSSI comes from the D4Rs pin 2, and passes through an onboard RC filter before being passed to the Naze.





Even though the FPV gear I am using can technically take direct 4S voltage, I have seen several reports of cameras and VTxs burning due to electrical noise from these Little Bees. One solution is to use a separate voltage regulator with a cap on the output. Here I am using a cheapo variable regulator (set to 9V as I will run both 3S and 4S) with a 1000uF 25V cap on the output. It will be connected to the "REG" pads on the PDB which would otherwise be used for a 12V Pololu style regulator.


My next post will be on setting up Betafight and BLHeli. I will not talk about frame assembly since it is pretty straightforward.

Ok here is a quick flight video on 4S. I did not go anywhere near full throttle since it shoots up like a rocket. This is LOS in Horizon mode. I am waiting for my goggles to arrive for FPV and I need some more space to practice acro. Crashes are at the end (no damage, not even one prop).



I will type out the electronics setup step and post it soon.

That looks like one "chained" angry little beast! What power! Great rolling btw!

Thank you. My dad tried to keep the quad in the frame but my double rolls were all cut out of the video since my punchout before the roll took the quad out of the frame. One of the crashes at the end was also because I was a bit too eager to do a double roll.

I will take the beast to the golf course next weekend and let him loose. Can't wait for my goggles to arrive. I need to practice some front and back flips as well as train in acro mode. I also need to upgrade to Betaflight 2.1.5 and enable Air Mode.

BTW: all rolls in this video were done at practically zero throttle (on my Tx). I have motor stop disabled (motors spin at arm) and PID_at_min_throttle set to PID so I get good control even at minimum throttle.

Wow! That's some cool flying man! 

Thanks a lot. I really appreciate it. Rolls are pretty easy with so much power on hand and horizon mode on. Now it is time for acro training. Once I get my goggles and get a good HD camera (probably Runcam 2) I hope to post some better videos

Here is the promised software setup step. I will upload screenshots once my Internet comes back on (using a data card):

I flashed my Naze32 with Betaflight as described here. You can choose to use regular Cleanflight firmware. I will now describe the settings I changed, menu by menu:

• Ports: Enable MSP for UART 2. This is what we will use to transmit voltage and RSSI data to the OSD as well as to enable communication between the OSD and Naze32 for changing settings in the OSD menu (more on that later).
• Configuration: Enable ONESHOT125 (a faster communication protocol between the Naze and your ESCs). I set maximum throttle to 200 and minimum throttle to 2000. When MOTOR_STOP is disabled, your motors will start spinning at minimum throttle as soon as you arm so you may have to decrease it if your quad tries to lift as soon as you arm. I am arming by a switch (AUX channel) so I also selected "Disarm regardless of throttle value". Yaw adjustment is set to 90 as I have changed the orientation of the Naze32 to fit my PDB (the arrow that should point forward points to the right). RX_PPM is selected as my receiver output is PPM rather than PWM. VBAT and failsafe are also enabled. Failsafe throttle is set to 1000 so the quad will drop out of the sky if signal is lost (IMPORTANT: You also have to set failsafe to 'no signal' on your receiver so the FC knows when signal is lost. READ the receiver's instruction manual and Cleanflight docs). Blackbox data logging is enabled as the Naze32 rev.6 comes with onboard 2MB flash memory.
• PID Tuning: The quad flies decently on stock PIDs (PID controller Luxfloat. I haven't tried Rewrite) but I have reduced them a bit as I noticed some oscillation in Blackbox. My quad is not yet fully tuned and I will post a different step for that. I have also set the rates pretty high. 0.45 lets me do double rolls pretty snappily. 0.1-0.3 are good rates to start with.
• Modes: I am using one 3-position switch on my radio for arming and flight modes. The top position is disarmed, the middle is acro mode (with AIR MODE) and the bottom is horizon. This lets me easily disarm or switch to horizon if I panic. The beeper is set to a different switch (for finding the quad if downed). Another switch is used to enable blackbox logging and a final one is used to switch off the OSD if I want to.
• Motors: This is very important. You will need to calibrate your ESCs from this tab. To do so, first MAKE SURE THE PROPS ARE REMOVED! Power up the naze32 by USB, connect, check the switch in this tab and move the master slider to full. Power on your quadcopter with the battery. You should hear a sequence of beeps that mean the ESCs have acknowledged full throttle. Then move the slider to the minimum. You should hear another sequence of beeps. Power off and on again and check that the motors all start up at the same time and spin up nicely (this can be adjusted in BLHeliSuite if required). Now go back to the configuration tab and set Minimum Throttle to the lowest value that gets the motors spinning up reliably (you should see this value in the motors tab on the master slider). Mine was 1025.
• Now it is time to set up the ESCs with BLHeli. One good thing is that now you can use your flight controller as a programming adapter for BLHeli. There are plenty of videos on YouTube that show how to program ESCs using your Naze32. I flashed the ESCs with the latest version of BLHeli- 14.3 (you should probably do this before calibrating or you will have to redo the calibration). I had a bit of a scary moment when I tried flashing firmware without the main battery connected and the flash failed. I was no longer able to communicate with the ESC but luckily I was able to save it using my Arduino nano and the C2 communication pads on the ESC.
• Now check that the PPM Max and Min values from the calibration are close (I chose to set them all to the same values.) I increased the Motor Timing to Medium-High and enabled Damped Light (active braking). I set "Enable PWM input" to off so that the ESCs don't confuse the Oneshot signal for normal PWM. I also unchecked "programming by Tx" to ensure that settings are not accidentally changed. Motors 1 and 4 are reversed as they were spinning the wrong way for me.