My QAV250... this one took me by surprise!

by midohioboarder | September 30, 2015 | (6) Posted in Projects

First, I'd like to think of myself as a heli guy.  Trex 450 & 600.  Fun stuff.  However, as I sit here writing this article, I can't keep from thinking about how much I like flying the 250 quad.  Wow, what a machine!!!  We've had 15-20 mph winds the last two days and flying the quad has been awesome.  I am currently thinking of it as a spirited flying brick. Brick, because it almost seems immune to the wind gust. Spirited because it is agile, quick.

 Don't get me wrong, the Trex 600 Pro EFL is locked in almost no matter what the wind is doing (well, except for the little hops it will take when the wind gusts)... But, the 250 quad is even more locked in. When the wind gusts, it just slightly drifts sideways. No hop, Brick.  (maybe it is the fact that there is not 600 mm blades swing toward my neck)  I would have never believed that I would enjoy flying this thing as much as I do.  And, I have only flown LOS (line of sight), which is not the end goal.  The 250 quad is going to squelch my need for speed via racing. (canl't wait)  I have to work through some video interference first.  Therefore,  I am a little hesitant to share my build.   BUT...


  • QAV250 G10 frame
  • Luminier 2406 2000Kv motors
  • BLHeli sn20a OPTO
  • Naze32 Acro
  • TBS core PNP 50 (OSD and clean power)
  • AR610 RX
  • ImmersionRC 5.8GHz 600mw 
  • Lumenier CS-800 Super - 800TVL S-WDR Camera (no case)
  • IBCrazy 5.8 GHz Airscrew Cloverleaf Ultra Antenna (single)
  • DAL 5/4 bullnose props
  • 475 grams (battery & Mobius not included)
  • AUW 661g or 1 lb 7 1/4 oz 
  • NanoTech 4S 1300mAh
  • Mobius for AP/AV
So, I import this picture below and I still find myself just staring at it in wonder!


I got the wire loom from  Wire lume is the braided plastic seen covering the motor leads.  I have heatshrink on the ends.  I got a 7 cm RG316 extension cable from ReadyMadeRC.  Using the cable allows any stress from the antenna being hit in a crash to go to the top plate instead of the TX solder joints.  I point out a few other components below as well.

 Most of the parts used to build this were purchased from either GetFPV or HobbyKing.  A few items were from ReadyMadeRC.

Below, I have labeled the double sided 3M foam tape I used to secure the TBS core PNP50 to the main frame. I used the 3M tape to mount the RX to the top of the core as well.  This put the top of the ESC signal wires right up against the top plate. Conviently, there is a whole cut in the top plate that the signal wires are able to pass through. Then cross over a crossmember of the top plate and back down through to connect to the Naze32.  The hole in the top plate is where I am also passing through the TX cables.  I made my own Mobius mounting plate out of some hobby plywood.  I also created a cover for the Naze32 with the same plywood.  

Ok, and so, if you are wondering what the white blob is behind the orange prop against the core and RX... well, it is some packing foam that I think ESky uses to ship thier motors in.  Great dense foam that really holds its shape.  I am using it to push back against the other foam I am using to put an angle on my FPV camera. 

I used 'how to build a qav250 the right way' as a starting point.  Using thier idea to solder the motor leads directly to the ESCs saved quite a bit of weight cleaned up the build quite a bit.  However, with the BLHeli OTPOs and the Luminier FX2206-13 2000kv motors, the switching of the motor wires to the ESCs is the opposite.  Two wires in motors 2 & 3 have to be crossed to get the proper motor rotation. Not on 1 & 4.

I flashed the Naze32 with CleanFlight.  I used Flite Tests tutorial to get the basic setup.   I also referrenced fpv-flightclub's video for setting up flight modes.  The Naze32 flew really pretty good without touching any of the PID settings.  The only thing I have customized is the yaw rate.  It turned way too slow for me.  I like to barely have to touch the rudder to have it start to turn.  So, I cranked up the yaw rate to 1.20.  With it at this setting, I can do nice coordinated turns just like I do with the Trex 450 or 600.  The only thing I think will will tweak next is my P on pitch and/or roll.  I believe it is a smidge too sensitive.  In my videos from the Mobius, I can see the shaking from the over correcting of them when I turn hard.  Perhaps the 'Auto tune' feature will clear this up...  I've yet to play with it.


Yaw Set video

Tough little bugger.



austinthemighty on November 4, 2015
That looks amazing. I cant wait to see what you do with it once you get fpv set up and running!
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My QAV250... this one took me by surprise!