Given the popularity of the 230/250 quads at the moment (blackout etc), I thought - wouldn't it be cool to have a rig that can do the ground skimming proximity stuff, but also with the normal "mod cons" of the APM?

Traditionally though, an APM would never fit. Until HK released the I built one.

I started with the Haldey-Bocks 230 frame, in Carbon Fibre. This was a mistake. I should have gone for the 250, because the fitting of the ESC's was a bitch of a job, especially with the thick 3DR power module hanging off it. And naturally, I forgot to solder in the XT for the video feed, so had to start again...

Anyway, this is the bare airframe:

So onto the fun part...

First, I fitted the camera, so I could make sure the clearances were good. I mounted it directly to the front CF plate to make sure I had as much room as possible behind it.

Second, I mounted the GPS antenna pole. This required a lot of trial and error, but eventually I found a position which worked.

Third, I fitted the APM mini in front of the post, and behind the camera. There is *just* enough room to do this. It is currently mounted with double 3M pads - I will review vibe damping after the first flight. Supposedly the blue balls do the "clean/dirty" thing, but is it enough to keep the APM within Z axis tolerances? Time will tell. These rcx are not the smoothest I have to say, and a propless spin up was really vibey.

I wired in the GPS, and the radio.

Then I mounted the 3DR telemetry radio to the roof. It is likely I will replace this with a minimOSD, and run a really simple OSD - volts, ground speed and home distance.

I then cable-tied the xt60 back on on itself on the PM - it was interfering with the props.

CoG is spot on, even though I thought it would be rearward.

Weight with tx will be 505 grams as you see it here. I have a wiring exercise to do (shorten and tidy), and to enclose the APM with some foam (for the Baro), and I hope that brings it down below the target 500 grams.

And that's it! It all fits together nicely. All the normal calibrations done - just compassmot to do (want to wait until I've got the camera and tx wired in first). Going for a really small 200mW 32ch 5.8. Will fit perfectly.

I didn't have time to get the thing in the air, but should able to get it in the air at the weekend. Can't wait to use DRIFT on this...:-)

Views: 19501

Comment by Jiro Hattori on May 7, 2014 at 2:33pm

Looks great! My understanding is that most of the flight controllers could not fly well on this type of small format. APM is also not good operation ability on this compact quad.

Please show off your video and PID data:-)

Comment by Roberto Navoni on May 7, 2014 at 3:34pm

Hi Euan Is not true ... VRBrain 4.5 fit without problem as in my last blog post :)  but Micro Brain is the best :) 

See this preview post on italian forum ... i'm preparing a blog post with last update on micro brain for the week end :)

first flight 

This flight doing last week with std VRBrain 4.5 with APM Copter 32 rev 3.1.5 In the next day i hope to doing same test with micro brain. I yet test all automatic function : Takeoff , follow me , return to home auto mode ecc ecc all work perfect !!!

Your frame is very nice :) I think that this kind of platform is very good for enjoy with it , indoor and outdoor:)

Comment by Gary McCray on May 7, 2014 at 5:39pm

Hi Euan,

This is a wonderful project.

I can find no reference on Google to Haldey-Bocks frames except this one and have been trying very hard to find it.

Hobbyking lists nothing similar to it although they have a nice new little plastic 250 mini.

I did find the Lumenier 250 frames and they even show one in Carbon Fiber that is not yet in stock anywhere.

Could you please send a link and more info on that frame.

I am already using Hoverthings Flip frames which I am very happy with but a decent smaller one would be very interesting although I would really prefer one that could still swing at least 8 or 9" props.

More in the 300 - 350 range.

If you would consider allowing me to include this in my dronesarefun web site I would appreciate it.

Best Regards,


Comment by mP1 on May 7, 2014 at 7:13pm


Why have you got two cameras, the mobius and a board cam ?

Comment by RC on May 7, 2014 at 11:10pm

Im doing tor a build around the HK 250 frame. It is a tight squeeze and lots of resoldering is needed for everything to fit and to remove excess wiring

Comment by Euan Ramsay on May 8, 2014 at 1:22am

@ Jiro - why would APM have a problem with a frame this small? I could understand that the 230 is not square like the 250, but delinking roll from pitch should compensate. Are you saying that the APM PID loop can't cope with a frame this small/fast? That doesn't quite seem right.

@ Gary: Hadley is on Facebook only, and builds frames to order; he's just a student, so can't really afford to go "full retail". However, he's doing some really nice work in the micro sizes - He's also got a Y6, a hex and a quad with the 2 rear motors at a 45' angle to roll axis (I forget what this format is called). All these in the micro sizes. When I get home (work blocks facebook), I'll send you his details. Feel free to include this build on your site, but I recommend waiting until we see it actually flying first :-)

@ RC Tech Se: Yeah, I had the same issue - I had to cut/solder nearly every single wire in the HK kit to get it running. And I've got it all to do again, when I shorten them all ;-(. I have a some heat shrink for the APM. I'm planning to add moon gel and some foam in there, and shrink it all together. Then cut out squares for the LED's.

@MP1: One is the flight cam, one is the HD video record cam. Mobius are too laggy for flight cams, and don't have any WDR to speak of. Plus I wanted some basic OSD info as well. The second reason is that I needed something on the front to keep CoG in the centre. As this is a shortened ariframe already, it's gonna be super sensitive to CoG.

Comment by Keyvan R on May 8, 2014 at 2:11am

I have been following the rise in popularity of the fpv 230/250 class quads. I built a cheap one from a kit by HK and put an old kk board I had just to check out how the frame and power system behaves. Had to dial values down on the board but it flies okay

The trouble is the lack of components. In particular motors and ESC 's. I am waiting for an artf blackout which is on pre order. He is waiting for stock on the tmotor 2300's. I am planning to put the mini amp in this one. I have never tried goggle based fpv so I might give that a try

This is also a similar frame to Euan's

I ordered one for a friend which is in transit... again waiting on sunnysky motors. Everything to do with this class of quad seems to be in short supply, even props!!! I am happy to see others here trying the apm platform on mini quads

Look forward to the flight videos.

Comment by Quadzimodo on May 8, 2014 at 2:26am
Euan - Very nice! Look forward to flight videos.

Jiro - Could you elaborate on the issues with FCs working on a frame of this size. Will going from 8-bit to 32-bit help? Can you point me at any discussions that will help me learn more about potential problems?
Comment by Euan Ramsay on May 8, 2014 at 2:35am

Yeah, this is the one thing I might have to change in the immediate future - the rcx motors are cheap, and boy can you tell - lots of vibes, even without props attached. The tiny frame sizes doesn't help. I'll be upgrading to SS as soon as I can find stock. The tmotor MN 1806's are just too expensive.

Comment by mP1 on May 8, 2014 at 3:00am


How many seconds lag are the mobius ?

Have you tried putting vibration foam between the arms and the board. I did that on a dead cat rebuild and i am pretty happy with the improvements in vibration dampening on top of my other efforts.


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