Building the "K-Quad"

[CurryKitten]

Where 'K' in this stands for Krikey, you can see information about his 3D design and print of the frame in this topic http://www.fpvhub.com/multi-copter/14/my-new-mini-quad-250mm/17133/ but rather jumble more stuff into his original, I'm going to use this topic to document my build of his frame.

So this is what krikey very generously gave me up at Mad Dogs 5.. which feels like a lifetime ago, but was only last week.



The initial thought was to put the lipo on top of the bottom section and have the electronics sit on the little shelf above.  But I found it was a bit tight for the 1600 2s lipos I was going to use.



Of course, I could have sourced shorter fatter lipos, but instead I decided to use the underneath of the bottom plate.  This means that the legs go on the top of the frame (whic isn't quite as designed) to give me a smooth section underneath for the lipo to hang down on.



Electronics wise, I really couldn't find much data on many small motors.  In my mini  H quad, I used the Turnigy 1811-2900's, which works fine, although a bit more poke would be good.  So in lieu of finding a decent alternative, I got some Turnigy 1811-3800's, with the theory that the increased KV will get me a bit more oomph



These produce a tad more ampage that the 2900's, so have gone slightly bigger with the ESCs and have got plush 10A's (which are still tiny)



...continued in next post, as I'm not sure what the limit on photos is

[CurryKitten]

So with the ESCs, I wasn't sure what layout I wanted, so basically put them in a few places to decide what I wanted.  My first thought was to put them all underneath the top section.



It's a little bit of a squeeze, even after trimming wires, and I'm not particularly good at getting things neat, so then considered the ESCs on the arms.



Which would be ok, aside from the fact that if you cut the wires down on the motors, they seem to reject solder sticking to them, so have eventually settled on a kind of half-in-half-out layout



Which should give me plenty of space to work with and keep things relatively neat.  So to keep things low profile, I got some 15mm risers to go between the top and bottom - which I think makes it look pretty cool



So, other things needed were some small bits an pieces like m2 screws and wire, but a few larger things on order from HK international like a new VTX and a KK2.1 board to run it all.  So a bit of soldering can be done now, but I'll need to wait for a few other bits to turn up before I can get it flyable.

[FPVSteve]

Looking good CK.

One handy hint I found on FPVLab a while ago to do with motor wires is (bizarrely!) to first heat the wires with the soldering iron while you have them rested on top of an aspirin tablet. This dissolves the coating on the wires and leaves pure copper onto which you can then solder :)

[bignose13]

Why don't you go for the nano wii board Wayne ?? Half the size of a kk board and saves a bit of weight
Looks awesome btw

[CurryKitten]

I'm a bit lazy in that I tend to stick with what I know, and I don't know multiwii at all.  I do really like the ease of messing around with the kk2, that built in LCD is a genius idea.

I don't want to be stuck in my ways, will schedule in some time next year to experiment with some different flight controllers.

[CurryKitten]

Little bit more work tonight.  First off with power distribution this time, I decided to use some PCB stripboard I had left around, and so cut a few small squares from this sheet -



So I cut the ESC motors to the power distro and motors, and bulleted the motors and ESCs, then put them all together like so, creating my little solder pads in the centre.



Once the top and some props go on, it's starting to look the business



What I do really like is how low a profile it has, from top to bottom, it's just 28mm right now :)



What is even more interesting, is that chatting to krikey on Skype tonight, aside from a few more design changes he's made to the frame, his ESC layout is completely different, which is interesting in such a small frame that there is more than one way to do things !

I'm stuck now probably for a week.  My UK channel order from HK only got dispatched today, and contains the KK2.1, VTX and some wire.  Also waiting on some XT60's arriving from the UK

[Brod]

looking good ;)

[krikey]

Looks great CK. Looking forward to seeing these both flying. Here's mine to date but with a KK2 tray rather than the flat top.

[CurryKitten]

A small update, but it's nearly done... frustratingly so.  So the post came today, and in it was a package from HobbyKing containing a KK 2.1 board, a VTX, and various wires and bits and pieces.

So I finished the main power stuff by wiring in an XT60 connector for the lipo, power to the vtx, and power to the onboard voltage alrm on the kk2.1



Plush ESCs default to lipo type batteries, so I changed these over to Ni-xx so i wouldn't suffer the low voltage cut-off



...and then I got a bunch of magic blue smoke !

I'm not completely sure what the problem was, it appeared to come around the voltage connector on the kk2.1 board... it wasn't exactly well marked, but I'm pretty sure the polarity was right.

I checked everything over and reconnected, fully expecting to have blown the board, or an esc or something.... but everything then powered on absolutely fine and was working ok.

So the latest pic looks like -



So my to-do list is -

• Make up USB cable for 808
• Make little holders for FrSky antennas
• Create a dampening mount for the camera

So hopefully I'll be able to test-fly it in the next few days.... although with the weather as it is now, this could be a very unexciting hover in my lounge.

[Brod]

neat,whats it weighin in so far without lipo?

[bignose13]

Antenna look nice Wayne  :-*
Sox mate, does look pretty good (The copter),
Ive started building my small T Copter after getting some inspiration from you and you small quad
Its a bit bigger using 8 inch props
I'll get some pics up today, I've called it the "Noseycopter"
Soz for hijacking

[CurryKitten]

Antenna look nice Wayne  :-*
Sox mate, does look pretty good (The copter),
Ive started building my small T Copter after getting some inspiration from you and you small quad
Its a bit bigger using 8 inch props
I'll get some pics up today, I've called it the "Noseycopter"
Soz for hijacking

Hehe, no worries - been looking forward to seeing your small T-copter, I've noticed you've stopped trying to call it a mini, which is probably appropriate considering the power of those motors you've put on it :D

[Gav]

Very good Wayne and nice frame Neil.  Top job.  Long gone are the days of a  hack saw, B n Q 10mm ally tubing and G10 fibre board  / bit of plywood with these ere 3D printers :)
Will look out for the maiden fpv video.
Gav

[CurryKitten]

Looks the business doesn't it Gav... of course, it's a little untested as to how well it will fly.  But I don't think there's any more flex in the arms that the average DJI 450 arm, so I think it'll be good.

It was my wifes birthday today, so I didn't have time to solder up my 808 cable, but I did at least get the antennas from the rx and the piezo buzzer tidied away so I'll be able to LOS it and start some tuning (which I need to do anyway before I think about putting the goggles on)

Here's it's (semi) final look, next to my "made of old tricopter legs" mini-h... which looks embarrasingly awful in comparison :D

[CurryKitten]

Yay, finished the build... well kind of.  What I mean is I've stuck everything on there, but of course it's not properly tried out as you've all seen the weather.

What I did tonight was make up my little 808 video/power cable and plumb that in.



As mentioned, I may need to add some dampening to that, but I'll come to that when I can actually get to fly it.  Of course, I immediately wanted to try it out, but came up with an embarassingly long list of things I'd forgotten/ignored making me a prize idiot.

First it was all over the place and didn't seem to respond properly... why, because I'd forgotten that KK2's don't just fly X quads, and the default setting is a + config, o that wasn't great.  Next a motor flew out of it's own mounting because I hadn't checked and threadlocked in the grub screws.  Then I found it would take off but yaw wasn't responding.  I'd managed to put the rear props on the wrong way, but had the motors running so they span up ok, but of course yaw didn't work !

Anyway, with all that corrected, I finally was able to do a little test hover.  I'm in the small space in my man cave here so it was short... and quite tense, and I haven't done any setup on the kk2 board at all (this is all default) so much tuning to do, but already the frame looks good.  Yay for 3d printing :D

K-Quad first little hover