Coaxial Oktocopter

[Wavess 0]

Hi all, after many satisfactory flights with my quad (Mikrokopter),

I decided to go farther and build an oktocopter. Basically I need mode payload than a standard mikrokopter can handle.

Looking at the oktokopter sold at mikrokopter site, I really didn´t like it´s frame made out with those 10mm x10 mm aluminium square tubes. Also it´s a very big quad making it dificult to store and transport.

So I decided the most compact way to have an okto was doing a + frame with 2 motors per arm (coax)

The goal is to mount a platform to carry a 500gr HD video camera.

The main equipment that it´s going to have is:

Flightctrl ME

Barometric sensor

MK3Mag

MK GPS

NaviCtrl

8x Holger ESC

8 x Turnigy 2213-22

8 x APC 10x4.7

FPV gear off course

Sony CX 500VE HD 1080 stabilized on both tilt and roll axis.

So I went ahead and thought about a frame used by MorenoenNYC1 over rcgroups. He used quality carbon fiber square tubes and gusset from dragonplate.com

I ordered them and paying a little more they cut the square tubes to the dimension you like.

So final lenght of the frame from motor to motor is more or less 60 cm, not small but not too big for transport.

[Wavess 0]

The Holger ESC´s are mounted on the power distribution pcb sold at mikrokopter.

Due to the dimension of thi pcb I had to redesign a new gusset bigger to fit properly this pcb. I made a .dwg file and sent it to dragonplate for cnc cut.

Meanwhile I mounted all the MK boards (few caps and conectors) and power pcb.

Also bought at sparkfun a bluetooth module that with a few smd components and setting it up at 57600 it´s totally useful for Mktool and realtime Mikrokopter data & programming.

[Terry 5]

Very interesting, please keep posting

Terry

[Kilrah 2]

Cool!

I'm about to receive a okto set, but will mount it the "standard" way. Yes it's huge, but that size also has a lot to do with its incredible stability. Efficiency is a bit better as well when the props aren't in each other's wash.

Edited December 16, 2009 by Kilrah

[Wavess 0]

Cool!

I'm about to receive a okto set, but will mount it the "standard" way. Yes it's huge, but that size also has a lot to do with its incredible stability. Efficiency is a bit better as well when the props aren't in each other's wash.

Nice, yes the "official Okto" is more efficient due to it´s motor placement than a coax. I didn´t mind to sacrify a bit of efficiency over the size. I have seen the "official okto" and flies incredibly stable, much more than a standard Mikrokopter

More pics, the bluetooth module and the top side of the power pcb

Edited December 16, 2009 by Wavess

[Wavess 0]

The bluetooth module pic (forum has 200k global upload per post)

[Wavess 0]

I plan on using the chip BTS-555, can handle 158A continuous, and prevent battery and quad conector from the starting load of the caps.

http://export.farnell.com/infineon/bts555/mosfet-smart-switch-to-218-5/dp/4109260?Ntt=bts555

I built a through hole board with the attached circuit, to be able to use the switch on the flightctrl that it´s handling only a few amps, the bts does the hard job here

I have installed a 10 AWG wire from battery to the BTS, and from the BTS to the ESC´s power circuit board.

[Wavess 0]

Also I made an extension of the BTS circuit that I have attached, getting 12V from the BTS and using it for leds conected to SV 2.1 and SV 2.5. The flightctrl only can handle 100 mA and I going to have 4 arms with all covered inside by leds.

[Wavess 0]

A little bit late but here are a few more pictures on my okto building and finished.

[Wavess 0]

more

[Wavess 0]

more

[Wavess 0]

finished with 35mhz receiver, no I use futaba 2.4ghz rx and a new hood, when I get some time I´ll post the new pictures

a video I put together with it + some parts with a quad

Edited November 25, 2010 by Wavess

[Wavess 0]

finished

[Terry 5]

Very nice

Any idea of the cost?

Terry

[Wavess 0]

Umm, since my wife doesn´t seem to visit the forum and no one else is hearing us aprox 1600-1800 €

[Mr.RC-Cam 126]

a video I put together with it + some parts with a quad

http://www.vimeo.com/16397013

Nice! Which HD camera are you using?

[Wavess 0]

Nice! Which HD camera are you using?

all this video was made with a Contour HD 1080p action type camera shooted at 720p 60fps.