Q: will it fly?  fly well?

I'm prototyping my latest design - got my motor mounts put together.  Other than the plate in the middle, this is the only thing that isn't out-of-the-box... but could be made very simply if they prove to be robust enough:

Am now toying with a 4+4 octo design - with 4 motors pulling, and 4 motors pushing such that the props can overlap about 2cm at the tip, but because of the over/under design never actually come close to interfering.

This is a mountain bike wheel - for a 26" wheel - the OD measures 22.5" with props @ 24.5" diam.  

(am going to try using 4 pulling 880kv motors with 11x4.7 blades, and 4x850kv with 10x4.7 blades)

The next step up using the wheel design, with similar mounts, would be a road-bike wheel which measures 25"diam. and would have props @ 27"diam.

Here is the 2cm overlap from above:

I'm interested to know what behavior I might get with this combo - has anyone tried it?  Am I off my rocker?  Working on fixing up the center stack now.  I've flown a quad with this setup before... it worked pretty well when the ESCs weren't overheating for the hot day + heavy camera load.

Feedback very appreciated!

~jake

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It's not exactly Octo... it might be at some point in the not distant future - but for now, Quad will have to do!

With the new uBlox GPS receiver, I am getting some incredible loiter accuracy... so much so that I was comfy pulling the iPhone out of my pocket and shooting a video with the transmitter largely unattended!

My original concerns that there might be too much resonant vibration seems to be unfounded - I'm happy to report!  And 4 spokes seem to be perfectly sufficient to carry the central load:

Ok... I flew the octo wheel today... Set up using octo +

4s 5000 / 22/15 900Kv / 20A ESC / 9/6 Props

The craft flew surprisingly well... overall the most stable multi I have flown to date.

Mavic 319 DISC rim 700c weight listed as 595 grams...

AUW for the octo wheel, including 4s 5000mAh 70c = 2.5 kg

Waiting for the gimble... and building landing gear... pics and video coming soon.

Yeah - now that I've had a few days to think on it, my bike-wheel quad was also the most stable I've flown, too.  Perhaps having the battery/receiver/APM stack isolated in the middle - suspended by a few spokes - is transferring less motor vibration to the APM?  Thus smoother/stable flight?  I was really impressed.  Looking forward to yours, Brian!

here she is .... tested in 30Km gusts w/ gopro hero and FPV kit.. still flies nice and smooth :)

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Nice job!
Any special trick to mount the motors and the center plate?

Weight-wise, with a ration of 3.14 per diameter, a circular design starts looking specially interesting for Octos. With larger arms the advantage increases.

Motor2Motor      500     600     700     800     900    1000    1100
Circular:       1570    1884    2198    2512    2826    3140    3454
Quad:           1000    1200    1400    1600    1800    2000    2200
Hexa:           1500    1800    2100    2400    2700    3000    3300
Octo:           2000    2400    2800    3200    3600    4000    4400

I used vinyl straps to mount the motors directly to the rim... the center plate is the standard plate from rctimer 450 quad. the APM is mounted on the top plate , which is "suspended" from the main plate (the one attached to the rim) with alloy stand off's and rubber washers...

Now I am looking thru my stuff for a 20" alloy rim for a quad ;)

I realized the largest diameter for a bike rim would be 622 millimeters.
So I looked for bigger aluminum rings. Thought of Hula Hoops.

Then I found this Hoola, just 13 EUR and 360g, 800mm diam. (have found from 600mm up to 1000mm), a flat surface (20mmx10mm) and of beechwood. Would it in your experience be strong enough?

Well... there is only one way to know for sure.... :)

my finished octo wheel...

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That is fantastic!  How does it fly?  Any video of/from it?

I have been whittling away at my next iteration.  I managed to get a hold of a 26" carbon wheel.  Ideally, I want a 29", but this'll do for now (it was free - from a cyclist that put a small crack in it).

Fabricating motor mounts has been a fun project.  My goal is to create interchangeable parts so I can easily swap wheel to wheel.  

A little fun:

My power distribution block:

My original motor mount design had a weak spot with the 180 degree bend... I found a crack in the bend on one that ran about 3/4's the whole width.  One more flight and I would have had catastrophe, fer sure.
(see also: 

So, I'm pretty pleased with how these turned out:

I guess we are the only two doing this....

I wonder when everyone else will catch on.

I like the tire... haha I bet it floats, and all the bits can be well sealed in the tube.

nice one.

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