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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Interesting.  I suppose one other option would be to mount the ESCs on the rim too, to prevent the spaghetti to the centre. You'd only need to wire out power wires and the little ESC signal wires. That would increase moment of inertia a bit though.

I hadn't thought of that, but I like it!  I could zip tie them to the rim and there'd be some great heat transfer & cooling there.  

I realized that I put the lower props on upside down, also.  Will be swapping out the lower 850kv's with 880s, too so that it is balanced power all around.

Nice, I had a similar idea for two main reasons:

I did not do the math, but thought that with an increasing number of arms (>4) and increasing arm lengths, at some point a circular design had to be lighter, stronger and stiffer.

Multi-rotors became cheaper taking leverage of other industries mass production (phones/sensors/low power chips), where to get cheap light carbon frames and other components? Bicycles!

I had in mind a Y6, but your X6 idea if it works, it should be much better, the best of both worlds: Efficient and redundant.

Another advantage I saw in this design was that it should be easier to hang a steadicam on the axis. I see two options:

Something like this

Or even better something like this (where the wheel would be already the external element

In this second option, the batteries would be used as balancing weight at the bottom. The bottom could even be another smaller wheel (or one can attach two bars) and function also as landing gear :)

Jake,
Have you flown your 4+4 yet? Normally in the biking world, the rim is seen as nearly a non-structural element until it is laced with spokes. The idea looks very interesting. This may be an idea for my next hexa I'm trying to get a frame for. Do your four "spokes" to the wheel center help to constrain the flimsy rim I'd note that your mountain bike rim is likely much stiffer than most road bike rims would be, so yours is likely a good choice. I take it your rim is aluminum?
I like your original thinking.
Larry

awesome idea. does it fly yet? fly well?

:D

I did something similar.  Pics and videos below:

Flat octo, wheel design.

Rick

humm... i thought i was the only one crazy enough to try this.... I just started to put something together last night, then found this thread.

I am using a 700c Road rim .... and I have the center stack laced into the wheel with stainless spokes.

Looks kinda cool actually, i'll snap a photo a bit later. I plan on using the spoke to lash some hardware onto.

I plan on setting it up as an octo, using 22/15 900Kv motors on 20A and 9/5.

APM 2.5.2 is running the show.

The idea is to boom a DSLR on gimble... More on that later.... did You ever get this thing to fly?

This is what I have so far.... a nice 29'er rim, double walled and true... Light and strong. Tunable with a twist of the spokes....

I plan on mounting a pair of alloy rods accros the rim, to bolt the gimble onto...

Attachments:

Would you believe I put this design on ice for a while, then ALSO began working on it this weekend?

I'm still a few steps away from reality... and not certain the 850Kv motors will have enough umph.  Been trying to get parts/plates from the spare octo frame to work as my hub.  I think it's going to come together nicely... but I'm still tempted to put 8 motors on it.  I'll see if I can get it to behave well with 4 first:

Your closer that I am.... I received the extra bits i was waiting for ... I'll try a hex first, running 9/5 on 900's

post a vid of that puppy in the sky :)

I feel less crazy now....

I had to pause for the workweek - but it flew, barely, with the 850Kv's.  Swapped in the 880Kv motors and it flew great.  Really stable - but clearly on the heavy side compared to all the small, carbon quads I've flown.

I am going to have no alternative but to set this up as an octo.  Perhaps this weekend... 

Sorry, I neglected to get video. Will do soon.  Still sorting out the lowers - gear, batt mounts, etc.

JB

Latest iteration just pre-flight:

Nice!

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