X8 Ring

[mr_westie]

Grettings all.

After the loss of my last AQ I have been wandering the multi rotor wasteland.
Not quite but it sounds good

While this may not be the most efficient build I wanted to try it out after seeing the fuss in this thread.
http://www.rcgroups.com/forums/showthread.php?t=1671523
Unfortunately the mfg has not given a firm release date.
The smaller one has been on preorder for months.
Their Facebook page shows the small ones arrived to them in feb.
The bigger one is being redesigned.


Back to the build

Ring, $130us shipped. Motor To Motor 620mm. 350g
http://www.aliexpress.com/snapshot/231843505.html
Arms, 16mm CF
Center plate / clamps, Rusty UAP1

Motors , W48-22 490KV
Props, Gemfan 11x4.7
ESC, HK Blueseries 40A, flashed with WiiESC COMP PWM
Battery, 4S 5Ah
Downlink, 3dr 433Mhz
Firmware, 6.6 r80 b1035 HW Rev2
RX, NER-649S PCM > PPM converter

AUW with battery, 2900g
Weight has not been optimised

The only tuning so far has been to drop the Tilt Rate D from the default down to 2000.
It was saturating the motor outputs.

I forgot how smooth the AQ is compared to others controllers I have tried.

Excuse the mess, it is a experimental platform after all.

http://youtu.be/__zOqhbwclg






Also have a YS-X6-P coming back from an upgrade that I should be able to compare it to.

The frame is just big enough to install 15" props.
They will be rather close together though.

The frame is ridged as advertised.
I could potentially get a lighter weight rim, 250g? by going with 2mm CF vs 3mm on this one.
How does it compare to a regular arm type build?
I don't have one to directly compare it with.
In theory, if I made the center arms less rigid, the weight of the center place could act as a dampening mass for everything attached.

The plan was to build a heavy lift so upgraded planned fro the AQ were,
.Upgraded Recoms
.Change the voltage divider to handle 6s
.Feed the spare ADC (unused pressure sensor pad) with a current sensor

The tricky part will be modifying the source for the different voltage range.
Adding an extra logging parameter fro the current sensor.



How did I loose the last one?
Overconfident pilot and suspected broken prop.
It was being used in a MilSim War game, Airsoft.
After many successful missions during the day it went up at night.
This was the 3rd night flight.
While I had a working GCS link I did not cache the map of the area before I headed into the field.
A carbon prop had cracked earlier in the day after a hard landing.
I failed to bring any extras into the field.
A quick repair with some kapton tape and it worked good as new.

While in a hover it started to toilet bowl.
I managed to manoeuvre it away over a safe area.
This was easy as we were on a small peninsula, surrounded by swamp.
I went a bit too far into the swamp when I cut power.

http://youtu.be/M80FOLphmVA
At least it will be well preserved
Many lessons learned the hard way.

[kinderkram]

Entertaining story, Mr. - and an interesting frame project!

Taping a prop is a no-go. But ... whome do I tell?
If it landed flat in the swamp where you could see it drop, there would have been a slight chance to find it. But it looks like it caused some impact in the "softer regions" to completely disappear.

Regarding the ring frames: they eliminate any wiggeling, single arms can produce by swinging forth&back, up&down. And the rings are known for taking a punch easily. In general round forms distribute the forces best.
The construction also eliminates the slight imbalance caused by the prop wash on single arms where the motors spin on the tips. Usually neglectable but on large airframes with big coax motors it might be taken into account...

Keep us updated,

Norbert

[chschmid]

Sad news. The good part is it will be well conserved in the mud.
I am very interested in your ring setup findings too.

Cheers
Christof

[Max]

Love the bike rim! I'm too cheap to get those for my actual bike, but now I got an even better use for one! Also I'd never ride on a cheap rim, but for this... nice. And agreed that the ring concept is excellent in principal. I've been kicking the idea around in my head for a while, but never occurred to me to use a carbon bike rim. Brilliant!

TR-D at 2K sounds like a vibrations issue? One thing about those rims, they definitely won't be absorbing any vibes. Maybe mounting a light tube/tire on it would help? I'm at least semi-serious... one of the things I've been meaning to try is wrapping the carbon arms on my multis with rubber, like an old inner tube split down the side. Theoretically this should absorb a lot of vibes, but I'm not sure how practical it will be.

-Max

[mr_westie]

[LPR]

Westie

I found the round frame in my flat octo has worked very well. After many crashes it still is in great shape. The ring is 16" OD and 12" ID made with 0.0050 . I use the AGL arm mounts to hold the booms to the rings.

Larry

[mr_westie]

New Recoms arrive and installed.

While on there I also added the tap into spare ADC.
3v3 zener clamp.
Bought out to an extra header.


Also added a zener to the adc voltage divider too.
On the rear occasion that I connect a fresh off the charger 6s battery at 25.2v

[mr_westie]

Current sensor a go

Using a ACS758LCB-100U
100A, 40mv/Amp

As used on the YS-X6
I did not use a voltage divider to get maximium range.
3v3 gives 82.5A


Zero A seems to float at 0.686v
Reducing my range to 65.25 A
Might have to use that voltage divider after all.


I had a look at the code to see if I could add current logging.
Did find a promising reference to ANALOG_VOLTS_EXT_AMP
Unfortunately after reading the code back and forth I could not find a way to enable it.
A little beyond my ability.

Would any coders be able to assist?
For you trouble I can send you a current sensor or two
Would need two extra parameters added to the system.
CURRENT_SENSOR_0 , 0 Amp voltage
CURRENT_SENSOR_FACTOR , multiplier for v/a

In this case
0.6866
25 , 1/0.04

[chschmid]

I can not help out with coding, but I am very interested in your current sensor project.
What AQ input (physical) do you use to read the current sensor?

Cheers
Christof

[mr_westie]

The spare adc for the second pressure sensor.



Maps to "Voltage12" in the QGC

edit: wrong image link