Accident with Octocopter

[kloner]

that was zoomed into the last powerup on the big file he posted..... it is showing motor outputs on #2 and 5. the y being so different is the problem. all i did was enable motor 2 and 5 because when i enabled them all those two really stood out as not being overlapping ie pushing on each other, the other picture is that same point in time but see how even they all are? you want all those as close as you can for best performance, makes all the props change there torque quickly so when the fc sends a command, the aircraft responds. Ever been around a multi that revs like crazy when in wind or descending? that's usually uneven motors.

In his case he is dealing with a frame i have years of experience with so have been fine tuning them for a while and this is the secrets to that "working out".

for whatever reason when i use Grab on my mac it is not showing that column, guess cause i'm clicked onto grab and not that window.

no problem, i enjoy sharing or wouldn't be here

 

[gtranquilla]

By the way.... are any of the larger, e.g., U7 or U11 motors using at least one thrust or so-called "end-thrust" bearing?
They last so much longer in VTOL applications as the do in our industrial plants where vertical pump motors are required.
http://en.wikipedia.org/wiki/Thrust_bearings

We built out a u7 and u11 rig this summer to take over all the red carrying duty. The 3520 fly the gh4 gimbals with 20 amp hours dead on 50% hover. overall the hobby grade mt/mn series motors are weak n the bearing dept,,,, even though theres 3. The u7 bearings are twice the diameter, hence the move

I've noticed them burn up when we get caught out in wind, like 20-30mph and have since reigned in the flight envelopes on this rig with epics to less than 10.....

 

[kloner]

the 3520's i'm on are tripple stacked bearings. I'm not sure on the u series or even kde,,, never looked. the u7 have a massive diameter bearing

 

[Lanzar]

Ok that surprised me, I would be thinking twice if I had to replace a motor every couple of gigs.
I have looked at these motor stats and they seem to be pretty good, even compared to the U7 which I am surprised about, I am sure @Lanzar knows his stuff and tested all this , but I am sure they were flying motors like this not so long ago before the likes of the Hammer came along, what suddenly makes it so dangerous now, these things have a 2KG thrust at 65% with 16" props and 3.5KG at 100% which looks pretty good to me.
Is the only answer to be flying a really heavy machine with 28" props for anything just over 10-12kg?

Is not tat I am saying that this things are not flying red. Its just that the brushless and all this prime lenses changed the weigth too much.
THe AV200 servo or FF cinestar 360 serv gimbal was more like 800g while now you have Chinese alexmoss gimbals flying at 2.2 kg. And ppl changed them without thinking about the extra waight they are adding.

For example our skyjib cinema had 1.6 kg pr motor on 53% and was t 9.8 kg without camera. So we had a rough 3kg for the camera and lense. Now I see ppl change to brushless and adding bigger bateris and they add 2 to 3 kg of weigh o them + the same camera and all the sudden they are on 70 to 80%

All I wanted to say was that with this kind off system you always need to watch out for temps, amps or ...
While now on u7 series or similar there is so much trust avalible that there is no more overheating or problems

 

[Lanzar]

were in 60-65% hover, it's been going like that for a year and a half, 40 gigs

we replace a motor or two every couple gigs.... bearing breaks. she handles the broken motors decent for what it all is. It's obvious when they go

for the record lanzar insisted ESC's would never work in a skyjib either...... thank god i didn't bite, would have never got to where i am

I never said they will never work but that they in 90% case don work well. Redesigned airplane ESC are what they are. This is why you see posts every few days.
Refresh my mind about esc and I will explain it more.

We always go for safe over sorry. And using MK with the adapter to ppm to use esc when you have special boards avaible for a fraction more. THen all I can say is that aerodrive and Hercules were a way to go.
Please check the internet and let me know who until now is flying U7 on esc. (close to none). The only u7 that are flying are with herkulesboads. I got at least 100 email with esc and U7 problems and crash video footage.
Now there is a sec that works with them but ......

 

[Quinton]

Now there is a ESC that works with them but ......

You always stop at the best part
Is there an ESC that works well with them?
Herkules is only rated at 30A though while the U7s are 40/44A

 

[Lanzar]

You always stop at the best part
Is there an ESC that works well with them?
Herkules is only rated at 30A though while the U7s are 40/44A

Well we are testing now so i will not post any comments before i can be shure.
Yes hercules is 700 wat per channel so this gives you on 6s so this is 30 amps. Peak a little more and since it has good cooling compared to the esc it works like a charm even in dubai or desert on 40 deg + celsius.
Well u7 come in 2 different setting and the KW12 we provide are the 3rd option.
If you use hercules and if you fly normaly for a film the amps on any copter will not exceed 180 to 200 amps. If you realy push it forwards and full trotle then there is a good chance if you hold on to full sticks it will fail , could be 1 or 2 motors.So it depends on okto ot coax, propeler size and copter weight.
@Quinton there are stock ESC from tiger that work (tiger sais they fixed it)

 

[kloner]

heres u7's flying awesome.... you just gotta go with what tiger recomends,,,, and it says "We recommended the T80A ESC as the default combination with U7 @ 6S"

 

[Quinton]

heres u7's flying awesome.... you just gotta go with what tiger recomends,,,, and it says "We recommended the T80A ESC as the default combination with U7 @ 6S"

Why so big though 80A ESCs for 40A motors.
I see you are using the 490KV any reason for this over the 420?
Also what telemetry is that you are using in the FPV video it looks great... actually why don't I just go and move into your house

 

[Lanzar]

Why so big though 80A ESCs for 40A motors.
I see you are using the 490KV any reason for this over the 420?
Also what telemetry is that you are using in the FPV video it looks great... actually why don't I just go and move into your house

HAHAHAHA @kloner you make me laugh, like you want to prove something to me, and belive me you should not. I know you know your stuff and i am not against you. If everybody knew as much as you do we would have less accidents and less problems.
BTW remember that this information is about 14 days old. We recommended the T80A ESC as the default combination with U7 @ 6S" And i am still not 100% that they are working fine. And this are the oficcial esc that actualy does not reset in air. Belive me we had them for 3 months now +- few days and are flying one big one with them. And this is something all that buy U7 should know and read so this ESC is a standard. THey work also with our old 75A that tiger made for us. We have a new testing piece but i cant say for now until its ready.
But i promise if it goes well we will post it.

 

[kloner]

because i tried several alternative and it produced commutation errors. in this case it isn't what it's rated at, it's what works

went 490 cause the numbers on a hex with 18" props and an epic made it so. it hovers at 45-50% with an epic, 30% with no payload, 40% with gh4

that is the tbs version ezOSD.... it has current sensing and rssi monitoring, main reasons i'm on it

 

[kloner]

I believe ya lanzar, so far i've been "so good"

Have had these stupid things causing alot of havoc around here and finally, something is working. been messing with them since november last year and am just now getting comftorable with actualy carrying a valuable payload with them.... the complete airframe there on is just over 9 lbs,,, carries 20 amp hours, flies forever compared to my 3520 jib that weighs in at 12+ lbs

 

[Lanzar]

490 is for 16 inch okto cause othervise you cant get the trust you need.
420 is for 17 or 18 inch coax quite good.
But 490 can burn 80 amps on motor easy and multiply this by 8 600amp + and its totaly doable. So you need 4 bateries minimum othervise with 2 bateries the voltage drop when you push it to max will be from full battery to 25v to 20v instant until you stop. And battery will get so hot that it could explode.
Based on testing it is easy doable with DJI to go over 600 amps with 19 - 20 kg total weight copter.

 

[kloner]

I ran em on 16", 17" and 18" and the 18"s bar none make her fly best,,,, amp draws with an epic hovering was 78, pushed it to 130 amps, has 400 amp buss.... 20 amp of 20c so 400 amp service all across the board, prc6 times 2 are probably my biggest limiter. Haven't felt much in the way of heat except in the esc's and there within operating range

yea, it's a little hex made to fly epics, she'll never go over 30 lbs AUW, your talking almost double the weight.... just don't see the need unless it was carry two epics

 

[Quinton]

But 490 can burn 80 amps on motor easy and multiply this by 8 600amp + and its totaly doable.

I really appreciate your feedback on this, it is great to learn these sorts of things from people who are out there doing it daily. Thank you Lanzar and [MENTION=1417]kloner[/MENTION]..however...
This part I do not understand, how can a motor that is rated for 40A continuous burn 80A, are you talking about for a very short time, like an ESC could do 60A even though its only rated for 30 for a short burst?
I really need to get better telemetry set up so I can learn more!

 

[Lanzar]

I ran em on 16", 17" and 18" and the 18"s bar none make her fly best,,,, amp draws with an epic hovering was 78, pushed it to 130 amps, has 400 amp buss.... 20 amp of 20c so 400 amp service all across the board, prc6 times 2 are probably my biggest limiter. Haven't felt much in the way of heat except in the esc's and there within operating range

yea, it's a little hex made to fly epics, she'll never go over 30 lbs AUW, your talking almost double the weight.... just don't see the need unless it was carry two epics

About the c rating : i always devide the data off the manufacturer by 2
SO if you have 2c on 10000 mah then this should be 200 amps but usable is 100, anything more than 100 then the problems begin. If you take one batery and hook 4 motors on it and do a 50 to 80% trotle you will see that once you go over 1c the voltage drops and the batery start to heat like its a heater . Better the batery, better performance but still the C ratings are more or less just a label thing.

 

[Lanzar]

Kloner.

DO you fly a Y 6 coax or normal hexa. If you fly Y shape please take off 1 bootom prop and try to fly with the same weight as you do with epic. And tell me what hapenes.
p.s.: Do not use epic and gimball for the test.

 

[Quinton]

About the c rating : i always devide the data off the manufacturer by 2
SO if you have 2c on 10000 mah then this should be 200 amps but usable is 100, anything more than 100 then the problems begin. If you take one batery and hook 4 motors on it and do a 50 to 80% trotle you will see that once you go over 1c the voltage drops and the batery start to heat like its a heater . Better the batery, better performance but still the C ratings are more or less just a label thing.

See now I am following this thread to try and learn a bit, however I like to get my figures right so I can understand (as I am a bit stupid sometimes, and try not to take things that I read for granted)
Don't you mean 20C and not 2?
10000*0.001*2C is only 20 Amps (not 200A) or am i thinking something completely different?

Also would be nice if someone could explain what was posted above, honestly I can not sleep at night until I can get my head around these things ..
"This part I do not understand, how can a motor that is rated for 40A continuous burn 80A, are you talking about for a very short time, like an ESC could do 60A even though its only rated for 30 for a short burst?
I really need to get better telemetry set up so I can learn more!"

 

[sk8brd]

quinton- i think he meant 20c...mah to amp hours times c rating. you got it

 

[Lanzar]

Ups yes 20C, if i replay in internet explorer i have some problem that keyboard does not respong well. So its my bad.