Help with WKM octo setup

[zorba]

Hi I am building a large octo I need help to configure the setup
My equipment are:
Wookong-M
Hobbyking 30A esc's with SimonK firmware
Avroto 2814/11 motors
4S 6000 X2
AUW 6.5 Kg
Props 12x3.8 CF
DX-8 Tx/Rx

Does this conf. looks ok?
Do I need to do any changes.

She flew fine for 6 min, landed and tried again but the esc temp was 140F
I tried lifting off again and she quit half throttle. I repeated and she quit again.

Any suggestions?
The camera gear and acc. amount to 3.5Kg


Cheers

 

[elossam]

6.5 kg + 3.5 kg or 6.5 total? 140F seems no to be so high imo for 6.5 kg tow but it deppens on your weather temp outdoors.

 

[zorba]

6.6kg total weight.
copter camera and video link.

 

[Sebas600]

View attachment 6030

Should not be a problem for the ESC's
But the high timing can make them hot.
Do you have photos of the config?
To long or to thin wires can make a difference.

I alway put on some heatsinks.
Don't really trust in a small plate on the chips witch is insulated with heatshrink tube from the air that should cool it.

View attachment 6031View attachment 6032View attachment 6033View attachment 6034

 

[zorba]

Thanks Sebas, Neet idea where did you get those heat sinks?

 

[Sebas600]

www.farnell.com www.rs-components.com
these were from farnell. 40x40 and made them a bit smaller to precise fit the esc, took of two rows of ribs.
make sure not to cut of all the heatshirink so the smal plate comes lose, leave some on the sides where the wires are. 3-5mm each side
have used heat conducting tape. applied it to the esc AND the heatsink, rub it on well with the back of a screw driver or something round and smooth.
and then put them together, this makes the best bond so de don not come off!!

 

[zorba]

Thanks Sebas. I used Artic silver for my sinks on the BL's
Will that do?
Also would be easier to mount the sinks directly on the fets instead of on the plate?

Cheers

 

[Sebas600]

I used this http://nl.farnell.com/jsp/search/productdetail.jsp?SKU=1219151 as adhesive, cut to size.

I put the sinks on the plate because the plate is still firmly attached to the esc, because of the edges being under the shrink tube.
Putting the sink directly on the chips would mean a lot less area to glue to and more possibility to come off, burn up, crash, cost more money and time

 

[zorba]

Once Artic Silver is on is for ever. I trie to pry the heat sinks off an old PCB and had a hard time.
And it was held on on only 3 fets. My esc's have 6 fets.

Cheers

 

[Search49]

In the United States the best place is: http://www.heatsinkusa.com/ - they will custom cut to the exact size you need

 

[Sebas600]

Once Artic Silver is on is for ever. I trie to pry the heat sinks off an old PCB and had a hard time.
And it was held on on only 3 fets. My esc's have 6 fets.

Cheers

Thanks for the great tip!

 

[zorba]

No, Thank you for the idea. I found some on Digikey here in Canada.
Easier and faster to get.
http://www.digikey.ca/product-detail/en/364424B00032G/HS391-ND/1216395

I used a toothpick to apply the artic silver. Don't use too much it will squeeze out the sides and moght touch the fets.
It is conductive and it might short things out.

I will let you know how it turns out.

Cheers