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Old Oct 10, 2012, 08:47 PM
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Originally Posted by p0st4L View Post
Seems to be a lot of problems w/ the Octo setup. Has anyone tried pairing motors and running an octo in a Quad + format?
Yes I have done this to try to solve the problems I had with the Flat Octo. It still is very unstable in the wind. It is a large octo, 1100mm with QC3328 motors it cost over $5k and I can't trust the WKM to keep it in the air. I am switching to MK.
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Old Oct 10, 2012, 08:58 PM
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Originally Posted by Papajeff View Post
Tarro, just a thought....did you use any copper tape on your Octo? I saw a post somewhere that said,
the more copper you use the better. It also suggested to shield the ESC leads into the WKM and the
leads between the WKM and the Rx.

Also, did you remove the "red" pins from the ESC leads that go to the motor
side of the WKM?

This is something i have not done, ie, removing the red wires, so i need ask, what is the reason that you need to do this, and do you have to ?
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Old Oct 10, 2012, 09:16 PM
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Originally Posted by Davebbb View Post
This is something i have not done, ie, removing the red wires, so i need ask, what is the reason that you need to do this, and do you have to ?
The manual states,
Quote:
If you use 3rd party ESCs, please cut the red wire (power wire) of your ESCs , as the power from V-SEN on PMU is
suitable to most of receivers and other electronic devices.
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Old Oct 10, 2012, 09:23 PM
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Originally Posted by Sniperp View Post
In may I was part if a DARPA UAV competition and I was using the full wookong waypoint kit. We kept running Into issues with losing RC control, flying 2.5miles away and trying to land on a roof with a forest between you will do that, we had it set up for hold last position. Only problem was we would toilet bowl so bad we crashed every time and would require several hours, one crash required a full tear down and rebuild, and because of that we could do as many flight as we're possible. This was the same time replacement GPS units were being sent to the Southern Hemisphere. I email DJI about it and was told I would get a new GPS to sole my problem. Several months later I emailed them again and was told I just need to turn my GPS counter to the toilet bowl to fix it. I did that and still have the same issues. I emailed DJI and never heard anything back, what can I do to get a replacement GPS unit to fix this as I have people looking at purchasing my UAV and need a solution. Also have been noticing white flashing more and more since the crashes.
Disclaimer: based solely on my personal trail and error experience, I have no inside information or technical knowledge to back this up!

I have found that the measurement relationship between the IMU, and the GPS is the most crucial to prevent the toilet bowl. even 1cm makes a big difference. I recommend precise placement of the GPS to the IMU first, and then extrapolate the distances by measuring from the center of the IMU to the CG. Then do the math for the GPS by adding the IMU/CG distance to the IMU/GPS distance

For example, if you have GPS at -12cm, and the IMU at -3 cm because the placement isn't at the exact cm mark, but the measurement between the IMU and the GPS is actually 10cm, then your hold won't be so good.

The measurement from the IMU to the CG seems to be less important than the measurement between the GPS and the IMU. So in the above scenario, -12 and -2 would be better because the IMU/GPS is more exact, even if the actual IMU/CG is -2.5 cm.

It's a bit tricky to explain because the IMU/GPS relationship isn't a parameter at all in the instructions, so when you round off the distances for the separate components, it's pretty easy to end up with an inaccurate GPS/IMU measurement.

Important for all 3 axis measurements!

Confused yet?

Of course, exact measurements for all relationships is the best possible scenario. But I had a 10m circle, and changed my gps by 1 cm to make the gps/mc precise and the circling stopped completely.

Also, you don't rotate the GPS for circling, only if the craft does not fly straight forward when you push forward in GPS mode. I flew at a ball field, and used the foul line to tune the amount of gps rotation. Mine ended up being really close to the 17.5į magnetic declination found at my geographic location.
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Last edited by furyphoto; Oct 13, 2012 at 07:53 PM. Reason: Mistakenly posted MC whenI meant IMU now corrected!
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Old Oct 10, 2012, 09:39 PM
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Trenton, NJ
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Originally Posted by Tarro View Post
I calibrated the esc's and all is well now. What esc's are better?
Thanks
Hi Tarro,

In regard to ESCís, I have found the Castle Creations Phoenix 25 amp ESCís to be the best performing and most reliable ESCís that I have ever used in the four years that I have been building & flying multi-rotor aircraft. As of March 30, 2012 they have the version 4.1 Castle Creations multi-rotor firmware available for them which is just as good if not better than the SimonK firmware and MUCH easier to program & update! In addition they are manufactured in the USA with components that appear to be top notch in quality and so far have performed flawlessly.
They are somewhat expensive, but when I am powering my quadcopter, worth over $3,000.00, I didnít want to scrimp on the price & quality of my ESCís. Iíve tried the cheap ESC route in the past & ended up with crashes caused by failures of cheap ESCís and I never what to go down that route again.
Since switching to them I have over 50 hours of actual flight time on them with not so much as a single glitch. I have flown my 6.5 pound quad in hot 100 degree weather and cold temperatures with no problems or overheating whatsoever.

You can find them here on eBay for as little as $46.95 a piece, which is the cheapest price I have been able to find for them. http://www.ebay.com/itm/Castle-Creat...item589689eac7 .

I have an older thread on RC-Groups found here, http://www.rcgroups.com/forums/showt...1606382&page=7 , which gives a lot of information & testing results on them. This link will take you to page 7 allowing you to skip over the first several pages that dealt with the earlier 4.0 firmware that did not work. The results on the newer 4.1 firmware starts at post # 94.

I had posted this information several months ago but figured that I would post it again for those that may have missed it and might find it useful.

Regards,
Tom
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Old Oct 10, 2012, 10:56 PM
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Thanks for the input Tom, I have found that the WKM does not handle large copter well. My octo was flying awesome with no wind, but as soon as the wind picked up it wobbles. It now is so bad that I can;t trust it. It may have been damaged in the flip crash I had last week, I want to send it into Robert to be checked out.
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Old Oct 11, 2012, 06:51 AM
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Originally Posted by Tarro View Post
The manual states,
I understand the manual states that, but for what reason? mine is a Quad, with 3rd party ESCs, but it has always performed ok and i never really comes across any flight issues, the only thing now and again is the odd motor warmer than others.

is there any unwanted effects by keeping the power wires connected? is harming anything by leaving them.

The main reason for asking, was i read if your ESC only has a 1A BEC, then it could cause issues, but if your ESCs have 2A or over, it didnt matter, so really just looking for some clarification.

This is the ESC, well , 4 off
A.E.K HighSPEED PWM ESC 12A Specifications
Battery: 2S ~ 4S lithium polymer battery
Maximum continuous current: 12A
Current capacity: 15A
BEC: 5V/2A linear mode
Size: 32mm x 18mm x 10mm
Weight: 13.4g (including wire)
Input: JST Female (length 215mm)
Signal lines: JR Male (length 365mm)
Output plug: 2.0mm female banana plug (length 20mm)

they have been performing great and dont get warm at all, but now im having a conflict, just spoken to someone that builds them for a living and does video shoots, now, he has told me to remove black and Red wires, only leaving the signal wire plugged into the MC, so, which is correct ?

Edit, just searched and found this thread http://www.rcgroups.com/forums/showt...5#post22971815

so will just leave the signal wire in and go from there
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Last edited by Davebbb; Oct 11, 2012 at 09:28 AM. Reason: saw another thread
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Old Oct 11, 2012, 07:00 AM
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-fury- thanks for the I of, I used a ruler to make sure I was close but looks like I'm busting out the calipers to get precise measurements. Turning of the GPS to fix toilet bowl didn't sound right to me either but it's what they said to do so I tried it and FAIL! Bad thing with this all is I have a flight demo with a local police department on the 21st and nervous to show them the lose comms capabilities since its toilet bowling on hold position and does about a 5' toilet bowl on auto landing. The toilet bowl on hold position is not small either it spins in a 50 foot circle. Here are some of the videos of the crashes, plus you can see the site we were flying at. I have one more that really shows the huge loop it does I just need to upload it.
attempt 4.mp4 (5 min 26 sec)

Attempt 3.mp4 (6 min 25 sec)
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Old Oct 11, 2012, 11:18 AM
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475 Posts
Anyone able to help me on this??? Anyone??


Quote:
Originally Posted by jerrymeister View Post
When I take off with my 550 hex, I usually go up and travel away from me. Once I get where I need to be I let up on the right stick. What happens is that once I let up the hex wants to come back to me on its own. It usually takes at least a minute of forward pressure before it stays on its own. Anyone know what I need to do here to make this not happen? Once it is steady, it doesn't travel anywhere on its own.

Jerry
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Old Oct 11, 2012, 02:01 PM
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Joined Nov 2010
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Quote:
Originally Posted by Davebbb View Post
I understand the manual states that, but for what reason? mine is a Quad, with 3rd party ESCs, but it has always performed ok and i never really comes across any flight issues, the only thing now and again is the odd motor warmer than others.

is there any unwanted effects by keeping the power wires connected? is harming anything by leaving them.

The main reason for asking, was i read if your ESC only has a 1A BEC, then it could cause issues, but if your ESCs have 2A or over, it didnt matter, so really just looking for some clarification.

This is the ESC, well , 4 off
A.E.K HighSPEED PWM ESC 12A Specifications
Battery: 2S ~ 4S lithium polymer battery
Maximum continuous current: 12A
Current capacity: 15A
BEC: 5V/2A linear mode
Size: 32mm x 18mm x 10mm
Weight: 13.4g (including wire)
Input: JST Female (length 215mm)
Signal lines: JR Male (length 365mm)
Output plug: 2.0mm female banana plug (length 20mm)

they have been performing great and dont get warm at all, but now im having a conflict, just spoken to someone that builds them for a living and does video shoots, now, he has told me to remove black and Red wires, only leaving the signal wire plugged into the MC, so, which is correct ?

Edit, just searched and found this thread http://www.rcgroups.com/forums/showt...5#post22971815

so will just leave the signal wire in and go from there
Yep it's best and safer to remove all power wire from each esc that's connected to fc.
say one of the esc gets bugged it can mess out the whole craft a power feedback fault on a single esc can also kill the fc with sorts and voltage spikes.

Yep cut or remove esc power wire And leave signal and ground.
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Old Oct 11, 2012, 02:04 PM
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Quote:
Originally Posted by jerrymeister View Post
Anyone able to help me on this??? Anyone??
Craft coming back to you.
Have you checked to see if the home lock thingy feature is activated?
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Old Oct 11, 2012, 04:38 PM
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Originally Posted by hexa View Post
Yep it's best and safer to remove all power wire from each esc that's connected to fc.
say one of the esc gets bugged it can mess out the whole craft a power feedback fault on a single esc can also kill the fc with sorts and voltage spikes.

Yep cut or remove esc power wire And leave signal and ground.
Well, did as i saw in that other thread, the black is actually doing nothing it seems when the red wire is removed, so at the moment i have it just signal wire only, just powered up ... shhhhh ( in the kitchen ) and all seemed totally fine.
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Old Oct 11, 2012, 04:55 PM
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Originally Posted by Davebbb View Post
Well, did as i saw in that other thread, the black is actually doing nothing it seems when the red wire is removed, so at the moment i have it just signal wire only, just powered up ... shhhhh ( in the kitchen ) and all seemed totally fine.
The black wire is giving a direct ground for the signal wire, you really should use it.
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Old Oct 11, 2012, 05:50 PM
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Originally Posted by Tarro View Post
Yes I have done this to try to solve the problems I had with the Flat Octo. It still is very unstable in the wind. It is a large octo, 1100mm with QC3328 motors it cost over $5k and I can't trust the WKM to keep it in the air. I am switching to MK.
I've noticed that the WK-M doesn't seem to be that stable in high winds when using those popular size motors, 700-770kv, the axi type. I built an octo around my old mk octo xl frame, with axi motors. Very nice when flown in no wind conditions. But when there's a little bit of a breeze, it becomes unstable and oscillates. I always have gains on my slider so I could tune on the fly. Still the same even with lowered gains. The only recourse on this setup seems to be changing the props to a much smaller ones. The graupner 11x5s seem to work very well.

DJI WK-M Octocopter XL Flight Test rcphilippines (2 min 28 sec)


After seeing the 6s builds by EndOfDays and Tony of RCDrones, I decided to build a big octo with low KV and 6s using 14-15 inch props. I bought the RCTimer 360kv and RCTiger 3515-15s and some graupner 14x8s and foxtech 15x7s. Really nice and stable. Even in a windy situation. I can dare say almost as stable as my MK Octo xl in the high winds. I've shot a couple of drifting races and some real estate stuff and so far I'm really happy with it.
My current DIY frame 1000mm size is a bit heavy. I'll place an order on a carbon core soon.



I shot this in a quite windy day.
Hard Hat Area-Aerial Shot in A Construction Site In Azure (2 min 28 sec)
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Old Oct 11, 2012, 06:04 PM
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Thanks AB74, I will start to experiment with prop sizes, I am using QC3328 motors right now.
The main thing I am worried about is the sluggish response to control inputs and a feeling like the copter was out of control. This happens after it starts to wobble in the wind.
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