Wookong-M on Quad (Build Thread)

[ovdt]

Hello everyone,

One month passed after recieving the shipment from djiusa and finally I gathered all the bits and parts. My first intention was to build a hexa or Y6 but, I found myself building a quad.

First specs:

* Custom frame
* MK3638 motors (These motors were purchaed with the QuadXL kit and never used, so it's time to try theö)
* Turnigy Plush 40A ESC
* Graupner 11x5 props (will change them to 13x6 JXF Wood)
* Afro Power Distribution Board (abusemark.com )

And some pics:

View attachment 1259View attachment 1258View attachment 1257View attachment 1256

First flight:


My gain settings : 170% 170% 140% 100%

Altt gain: 70% 70%

If you look at 1:05, I yaw left with the sticks. But, it corrects the yaw at 1:07 (I don't touch the sticks).

First impressions: Alttitude hold is impressive and quite easy to fly.

Even though I did the throttle calibration and played with various ESC settings, I'm not happy with the throttle response and linearity. The throttle is very linear and responsive with MK Bl Ctrls.

It's rainy and waiting some shiny days to try new settings. Thanks to Boris and Ken for their useful topics. They made this build very easy for me.

 

[BorisS]

I havent seen or heard of a similar situation with the yaw like you are experiencing very strange.

After having seen your bird i think its best to forget about all the setting from Ken and me (or maybe use kens when he first tried the WKM on a Quad) but i think you will be best off with default settings 100 100 % etc. for all. Up to now from what i heard the WKM showed best performance on quads and i think that was the basis for their default settings.
For me throttle control is also very different than with the MK but keep in mind you are always when in attitude mode flying with altitude hold mode, comparable to MK Vario. So i guess the your throttle position is never directly forwarded to the ESCs but always an interpretation from the WKM. I would probably take them to change something in the firmware or to open some variables to get this the way you would like it.

What timing do you have your ESCs on ?

My gain settings : 0 0 0 0

Altt gain: p p p

I am confused you mistyped or you were able to get some letter in a numbers field ?

I dont think you will be happy with changing to heavier/bigger props. I got my best results with the light 12 3,8 11 gram carbon props from the MK shop and as far as i remember correctly ken also had his best results with the Graupner.
Thats my mission at the moment to find something weight wise proportionally comparable to the 11 gram CF prop but bigger in size.

What are you impression considering the build time ? I think this is a prefect solution for RTF dealers.

Boris

I am embarrassed to admit, but to tell the thruth i never did a throttle calibration with the Plush Turnigy,because i didnt know about it. I dont think it is necessary. WKM calculates everything new i think at every takeoff considering the data it gets from it altitude sensor. Thats the only way for it to take off with different weights on the bird, always with a little bit over midstick.

 

[ovdt]

Hi Boris,

I am confused you mistyped or you were able to get some letter in a numbers field ?

Sorry for the forum bug, my values are:

My gain settings : 170% 170% 140% 100%
Altt gain: 70% 70%

For me throttle control is also very different than with the MK but keep in mind you are always when in attitude mode flying with altitude hold mode, comparable to MK Vario. So i guess the your throttle position is never directly forwarded to the ESCs but always an interpretation from the WKM. I would probably take them to change something in the firmware or to open some variables to get this the way you would like it.

Yes, that's weird at first but I think I'll get used to it. But alttitude hold is definitely much better than the MK. Landing on and off are easier.

What timing do you have your ESCs on ?

ESC timing is Low.
Brake - off
Startup - Normal

I dont think you will be happy with changing to heavier/bigger props. I got my best results with the light 12 3,8 11 gram carbon props from the MK shop and as far as i remember correctly ken also had his best results with the Graupner.
Thats my mission at the moment to find something weight wise proportionally comparable to the 11 gram CF prop but bigger in size.

For this quad, I need to put 13x6 for lifting a 550D sized camera I'll try it and write my impressions about it. I want to understand how DJI W-M acts against changes made in the copter.

What are you impression considering the build time ? I think this is a prefect solution for RTF dealers.
.

Figuring out how to calibrate the ESCs, throttle calibration, wiring from Motor to ESCs and from ESCs to PDB took my 6 hours I build a MK Hexa almost within the same time. And I thinkered a lot of IMU, MC and GPS positioning.

I have confused feelings but still too early to make comments. What I like about my MK is, I can see everything from my JetiBox. Voltage, BL Temps, altitude, heading direction in degrees etc.

I'm using Spektrum DX8 with telemetry unit to watch the Lipo voltage. But somehow, the telemetry unit shows lower value than the actual voltage value. For instance, when the telemetry is telling me the voltage is 10 volts, it's 15.6V actually. That's another weirdness though.

 

[BorisS]

I got my PMU unit late so I never tried the voltage monitoring "compromise" they offer. Will be flying this weekend again and i will keep an eye on it. I think ken also didn't use it yet.
I will also try 14 4 and 14 4.7 on my hexa this weekend. My bad results were at the point were i still thought that a higher altitude gain value will result in a more stable flight. That was a misunderstanding
from beginning on higher attitude gain results in the bird holding its position without GPS and thus strongly regulating when wind hits it, but its not the value you want high when you want no wobbles on your cam.

But cool its up and flying i think with some time your feelings will turn to the positive side !

Boris

 

[RTRyder]

I just built a WKM Quad based on MK Octo center plates with standard Hexa arms, works out to about 580mm motor to motor. I'm using 4 Flycam 925kv motors with Graupner 10 x 5 props on a single 4S 5000 battery. Underneath I have a set of Coptersky 210 landing gear with their GoPro 2 axis mount, RTF weight is just over 2 kilos by about the weight of a GoPro Hero HD.

The settings I found earlier today that work really well in wind are 150 150 160 140 with the ATTI both set to 110%, a huge difference from my large WKM hex which is at 300 300 250 200 with ATTI at 65 on both. When I first flew the WKM now on the hex it was on this same frame but with only a set of Trex 600 landing gear underneath and it flew nice with the default settings, so clearly hanging weight down off the bottom of a frame with WKM controller makes a BIG difference in where your gain settings will wind up. On the hex I have Droidworx landing gear (the smaller version) with a Photohigher AV130 and a pair of 4s 5000 packs which is by far the heaviest part of the hex so there's a LOT of weight down low. One thing I did find to help a lot is to find the true center of gravity of the frame with everything you will be flying with in place. Measure accurately from that point to the center of the IMU and to the GPS unit and it does make a difference. On the hex doing that eliminated a slight wobble that I had tried to get rid of from day one and could not until I found the true COG was around 6cm lower than what I had assumed it to be.

Now that I have two WKM flying I find it difficult to fly either of my MK for APV now, they just don't feel as solid and locked in as the WKM does. They still fly great and have more capability, but when it comes down to line of sight fliying with a camera recording, I'll take either of the WKM over the Droidworx AD6 H/L or standard Mk hexa every time. The little quad I find to be outstanding for flying into places I wouldn't dare try to fly the big hex into. I did a few flights today with one of my GoPro on the mount and by sometime tomorrow morning I'll have one or two of them up on Youtube. I have to replace the servos that came on the GoPro mount because they're crap, very twitchy and impossible to get smooth compensation on either axis. Tomorrow afternoon I'll head over to the LHS and see if I can find a set of Savox that will fit, going to rain here for the next two days so I have some time to do a couple things to the WKM hex to get it working the way I want. So far it's doing great, just needs a little fine tuning to be right.

Ken

P.S. I'm using the power module on this one, have it soldered directly to the Minsoo Kim power distribution board which the Abusemark board is a copy of (Minsoo made it first and Timecop copied it). I usually fly the 4S 5000 packs for 8 or 9 minutes, today I let it go to see the power management functions work. It went to LED alert at about 9 1/2 minutes and it went red at right around 11 minutes then landed itself a 1/2 minute later. When I checked the pack it had 10% reserve so it actually went lower than I like to run them. I think landing right around 10 minutes would keep it at no less than 20% reserve so I'll continue to use the timer on the TX and not worry too much about it.

 

[Droider]

I Just want to get home after reading this thread as my WMK has arrived according to her indoors quote "ANOTHER BOX HAS COME..... WHAT NOW"

Its going straight on a quad I have half built so this info on here and Ken 'THE doctors' thread on his build is invaluable to get it up and flying asap

Dave

 

[BorisS]

I Just want to get home after reading this thread as my WMK has arrived according to her indoors quote "ANOTHER BOX HAS COME..... WHAT NOW"

haha love it

 

[ovdt]

Thanks for the details Ken. I didn't think the vertical CoG was important.

I'm going to play with the placement settings of IMU in the conf tool and see what happens.

I think my yaw problem is due to the orientation of the IMU, I changed it a little bit and will see what happens.

I think I will need to recalibrate the compass again.

I recieved power module and I've already installed it. Gonna activate the warning and safe landing.

What we really need is a downlink for ground station. They've announced it and for serious AP/V it's a must.

Dave, once you build your new bird, make sure the orientation

 

[Gunter]

ovdt, I was planning to paint my hexa black with orange landing gear, but just spotted you have the same colours! Good choice

 

[Emowillcox]

Ken really... it went red at 11minute and then landed itself? Did I read that right? So the self landing function works?

I just built a WKM Quad based on MK Octo center plates with standard Hexa arms, works out to about 580mm motor to motor. I'm using 4 Flycam 925kv motors with Graupner 10 x 5 props on a single 4S 5000 battery. Underneath I have a set of Coptersky 210 landing gear with their GoPro 2 axis mount, RTF weight is just over 2 kilos by about the weight of a GoPro Hero HD.

The settings I found earlier today that work really well in wind are 150 150 160 140 with the ATTI both set to 110%, a huge difference from my large WKM hex which is at 300 300 250 200 with ATTI at 65 on both. When I first flew the WKM now on the hex it was on this same frame but with only a set of Trex 600 landing gear underneath and it flew nice with the default settings, so clearly hanging weight down off the bottom of a frame with WKM controller makes a BIG difference in where your gain settings will wind up. On the hex I have Droidworx landing gear (the smaller version) with a Photohigher AV130 and a pair of 4s 5000 packs which is by far the heaviest part of the hex so there's a LOT of weight down low. One thing I did find to help a lot is to find the true center of gravity of the frame with everything you will be flying with in place. Measure accurately from that point to the center of the IMU and to the GPS unit and it does make a difference. On the hex doing that eliminated a slight wobble that I had tried to get rid of from day one and could not until I found the true COG was around 6cm lower than what I had assumed it to be.

Now that I have two WKM flying I find it difficult to fly either of my MK for APV now, they just don't feel as solid and locked in as the WKM does. They still fly great and have more capability, but when it comes down to line of sight fliying with a camera recording, I'll take either of the WKM over the Droidworx AD6 H/L or standard Mk hexa every time. The little quad I find to be outstanding for flying into places I wouldn't dare try to fly the big hex into. I did a few flights today with one of my GoPro on the mount and by sometime tomorrow morning I'll have one or two of them up on Youtube. I have to replace the servos that came on the GoPro mount because they're crap, very twitchy and impossible to get smooth compensation on either axis. Tomorrow afternoon I'll head over to the LHS and see if I can find a set of Savox that will fit, going to rain here for the next two days so I have some time to do a couple things to the WKM hex to get it working the way I want. So far it's doing great, just needs a little fine tuning to be right.

Ken

P.S. I'm using the power module on this one, have it soldered directly to the Minsoo Kim power distribution board which the Abusemark board is a copy of (Minsoo made it first and Timecop copied it). I usually fly the 4S 5000 packs for 8 or 9 minutes, today I let it go to see the power management functions work. It went to LED alert at about 9 1/2 minutes and it went red at right around 11 minutes then landed itself a 1/2 minute later. When I checked the pack it had 10% reserve so it actually went lower than I like to run them. I think landing right around 10 minutes would keep it at no less than 20% reserve so I'll continue to use the timer on the TX and not worry too much about it.

 

[Borneoben]

Hi Ken

Regarding your observations of the pendulum effect and very low CoG has on the larger Multis, do you think the relatively poor wind handling of heavy Multis could be improved with a higher CoG and minimal pendulum effect?

We all make sure that the Multi has a perfect CoG on the Z axis meaning that for aft and side to side the multi balances well.

But if you took the CoG on the X or Y axis we will find that the Multi is very bottom heavy due to heavy camera equipment etc.

Do you think that if a heavy enough item, say the batteries, were placed high enough above the multi to bring our X,Y and Z axis CoG to the same point in 3 Dimensions this would help the performance in Wind?

What do you guys think?

Would it help?

It would be pretty difficult to achieve i think??

Cheers

Ben

 

[RTRyder]

Ken really... it went red at 11minute and then landed itself? Did I read that right? So the self landing function works?

Yes, the voltage monitoring and failsafe work exactly as they describe in the manual. I have one nit to pick with it though, whatever voltage drop you set for level 1 carries over to level 2, I really would like to be able to set different values for each so it doesn't drain the pack quite so much having to see the same voltage drop from one alert to the next to get into red and auto landing.

Hi Ken

Regarding your observations of the pendulum effect and very low CoG has on the larger Multis, do you think the relatively poor wind handling of heavy Multis could be improved with a higher CoG and minimal pendulum effect?

We all make sure that the Multi has a perfect CoG on the Z axis meaning that for aft and side to side the multi balances well.

But if you took the CoG on the X or Y axis we will find that the Multi is very bottom heavy due to heavy camera equipment etc.

Do you think that if a heavy enough item, say the batteries, were placed high enough above the multi to bring our X,Y and Z axis CoG to the same point in 3 Dimensions this would help the performance in Wind?

What do you guys think?

Would it help?

It would be pretty difficult to achieve i think??

Cheers

Ben

I do think there is merit to considering this, take a look at the Cinestar frame and you'll see the battery tray is located up top to keep the CG as close to center as possible and there's no argument with the results I've seen from those frames so far.

Ken

 

[ovdt]

Okay, I had 15 minutes of flight today. I started playing with gain settings and the position of IMU/GPS. Yaw seems better but I still have problems with yaw.

I'm getting impressed by the stability of altitude mode. It's so simple. A person with a 2 minutes of stick learning session coud fly this bird.

BUT...

There are some inconsistencies I have to work out:

* W-M corrects my yaw movement in only one direction, very minor right now but disturbing. Even though I made the positioning very straight and level again, I think the most important thing is the placement of IMU/GPS and their offsets in the conf tool.

* When I give full throttle, the bird doesn't ascend very stable. It rolls left very harsh. But, when I ascend with slow stick movements, it's just perfect and very smooth.

* When flying high, descending will be problem for me. Altitude mode works like the MK's vario height control so, when I move the throttle stick down, it comes down pretty slow. I'm afraid to put throttle stick more down because the motors stop at the lowest position. This can be fixed but throttle channel adjustment but this time, when I power on the copter and turn off throttle hold, the motors start to turn at high speed than I prefer. So, with this setup, I wouldn't fly high. I'm not yet confident with the current setup.

There are so many things to try before making this copter fly perfectly.

 

[BorisS]

I actually started to use the digital trim on my Graupner. To start the engines I trim the throttle until the motors start. Now i know bringing down the throttle all the way will not kill the motors. Landing it the motors are switched of by bringing the trim down again. I dont know how your throttle channel adjust works, but trim could be a better method and resulting in the motors not starting with high speeds.

 

[Tahoe Ed]

Okay, I had 15 minutes of flight today. I started playing with gain settings and the position of IMU/GPS. Yaw seems better but I still have problems with yaw.

I'm getting impressed by the stability of altitude mode. It's so simple. A person with a 2 minutes of stick learning session coud fly this bird.

BUT...

There are some inconsistencies I have to work out:

* W-M corrects my yaw movement in only one direction, very minor right now but disturbing. Even though I made the positioning very straight and level again, I think the most important thing is the placement of IMU/GPS and their offsets in the conf tool.

* When I give full throttle, the bird doesn't ascend very stable. It rolls left very harsh. But, when I ascend with slow stick movements, it's just perfect and very smooth.

* When flying high, descending will be problem for me. Altitude mode works like the MK's vario height control so, when I move the throttle stick down, it comes down pretty slow. I'm afraid to put throttle stick more down because the motors stop at the lowest position. This can be fixed but throttle channel adjustment but this time, when I power on the copter and turn off throttle hold, the motors start to turn at high speed than I prefer. So, with this setup, I wouldn't fly high. I'm not yet confident with the current setup.

There are so many things to try before making this copter fly perfectly.

I have used Vario AH on my MK since I first built it. The AH on the WK-M seemed like second nature to me and I found it easy to use and adapt to. I was never comfortable with the AH by switch. You will get used to it in a short period.

 

[Tahoe Ed]

I actually started to use the digital trim on my Graupner. To start the engines I trim the throttle until the motors start. Now i know bringing down the throttle all the way will not kill the motors. Landing it the motors are switched of by bringing the trim down again. I dont know how your throttle channel adjust works, but trim could be a better method and resulting in the motors not starting with high speeds.

I am using a Dx8 and found that I could adjust the Throttle by the sub trim to get the motors to spin on startup to work for me. I do use Throttle Hold when connecting the Lipo and when shutting down just for safety.