New F550 with WKM born the WE

[Topper]

HI,

I finished this weekend a F550 with WKM in there and had a few test rounds last two days.

View attachment 3052

stable unit by now, only in GPS mode the Hexa does gear all times some 10-15 degrees left. Calibration of Kompass done several time, any idea how to solve?

Greetz Topper

 

[BorisS]

Hi Topper,

its looking like your GPS modul is point backwards and not forward could that be. There is a little red arrow on the gpd modul that has to point foward.

Boris

 

[Topper]

Hi Boris,

i decided to have red arms on backwards so my LED's are like card lights... white front red back. the GPS module does face forward and 95% straight to front with the red arrow. Kind of hard to make it 100%. GPS at it self is very solid, only issue is the Hexa does on its own move every time 10-15 degrees counter clockwise for whatever reason.

Rgds Topper

 

[BorisS]

Topper have you ever seen the videos from the MK forum how much magnetic field a lipo under load can create. I can image that the lipo direclty under the GPS module could be the issue. If you dont get a yaw under aittude mode than i guess mechanical everything is okay with your setup. If you get the yaw when you switch to GPS it has something to do with you digi. compass. Have you tried mounting the lipo under your center platte just to test if the problem stays.

Boris

 

[Topper]

Hi Boris,

sounds valid, i will give that a try next flights. The F550 is unfortunately a bit close to ground for mounting LIPO's all time the suggested way. The F550 is anyways just the "test frame" for the WKM. If I'm happy with the WKM the F550 will get a Naza and the WKM will get a state of the art surrounding. Might the new DJI S800 Hex frame will be in scope.

Lowlight on the WKM by now is that you can't see or debug any internal data, like GPS and Compass. But the rest is stunning. Best PH/AH i have seen so far in air.

Rgds Topper

 

[BorisS]

japp I also dont like it. Would be nice to see what the gyros are doing and the digital compass.

Boris

 

[Tahoe Ed]

I have my lipo under my GPS on my F450 with WKM. No issues. It is a 2650 3S vs a 4000 4S that I use on my F550. But the F550 is only with a Naza right now. My guess is that you need to get the unit pointing 100% forward. There is no deviation for this mounting. Even in the manual, it states if you are yawing in forward flight you can adjust the GPS to counter act that.

 

[BorisS]

japp 100% is also a good approach, but consider that their are differences when it comes to lipos some have these issue and some dont, probably the same brand varies.

min 4:40

last test

Boris

 

[Tahoe Ed]

I am using Turnegy NanoTech and a few other off brand lipos. You are right different manufactures products can vary.

 

[Topper]

I have my lipo under my GPS on my F450 with WKM. No issues. It is a 2650 3S vs a 4000 4S that I use on my F550. But the F550 is only with a Naza right now. My guess is that you need to get the unit pointing 100% forward. There is no deviation for this mounting. Even in the manual, it states if you are yawing in forward flight you can adjust the GPS to counter act that.

Hi Ed, i have seen that in the manual but the strange thing in my issue is that the Hexa does not yaw while flying... it does only yaw to the left when in Position hold. While flying everything is fine, no unwanted yaw.

 

[Tahoe Ed]

Topper, when you are flying are you in ATTI? I still think this leads me back to the alignment of the GPS. That would only effect the performance when you are in GPS/Position Hold. I know that on my F450 the GPS will move about 2-3 degrees. I always make sure before I fly that it is pointed exactly forward. When I remount it I will make sure that the rod is tight before I mount the GPS with the double stick tape.

I assume that you have done the compass calibration recently? At any point, has it not yawed?

 

[Topper]

Hi, I have done some changes on the Hexa and re-aligned the GPS/Compass. Painful to remove the plastic housing from the double stick tape, felt like I'm just ahead to break it. Aligning it straight is somehow not real straight forward (tips welcome) but I think I made it now 99% accurate facing front parallel with the X axis. As well with the LIPO on top I change the CG on the Z axis to some positive number.

I removed as well this fancy daisy-chained deans/XT60 power cord that comes with the WKM to EC5 plug straight, now I have plenty of LIPO’s to test. Testing will follow as soon as time and weather will allow to take off. Are you guys playing around with GAIN settings, is there some recommendation for the WKM in a pretty stock F550 Kit?

Rgds Topper

 

[BorisS]

Tooper there is a whole google docs thing about the gains settings for the flamewheel birds. To tell the truth i personally wouldnt go by it, but put your gains on the radio basic roll pitch yaw on one slider and attitude gains pitch roll on another one. Take the bird up and try the different gains. Gains are very different do to prop payload etc. And the ones persons experience what a stable bird is might be very different to the approach someone else has. So finding it for your self i would say is the best way ! By putting the gains on a slider its really an easy thing. The only thing annyoing is that if you get it right and you want to know what the gains are you have to take the bird down leave the radio on and connect to the config tool to read out the gains that you set.

Boris

 

[Topper]

Hi,

as wrote above I have re mounted the GPS and tried to adjust it as best as possible facing the front, do you think this should work now?


View attachment 3110

 

[Topper]

Hi,

had a short test today. The Hexa does yaw left in GPS and Atti mode so nothing to do with the compass i suggest!?. I have checked arms and motors they all seem to be leveled. Normal a steady yaw would say one or more motors and/or arms are not leveled but the are all in a acceptable range. As smaller the LIPO (therefore weight) as less the yaw effect is there. While do full yaw on the radio it does extreme quick yaw left and not even half that quick to the right.

2 of the 2212 feels sort of strange by turning then by hand since building the Hexa, both CW. I think about changing them to see if I get rid of this yawing.

With a 5000 S4 Lipo I need half trim way to keep him in direction. I have changed the full set of props, did not make it any better.

Any suggestion were to search?

Rgds Topper

 

[Topper]

Hi,

next round of tests done yesterday after now changing 4x 2212 motors. Seems to me the ones that were comming with the F550 are from a bed charge of production. Now all motors spinning as expected not strange feel and noise any longer spinning them by hand but... Hexa still steady yaw left. Compass calibation done again and the compass is working perfect im Home lock while the Hexa steady yaw to the left.

Any of you an idea were to search?

Rgds Topper

 

[Topper]

Hi,

non of you any idea? Moving the LIPO to the bottom did not helped either. I'm wondering why he don't stop yaw to left when the compass is working in GPS mode. The WKM should recon that the Hexa does yaw and force against that. Does the WKM use the compass as well in ATTI mode?

I will contact now DJI direct as well, tho is not the first MR I have build up but no I'm out of ideas, might the WKM/IMU has a fault with yaw gyro?

Rgds Topper

 

[kauaicuda]

Did you do the compass calibration procedure?

 

[Topper]

Did you do the compass calibration procedure?

sure several times and don't get any errors. I'm wondering if one of the DJI OPTO ESC's are defective or don't know the throtten, can that cause the Hexa to continious yaw left? Did anyone here reprogrammed them for throttle already?

As the Hexa don't keep direction even in GPS mode I'm wodering if something bad send from my radio, a yaw to the left command from the radio will overwrite all electronic ike GPS and/or compass.

Rgds Topper

 

[Paul@scc]

Hi,

as wrote above I have re mounted the GPS and tried to adjust it as best as possible facing the front, do you think this should work now?


View attachment 4493

Out of interest. What are your X, Y and Z measurements.