Rob215's QAV400 Build

[Rob215]

Greetings,

I'm building a QAV400 and I'd like to share my experience. I'll skip documenting the frame build because there's already an excellent resource with great photos here:

http://www.fpvmanuals.com/2013/02/26/qav400-manual/

My initial build will be as follows:
- Lumenier FX2216-9 1100KV motors
- Lumenier 30A SimonK ESCs
- APM 2.6 flight controller with uBlox GPS/compass kit
- Graupner 8x5 E-Prop
- QAV Quick-mount 2-axis brushless gimbal with a GoPro 3 camera
- Lumenier CS-600 FPV camera
- Lumenier 3300 35C 4S battery

Initially, I'll be testing the quad without the gimbal or the GoPro. I'll be using 5.8gHz for FPV and my Taranis radio with its internal module for control. Eventually I'll add more features and probably move to a LRS and 1.3gHz for FPV.

I'll be posting photos and questions I'll have during the build. Hopefully this thread will become a learning resource for everyone.

PLEASE post any suggestions you have during my build! I'm here to learn!! =)

Thanks

[Rob215]

APM 2.6 might seem like an odd choice for the QAV400.

After searching around, I could NOT find a QAV400 build log where they used APM. Every build I found was either OpenPilot CC3D or DJI Naza. At the same time, I found all kinds of great experiences using APM with other frames.

Here are the other flight controllers I considered:
- OpenPilot CC3D
- OpenPilot Revolution
- Crius AIOP
- Vector (Eagle Tree)
- SuperX (XAircraft)
- Naze32 (NOT DJI)
- Pixhawk

Some of these systems seemed too new and untested, while others lacked features I wanted. I spent hours and hours reading many pages of forum posts. I talked to several experienced builders and pilots. I probably made the decision more complicated than it needs to be, and I'm still not sure I made the right one but we'll see.

[Rob215]

I used the X8R receiver that came with my Taranis to check the motors and see if they were spinning the right way. I had already bound the receiver to the radio. I simply connected each ESC to channel 3 (throttle) then I could spin the motor using the throttle on the Taranis.

As luck would have it, 3 of them were spinning the wrong way! Oh well, not a big deal. All I had to do was switch any two of the motor wires on each ESC.

I decided to solder the motor wires directly to the ESCs. I wanted to eliminate bullet connectors being a possible point of failure. Also, I labeled the servo connectors 1 to 4 so they would be easier to connect to the flight controller.

[Rob215]

The numbering of the motors comes from this page:
http://copter.ardupilot.com/wiki/con...ut-and-motors/

Obviously, I'm testing the motors with NO PROPS! However, I do have the prop nuts and spinners installed and hand tight.

As I was testing the motors, I noticed a problem...

THREE of the motors are silky smooth. I can touch my finger to the spinner while each one is running and there is no vibration at all. However, number 4 motor has some noticeable vibration. I've tried swapping spinners but that doesn't make any difference.

I've ordered another motor and prop adapter because I don't want to swap prop adapters on existing motors that are working perfectly. I used thread locker on all of the prop adapter bolts.

[Rob215]

Here's the build so far...

I'd like to make the wiring a bit cleaner. Any suggestions?

[tfmccull]

Rob, I recently tore the cc3d out go my QAV400 and replaced it with an APM I had that wasn't being used very much. It's a terrific FC, and while it may be showing its age a bit, it's great for a rig with a gimbal, and the autonomous features work great for photography.

Unfortunately, I'm in the middle if rebuilding it. I had an issue with a battery failsafe and tore the servo leads off a couple of the ESCs.

Very nice photos BTW.

[Rob215]

Rob, I recently tore the cc3d out go my QAV400 and replaced it with an APM I had that wasn't being used very much. It's a terrific FC, and while it may be showing its age a bit, it's great for a rig with a gimbal, and the autonomous features work great for photography.

Unfortunately, I'm in the middle if rebuilding it. I had an issue with a battery failsafe and tore the servo leads off a couple of the ESCs.

Very nice photos BTW.

Thanks! I'm glad I found a couple of people using APM with the QAV400. I'm sure I'll have some questions since APM is completely new to me.

[fpvgavin]

Hi Rob
I have the QAV400 with the plug and play gimbal i think you might need a bigger battery with the gimbal i use the ready made 4s 5100 and get good flight times i'm using the naza v2 in the quad it came out of my old TBS Discovery that i crashed and it still works fine.
Ill be watching to see how you go with the build so far it looks good

[Rob215]

Last night I ran Mission Planner to do the INITIAL SETUP items. I did the Compass, Accelerometer, and Radio calibrations. On my Taranis, I set channel 5 to the SG switch for flight modes. In Mission Planner, I set the default flight mode to Stabilize.

According to http://copter.ardupilot.com/wiki/initial-setup/ my next step was ESC Calibration. I used the All-At-Once method and everything seemed to go well.

I already knew my motors were all spinning in the right direction, so I went ahead and tried to arm the APM. It armed after 5 seconds of holding the throttle to the bottom right and all 4 motors started spinning! [NO PROPS INSTALLED!]

I throttled up and the motors spun a little faster but WOULD NOT GO ABOVE maybe 10 percent (my estimate).

Next, I tried manually calibrating each ESC, one at a time. I unplugged all servo cables from the APM and connected each ESC to channel 3 of the X8R as I had done originally to test the motor direction. I calibrated all four ESCs, and checked to see if each motor went to full throttle. All four motors worked perfectly and I connected everything to the APM again.

IT STILL DID NOT WORK!!

Finally, after searching around the net, I found this thread:
http://diydrones.com/forum/topics/mo...-won-t-spin-up

He found an advanced parameter in Mission Planner that was set wrong. His "Throttle Maximum" was set all the way down. I checked mine and sure enough, it was set ALL THE WAY DOWN TO 80! WTF? I changed it to the recommended value of 1000 and I was all excited because I was sure it was going to work now.

IT STILL DID NOT WORK!!

I was a bit frustrated at this point but just for FUN, I decided to run the Radio Calibration again in Mission Planner. I also disconnected everything from the APM and manually calibrated each ESC again. I'm not sure which of those things resolved the problem but...

IT ALL SEEMS TO WORK NOW!! =)

Here's the relevant screen:

[Rob215]

As soon as I put the propellers on my QAV400, I noticed a problem...


I noticed two potential issues with my original placement of the power module. First, the stiff 12 AWG power wires are attached to the "clean" frame and this might transfer vibrations from the "dirty" frame. Second, the battery connector came REALLY CLOSE to the propeller!!


As you can see, my original plan was a little too close for comfort. In fact, a larger battery may have pushed the connector into the prop!

Now for some updated photos...


The power module is now attached to the lower "dirty" frame of the QAV400. Only a thin ribbon cable connects the power module to the APM.


This view shows how the GPS mast can fold down next to the X8R receiver. I made a bracket from thin plastic to hold the receiver and its antennas. The receiver attaches with velcro. The plate is attached using the existing screws on the rear frame posts. I just used slightly longer M3 screws.