Building A New Quad From Spare Parts & Parts Salvaged From A Crash

[GlassKnees]

I totaled my Tarot FY680 Pro hexcopter due to a series of problems beginning with pilot error. The aircraft ended up falling out of the sky from about 90 feet. I salvaged five of the motors, ESC's UBEC and the motor mounts. At home, I had some spare parts for a Parallax Elev-8 (V2), and decided to build up en Elev-8 variant using the Tarot 4006 motors.

The build is going fairly well, but I decided that I'd like to make this a flying video platform and so I added some Tarot clips to fasten carbon fiber rods for mounting the gimbal and battery (has to be position aft in order to counterbalance the gimbal/camera). But I discovered that the way I've installed the rods, there will be too much flex:

I couldl not attach longer rods that would go the full length of the aircraft because the standoffs that hold the flight controller base are in the way. I've decided to fabricate another flight controller base and reposition the standoffs so I can run long rods the full length of the aircraft, resulting in stiffer mount for the gimbal.

 

[GlassKnees]

I've built an Elev-8 before and modified it to fly using an APM 2.6 flightr controller instead of the stock Hoverfly board. Since the APM is sensitive to vibrations, I had to get a vibration dampening mount that comes in two pieces separated by rubber ball vibration dampeners. Right away, I discovered that there are no holes in the chassis that line up with the mounting holes on the APM dampening mount, but I discovered that the Hoverfly baseplate has holes that line up, so I used it as an "adapter":

I didn't have a hoverfly baseplate for my current build, so I fabricated one out of a piece of basswood. After installing it, I then realized that the standoffs I used to mount the assemblyl onto the copter chassis interfered with the carbon rods that I wanted to mount the gimbal, as shown in the previous picture.

So I made another adapter plate out of basswood that had a wider spacing:

With the adapter on the left, I was able to mount the APM onto the aircraft and run the carbon rods over the quad's chassis and under the flight controller:

I have a couple of issues to work out:

1. I had to lengthen the signal/ground leads from the ESC's (they mount underneath the motors), so they can reach the input ports on the APM. I goofed in my measurement and two of them are too short, so I will have to lengthen them a couple of inches.

2. The GPS module is defective. 3DR doesn't seem to sell then anymore, and so I bought a compatible one from Amazon, only to discover that the leads are too short, I'm no confident about going into the module and soldering longer wires, so I searched around and found a module for $20 that I believe will fit in the 3DR case.

The firmware has been loaded in the flight controller and I've done the accel calibration. As soon as I get a working GPS and fix the ESC leads, I will connect it all up and do the compass, radio and ESC calibrations. Then I have to wire up the gimbal and install the video transmitter that I ordered.

 

[GlassKnees]

Latest update. Details, details! I realized that I didn't have a USB plug for the GoPro to the video transmitter so I had to order one. And then I agonized over how to power the gimbal and video transmitter. Before, I spliced the power and ground leads of the two devices together then then spliced them to a plug to the power source. This time I decided to splice separate JST connectors and use separate small 3S lipos to power each device. By mounting the batteries forward on the aircraft, I'm hoping to help counterbalance the bigger heaver 4S lipo that will be in the back, which will power the aircraft and other electronics. From experience, I know this won't be enough and I'll have to slide the big lipo farther foraward so part of it will be under the chassis.

Anyway, I've installed the gimbal and video transmitter and I have clean video signal being transmitted to my video monitor:

I'm still waiting for the GPS module that I will fit into the 3DR case and install on the mast. In the meantime, I have to fabricate longer leads that will go from the receiver to the flight controller. Also I have to lengthen two ESC leads as well.

 

[GlassKnees]

Finally! I have completed the wiring except for the GPS - still waiting for delivery of the replacement module. I was too aggressive on the ESC signal leads and had to lengthen the signal/ground leads for the #1, #3 ESCs to the APM:

And I needed longer signal leads from the receiver to the APM:

I will perform the radio calibration tomorrow and as soon as the GPS module arrives, the aircraft will be complete and ready for it's maiden flight.

 

[GlassKnees]

As usual, I progress one step forward and have a setback. I was concerned about low endurance flight times, and so I tried connecting two Lipo's in parallel and tried flying that configuration with my other Elev-8. I found it hard to fly and the motors were straining with the additional load. I abandoned the flight after only a couple of minutes and all four motors were really hot to the touch! Now I fear I may have damaged them, though they appear to be okay, visually.

So, I've decided to replace them - haven't yet decided what I'll get, but thinking T-Motors. Anyway, I pulled the GPS off that Elev-8 and installed it on my Frankenstein quad. I went through the compass calibration but it was unsuccessful. Damn!!! I tried several times but kept getting a cryptic error message about #1 compass failure. A search on the arducopter forum produced recent posts by others complaining of the same problem. It would seem that a bug was introduced in the latest version of Mission Planner.

I uninstalled M.P. and re-installed as well as updated with the latest beta software. Tried the compass calibration again and it said that it was successful but I'm still getting a "Bad Compass Health" warning.

Meanwhile, the new GPS module FINALLY arrived from China:

The new one is purple module on the left. It has the same footprint so I'm confident that it will fit in the plastic case. Now, if I can only get Mission Planner to work!