February 18, 2014

Tri-copter build and first flight

I have since the last post managed to put together the tri-copter, fly it indoors, crash it outdoors, re-flashed it with the wrong firmware and put it up on the wall.

The assembly of the booms with ESCs and motors took some time. I re-built the tail after realizing the the capacitor on the ESC might touch one of the tail mounting bolts which could result in a short circuit. It took it apart and insulated it. The slots for passing the motor leads out of the boom were not hard to cut, but hard to get a good look. Mine does not...
I should have used shorter servo lead extensions, maybe 15cm (maybe even 10cm) instead of the 45cm I use, they take up a lot of space and cause a lot of ugliness. On the last two booms I applied a bead of hot glue to the connectors to avoid them from slipping if you accidentally tug on them during assembly.

The X900 has no form of power distribution built-in. I soldered the three pairs of ESC power cables together with the BEC supply cable to a 12AWG (very oversized) battery cables. An E-FuelGauge is also attached to the battery cable. I use EC3 connectors to the battery.

The long servo leads cause a big ugly bundle of cables attached to the body. But this is nothing to the bundle caused by the S-BUS decoder. I use a Corona decoder, which has long leads both for the inputs and outputs.

My KK 2.1 board does not feed +5V to the servo connectors, which I find a bit strange but for a quad+ multi-rotor it isn't needed. The tri-copter however has a servo connected to the servo output, and gets no power! I made a split on the power lead from the BEC and needed to use a Y-harness to plug power in through one of the input-connectors together with the channel. Truly a big mess!

After having spent some time fixing the power supply pitfalls I finally tested it indoors with FPV gear mounted and the googles on my wife. Worked fine!

The other day I flew it outdoors. It flew fine until one of the props came off. No greater damage seems to have occured. However, I got really tired of the ugly bundle of cables because of the S-BUS decoder and I misread an announcement from RC911 concerning a new release of the KK2.1++ firmware. I thougt it was for the S-BUS version. It wasn't. The device is already re-flashed and cables removed. I think I will wait a while and hope RC911 comes up with a S-BUS firmware for the KK2.1.

Until them, I've made a simple wall mount to get it away from the workshop to move on with other projects. Waiting in line is a reconfiguration of a 250 with 3GX, repairs of an EDF and installation of an E-fuelguage and CGY750 in a 550.


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