March 8, 2015

Trifecta; ESC replacement

It is with mixed feelings that I come back to write this post and my last post was about my first successful flight with the Trifecta. It was also the only successful flight. Because during the second one one of the ESC started acting out.

It was equipped with a RCX Sky 12A which was a first test of this ESC to see how it performs considering the low price. Here's my review: It's big and heavy, badly put together. And it's useless.

I had already considered replacing the arms ESCs on the frame with Afros, simply because the build looked very ugly with the clumsy ESCs on the arms. And they couldn't even fold properly. I had already ordered Afros and was waiting for them when this happened. HobbyKing sent them via Singapore, bad luck I suppose, and it took a month before they arrived.

My initial configuration had the motor rotation reversed to the recommended for tri-copters. I have no idea how important this is, but I took the opportunity to correct that when replacing the ESCs. The tail ESC is a KISS and it has a solder jumper for reversing the motor direction. It took some effort to get into the frame and apply the solder.

Trifecta frame while reconfiguring tail ESC

I decided to put LEDs on the arms, something I considered doing right from the start but it didn't happen. One set of white LEDs to the front and one green and red to the back. I connected everything the ESCs. The front LEDs to the battery leads since they're made for 3S and I run the back/downwards facing from the otherwise unused BEC since they're 5V.

LEDs attached to the ESC

Not even this tiny ESC fits into the slot in the arms, I almost consider that a design flaw, 2 more millis and the ESC that HobbyKing wants to sell with the frame will actually fit. I forgot to take a photo of this, sorry. We now skip a few steps.

ESC and LEDs attached to the Trifecta arm

On the arm there's a slot for the one and only zip tie you can place on that area of the arm without it interfering with the folding. If you need more, they'll need to go on the outer part. Because of this I needed to tape down the ESC and cables and attach a zip-tie only to keep everything safe and attach the LED strip. I could have used heat shrink instead, but it will also prevent the arm from folding if located to far inwards.

The Afro ESC Ultra Lite 12A has one soft spot; the linear 0.5A BEC. On this build I'm running a receiver with telemetry, telemetry device, flight controller, FPV camera, tail servo and camera tilt servo from the BEC. And 0.5A is not enough if I want to play it safe. I installed an additional BEC on top of the frame. It adds a little weight but I hope/think it corresponds to the 5g difference between the Afro and the RCX.

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