March 15, 2015

Trifecta; second maiden and FPV maiden

Between painting and putting the baby to bed I managed to squeeze in a first test flight with the Trifecta after replacing the ESCs. And it was a success. It flies very well and reliably. I fitted it with a 2200mAh battery for curiosity and with this heavier battery it runs at an average of 10A. Which I think is great!

Flight data from the first flight:

Now that was yesterday. To my surprise I got an opportunity to fly today as well. This time, FPV. I usually fly LOS until I'm confident with the setup of the machine, often doesn't take many flights. So today, it was FPV time. Flying FPV gives a lot more input into the setup of the machine and its flight characteristics. I can still claim that it flies reliably and it does what you expect it too. I don't feel any insecurity in terms of maneuverability. However, there most be room for tightening the PIDs, which will be the next step. I sense a little sloppieness and there's a small bouncy feel to the stable flight.

Flight data from the first FPV flight:

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.

March 1, 2015

Trifecta; First test flight

I did my initial CC3D configuration in the living room. This is an efficient method to get the initial settings right. But it's not final. More adjustments are needed after doing more than hovering, testing pitch pumps and windy conditions.

Yesterday was the season opening at the local flyers club and I brought to Trifecta to give it its first spin. With success. It was windy and cold and it flew as expected with slight tendencies to oscillations, quite common after an in-door setup.

In terms of result I had an average current of 9.5A. I was mostly hovering but it was also cold outside which led to a lower-than-usual voltage reading on the battery. The two factors may or may not compensate for that and I'm expecting a higher current draw while flying. Considering this I will probably need to increase the battery size slightly to get a respectable flight time. I will test it with a 1800 and 2200 in the future.

I took it for a second spin today with less success. I strapped a larger battery on it to get some current measurements while flying it a little heavier, some 90g more, totaling at 650g. What happened now is that one of the motors starts to skip. I have no idea why nor why it didn't happen the last flight. I have sent a message to the vendor of the motor and ESC to ask them.