January 31, 2014

More stuff!

I got some stuff from HobbyKing today. This time, delivery took 23 days with the cheapest shipping option. It used to take 10-15 days, but ever since LiPo-gate they pack everything up, send it somewhere else by ship and post it in that country instead. Even if it does not contain any LiPo:s. My last packages has gone through Malaysia. Maybe Hong Kong post does not accept parcels from HobbyKing any more?

Anyway, this was not a big package but it contained a lot of stuff. Primarily stuff for my future tri-copter build. I decided to try out the Afro-slim ESC:s. Here they are along with wires. More stuff will arrive in another shipment. Edit: The servo is not for the tri but for a 450.

Parts for my Starmax F-35 which took it's last flight right before winter. I had the impression that the motor had turned weak and could manage to make it fly. The takeoff ended in a crash and the motor seems to have lost a phase. This is the replacement EDF unit with motor and ESC. Also new hinges for the elevators.

Here are a few spare parts that I didn't really need for the latest 450 Scrap build, but the result will look slightly better with them, should I choose to use them...

And, as always, the stuff you never know if you'll make any good use of. Some screws, hinges, clevises, heat shrink and wire mesh guards.

January 26, 2014

E-fuel gauge telemetry log visualization

Whenever I know I will get a few hours of peace and quite, which rarely happens, I try to continue my work on a primitive flight logger. Lately, since I have been starting to collect telemetry logs from my flights, I've started to shift focus to a telemetry log visualization tool as a complement to the flight logger.

Below is a screenshot of the e-fuel gauge data from a recent flight with the Bixler. Still, any uploaded files cannot be saved, they need to be merged beforehand and there is no dynamic or smart configuration of graphs. Hence, not yet ready for use. But this is a sample of what it might look like one day.

Update: If you would like to try out the visualization, create a flight in the flight logger and you can then add telemetry data to the flight.

January 20, 2014

Bixler repairs

Bixler fixSince i managed to hit a fence last time I was out flying I had to do some repairs on my Bixler. I'm usually not working with this kind of repairs and fixes since helicopters are my main interest and they always need special parts for repairs. I bet Bixler himself would not be proud of this.

I've simply taped up the broken aileron control surface with a white fiber enhanced tape. I also had to replace the old push rod with a simple bent piano wire since the clevis was broken. I had intended to use a helicopter ball link as replacement but the threading on the original push rod was too small and the ball link is much shorter than the broken clevis. So I just went with the simplest solution.

This will work fine. But once I get new clevises and hinges I'll fix this better.

January 12, 2014

CopterX 450 motor running hot

I ordered a new CopterX 450 PRO DFC v5 after a late season crash since the crashed one was too badly damaged. I even had to order a new ESC and motor for the new setup. This time, I went with the CX-ESC-40A and the CopterX 430XL (CX450-10-04) motor. The rest of the electronics is non-CopterX. It took me some time to get started with the build, but in november I did my first test flight. After the flight I noticed that the system had drawn a surprising amount of power. I didn't pay more attention to it at the moment since I had problems with the swashplate and blade tracking.

Yesterday a friend of mine tested out his new, of the same model with the same power system. This was indoors so we just did some hovering and adjustments to the radio. However, after the flight, of about 5 minutes, the battery and motor was hot and the battery cells was down to 3.4 volts. Bad for the battery and the hot motor is indicating something is not well. We speculated a lot in belt tension and so forth but did not reach any conclusion.

Today i spent some time on google and found a lot of speculative answers in various forums. One was that the ESC was incorrect since the CopterX motor is supposed to be a 8 pole motor. I have now tested that, I have set the timing to middle (was low, but still unsure if it is right) and put in the usual 3S 2200mAh battery and took it out into the -12 degrees winter in the garden.

And here are the results: After 70 seconds hovering the battery had turned warm. Motor was cold, but that might be because of the air temperature. I had a 3.9 volt per cell reading which I think is low for 70 seconds. And the charger tells me I have used 516 mAh. This gives an average current 27A while hovering. I think this is high. But then again, my battery (Turnigy nano-tech) is rated at 25-50C which should be able to deliver 55A without getting hot.

Conclusion so far: My CopterX setup is bad and my battery pack is also bad.

January 2, 2014

E-fuel gauge on the Bixler!

I actually managed to get some time to solder and try out the fuel gauge already tonight. Here it is hooked up to on my Bixler. I quickly tested it out and it seems to be working as expected. Also, the transmitter is displaying the values, speaking them out in the headphones and hopefully writing the to the telemetry log as promised by Futaba. With some luck with the weather I'll be taking it out for a flight this weekend.

E-fuel gauge

This little device arrived in the mail today. Actually two of them. It's a electronic fuel gauge which measures voltage, current and capacity which is connected to a telemetry receiver using S.BUS2. I will try them out in the Bixler and the 550. I would love to have more of those in my installations but the telemetry receivers from Futaba are a bit expensive (and I have too many models).