January 26, 2016

WLtoys Q282G

I always told my friends; don't buy that shit. I was talking about mini quad-copters, ready-to-fly, with FPV capability. They've been on the market for some time and at the local shop machines like the Hubsan X4 FPV sells for about 150~200 EUR (surprisingly small price difference to Chinese vendors). And people buying the Hubsan has been very disappointed with what they got for that price tag. It might seem I'm blaming everything on Hubsan and yes they did set a low water mark with what they promised and what they delivered. But maybe things are starting to change with the next generation of cheap FPV packages.

There was a massive new years sale at banggood and I noticed the WLToys Q282G. I've had a lot of WLToys stuff before and I've always considered them price worthy. It is cheap, you get what you pay for, but isn't that bad. And this micro FPV hexacopter was down to only 55 bucks. Not only that, it had one feature that caught my eye: 5.8GHz video link. I imagined a micro FPV quad that I can fly with my goggles, at work, annoying the boss and my co-workers.

I ordered it!

Yesterday, I got it. Should I spend time on the unfinished FPV 150 or rip open the package waiting for me? Guess what I did!

I'm gonna stick to the important parts and spare you the massive review for now. First off, what's in the box.


WLtoys Q282G


You get what you'd expect in the box, plus a few extras. There's a remote control, the hexacopter itself, a video screen, some extra props and two chargers. And a memory card with a USB memory card reader!

There are two things that are a bit special about all the stuff that you get here.

First off is the video screen. It is a small screen with built-in 5.8GHz receiver and a built in rechargable battery. This isn't the top notch screen, but a cheap screen with the same functionality is at least 100 dollars on it's own. It would be better but still not very good. Other FPV micro packages would come without any screen and you'd need your own smartphone instead.

A memory card, with reader. Wow, I've never gotten a memory card with any product. Ok, it's only 4Gb but I'm still surprised.

I did a quick indoor flight to check if everything worked as expected. It flies quite well LOS, as expected. Micros have become very good and stable and this is no exception. However FPV is harder than I expected. The camera has a quite narrow field-of-view which makes it hard to fly indoors. I tried it both with the screen, which is alright for the price, and with my Fatshark goggles. But I only got through one door post and crashed when I tried to make a turn in the kitchen. Sounds like fun doesn't it?

Wait, did I say Fatshark? Yes, but no. It does not work with Fatshark. There's no way to change the frequency on the transmitter or receiver, at least not visibly and without a screw-driver. I hooked up my Fatshark goggles to my standalone video receiver and found that it was transmitting on 5.645 GHz (channel 14 in the receiver table). Video quality reception is good and you can use the Fatshark goggles this way. But the Fatsharks are not capable of receiving this frequency with the built-in receiver.

But still. I can fly this at work, with the screen and nothing more. And if people would like to try out FPV with goggle I can let them use the goggle with the standalone receiver. And all the stuff needed will still fit in my drawer at work!



January 14, 2016

Get me my propellers!

The 3545 propellers that I ordered for my upcoming 150 FPV racer didn't fit! What a big bummer! I suspected it would be tight when I got the frame and ordered a 3030 propeller right away that I really hope will work out. But it hasn't arrived yet.

Yesterday I tried to mount the 3545 propellers on the frame and it was very close a win. But not close enough, the rear props touches the standoffs ever so slightly and the front props hits both the standoff and the upper frame plate.

So now I'll have to wait. Or try to cut them down by a millimeter. But I suspect the result of the latter will be so-so, since it can be quite hard to balance a propeller of this size properly.

January 8, 2016

Started building the FPV 150

I finally started the 150 FPV racer build that I mentioned earlier. This might take a while to complete since I don't get many minutes of build time each week. At least I've managed to get the ESCs and motors in place on the frame. That was the easy part. How to squeeze flight controller, video transmitter, receiver, OSD and camera into the frame and still leave some place for a battery is still a mystery.

I've set up a build page and most build information can be found there.

January 7, 2016

FPV in the cold cold snow

I managed to fly two batteries the other day while the kid was having a nap. Unfortunately it was -16°C and that has a major impact on battery life. I only got half the flight time I would expect and almost crashed when I pushed the throttle too hard and had a voltage drop. You can clearly see the voltage drop in the telemetry graph from that flight.

First flight I had the mobius in still image capture to try to get some nice winter photos. Second flight I was playing around in the snow. The snow was new and really cold and it would have been a great day to fly a helicopter and capture some turbulence in the snow. Instead I got some on board snow footage, which could have been great if the mobius hadn't gotten full of snow right away.




DSC_0412
Quad after racing in the snow


The quad looked quite terrifying after the flight, jammed full of snow. I blew it clean and haven't noticed any issues with the machine because of the snow so far.

January 6, 2016

Replaced an axle carrier on the e-revo

I wrecked the e-revo the other day. No, not really, but I hit a rock which looked like a grassy bump as high speed and one of the axle carriers broke. I haven't needed any spares until now and had none at all.


Broken axle carrier
Broken axle carrier

I ordered the broken part, TRA 7034. I also had to order a set of TRA 7033. This set contains the ball caps which keeps the pivot balls in place in the axle carrier. When the axle carrier broke, the ball cap was lost and unfortunately they do not come with the set of axle carriers. So now I have a lot of extra pivot balls I don't need.


Broken and new axle carrier
Broken and new axle carrier

While reading up on this particular part it came to my attention that it brakes a lot. People in the communities often call it a weak spot and upgrade it with a metal version. But I didn't. The fact that this part is cheap and easy to replace makes me think of which part will break if I upgrade this one to a metal part? Will it be the suspension arm, the drive shaft or some more central part like the bulk head? In any case the effort in repairing it will be much more substantial. This fix took maybe 15 minutes, including the "assistance" of my 3 year old son.

After reassembling the broken suspension it came to my attention to what degree this wheel was now fixed to the assembly. All the others have much more slop in the pivot balls, which I before thought was normal. It turns out that the axle carriers are worn down faster then I would expect (haven't driven this car for more that 2 hours total) and slop is introduced in the axle carrier. Unfortunately the ball caps cannot be tightened and replacing the axle carrier is the only option. There is an alternative axle carrier which has adjustable ball caps, but apparently that one is shit.

January 1, 2016

Voltage alarm in the E-Revo

I'm only using lipo batteri in my E-Revo 1/16 VXL. The car runs for quite a while on one battery and very much depending on how you run it. In contrast to flying machines the timer is not as useful. Especially when I crash a lot and pass the remote around to people to drive.

I've had the possibly bad approach to run the car until it starts feeling sluggish. This is too long. When you get that feeling you should have stopped a minute ago.

There are new speed controllers that have low voltage cutoff to protect lipos, but mine doesn't. Instead I'm installing a separate low voltage alarm into the car. I initially intended to use a simple alarm plugged to the balance lead, but it turned out to clumsy. There's really not much space under the canopy of this car.


Low voltage alarm installed in the front of the chassis.

Instead I'm using one of the many low voltage alarms out there. This particular one has two buzzer, a bright blue LED that you see clearly when it start getting dim outside. It is connected directly to the main power lead and senses automatically how many cells the battery has.

I made this installation while at the same time changing the battery connector to EC3 ( from TRX connector) and replacing the gears of the steering servo. I dabbed down the wire to the alarm using some hot glue, seems to work just fine.

Result

Low voltage alarms like this one is not made for for car applications. In fact, the car draws a lot of power when starting from standing still which will case a half a second voltage drop and trigger the alarm. Fortunately this alarm reacts fast and does not keep on buzzing but gives a short beep and a blue flash. When power is running low the alarm will warn continuously. Works well but I did not foresee the initial warning beep that can be annoying but safely ignored.