At the beginning of 2012 I was kind of passively looking for a super micro airplane with full aerobatics capabilities to convert for FPV flight. I've already made several small FPV models, but they were always "calm fliers". With the fun I recently had by doing FPV aerobatics, I really needed a small version with head tracking and all the fun things.
I had already tried the cheap-but-not-so-much Slick 360 from HobbyKing, and was disappointed. While it looked good and the canopy seemed like it could be clear enough to be left on top of the camera, it was really low quality (bent motor axle, heavy) and really didn't fly so well even without any additional equipment.
That's when I randomely came across E-flite's Sbach 342 UMX during a visit to my LHS. I love the look of that plane, and the price was right, so I just couldn't resist. E-flite is also much more of a reference in terms of quality, so hopefully it would be better. And yes, that proved to be right. I have already flown quite a few larger aerobatics models (Katana MD, Kyosho Edge 540,...), and I was surprised to find the little one flew... just the same. Very nice handling, very precise flight, a lot of power reserve, and... long flight times, about 10 minutes on the stock 2s/180mAh pack! Of course it will get shaken more in windy conditions, but that's to be expected. A micro plane is for calm conditions anyway.
So there is no doubt the flight characteristics of that model are MUCH better than the ones of the HK attempt, however things haven't been perfect on my sample either... I have had two early failures, the first being a couple of engine losses in flight that I finally tracked down to a broken solder joint between one of the motor supply wires and the actual motor winding. I had to take the motor out, remove the shrink tube, resolder the wire and reassemble everything. It's small, but thankfully quite easily doable when you're used to working on small things. The second failure was the right aileron servo regularly locking up. That led to a couple of hairy landings, especially when it decided to block itself fully deflected. Of course spares were out of stock for a long time... so after a while I just decided to try putting a couple of drops of alcohol in the faulty pot and exercise it a bit. That has apparently worked, I never had a single issue with it anymore after that.
As I intend to add a camera on a pan servo, and would like to use my head tracker for realistic flight, I had a more detailed look to see whether it would actually be possible to control it without an additional receiver. After all, these ultra micro models have all-integrated "bricks" with receiver, ESC, and sometimes servos on a single board, making it difficult to access anything they don't give you out of the box. Fortunately, this model uses a rather versatile one, the Spektrum AR6400NBL, a 6-channel model with 4 main servo outputs, the integrated ESC, and an X-Port on which a 5th servo can be connected if the receiver is configured accordingly (CH5). The main outputs are CH2,3,4,6, with the CH6 output being configurable as either the actual CH6 or reversed CH2 to allow using 2 aileron servos with a cheap 4CH radio (which is the case on this model by default). This means that once configured correctly, I will have CH6 available for my pan servo!
So all in all... I'm very confident it will be able to accomodate the extra video equipment without too much degradation of the flight characteristics! One side effect of this choice of model is that it has made me rethink entirely my radio setup... more about that in another post.
Oh, and it also doubles as a great photo subject!