My latest addition to my fleet is Align’s newest micro helicopter, the TREX 250. This little baby captured my interest the first time I laid eyes on it… or rather the first time I laid eyes on the box. My next encounter with it was by reading an article on RC HELI magazine which featured the new comer. What got me interested was that the combo kit came with almost everything that you would need to get this heli up and flying except for a radio, receiver and battery. Apart from those three items, it came with everything like its very own digital servos, 3 for the cyclics and 1 for the rudder and it also comes with a high quality gyro fit even for larger birds.
The build of this heli was done over a span of 2 weeks although I believe you can actually get it done in 1 night since most of the heli was already pre-built. I took my time because I had to order LIPO batteries for it. For those of you who are short sighted and have fat fingers, do be warned… the screws and parts are really really minute! Don’t drop any screws or you’ll spend the rest of the night looking for them! Having said that… the instructions that came with the kit was pretty well written and laid out. Oh might I also add the quality of this kit is unbelievably good with its machined metal heads, carbon fibre parts and basically smooth operations of the tail drive and all head linkages.
I have just managed to fly this baby last Thursday / Friday but found that the GWS receiver which I used was prone to interference (which almost cost me to lose the chopper a few times). I have since changed it to a ‘spare’ 8CH corona receiver which seems to be doing very well.
I was also hit by the dreaded tail wag issue when gain was only set at 51% (head-holding) or 49% (non-head hold). Needless to say, the tail held terribly. I was so sure that I used the correct ‘+’ (plus) shaped horn measured at 5mm but still I decided to try to change it to the ‘o’ shaped horn which seemed to have the mounting point just slightly closer to the center than the ‘+’ shaped horn. Unbelivably, that cured the problem! So if you guys are having tail wag problems, make sure you use the right horn with the Align DS420 servo and Gyro! 5mm is the magic number. you might even want to try 4mm if there’s such a mount point! My rates are not at 65% there abouts and the tail holds like a dream. I have also set my gyro to have a delay of close to 100% since a 0% delay seemed to give me a slight wag. I think the servo might be a little too quick for the tail and gyro to keep up!
Alright that’s all I have to report for now. Btw I’m using a Zippy 1000 mAH battery that’s rated at 25C. It was a little tight for the canopy but that was cured by drilling two new holes just about 7 or 8 mm back from the original holes. The power is good but I will need to try some pitch pumps and see how well the power holds now that my tail wag problem is gone and that the tail holds rock steady!