I got my first helicopter this week, a Revell "Big One Pro" Coaxial 3 channel 2.4 GHz. At 100 Euros and only 3 channels, I was warned by the sales clerk that it was merely a toy, however, what are these models for if not to play with?
Comparing it to my AR.Drone which broke down last year, it has several interesting properties and features: Overall, I am impressed by the simplicity yet robustness of the frame construction, mechanics and electronics. Most of the frame is in what I assume is aluminium or magnesium, with a few parts of plastic in between. It feels solid, which a number of crashes have proved. The controller / main board is refreshingly simple, but also modular in the sense that motors and LEDs are JST plugged rather than soldered. Only the battery connector and power switch is soldered directly onto the board. This looks very promising as a platform to experiment with.
Apart from the basic electronic components, there are only three interesting chips: The radio receiver; what I assume is the main chip (designated 9118) and a vertically mounted chip, some kind of gyro maybe? Compared to the AR.Drone, refreshingly simple. Shuang-ma charges $15 for a replacement board, and they seem to be available many other places as well.
The battery is a 7.4 V 1300 mAh 2 sell LiPo, with brand name Tianpeng. Revell sells a spare one for 22 Euros, but I found a similar at DealExtreme for $10.5 so ordered that. Then Hobby King has a 1000 mAh for $3.5 so could try that as well.
Finally, the two main motors are designated 9093. I cannot see any make, but they look similar to this Syma Dragonfly. It would be interesting to find more specs on those.
So, I've been given a lot of praise. Are there any down-sides? Well, yeah. First, the plastic hull or shell is of the most fragile kind. After the first flight and crash, there was already a crack. And on the second day a big piece came off. So now I've used all the electrical tape I could find and taped it all together. It doesn't look so nice, but at least it will not crack so easily. I considered removing the hull altogether, however it does protect the LiPo from taking a direct hit in a crash, which is probably good enough reason for keeping it. Once I get into changing a lot of batteries, I might reconsider that, though.
Speaking of batteries again. Five minutes flight time a couple of times a day is not too much fun. In fact, it is rather poor. As mentioned, I've already ordered more, but I wonder if it would be possible to combine some for a bit longer flight time as well.
Finally, on negative notes, the axis for the lower rotor come loose quite often, after a few crashes. I just have to tighten the two screws attaching the lower gear, but is still a bit annoying. Maybe there's a better solution to that.
Overall, I think it was a good buy. Had some fun already, and hoping for plenty of more. Then there are several potential projects and thinking to get into, and repairs to make.