This is part 2 of the review. In part 1 I discuss an overview and setup (including betaflight settings from factory) are covered in detail: Part 1 review
Firstly a very important correction. In the first review I showed a picture of the quadcopter minus battery sitting on a set of scales at 65g. I took this for granted and after measuring on my own scales got 84g. I don't usually trust weight in text but seeing it was sitting on digital scales I did not measure myself. Disappointing as this is misleading so I updated Gearbest immediately. To their credit they promptly took the image down and corrected the weight in the description - see below.
Preparing for flight
Just some minor housekeeping prior to the first flight. XM receiver was fixed in place on top of the VTX as it was dangling free when I received it. Antenna was fixed in place with a cable tie off the rear arm and heatshrink to secure. VTX antenna got the same treatment off the rear upper-deck of the frame. Lastly I replaced the rubbish battery strap with one from RJX hobbies (review here). Although a buckled strap was included as well as the one picture above, it was much too long? Weird.
Flight performance on 2s
Just because the Bolt X120 *can* fly on 2s doesn't mean you *should* fly on 2s. I used my Turnigy Nanotech 2s 950mah (47g) pack and needed about 40% throttle to hover. I could fly but performance was lacklustre and I got bored. I did get about 4 minutes flight time but won't say any more.
Flight performance on 3s
After my initial disappointment on the weight, performance on 3s 450mah turnigy nanotech was better than I had expected. It felt controlled with enough speed to be enjoyable. I had to switch to default betaflight 3.3 PIDs though since the customised PIDs look more like a 4s tune and felt sloppy as a result. I did manage to get good flight times on these little batteries of approximately 2.5 - 3.0 coming down at 3.75 volts and had fun doing so. Given then power of the quad I'd probably pefer a 650mah 3s for another minute or so of flight and would have less concern about sagging on big throttle punches. For the places I usually enjoy micros the most (tight with small trees) I found 3s the most fun.
Quick update: compared back to back on same batteries with my Leader 120 which is lighter (68g vs 84g) with 'smaller' motors (1104 7500kV vs. 1106 4500kV). I found it was similar speed with comparable handling and I actually got as good if not slightly better flight time on the Skystars Bolt - the extra stator size was negated by the lower kV from an efficiency standpoint. The leader however cannot do 4s...
When I went from 3s to 4s on the BabyHawk R 3" (review here) I got a reasonable increase in speed but not 33% as you'd probably expect. Given the same motor size (1106 4500kV) I was expecting something similar here but got a complete shock here - This thing ABSOLUTELY SCREAMS on 4s. I've always liked the Gemfan 2540 props (review here) but have never tried them on 4s and boy, they sure hold up and deliver on the extra power, it was like a different quad altogether. The speed was like nothing I'd felt on a micro and I had real trouble managing in a tight area. This probably wasn't helped by the fact I was using a CNHL Ministar 4s 650mah battery which weighs 87g so I was really blowing out on corners, even with a lot of extra throttle. It reminded my of running a heavy 4s 3 inch with 1408 motors - super fast but handled like a brick. I'd dare say 450mah 4s at around 62g would be a better option for weight control. at the cost of some flight time. As it stood I was getting 4 - 4.5 minutes on the 650mah battery. I've since moved to betaflight 3.4.0 and have got the tune tighter without oscillations but it is still a handful. For my piloting ability running this quad on 4s requires a bigger area akin to my 4 and 5 inch quads but that kind of deafeats the purpose of this micro. For my money and ability I actually prefer this on 3s - It is much quieter and handles better with the lower weight which is better suited to small parks. The noise alone on 4s makes people more wary of this one.
Rather than trying to recommend how many cells you should run I've merely stated my opinions on what I want from a micro. The most important thing here is that this Skystars Bolt X120 is well and truly capable of comfortably running 3s or 4s depending on where you are flying or how you are feeling on a particular day. The new throttle limiting feature on betaflight is a great way of limiting power to fly on 4s if for example you want to stick with just this battery size with power more akin to 3s. I've written a full tutorial on this here including how to assign to an AUX switch.
Although I alluded to the similarities to the original Leader 120 (review here) it is clearly a different quadcopter with a different feel and different capabilities - it has a much better camera and VTX but is much heavier and designed to run on more cells which make it heavier again for a different flight feel. A better comparison is perhaps the BabyHawk R 3 inch which I find handles better but lacks the speed of this model, particularly on 4s. Images below on a scale for all of these for comparison.
The Skystars bolt can be bought exclusively from Gearbest in several different formats - an unbuilt kit with no receiver (PNF), a built quad with no receiver, or as a built quad with FRSKY or Flysky receivers.
Check on my discounts page regularly for specials but at the time of writing the unbuilt kit is available for $117 and the FRSKY BNF as seen here is available for $134