The Leader 2.5 is a recent release from FullspeedRC and as well as being available on their own website, is also available from Banggood and Gearbest. If you do decide to purchase, Fullspeed over many more customisations and offer free shipping till Jan 2019. The Leader 2.5 follows the recent Leader 3 but is limited to 2.5 inch rather than 3 inch propellers. My objective for this blog is not to write a tradtional review due to the similarities to the Leader 3 but to cover the keys settings and physical changes I'd strongly recommend to enjoy this quadcopter.
If you haven't yet seen the first part of my Leader 3 (SE) review, click here. In it I cover an overview of the New Leader 3 including full discussion of the components, build and software setup. A quick correction too: I mentioned originally that the flight controller (namely the gyro) will only do 8kHz loop times. This is incorrect - it will actually run up to 32kHz! Certainly the first I'm aware of on a board this size and something for me to test in future.
Before I go any further I should note that my Leader 3 is a review model and so there may be minor improvements in the final version shipped to buyers. I'm in regular contact with Full Speed RC to give them feedback on what I find to assist with these improvements. The Leader 3 is available directly from FullSpeedRC.com, Gearbest or Bangood.
Since FPV performance is common between 3s and 4s I thought I'd cover that first. In short it is outstanding. Fullspeed RC shared a lot of the development of the included TX600 vtx with me an a lot of effort went in to ensuring a clean video signal all the way up to 600mW and the results sure doesn't disappoint. The result is that the Leader 3 has the cleanest video signal I have every used. There is absolutely no impact of throttle or other electrical noise on signal and it is hard to put in words just how much more enjoyable this makes the signal. I do miss the audio that AKK VTXs allow for but most people don't rate this as being important, especially on a micro. It's noteworthy that the the transmission power will go as high as 600mW - equalled only by the AKK FX3 ultimate (review here) in this form factor. OSD control of settings via Tramp works as expected. Antenna connection is via UFL is common for micros and fit for purpose.
No propellers in FPV view
Great news for those who don not like seeing their propellers - the frame design means that even with fairly modest camera angles of around 35°and up there are no props in view. Hopefully this is clear from my videos below. This also make the drums for a Caddx Turtles HD camera install beat even louder...
I wanted to clear things up on camera angle since Nick Burns mentioned it couldn't go past about 45° in his otherwise excellent review. I can confirm that the camera connector does not foul on the flight stack and does infact smoothly go all the way up to about 90° amgle. Pictures are best here so please see below:
Performance on 3s
When the Leader 3 was shipped to me, 2 custom PID prodiles were programmed in by fullspeed, Profile 1 was designed for 3s and profile 2 for 4s. 3s was tested with profile 2. Both of these profiles can be seen in full in part 1 of the review here. For 3s testing I used Turnigy Nanotech 3s 450mah 65c batteries. They weigh less than 45g meaning all up weight was around 140g. Flight time using these batteries was typically around 2.5-3 minutes with batteries coming to a resting voltage of arounf 3.75v per cell.
Flying exclusively with the HQ 3x3x3 propellers flight felt very 'balanced' - what I mean by that is the quad didn't feel overly heavy (or light), top speed was fast enough but not ludicrously fast like the Skystars Bolt X120 on 4s (review here). It was however very predictable - I could hit gaps and avoid obstacles in a way where I felt I had complete control. It was fairly similar to the way the Emax Babyhawk R 3 inch felt (review here) but the HQ props felt more predictable and familar compared to the EMAX Avans. This makes sense - both the Leader 3 and Babyhawk R are of similar weight and with 1106 4500kV motors on 3 inch props and both have optimised PID tunes. Full Speed RC seem to have done a good job on the tune here not just for the feel during flying but also in keeping propwash to a minimum, even when I tried to put myself in dirty air in 180° turns or descending directly down.
Below is a video from an early flight (2nd pack ever) in a local carpark. Typical I had DVR issues in a flight later that day where I'd gotten more familiar with the flight characteristics :/
Performance on 4s
The battery I used for all 4s testing was the China Hobbyline Ministar 4s 650mah pack. It is an excellent battery that I even use on my 4 inch racer so is very capable although a little heavy at 87g.
First of all I'm going to talk about straight up speed and my perception. It did not feel as fast as the Skystars Bolt X120 using the same battery. This is not an objective measure, purely feel. It did feel faster than the Babyhawk R 3" using the same battery.
To dig in to this further though I do need to say that that Skystars Bolt X120 is very hard to control with this battery and I did not enjoy flying it because it felt difficult to control. It felt like it needed more open space which then kinda defeats the purpose of a micro. By comparison the Leader 3 felt in complete control using 4s and PID profile 2 as customised for 4s by Full Speed RC. As a result it felt right at home on 4s with all the control and balance I felt on 3s. I think part of this is due to tune but moreso that that larger 3 inch blade is able to better support the additional weight from the heavier pack and hasn't overloaded the propeller (disc loading theory).
All other features of flight were similar to 3s - excellent video, precise handling and minimised propwash. I was really enjoying flying this until...
When I first received this model, Full Speed RC cautioned me to use 4s using the smaller Gemfan 2540 props (review here) since motors could overheat. Since I was the only reviewer to receive mine where it is winter presently rather than summer, this was less of an issue although I did keep an eye on motor temps. For this reason I stuck with the included 3 inch props for 4s.
About 10 packs in of warm motors (40-50°C only) I fell out of the sky when attempting a short speed run (see video below). On closer inspection the left rear corner had failed that I could later confirm as a motor failure (as opposed to ESC). The motor definitely was warm only as above and not hot. The only other time I've had a motor failure was on the babyhawk r when I used PIDs with too much P and D on 4s and even then the motor did not fail mid flight, rather afterwards intsead. This motor was scorching hot.
I discussed this with Full Speed RC and found that they will be using a stronger motor on the production version - the review version like I have are a prototype. As you can see below when comparing to my burnt out motor on the Emax Babyhawk R, the Fullspeed one does not look nearly as abused - it failed at a much lower load. Interestingly shortly after this I saw Andy RC's review and found he had an identical problem - motor failed mid run using 4s with HQ 3x3x3 props. Update: The prototype motors are actually 4800-4900kV and the production version will be 4500kV.
So, what does this mean for you? Until I can confirm that Fullspeed RC have moved away from the proptotype motors I can't recommend using the HQ 3x3x3 props with 4s, even in cold weather. For now stick with Gemfan 2540 props on 4s. Of course if it ships with new motors then all bets are off. Full Speed RC is sending me a full set of new motors so I will test with these and post my results in a follow up review as soon as I am able. Update: The prototype motors are actually 4800-4900kV and the production version will be 4500kV.
The Full Speed RC Leader 3 is as an excellent flyer on 3s - great video signal and predictable handling make for an enjoyable flying experience. On 4s the Jury is out... custom pids make this fly well too but the motors' inability to cope with the included 3" props are a bit disappointing. For now a bandaid solution is to run with Genfan 2540 props on 4s but I expect that Full Speed will release with a stronger motor for launch as they did with the original Leader 120. Again, my sample is a reviewer model and this feedback is used to make changes if needed to the final launch product. Full Speed RC has proven themselves to be a reputable company with well researched (and tested) quadcopters and I expect them to follow through on this model too.
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