FULL SPEED RC LEADER 3 SE REVIEW PART 2: Flight performance on 3s and 4s

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.

Video performance
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...

Camera Angle
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:

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Hats off to you if you fly at this camera angle

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...

Disaster Struck!
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.

Coil lamination seem to have failed without excess heat in the fullspeed motors?

I absolutely cooked these emax motors - came down scorching hot and even then didn't fail mid flight.

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.

Conclusion
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.

The Leader 3 can be purchased directly from FullSpeedRC.com - their shipping is a little more expensive ($8) but is the fastest. Alternatively you can now purchase at Gearbest (standard version) or Banggood (standard or special edition) or Hobbycool (special edition)