Recently I purchased some of the new Gemfan 2040 "Hulkie" props to try on my lightweight EYAS X2 build (more details on the build here on rotorbuilds).
The props are well priced and sold by many vendors now. I used banggood as they offer free international shipping which is especially handy if, like me you live outside the US.
I'll be comparing these a lot to the Gemfan 2035 4 blades (cheapest on Gearbest at present) which have become the defacto standard for performance and durability in 2" props. Here are the key qualitative differences I've found:
Blades are less durable. The material of these blades are more rigid and seemingly more brittle as a result. It takes a lot off effort to kill a 2035 on a light quad but the hulkies seem to like snapping at the hub as in the pic below. Additionally they chip at the tips which the 2035s don't seem to do. Note: they are still much more durable than the king kong 1935 props which although good and well balanced can explode just by staring at them too long. Last pic is where I flew on Tuesday morning rather than working. Shhh.
They are well balanced. Not much else to say here. They are on par with the 2035 and the king kong 1935. Don't underestimate well-balanced props even on a 2 inch quad - I've had some shocking 2" props (looking at you racerstar)
They may be able to handle more powerful motors. Although more brittle, these props are noticeably stiffer and I'd expect they will be able to handle a more powerful 11xx series motor better than the 2035 by not flattening out at high rpm. This is only a hypothesis though as I prefer a larger prop/frame when using bigger motors than an 1103.
Efficiency/lift feels similar to the 2035. Gemfan's data at the end of this review suggests that the hulkie props generate more lift at the same current compared to the 2035. Purely from my subjective feel they seem to hover at a similar throttle, have a similar punch out power and get a similar battery life to the 2035 - certainly I couldn't pick up a real difference. Note: my quad is very light at 40.5g dry, 58g with 2s 300mah battery. Interestingly the hulkies have a wider blade than the 2035 meaning the total blade area for each prop is roughly the same.
Hulkies are louder. New hulkies are louder than the 2035s and louder than what I remember of the king kong 1935 props. Not 5" loud but not quite as stealthy.
They have a slightliy bigger diameter. The 2040 version of the hulkies has a slightly larger diameter than the 2035 which is already a hair over 2". No problem if your frame has plenty of clearance but a big deal if you have a frame like the flex ascent v1, x2 elf, x2 eyas and others. At least there is another option - The Hulkie 1940 which has less thrust but less current draw as well as being physically smaller. I have not yet tested so it would be hard for me to comment further on these.
So, my overall verdict? I tried these out after getting bored of the Gemfan 2035s since they just didn't break. The 2035s bend on crashes and I'd bend back, good as new whereas the hulkies usually bend half the time and snap the other half. In the real world the performance of the gemfan 2035 and hulkie 2040 is similar but the durability of the 2035 wins it for me. Only reason I'd stick with the hulkies is if I crashed less (not happening) or if I have more powerful motors than needed a stiffer prop.
I recently bought a low-cost XT30 balance board that I would share here given it does the job I would expect at a low price: the XT30 1S-3S Plug Parallel Charging Board For IMAX B6 Charger. Although advertised as working with the Imax B6 charger, it will work with any 1-3s capable lipo balance charger that uses banana plugs.
The balance board can be used with 1,2,3,4 or 6 batteries with a XT30 connector and standard balance plugs for 1-3s batteries which will cover most micro builds. Each XT30 discharge lead is protected by a fuse if there is a large voltage differential on connection.
I also purchased this lead that I will modify to with an XT30 male plug from this set for input so that I can also use this balance board for my batteries with JST discharge plugs.
Below is a list of key rules for balance charging but certainly no exhaustive in terms of instructions:
This is part 2 of my review of the Leader 120 by Full Speed from Gearbest. For part 1 click here. As at September 2017 try code HarvestRCnew7 to get this for only $US93.99!
None of the dreaded "brown outs" here
Straight up I have had none of the reported issues of brownouts as many of the youtube reviewers found on the first version of the Leader 120. In saying that my review modelis version 2 which I has the fullspeed branded black motors. The default idle speed of which there was a lot of chatter about was set at 10% from the factory in Betaflight 3.1.7. This is very high and reducing it to my regular 3.5% caused no issues. So on to the more interesting stuff!
This is a great little flier, As I expected from hearing the motors run in betaflight they are very quiet and coupled with the well-balanced KK 2840 props it lets off very little noise in flight. Coupled with the size, this makes it much more socially acceptable to be flying in areas that aren't completed isolated. The rates are not stock either and I actually really liked them, even compared to my stock betaflight 3.2.0 settings when I flew my 5" quad immediately afterwards. There are an awful lot of micros that have poor or no tuning from the factory so was escpecially pleased when the tuning here required practically nothing for those either lacking the know-how or too lazy to do. Power is excellent on 2s and comparable to many 2" quads on the 3s - the bigger props and relatively light weight really make these motors come alive. Handling was predicatable and I felt I had good control even in heavy gusts.
The stock battery can be described as adequate. I can see the voltage alarms were set low at 3.0 warning, 2.9 critical to allow for the sag but it keeps you in the air with moderate flying for up to 4 minutes. Considering I was able to flow without esc desync, losing vtx signal or getting failsafe, this probably makes it better than 90% of included batteries out there (not kidding).
I'll have a follow up tips and tricks article soon where I look at some of the other internationally available battery options including 3s.
FPV - Camera and VTX
Ahh a chink in the armour. Hitting a sharp price point eventually means compromise and I think I've found it. Typical of All In One (AIO) cameras this handled low light on a dull day poorly even with the focus correct. Kind of makes branches jump out at you when flying under trees - that's my excuse anyway. Secondly although the VTX does well enough for 25mW, it still only does 25mW. That means that I started seeing breakup at 100-150M away or as soon as I was on the wrong side of even small trees. The good news is you can pop this on your RC car or tiny whoop (I STRONGLY recommed the Eachine E011) and upgrade this one. There is more than enough lift for the extra weight of a micro CCD camera like the Foxeer arrow micro or Runcam swift micro and a Vtx like the new one from fullspeed that is 25mW/200mW switchable to mount on the back. I'll be making such a change in the near future and reporting back in a new article in the tips and tricks section.
This model is an amazing combination of well-matched parts with good assembly and a custom tune making it compelling on paper. I'm pleased to say that this transfers into flight characteristics and power making it an option you should definitely be considering if looking at a micro in 2017. I personally think this frame size that allows for a 2.8" prop rather than 2" is much better matched to this motor size and not nearly so sensitive to weight meaning for a more robust and enjoyable flying experience. My only real gripe is the video quality where camera light handling and vtx power lets it down. It is hard to argue at this price point though and in a future article I'll be doing a budget mod to address this.
Most interestingly, I built a model from parts that was very similar to this before this model was announced. Cutting to the chase the PNP version from Gearbest was more quiet and felt more solid in the air (perhaps due to the tune/rates) than my own build. Power was similar: although noisier I think the DYS motors had an edge although for the small difference I prefered the ones in this PNP model. I preferred the adjustible power vtx on the model I built to bump up power but this is really starting to split hairs. This does have me second guessing my build vs buy strategy but I think this is testament to the well thought out component list Full Speed have chosen.
Buy the Leader 120 from Gearbest
Firstly, thank you to Gearbest for supplying this model in exchange for a full review including my observations and recommendations from having built a very similar quad from parts. I'll review here and then run a series of tip, tricks, mods depending on how it flies stock. You can find the PNP version (no receiver) here. As at September 2017 try code HarvestRCnew7
to get this for only $US93.99!
I'm going to skip the unboxing, I don't have anything to add other than the picture of all the parts included below, so straight to the good stuff.
The parts included and build quality have improved...
First off the motors are no longer and unbranded red 1104 7500kv. They are now branded SZ speed and full speed but are still rated the same. From what I can see the shaft length extending through the bell is shorter. Great idea - the only job this does is to centre the prop which the screws hold on. Less stress when trying to put tight props on (looking at you Gemfan 2035) and you don't have a 1.5mm drill bit. Below is a comparison to my DYS 1104 7500kV. You can see my review on these here
The comparisons to these motors don't stop there. Both are similar external size, and the magnets are simlarly strong - very notchy compared to the racerstar motors. From there the leader 120 motors are better. Wires are multicore, slightly thicker and much more flexible and easy to manager. On spin up in betaflight they are so quiet and smooth! Not noisy like the DYS even when they were new. In fairness the DYS are powferful so if the stock leader 120 motors get anywhere near this I'll be happy, especially given the improvements.
This flight controller and ESC is ubiquitous and first appeared on the ARFUN90. I've reviewed one in full here - in short reliable and well featured. What impressed me here was the quality of soldering and the cable managent, just so clean - see below. I wasn't going to compare my efforts but I'd already soldered in the receiver and the macro image makes me feel inadequate! From what I can see of the earlier reviews, this looks to have improved substantially.
Betaflight setup and the Flip of Death
This model shipped with the full release at the time of writing - 3.1.7 (3.2.0 still in release candidate). Interestingly along with the physical changes the software settings have been changed to address some of the brownout/flip of death issues the early reviews had. Most notable digital idle is set at 10%. Since I'll maiden this with stock settings I'll go with that and see if moving back to my standard of 3.5% is still viable. 10% is not ideal for me as you will never be able to fully chop throttle for flips and whatnot. Cool to see that they have addressed it and looking forward to seeing if this issue may have gone altogether.
I'll post some pics of the key betaflight screens for prosperity below (flip through them) but I intend to move to 3.2.0 as soon as I have completed initial flights and can confirm everything is functioning as expected.
I'm something of a lightweight jukie when it comes to miniquads, benefits include longer flights, better agility, greater crash resistance through lower intertia. See the gallery below for the various weight measures but in short 64g dry, 94g AUW ready to fly with the stock 2s 500mah battery. This include an ibus FS82 1g receiver which was not present when I too the photos.
This is a very respectable weight for a micro that swings 2.8" props as these props generate a significant amount of lift in combination with a motor of this rating.
All this and it includes my favourite beeper/led combo (reviewed here) - a beeper is a must for micro quads as you can loose them even in short grass! I can anyway.
Size comparison to other micros
This is not a big model by any stretch. The beauty of these micros - and to be clear this is still a micro - is you can fly in small areas (not indoors!) with less danger and concern to the public. They are also quick to get in the air and consumables like batteries and props are cheaper too. This model measures 120mm diagonally motor to motor and offers most of the experience of a 5" FPV quad. Picture below compare to an E011 typical tiny whoop and an 80mm EYAS x2 with 2" props
This 20mm x 20mm F3 flight controller and ESC combo is probably the most common combo appearing across BNF or PNP micros and so there is a lot of information around on it. It is sold by GearBest as Mini Brushless F3 Flight Control System. As at the beginning of September it was not available so would recommend the FuriBee Flytower Plus Mini F4 Flight Controller which uses the same 20a ESC but has the faster F4 flight controller processor.
Key features for this board are:
Probably the only thing I really need to say about this combo is that for me, everything has just worked as I had expected, no issues with upgrading and using features of betaflight, even the release candidate of 3.2.0 with dynamic filtering. I've never had a brown out on this unit, either on my 2 inch build or 2.8 inch build.
There's not much else to say, no quirks or issues and it makes sense that many manufacturers base their build around this one. I'd buy this again (update - I actually did for my lightweight 2 inch build)
My recommendations? This is pre-wired and built into the tower. Wire up as below and you should be away. If you want a lower stack height see my tips and tricks coming soon...
See below for the all important flight controller pin out diagram:
Not massively exciting this one but cheap, lightweight and very functional. The FULL SPEED FSD - BBV1.0 5V 80dB 10lm Buzzer is a lightweight (1.3g) buzzer and LED combo that solders just to you buzzer output on you flight controller. When activated it will beep loudly and flash a suprisingly bright LED. I cannot recommend one of these enough to act as a lost model beeper bound to one of the auxillary channels on your transmitter and secondly as a low voltage warning if you have no OSD or you fly line of sight. In case you weren't certain, the LED is very useful for locating in the dark. Just sayin'. Grab a few already and wire them up to anything with a buzzer output.
My first impression here was not great - I was not used to the notchiness or seemingly noisy bearings and I had heard bad things about the wires. This was largely solved during build and first few flights - the bearings settled down, the notchiness was the sign of strong magnets and the wires were manageable although still difficult to solder compared to multicore silicon wires.
Flying on a 2 inch quad
These firstly went on a 2 inch quad here but it felt like it was working to hard just to stay hovering. It was super quick on punch outs but general flying was not enjoyable. My thoughs after some time that the motors were too much for the props (King Kong 1935 or Gemfan 2035) so decided to try a larger build
Flying on a 2.8inch quad
I transplanted the running gear over to a FD120 frame which is more commonly know from the excellent PNP leader 120 on this build here. The improvement was immediately noticeable - hovering at a lower idle and flight with a lot more control and resolution, really shining with the larger 2.8 inch King Kong 2840 props. It is fast on 2s and mental on 3s. Although I am a big fan of lightweight for micro builds especially, this build could manage the weight a lot better... batteries ranging in weight from 48g 2s 950mah to 18g 2s 300mah was not as different as you would think.
Final thoughts and recommendations
Firstly I would encourage soft mounting for absolutely all brushless motors. Here is a link for 11xx series motor soft mounts on thingiverse, I got 12 printed for less than $US3 on 3dhubs. Secondly I think these are too much for a 2 inch prop. You may have a different experience but this is mine. I thought a 2.5-2.8 inch prop is right at the sweet spot or 3 inch for a 2 blade like the gemfan 3025. I find the motors themselves well built and very powerful. They have the ability to draw a lot of current, especially on 3s. Because of this I would recommend these 7500kv version for 2s although they are certainly capable of 3s without overheating - I do actually run 3s more often than 2 on this quad. Having had my time again I would have gone 6500kv for mostly 3s as they are more efficient: less current, more torque, longer run time with a small hit on top speed. If I was building the same quad tomorrow from scratch in 2.5 inch and 2s, I would by these again. For 2 inch I would rather go for a lighter build based around 1103 motors.