Good day! I've got somewhat of a "special" micro FPV build coming up and I need
to get a good flight stack for it and there are several good ones out there to
choose from. So, I thought I'd take you along my thought process while I
compared the spec's of some of the best full-featured flight controllers along
with their associated ESC's. So in today's video, I'm gonna do a
side-by-side comparison of four of what I consider to be the best 20x20
mount micro FPV flight controllers, look at the specs and features of each,
and explain what I look for when choosing a flight control stack. I'll
take the opportunity to explain a little about the anatomy of the flight
controller and by going through this process
my hope is it will help you make a well-informed decision for your next
micro FPV build. If this sounds good to you, give it a "thumbs up" below hit that notification bell, and subscribe to
your TMac FPV channel - your home for your "Journey to Better" FPV fun, flights,
and racing stuff! The four flight controllers we'll be looking at today
are the Diatone Mamba F722 Mini, the HGLRC FD435 F4, the Flywoo Goku
F722 and the HolyBro Kakute F7. I want to thank my friend Alanzo for
putting me onto one of these so "Thank you Alanzo!"
These are the features we'll be comparing among the four flight
controllers and these are the ones I look at when considering which flight
control stack to purchase for my quads. If you have any experience with any of
these, please share your opinion in the comments section below. The HGLRC F435
F4 mini is highlighted in green simply because I had already purchased that one
and installed it in my last build - the Pob 150 which you can check out that
build and flight video through a link in the video description below. So far I
found it to perform very well and be very reliable - I've got no complaints
with it. It's also the first HGLRC flight stack I've used without pins and
I've been very happy with it. By the way, if you're interested in any of these
flight stacks, I've got links to all of them for your
convenience in the video description below as well. Since I primarily build
and fly micro FPV quads which are those that spin two to four inch props and
the fact the smaller flight control stacks are now capable of handling up
to 6s LiPo batteries and their associated ESCs are becoming much more
robust, I only consider stacks with 20x20
mounting patterns. Of course, all 20x20 stacks are not the same size and weight
and when you're talking about building a high performance
quad it all comes down to your thrust-to-weight ratio. So the smaller and
lighter your flight control stack can be the better. You also want to make sure
that both your flight controller and ESC can handle the size batteries you plan
on flying. Most modern F4 and F7 flight controllers
can handle anywhere from 2-3S up to 4-6S LiPos. One of the
most important features for me is to ensure the flight controller has an MPU
6000 IMU or inertial measurement unit. The MPU 6000 has proven historically to
be one of the, if not the, most stable and least susceptible to electronic noises
and vibrations compared with others on the market. So what does that mean to you?
Well, the less susceptible to noise and vibration means your quadcopter is going
to be much easier to tune. The HolyBro Kakute F7 uses the ICM 20689
instead of the MPU 6000 and historically that has been more
susceptible to noise. So, if I have the choice of a comparable flight controller
with an MPU 6000 instead of the ICM 20689, I'll go with one with the MPU
6000. I personally no longer use flight controllers that have pin connectors
instead of solder pads. I've had bad experiences with pin connectors breaking
on minor crashes so I just don't purchase them anymore.
The number of you UARTs is important and we'll go over that in more detail here
in just a little bit as we will with documentation. I always like to have the
flexibility of using an external buzzer such as the Luckybox buzzer from FullSpeed
or the Vifly which are both self-powered so if you happen to eject
your LiPo you'll still be able to find your quad. Black box capability is your
flight data recorder which saves information for your flights in a file
that you can go back and analyze using the Blackbox Explorer application to
help you fine-tune your quad if need be or to troubleshoot issues that may arise.
The HGLRC, the one I've already purchased and installed on my most
recent build, doesn't have that black box capability. Fortunately, I haven't needed
it yet. Some flight controllers have an integrated barometer which can inform
you of your altitude using barometric pressure.
Two of these don't have a barometer which doesn't mean a great deal to me
right now but could come into play with possible new regulations on the horizon.
LED support isn't that important to me right now but you can remap those pads,
if they're available, for another use if they do exist. The associated ESC
firmware, power capability, and physical size and weight of course are very
important and we'll take a more detailed look at that shortly.
Considering the total weight of both the flight controller and ESC
for each of these stacks, the Mamba F722 weighs the least at 11.5
grams total whereas the Flywoo Goku F722 comes in the heaviest at 12.5
grams. That's a difference of 2 grams between the lightest and the
heaviest stacks. Of course, you have cost which can always be a factor. I'll
quickly show you the type of documentation you can expect from each
of these flight control stacks. This is not something to be overlooked. The
better the documentation, the easier it's going to be for you to figure out by
referencing it how and where you're supposed to connect your receiver, VTX,
camera ,etc. to your flight controller. If you purchase a flight controller with
bad or no documentation, you're gonna end up with issues. The Mamba F722 has a
fairly detailed schematic with suggested UARTs usage. The HGLRC F435 flight
controller has a 24 page PDF manual and this is just an excerpt from that. Here's
an example of the HGLRC F435 put to use and as I mentioned earlier, you can
view the video on this build through the link in the description below. The
Flywoo Goku has this schematic also with suggested UARTs usage and the
HolyBro Kakute F7 has an 18 page PDF manual. I also wanted to take this
opportunity to pass on a little more information on the anatomy of a flight
controller which isn't always easy to find.
I'll use the Mamba F 722 Mini as our example. The big chip on this side of the
flight controller is the CPU (or the MCU) which on our Mamba is an F7 with a 216MHz
processing speed and a 1Mb memory. For comparisons, F4
flight controllers have a 168MHz speed. The little
chip next to it is for your black box capability. Here in the middle you have
your IMU - in this case the MPU 6000 which contains your gyro and accelerometer, as
well as your integrated OSD. On the right over here I've labeled UART 5 and
UART 6. UART stands for universal asynchronous receiver/transmitter. All
you really need to remember is these are solder pads available to connect various
external devices to like a receiver and for things like video transmitter
control, telemetry, and GPS. So the more UARTs you have, the more flexibility
you have to connect things to your flight controller
such as GPS or any other external device soon to be required by possible
regulations. One of the questions that always comes up is what size ESC do I
need? Well, the answer really depends upon how you plan on building and flying your
quad. What size motors will you be using with what velocity constant (or kV rating)
and number of LiPo cells are you considering? The size, number of blades,
and pitch of props you use all have an effect on the amps drawn from your ESC.
Here are some examples of various motors with different batteries and props. The
thing to keep in mind is amperage ratings of ESC's are normally stepped
in 5 amp increments and you want to have a buffer over that of the max amps drawn
by your motors given the type of props you're using. So, for example, if your
motors draw a max of 25 amps you're going to want to get an ESC with at
least a 30 amp rating. So that's our side-by-side comparison of four of the
best 20x20 mount micro FPV flight control stacks. Let me know in the
comment section below which of these four stacks you think I should use on my
upcoming "special" micro FPV 3" quad build. Which one would you choose?
I hope is that by going through this process with me you'll have a good idea
of things to look for when choosing your next flight control stack. If you found
this useful, share it with your friends, hit that notification bell, and subscribe
to your TMac FPV channel! Thanks for your time. I'll see you next video.
Clear skies friend!