All-in-ones and “flight stacks”, which combine many components into a single package, have been trending. We wanted to see whether the simplification in build and setup is worthwhile vs. sourcing separate components, so we’re taking a look at the EXUAV Flytower F4 Pro V2.

So-called “all-in-one” (AIO) boards combine one or more of flight controller, power distribution board (PDB), electronic speed controllers (ESCs), video transmitter (VTx), and even radio receiver. The exact mix varies quite a bit, and some boards are more deserving of the AIO label than others. When you’re buying AIO, you need to be clear exactly what you’re getting—and what you’re not. Even among EXUAV’s Flytower line, there are quite a few options:

We’re looking specifically at the F4, standard 30.5×30.5mm size, with 35A BLHeli_S 4-in-1 ESC; which Banggood provided for review.

This Flytower comes with a variety of cables for connecting to your (FrSky or Spektrum) receiver, LEDs/buzzer, and camera. You also get four metal mounting screws, a set of four thin and four wide spacers, and four small lock nuts. For the VTx, you get an MMCX pigtail that terminates in an RP-SMA connector, and a short rubberized dipole. Not pictured on the product page: I found a 220mF electrolytic capacitor in the box as well. And, of course, there are a few stickers.

It doesn’t include an XT-60 connector or a buzzer. You can get a buzzer and LEDs on a stand-alone board with a connector/wire that matches one of the Flytower’s output ports.

Features

EXUAV Flytower F4 Pro V2 board detail (top)

The Flytower board is crammed with components. Half of it is VTx, with heat sink. Only a few solder pads are available, seen here on top.

In addition to the features we mentioned above, (F4, 30×30mm mounting, OSD, BLHeli_S/DShot600,) the gyro is an MPU6000. Onboard ESCs are rated to 35A/50A and support up to 5S. Take note of this last spec: the Flytower isn’t the right choice for your new 6S rig. All together, it weighs only about 20g, and the mounting hardware adds another 5g.

The VTx is 48ch, power-switchable from 25 to 600mW, and supports the Tramp protocol for FC-based channel switching. Video channels span the standard 40 you expect (A/B/E/F/R) and then they’ve chosen a band labeled “H”. This doesn’t match up with other manufacturer’s L- or H-band specs, so you may have trouble mating it to a receiver. For most people, this shouldn’t matter; it’s not a great idea to use these “extended” frequencies anyway. It’s a good thing the Tramp protocol is supported, because the one-button interface and indicator LEDs for changing band/channel/power will be well-buried inside most frames.

The biggest selling points here are really the ease of setup, (which we’ll get into below,) the weight, and the extremely low profile of the stack. EXUAV has managed to cram all of these components into just two regular-sized boards which sit very close to each other. We looked at this model specifically for this reason; some of the other EXUAV Flytower products have a three-board stack or use external ESCs.

There’s important feature omission here: no microSD card slot or onboard flash memory. Unless you source and use an external data logger (and all the hassle that comes with installing and configuring it, plus connecting and getting data off), you won’t be getting any Blackbox data. Many pilots never use Blackbox at all, but there are some really important reasons you might want to. These range from being able to debug problems with flight performance and get help for these problems from online communities, to adding stick overlays on your video, to using analyzers like plasmatree to tighten up your PID tuning.

Form factor and layout

EXUAV Flytower F4 Pro V2, installed

The VTx channel/band/power button is between the receiver port and the antenna, tucked way back at the center/rear of the board. You’d best be changing settings remotely.

If space-saving is what you’re going after, this stack is a huge step forward. Most of your electronics are covered with just the two boards totaling 14mm high.

Most of the board’s features are accessed through connector ports instead of the typical solder pads. All three ports have the same type of 4-pin connector. This means the included cables all fit in any port but have different wiring and connectors on the other end. Be careful and double check which one you use and which port you use it in (see wiring guide below). You do get surface solder pads for UART1 and UART4, intended for your telemetry and camera control, respectively. These solder pads are pretty small—about a quarter the area of a standard 0.1in through-hole via. They’re clustered together in one part of the board so a steady hand will be needed to solder. These pads are barely perforated, so be careful to secure your wires so they don’t tear out. If you’re looking for the boot button, it’s nano-sized and next to these pads.

Soft mounting the Flytower will take some extra effort. Nothing in the box will help you do it, and it doesn’t have a floating gyro or anything fancy like that. If you want to use silicone standoffs, you’ll probably have to replace all of the other mounting hardware with your own, too. EXUAV’s solution is a set of rubber washers. These are sold separately in a pack of 20, so unless you buy a bunch of Flytowers you’ll have plenty of spares. At least they’ve chosen the MPU6000 gyro; this one is known to be better resistant to noise than many of the others in use today.

Wiring

No documentation is included in the box, and the connector ports on the board are unlabeled, so you’ll need to consult a wiring guide. Here’s what Banggood provides, which appeared accurate as far as I could tell.

EXUAV Flytower F4 Pro V2 wiring guide EXUAV Flytower F4 Pro V2 wiring guide

Setup

EXUAV Flytower F4 Pro V2's ESC board, sitting in half-built frame

Add an XT-60 connector directly onto the board, if you like. Here you can see the temporary mounting used to help build before swapping in the real hardware.

You’ll want to assemble the tower in a few steps rather than build it all up at once and then try to solder on. (You could do it that way too, but you won’t leave yourself much room to work.) EXUAV’s washers are smooth inside and won’t hold the screws in place. Tape would hold them, but I had other threaded standoffs nearby and used those temporarily. First, I set the 4-in-1 in place and wired it up. Just attach the motor wires in whatever way makes sense—it’s super easy to change the motor direction afterward in software. The battery connector has an interesting U-shape design that will accept an XT60 soldered directly onto the board. This method would have conflicted with the frame I was using, so I built an XT-60 pigtail. Soldering wire to the oddly shaped battery connectors was harder than a flat pad—it’s a little tough to get the iron tip where it really needs to be without touching other components on the ESC board.

Next I swapped out the temporary mount hardware and used the screws and washers in the box. You still have to hold them in place through the process because only the top nuts hold the stack together. A piece of tape underneath may prevent searching for small parts on the floor. At this point, I discovered two of the ESC pins were bent. Pulling them back into place was enough to fix the problem and then the FC board press-fit onto the ESC board perfectly. Topping it off are four lock nuts. Most manufacturers trust this job to a nylon screw so a lock nut might be overkill; I guess EXUAV wants to be really sure they don’t come off accidentally. No complaints here.

After this, plug in the connectors for your other components. Since the OSD and VTx are both on board, there’s just one connector needed for the camera. EXUAV supplies 5V on the camera port’s VCC line and a 3-pin plug that fits most (but not all) cameras. The correct cable for my receiver had a servo plug on it, which I had to cut off and solder directly—but if you have a pinned receiver, this should just be plug-and-play as well. You might be able to get telemetry this way also if you set up F.Port, but I already have an uninverted SmartPort wire on this receiver so I soldered it to UART1.

EXUAV Flytower F4 Pro V2 ESC connector detail

Watch those pins.

The Flytower arrives pre-configured for the various ports: UART1 for telemetry, UART3 for VTx control, (internally connected: no access to it is provided,) UART4 for camera control, and UART6 for a FrSky receiver. Otherwise, Betaflight is pretty much stock. EXUAV does provides a pre-set calibration value for the current sensor, which seemed to be reasonably accurate. Plan to spend a little while in Betaflight getting things ready, and take a look at our Betaflight configuration guide if it’s not completely familiar to you.

Performance

The FC provides a great flight experience, as you expect from any F4-based chip running a recent version of Betaflight. There’s nothing groundbreaking in this area—the F4s have been dominant for a year now—but the reason for this is because they work very well. I had a very enjoyable flight experience on the Flytower whether it was planted lines in course flying or just throwing it around for some freestyle acro. The board did everything I asked of it and nothing unexpected.

Flytower camera wire severed despite being well inside the protection of the frame

I have no idea how this camera wire got severed in a crash.

One poorly performing part of the system—to nobody’s surprise—is the video reception. This comes down to the crappy dipole antenna that it ships with. Once I switched to a circularly polarized cloverleaf, the reception improved considerably. The Flytower’s board connector is MMCX, giving you a good foundation to improve this critical component. Swap to an SMA pigtail to use your other antennas, or choose from a number of small lightweight antennas with MMCX connectors already on them.

I decided to fly without the included capacitor at first to see whether it would be necessary. I was happy to find that I couldn’t see any motor noise coming through in the video even during punch-outs and at the end of the pack, and I didn’t feel like the flight performance could improve much with it either. Installing it may still make sense with more noisy motors or a more sensitive camera.

It’s hard to say, but there might be a quality issue with the wiring that’s provided. After a moderate crash, I lost video and found the camera wire had been severed. I can’t explain why; the wiring here was well protected inside the frame. It’s possible that this was caused by a very unlucky bit of debris, but perhaps the included wires are more brittle than they appear.

Conclusion

EXUAV Flytower F4 Pro V2, built up on a Floss 2 frame

All-in-ones are a great match with small, lightweight frames like the Floss 2 that don’t have a lot of room or mounting options for parts, yet still have thin arms that aren’t designed for bulky ESCs.

EXUAV’s Flytower is a great way to get a lot of your components assembled and your wiring done quickly, and could be a good choice for those who want to avoid as much soldering as possible but still prefer to build their own vs. buying ARF/RTF. It brings a good feature set and performs well, offering a great flight experience from its F4. The low 2-board profile will fit into all but the very tightest frames. It was faster to assemble than the typical mixed-bag of components, but not so much faster that I’d consider this a major selling point. There is some weight savings: the Flytower weighs in at about 21g; typically you can expect about 28g for a FC, 4-in-1, and VTx together. The biggest benefit I found over having discrete components was not having to figure out how and where to mount them all—and that’s definitely worth something.

All-in-ones like this one are a higher risk: if any one component breaks, the entire investment may be worthless. Spare parts will be hard or impossible to find, and other 4-in-1 ESCs are unlikely to be compatible. (Beware other products also called “Flytower” by different manufacturers, such as Eachine—these almost certainly will not match up.) The lack of an easy way to capture Blackbox data also puts a caveat on any recommendation, since this cuts off the owner’s ability to understand what’s happening or get help with the controller. Many pilots never touch Blackbox, so you’ll have to decide how important this is to you.

You’re not getting the latest and greatest features like 6S-capable, dual-processor, dual-gyro, self-dampening, or anything like that. And you won’t be sharing or analyzing flight data in order to squeeze the top end of performance out of the hardware. For these reasons it may not be suitable for hardcore racers or early-adopters. But, the EXUAV Flytower offers a current-generation flight experience in a very compact and easy to use package. All together, it’s about convenience, and on this it does deliver. If you don’t need the most top-line features and refinements, the EXUAV Flytower F4 Pro V2 could be an easy route to a having great time in the air.

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