Introduction: FPV Mini Freestyle or Long-Range Drone

By www.youtube.com/ImaginationTech

We're going to be building this 5" Freestyle with great parts like the Furious FPV Racepit Flight Controller, Ummagawd Hypetrain motors, and it can even go long range with its Crossfire, GPS, and Unify Pro VTX.

If this is your first time building an FPV Quad and none of what I just said makes any sense, don't worry I will be making this as beginner-friendly as I can. I will be providing a lot of explanation for you to follow around and to understand the basic concepts of building a quad, as well as the basics of all of the parts that go into this quad. And if you're following along on this build, you don't necessarily need to use all of the same parts that I'm using here because the concepts are going to be very similar even if you use different parts. You just have to be able to locate the user's manual for your particular part that you're going to be using. But in general, the way to build a quad is the same; once you build one you'll know how to build a different one.

So I'm going to be putting a lot of information here including all of the parts that I used for this quad (as well as some alternative options), links to the 3D printed mounts, as well as all the tools you will need to build an FPV quad.

Spec Notes: As I built this quad more than a year ago, you may find difficulty sourcing some parts or need to replace them with something newer. I've put "Spec Notes" at the end of each step so you know what to look for in a replacement part and to further explain the parts used.

About me: I have built probably a dozen or so quads since 2016/2017. The technological landscape certainly changes quite fast, and what could have been state of the art back then is certainly old-school by now. So certainly, this Instructable will show you how a quad would be built in 2021. Do check out my videos on YouTube as well!

Supplies

Quad Parts:

Total $350 or less

Extra Stuff:

3D Printed Parts:

Tools (from your local hardware unless specified):

Step 1: Waterproofing

If you're planning on applying some conformal coating or some kind of water proofing on your Electronic Speed Controller and Flight Controller, then you might want to do that beforehand because it's going to be hard, but not impossible, to apply conformal coating when all the motors are attached to your ESC and when you're FC is already wired up.

Step 2: Assembling the Frame

The frame we're using is the Glide frame designed by Kabab FPV (Bob Roogi). If you're coming off from a DJI camera drone or a toy drone, you may notice that all of these are made of (quite thick) carbon fiber, which is not only light but also strong and doesn't flex too much. It also allows your quad to come out of a crash alive unless it's a really bad crash. It comes with a main bottom plate, a top plate, a sandwich plate (which sandwiches the arms between the bottom plate, hence the term), and of course the four identical arms which are 5mm thick to give it even more strength since they are usually the first ones to hit the ground or object in case of a crash. It also comes with standoffs, which are like the aluminum posts that hold the top plate up above the bottom plate, and also a bag of screws and nuts. Some other frames would give you just enough screws to assemble it, but the Glide comes with a whole lot more extras.

The first thing you need to look for are the longest screws in the bag, which is meant for your flight controller board or electronic stack (standard sizes for flight controllers, 4-in-1 ESCs, and sometimes a receiver and video transmitter mounting board are either 20x20mm or 30x30mm and can be stacked on top of each other). The Glide has holes for both a 20x20 stack or a 30x30 stack. There are long M3 and M2 screws; if you're going to be using a 20x20 stack, you'll need the M2 screws, and M3 for 30x30 stacks. You'll also need to look for their corresponding M2 or M3 plastic nylon nuts. Put in the screws for the stack through the bottom plate. Once you assemble the arms and sandwich plate, you won't be able to work on these screws anymore so you'll need to decide what stack you're gonna be using now. The Racepit Flight Controller I am using is a 30x30 board.

The screw holes may have really tight tolerances, so you may have to wiggle the screws in the first time.

Now lay the sandwich plate flat on your table. Each arm would have 2 holes and would match the holes on the sandwich plate, so you can lay each arm on the sandwich plate so you can visualize how they would go together. You can then take your bottom plate and lay it on top of the arms (the 2 holes would also align). So now you need to get 8 screws (8mm I believe, slightly shorter than the stack screws) which you would insert from the bottom of the sandwich plate, through the arms, and out on the top side of the bottom plate. Their length should be just enough to screw on the steel nuts on the outer screw of each arm. For the inner arm screws, get 4 standoffs and screw them on those screws. For now, you don't have to screw in everything too tightly. Once you're done with this part, we are going to put this frame aside for now as we work on our electronics.

Spec Notes: This is a 5" freestyle frame, which pertains to how long the propellers can go on them, in this case 5 inches in diameter. You can use any other 5" frame, even a racing frame.

Step 3: Electronic Speed Controller (ESC)

This is the JHEMCU 40 amp 4-in-1 ESC (Electronic Speed Controller) and it comes with 14AWG wires, an 8-wire cable, and 1000uF 25V capacitor. It doesn't come with an XT60 connector so you're gonna have to buy that separately. It also doesn't come with M4 gummies (so that it fits snugly with your M3 screws). All of my previous builds and all my previous flight controllers and 4-in-1 ESCs used to come with these gummies so thankfully I have a couple lying around. If this is going to be your first build or if you don't have any extra gummies lying around, you might want to order some, or getting a different ESC. But for about $30 you really can't beat the price of this thing.

So you just need to squeeze in the gummies through the M4 holes. For the capacitor it came with, it's adequate only if you're going to be using a 4S battery (16.8v max), but since we're planning on using this with 6S battery, you might want to consider getting something like a 1000uF 35V capacitor because a 6S goes up to 25.2v.

Next we just need to pre-tin all of our pads. Pre-tinning is basically just applying solder onto the bare copper pads so that it's easier to solder wires and capacitor (which would also be pre-tinned) onto them. For the capacitor, we shortened the legs as short as we can, and we solder them on the underside of our ESC. Once we have that out of the way, we can solder the thick 14AWG wires on the top side.

Once you're happy, you can just plop it onto our frame and make sure it's flat. You may have to bend the capacitor so that it lays flat. We also need to solder an XT60 connector to the other end of our 14AWG wire. Pictured is an Amass XT60 connector which I recommend because it comes with a shroud, so you don't need any more heat shrink, though I still recommend you get a set of heat shrink for general use. Those of you who are going to be building for the first time, get yourself one of these connectors and they usually come as a pair, so you just get a whole bag of them. This is the male connector. It's male because you judge the "gender" of the connector with its copper pins. I also recommend that you get the female side of the pair and plug into the male side when soldering because the heat might deform the plastic otherwise. Remember to slide in the shroud through the wires first before you solder the actual connector, and that the flat side of the XT60 is the positive side.

If you have some helping hands or Blue Tack, because the XT60 gets a little bit hot. Let's pre-tin this XT60 connector with a little bit of solder, then grab your tweezers then melt the pre-tinned solder together. Once you're done with both wires, just slide the shroud and snap it close.

Spec Notes: I used a 4-in-1 ESC, meaning it has 4 ESCs (one for each motor) on a single board. This makes life much more convenient than buying 4 single ESCs, but it's your choice. I also used a 40A ESC here. You could get away with a 30A ESC, but it's safer to go higher to make sure your ESC has enough amps to drive the motors even when flying aggressively.


Step 4: Motors

Next up we're going to be screwing on our motors to our arms. If you have some ThreadLocker, now would be a good time to bring them out and squeeze a couple of drops onto a piece of plastic. The screws that came with the Ummagawd motors are a little bit short because the Glide has really thick arms, but thankfully the Glide came with their own set of screws. So just take them, dip it into some ThreadLocker and screw them through the arm to the motor loosely. Once you have all four screws in place, you then tighten all four together. When you're done with one arm, you just have to repeat with the other arms.

Each motor has 3 wires, and there are 12 pads in total on our ESC for our 4 motors. It doesn't matter at this point what order the wires are soldered on the ESC, as long as they are grouped together by motor. It's a good idea to trim our wires first, so that there isn't too much extra slack. Not only is it neater, it also prevents the wires from accidentally getting into the propellers and getting chopped off. Once trimmed, pre-tin the wires and solder them onto the ESCs.

Now let's tidy up our wires a little bit because you don't want your wires to be hit by the propellers when they're spinning, so you just take a piece of ziptie, just wrap it around those wires and tighten that. A ziptie is a very practical item you need to have in your toolbox. Once you've tightened the ziptie, just cut off the end. Another alternative you can use, and what I would use, is to just wrap the wires with cloth tape. I prefer this because for me it looks a little bit neater, nicer, and more professionally made than ziptie. So we do that too with the rest of the arms.

Spec Notes: This motor is a 2306 2150kv. The first set of numbers ("2306") basically means the motor stator is 23mm dia. x 06mm high. Some people prefer a 2207 motor; it's a personal preference. Either would do fine. The next set of numbers (2150kv) means it spins 2,150rpm per volt applied to it. This motor is technically designed for 5S, but we will adjust it in software later. If you want a real 6S motor, you would look for something in the range of ~1700kv to ~1950kv.

Step 5: Flight Controller

Our 4-in-1 ESC has an 8-pin connector and came with its own 8-pin wiring harness, so we can just plug one end in and solder the other end of the wires to the appropriate pads on your flight controller. What you do need to take note of are what each pin/wire actually does, in this case it's (from L-R) VBatt, Current Sensor, Ground, Telemetry, Motor 3, Motor 1, Motor 4, and Motor 2. In our case, our flight controller also has an 8-pin connector, which is (from L-R) VBatt, Current Sensor, Ground, Telemetry, Motor 1, 2, 3, and 4. The nice thing with the flight control is it comes with two wire harnesses, one is nice and short, and the other one has the wires not yet attached to the connector. What we just need to do is just plug the appropriate wires to their respective pins to match that of our ESC on one end and our FC on the other. So the first four wires would be the same, but the 5th wire from our FC would be going to the 6th pin of our ESC, and so on. Now that we're done with our harness we can just plug that in.

So now I've put in the gummies for the flight controller and screwed it down with nylon nuts. Normally you'd also want some nylon nuts in between the two boards, so that 1) you can keep the ESC board down and 2) ensure separation between the two boards, because you don't want them to be touching each other or else you'll have a short circuit and you're gonna have a really bad time! In this case I have all my wires going in between the two boards, and that's preventing the flight controller from going down and touching the ESC board. It's still your preference, but in my build I opted not to put in any nuts anymore, and just used nuts on top of the flight controller to secure it to the stack.

The nice thing about the Racepit flight controller is it gives you a lot of flexibility and control with onboard selector switches, such as a selector for either 5V or Vbatt (that is, giving full battery voltage) for your camera, and also for the Video Transmitter (VTX). That would really depend on what camera or VTX you have. Some VTX and cameras only takes up to 5V while some can take up to 6S (up to 25.2V) voltage. The Micro Eagle and Unify Pro HV that we will be using can handle 6S voltage. You can also set this up so that the VTX is always turned on, or if you want to be able to turn it on and off from a switch on your transmitter.

Now, we need to pre-tin all of the pads that we are going to be using. So you'll need to solder the pads for the camera (ground, Vbatt, and video signal), the four pads for our VTX (Ground, Vbatt, video signal, and Smart Audio).

In the next steps, we're going to be connecting our other parts to the flight controller. You can also remove the flight controller from the stack while you work on it if that makes it any easier for you.

Spec Notes: This is an F4 flight controller, but basically any other F3 or F4 flight controller would do. You would be relying on the wiring diagram/manual anyway to know what wire is soldered onto which pad.

Step 6: How to Test Your ESC and FC

At this point you might want to take out your smoke stopper and you plug in one end to your battery and the other to your quad. What a smoke stopper does is it limits the current, so if you do have a short it doesn't burn all (or hopefully none) of your components.

If you don't have a smoke stopper but have a fairly modern smart charger like an ISDT Q8, ToolkitRC M6D, or something similar, you should have an option to output power to one of its output channels, you can just set it with a low maximum current like 1.0A. It just needs enough juice to turn on the flight controller and ESC, but if anything goes wrong it's not gonna supply a lot of current and won't burn your parts.

So before we solder any of our components to our flight controller, plug it in to your smoke stopper or smart charger, and it should power right up without a problem and without any smoke.

You would want to do this periodically after each step.

Step 7: Receiver, Video Transmitter, GPS, and Camera

In the case of our receiver, we would put in our 4-pin header that comes with our Crossfire RX Nano receiver into the through holes of the FC and solder those. But first we need to trim the receiver header pins so that they're not too long (you can measure how much you need to cut by test fitting the header onto the flight controller and the receiver onto the header pins). And now we are just going to solder it to our receiver. I've coated the receiver with conformal coating, but I'm still going to use the heat shrink to help secure the antenna. You can still push the receiver button through the heat shrink. Then slide the heat shrink over the Crossfire Nano receiver and cut a notch for the header pins, and shrink it with a heat gun or blower. We put on some double-sided tape and we're just going to slot it into the holes on the flight controller. Now we just need to solder the header pins to the flight controller.

If you took the flight controller off the stack to work on it, you would want to put it back onto the stack for the next parts.

We will now install the Runcam Micro Eagle camera onto our frame, using the included TPU mounts that came with the frame and the M2 screws that came with the camera. Now we just need to solder the wires from the Micro Eagle to their respective pads (cut the wires shorter if there's too much slack or excess wire).

Now we're going to solder our VTX onto our flight controller. Since I mounted the VTX sideways, we're going to solder the Smart Audio wire first since it's the furthest one from the VTX. Next would be our video wire, ground wire, and finally VBatt. Once we're done, we can trust our wire harness as a bundle, that way it's a little bit stronger in the event of a crash, and then plug them back into the VTX. Now take the pigtail and insert into the TPU antenna mount and slide the TPU antenna mount down the rear aluminum standoffs. Now all we need to do is just screw on the antenna.

Next we just mount our Crossfire antenna with the TPU mount that just slides over a standoff and slide one side of the antenna in there and snap it into place.

One last thing to attach to our quad is our BN-220 GPS module. It comes with double-sided tape and a couple of wires, which are not silicon wires, but we'll just make it work. It comes with black (ground), red (5V), green (rx pin, which connects to the TX6 pin on the FC), and white (tx pin, which connects to the RX6 pin on the FC). We just need to shorten the wire just enough to reach the pads and not have too much excess. Be sure to twist the wire before cutting it.

Now that we have all components installed, go back to Step 6 and test again with the smoke stopper or smart charger.

Spec Notes: Our receiver is a TBS Crossfire RX Nano, which use the CRSF protocol and requires a Crossfire module on your radio. If you just have a basic radio (w/o a Crossfire module), you could use a receiver that uses the FrSky (Sbus) protocol, and it's wired up similar to the Crossfire RX Nano, but instead of Ch1 you have Sbus, and instead of Ch2 you have telemetry/F.Port.

For the camera, you can use any FPV camera you have access to. Different cameras will have different performance, size, and image quality, but the main spec you're looking at is whether it can take 5V or full 6S voltage.

The VTX, like the camera comes in different shapes and sizes, but you'll be mainly looking at what voltage it can take, whether 5V or Vbatt. Another spec to look at is the maximum output power; the TBS Unify Pro can go up to 800mw, but you'll be fine with something like 200mw-400mw if you're just gonna fly at a park or field and not doing really long range.

As for the GPS module, I used a BN-220 but you can use a BN-180 as well. It's slightly smaller, but takes longer to connect to satellites. You can also get a TBS M8. All these GPS modules have the same four wires, but the wire order might be different, so make sure to check their wiring diagrams.

Step 8: Configuring Betaflight

If you don't have Betaflight installed yet, go to the Betaflight Release Page to download the latest release. Click here for Installation instructions.

I'm not gonna discuss in detail how to use Betaflight; there are a lot of guides on the internet for that.

Firmware Update

With Betaflight running, first we're going to plug in a micro USB cable to our flight controller and to our computer, and you should see the COM port update on the upper right corner of the Betaflight screen. You can keep the firmware version to whatever stock firmware the flight controller has from the factory, but I recommend updating it to the latest release (4.2 as of this writing).

First, click the Connect button, then click on the CLI tab. From there, click on the command line at the bottom of the screen and type "version" and hit enter. It should show you the current version it has, as well as the name of your flight controller (FF_RACEPIT in the case of the one I use). Next, click the Update Firmware button. From the Firmware Flasher screen, choose FF_RACEPIT from the top-most dropdown box, choose the latest Betaflight firmware from the dropdown box below that, and make sure "Full Chip Erase" is turned on. Click "Load Firmware (online)" at the bottom, and once it finishes, just click the Flash Firmware button to its left.

Now that we have our firmware updated, we just click on the Connect button. A pop-up dialog box will appear, and you should click "Apply Custom Defaults" because we just flashed a new firmware. You will need to click "Connect" again after the flight controller reboots. Make sure your quad is on a level surface, then click Calibrate Accelerometer.

Now let's go over setting this up by system, starting with the receiver.

Setting Up Your Receiver

The first thing we are going to do is head over to the Ports tab. We need to set up all of these things. Depending on what flight controller you have, it's going to look different. The ports page basically tells Betaflight what components are attached to where. In our case, our Crossfire receiver is hooked up to the specified Crossfire pads and for Racepit that means UART1. So just consult the manual of your flight controller, or depending on which UART you soldered your receiver to, that is what you will enable for Serial Rx. For Smart Audio, we have that connected to UART4, so under Peripherals we choose "VTX (TBS Smart Audio)" on the UART4 row. Now we just click "Save and Reboot".

Once it finishes rebooting, click "Connect" again. So we've set Crossfire in the Ports tab, next we need to go to the Configuration tab and make sure Crossfire is selected. Scrolling down, to the "Receiver" section, we need to make sure your receiver mode is set to "Serial based receiver", and then choose "CRSF" on the Serial Receiver Provider list, and click "Save and Reboot".

Onto the Receiver tab, with your transmitter turned on and a battery plugged into the quad, and I'm assuming you've already bound your Crossfire receiver (for more info on binding and all about the Crossfire system, you can refer to this Guide to Crossfire). You can check if all your control inputs are working and reflecting on screen to verify that everything is working properly.

Setting Up Your VTX

We now go on to the Video Transmitter tab. We have a TBS Unify Pro which means we need to load the VTX tables for Smart Audio 2.0 from Betaflight's Github page and have it saved beforehand, click on Load from file and choose that file. You can now set your band and your channel and power levels. The default has just 3 power levels, but the TBS Unify Pro has 4. So just increase the number of power levels to 4, put "3" as the value and put "800" as the label.

Motors & BLHeli

Back in the Configuration tab, you can see a diagram showing which direction each motor is supposed to spin. It doesn't actually control which direction the motors spin, but only tells Betaflight which direction it should expect the motor to spin. Enable Motor direction is reversed (it just flies better), which is normally called a "props out" configuration because the props are spinning outwards with respect to the camera. So please take note of these directions. Here on the Motors tab, you're going to need to plug in your battery to be able to use this. Before anything else, make sure you don't have any props on your motors because you don't want to injure yourself or damage anything. Then tick "I understand the risks", and if you move the Master slider just slightly upwards it's going to spin the motors and you can now check which the directions the motors are spinning and you can compare it with the direction Betaflight is expecting it to spin. You can put some tape on the motors or you can just feel it with your fingers to determine if each motor is spinning in the same direction as with the diagram. If any of the motor directions need to be reversed, make a note of which motor(s). Click Disconnect, then start BLHeli Configurator/Suite. With the battery still connected to our quad, click on Connect, then Read Setup. We need to select which motor needs to be reversed, and just toggle it between normal to reversed or vice-versa. Afterwards, click Write Setup to save it into the ESC firmware, and then click Disconnect. You can go back to the Betaflight Motors tab and do what we did earlier to verify motor direction.

Motor Output Limit

You only need to do this if you are using a 5S motor like the one I'm using. If you are using a 6S motor, you can skip this part. We go to the CLI tab, and by default it has PID profile 1 selected (which is profile 0 in CLI). Type in "get motor_output_limit" and it should show you 100% by default. To choose the 2nd profile, type in "profile 1" and once again "get motor_output_limit", which will show you it's also 100%. This time, we type in "set motor_output_limit = 84". Now we can switch between profiles and use the 2nd profile for when flying with 6S batteries.

GPS Rescue

For this, we first need to enable Expert Mode (toggle at the left of the Update Firmware button). From the Ports tab, since we have GPS hooked up to our flight controller on UART6, under Sensor Input we select GPS in the UART6 row, and click Save and Reboot. In the Configuration tab, scroll down to the GPS settings, enable GPS, Auto Baud, Auto Config, and Set Home Point Once. Choose either UBlox Protocol for the BN-220 we are using. Clicks Save and Reboot. You can verify this is working if you can manage to bring your quad and laptop outside, and going to the GPS tab where you would see it connecting to satellites and updating its GPS longitude and latitude. We then go to the Failsafe tab. Under Stage 2 settings, select GPS Rescue, and enable "Allow arming without fix". I also prefer lowering minimum satellites to 6. Click Save and Reboot.

Modes

In Modes tab, you assign functions to each aux switch you set on your radio. You can customize it how you wish, but I've set mine like in this screenshot.

Others

In the Configuration tab, let's set the Arming Angle to 180 degrees. The Arming Angle by default is set to 25 degrees, and if your quad is tilted more than 25 degrees, it's not going to arm. In case you get stuck in a tree and your quad is stuck upside down, you want to make sure you are able to arm your quad no matter what, so we set that to 180 which basically tells the flight controller to arm regardless of the orientation. We can also give our craft name a name. Here I just named it "Glide". Scroll down to Dshot Beacon Configuration and enable RX Set. Since we didn't have a beeper, we want our motors to make a sound when we flick the Beeper switch. Click Save and Reboot when done.

Step 9:

There you have it! If you followed along on this build or used similar parts, you're going to have a quadcopter that's gentle and smooth with a 4S battery that's perfect for beginners, or great for freestyle with a 6S battery for more seasoned pilots! With its Crossfire receiver, 800mw VTX, and GPS module, it's also perfect for long-range or mountain surfing!

If you have any questions, please comment them down below!

Please do check out my other videos and tutorials on my YouTube channel as well!

Anything Goes Contest 2021

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Anything Goes Contest 2021