Building a 250 Sized Racing Drone

This is a homemade 250 sized racing quad that I built for my friend Lance. He introduced me to drones when he flew his Quanum Nova with me last year. He actually wanted a DJI but instead got the Nova for its price. After that, I always wanted to have my own quadcopter. This Christmas, he gave me a Cheerson quadcopter and I wanted to give him a racing drone (albeit a little late). However, there is not much tutorials in the internet that shows how to build a racing drone for 15 year old noobs like me. I had to visit a bunch of websites (at one point I had over 100 tabs on Chrome) to set up each part of the drone. I wrote this instructables to help others how to make a 250 sized racing drone in a complete and comprehensive guide with numerous pictures.

Skills needed:
You will need basic soldering skills (don't worry I just learned how from watching YouTube videos and the first thing I soldered was this drone). Apart from that, you will not need any other specific skills, aside from connecting wires and inserting screws. I mean seriously, if I could do this (a 15 year old student) without any knowledge at all, you can do this with this guide. You will also need basic common sense. Which brings us to

Safety precautions

This guide involves using a soldering iron. It is VERY HOT, so please don't touch it just to see if it's hot. Also, the propeller on the motor could be very dangerous if for some reason you decide to stick your fingers in it while it's running. But don't be scared by this, it is very safe as long as you use your common sense.

PS. There is also no flying photo since I wanted my friend to be able to be the one flying on its maiden. :) Also, if you like this instructables, please vote for me in the contest!!! :))))))

Step 1: Choosing Your Parts

Every quadcopter has these basic parts:

A motor (pretty much self explanatory). A motor for a 250 sized racing quad (short for quadcopter) usually used 5-6 inch props. Motors will usually say how much KV they are. It is quite complicated, and the only thing that you need to understand is that higher KV motors spin faster thus needing small props only and lower KV motors spin slower, thus requiring larger props. For a racing quad, you'll need a motor that spins at a higher KV than aerial photography drones, as you'll want more speed. I chose a DYS BE1806 2300KV motors since one, they are cheap, and two, they are reasonably famous since I could find a dozen reviews of it on the web.


An electronic speed controller. An electronic speed controller basically controls how fast the motor spins. Since a quad is controlled by spinning the motors at different speeds, the esc is an important part to building a quad. They usually come in sets with the motors like mine, but you can also buy them individually. They are rated in amps, meaning how much current they can handle, which is why you'll have to get an esc that can handle the current of your motor, which is usually listed in the page where your buying the motors from. If not, search the web and if there is still none, just don't buy that motor. That motor could be not that famous and you'll have a hard time fixing it if it has problems.

A flight controller. This is essentially the brains of your quad. Choose something that is famous, and has lots of tutorials on the web on setting it up as you don't want to have a hard time configuring your flight controller. The more famous ones that I've found are the Naze32, KK2, and the CC3D. There are others more, and you can choose anything you want, as long as it can self-level (AKA not go into rate mode, which is like the expert flying mode) and can support Cleanflight/Betaflight(I'll explain later). I personally chose the Naze32 Acro Rev6 since I found lots of decent tutorials on the web, it's light, it's compact, it's cheap, and it supports Cleanflight. While it does nohave GPS, it is still a good racing drone flight controller. I mean seriously, who needs GPS when you're racing? :)


A flight controller software. It is the software of your flight controller. I chose Betaflight since the GUI looks clean and it is updated on the web. Cleanflight also seems nice as this was where Betaflight came from. My friend prefers Cleanflight, and we always have an endless debate on which is better, but both of these are pretty decent since it is extremely reliable and has a GUI.

A battery. A LiPo (Lithium Polymer) battery is usually used for quadcopters, and rc in general. It has a mAh, S and C rating. mAh is the capacity of the battery, meaning a 5000 mAh battery will last longer than a 1000 mAh battery. S is how much LiPo cells are in a series, meaning if it is a 2S battery, it is 3.7 x 2 = 7.4 Volts. C is like how much current the battery can discharge at a given time. Multiply the C by the mAh, like 1000 mAh x 20C = 20,000 mA or 20 Amps. So this example battery cannot provide more than 20 Amps in a given time. Make sure to choose your battery based on your motors. Racing drones typically have 1500-2500 mAh and are 3S. Make sure that the current draw of your 4 motors combined won't exceed the maximum current the battery can provide, calculated by the C rating as shown above.

A frame. Don't forget this one like me or you'll be waiting another 3 weeks for one to ship (or make one out of cardboard like me :). A good frame is made out of carbon fiber, as it is strong, light and crash-resistant. One famous frame is the Luminier QAV 250 frame, since it's both sturdy and light (but it's expensive). Look for frames with vibration dampers, as this is where you'll mount the flight controller plus a camera if you have one. Also make sure that the frame is 250 sized or larger, so it can support 5 inch props.

A transmitter. You'll need a decent but cheap transmitter. I strongly recommend the Turnigy 9x, as it is cheap, reliable and is very famous. There are numerous tutorials on the web on setting it up and you can trust your drone to this remote. I mean, for 60 bucks can you get a 9 channel remote with good reliability? If for some reason you don't like this transmitter, pick something with 6 channels, as you don't want to outgrow your transmitter to quickly. There is also mode one and mode two. Pick one that you feel comfortable with. I picked mode two since it is what feels "normal" to me; throttle and rudder on the left and pitch and yaw on the right. Some good brands are Futaba and Spektrum, but they are expensive which is why people also like Turnigy. Don't compromise on the transmitter as if your $200 drone goes down because of signal loss, you won't say "the transmitter was just 10 bucks anyway".

The other remaining parts are pretty much self explanatory, and don't need much explanations, but I'll still explain it briefly in the parts list below. Links are also included for some parts, and they mostly from Hobbyking. I chose Hobbyking since they are pretty much a known company, and I wouldn't buy from a website that doesn't look that good. But Hobbyking isn't the only good source of hobby parts, there are others more that are equally or even more reliable.

So here is the complete parts list with links (some don't have since they can be easily found):

Afroflight Naze32 Rev6 Acro Flight Controller - Includes breakout cables too. Make sure to buy some is yours doesn't come with it.
Turnigy 9X with 8 channel receiver (Mode 2) - This includes a receiver already. If yours doesn't, make sure to get one that binds with your transmitter.
Hobbyking Power Distribution Board Lite - Distributes power from the battery to all four motors.
DYS BE1806 2300KV Combo Set with 16 Amp ESC - Motors with ESC. Plus it's cheap and on sale! Commonly includes prop adapter and mounts.
Gemfan 5x3 Props - 5 means 5 inch and 3 means the pitch. Higher pitch results in stronger power but higher power consumption.
Turnigy 2200 mAh 3S 25C LiPo - 25C and 2200 mAh means it can support up to 55,000 mA, or 55 Amps. It can also handle bursts of current (that's just my excuse since I made a mistake of buying a battery that can't support the motor current. At least you know not to make this mistake. Plus Lance can just replace this with his own LiPo.)
A250 Carbon Fiber Racing Drone Frame - Forgot to buy one but this is a good racing drone frame. It is reasonably cheap, it's carbon fiber and it has vibration damping. For this guide I'll be using a cardboard frame I built. Feel free to also use a cardboard frame, but don't use it for acrobatics and stuff. I still strongly recommend you to get a carbon fiber frame; I was supposed to get one but I forgot so I just made a cardboard one. Don't worry, you'll still be able to follow this tutorial even with a carbon fiber frame.

Some accessories that you'll also need:
Turnigy Accucell Battery charger - Pick a battery charger that can accurately monitor and charge your battery. You don't want to be damaging your battery with a bad charger.

A 11-18 volt 7 amp D.C. Plug - the Turnigy Accucel Battery charger does not include one.

Prop guards - For protection.

Turnigy Fire Retardant Bag - Just to be safe. :)

Soldering iron, plus non-leaded solder - You probably already have this, but if you don't, you'll just need to make a quick trip to the hardware store.

Helping hand - Handy tool for soldering. Small price for big help.

Step 2: Making the Cardboard Frame

If you bought one of the premade frames, go ahead and assemble it according to the manual that came with it. After that, you can skip to step 3.

If you're making a cardboard frame, you'll have to add a few parts:

Cardboard - Probably lying around somewhere. I used one box of Kirkland milk box that was going to the trash.

4 Vibration damping balls - For reducing vibrations.

Scissors and razor knife - Somewhere in the drawer too. If not, you can get one almost anywhere.

Drill bit or screw - Basically anything to poke holes for the motor mount. The hole should be around 1.9 mm in diameter (M2 size).

Gorilla Glue - A small bottle will be fine. I choose Gorilla Glue for its strength.

The dimensions for the frame parts are these:

Main body part - 6.5 x 2 inches

Clean body part - 4 x 2 inches

Arm part - 9 x 1 inches

Standoffs - 1 x 2 inches

Just use a ruler and outline it in pencil. Afterwards, cut with scissors and trim with precision knife.

Cut 2 arm parts, 4 main body parts, 20 standoffs, and 1 clean body part.

After cutting all the parts, poke the four M2 holes for the motor mount using your drill bit (or whatever you have). To align the holes properly, use a ruler to measure the motor holes then trace it on to the cardboard.

Then glue two body parts together to create one double body part and two body parts. Make sure to dampen the surface since gorilla glue is activated by moisture.

For the standoffs, the number will vary depending on the height of your esc and flight controller. What I did was I kept on glueing standoffs together until it was tall enough to support the main body part.

You may also spray paint the parts if you want.

Step 3: Setting Up the Flight Controller

The Naze32 I got included the header pins and breakout cables. Go ahead and solder that just like in the picture below. Make sure that the red and black part of the breakout cables corresponds to the positive and negative power of the flight controller pins. I forgot to check this and soldered it wrong, which made it much more difficult later on to identify the wires.

After soldering it, you can plug it to your computer using a micro USB cable. Micro USB cables are commonly used as chargers, such as Samsung chargers, or in my case a Kindle charger. But before you can interact with the flight controller, you must download and install this driver first. You must also download the Betaflight GUI from the Google Chrome Web Store, or Cleanflight GUI, whichever you prefer.

Open up Betaflight then plug the Naze32 to the computer. To flash the firmware, select load firmware online and select the latest Naze32 build. After that click flash firmware. If for some reason you can't flash it like me, you'll have to short out the boot loader pins on the Naze32. I used scissors to short the pins together.

After successfully flashing the board, you'll encounter this screen.

This is where you'll be configuring your flight controller. But for now, let's leave this screen to connect the motors, flight controller, ESC and PDB first.

Step 4: Connecting the Motors, ESC, Flight Controller and PDB

My motors and ESC came in a set. It included the prop adapter and some M2 screws.

The motor has three wires. These three wires should connect to three other wires to the ESC. The other side of the ESC has two power cables that connect to the PDB and two cables that connect to the flight controller. The motor has male bullet connectors, and the PDB has female bullet connectors. However, my esc did not come soldered with connectors so I had to solder male bullet connectors to the power cables and female bullet connectors to the three wires going to the motor.

After soldering the connectors to the ESC, you can now connect the three motor wires to the other three wires of the ESC. The arrangement determines the rotation of the motor; switching the outer two wires would result into the reverse direction of the motor. Don't worry, you can check the motor direction later on and fix it.

Connect the two power cables of the ESC to the PDB. Make sure that red goes to red and black goes to black.

The remaining cables of the ESC goes to the flight controller. Follow the motor numbers below.

Connect the first motor to the first motor port of the flight controller, the second motor to the second port, and so on.

After this, you'll have to provide 5v to your Naze32 (or whatever volts your flight controller needs). Since my PDB did not include a 5v out unlike most PDBs, I had to solder a 7805 voltage regulator to reduce the voltage to 5v.

Connect the 5v power to the extra motor pins of the Naze32. Make sure that you don't get the polarity wrong. Double check and double check.

Plug the LiPo to the PDB and check if the flight controller powers up. The esc will also make beeping sounds signifying they are powered up.

Step 5: Setting Up the Receiver and Transmitter

I did not need to do this since my friend has his own transmitter and receiver, and he'll set it up by himself but I also wanted to show how to do it since it could be a little bit confusing.

First you'll have to bind the receiver to the transmitter. Power up the receiver through plugging the 5v pin out and ground pins of the Naze32 to the battery port of the receiver. Again, double check the polarity before connecting.

The receiver will blink red showing that it is unbound and powered up.

Power up the transmitter according to the manufacturers instructions. On a Turnigy 9x, insert 8 AA batteries. The Turnigy 9x may say "switch error" at startup, but you'll only need to put all the switches in front towards the back and all the switches at the back towards the back.

To bind the Turnigy 9x, hold the bind button at the back and turn the transmitter on. Do not let go until the receiver lights up a full red without blinking.

To connect to receiver to the flight controller, plug the third wire on the Naze32 breakout cable, or the pin for signal 1 to the signal port of channel 1 of the receiver. Do this for four other pins, a total of five signal pins.

Step 6: Configuring Through Betaflight / Cleanflight

You can now connect the Naze32 to the computer.

Go to the configuration tab and put the receiver to PWM. Hit save and reboot.

Once you go to the receiver page, you should see that moving the sticks on the transmitter will move the sliders. You might also notice that the values are jumping around 1 or 2 (in the picture it does not because I turned off the transmitter to get a clear photo). You can set the RC deadband to the amount that keeps jumping around.

We'll have to calibrate the esc but first REMOVE the LiPo. To calibrate the esc, go to the motors tab and put the motors in full power. Connect the battery now to the PDB. The esc should make beeping sounds. After it has finished beeping, lower the throttle to the minimum. You might have to move it up and down twice like mine.

Once we've done that, we can now fix the motors. Go to the motors tab and slowly increase the throttle. Take note of the direction of the motor. If it is wrong, switch the outer two wires of the esc and motor.

We'll also have to set an arm switch. Since we plugged in 5 channels a while ago, we can use one of the buttons on the transmitter for arming. To do this, go to your transmitter and set channel 5 to be any button you like. On the receiver tab, when you hit the switch on the transmitter the values on Aux 1 will change. Take note of the values. Go to the modes tab and click add range for arm. Set it to Aux 1 and set the value when you hit the button a while ago. Add 100 and subtract 100 to the values so you have a range, just in case the transmitter or receiver has slight jitters.

If you like, you can also do that for angle mode. Basically angle mode is like the self level mode, where the quadcopter levels itself out. I highly recommend this mode.

Step 7: Putting the Parts to the Frame

If you bought a frame, good for you. You can stuff all the parts in, and bolt the motors to the frame. Make sure to put the flight controller to the clean part where there are vibration damping balls. After this, you can skip to step 9. :)

If you're using the cardboard frame, stuff the esc and PDB on to a single main body frame part. To keep it down, I used a little Blu-tack. Add cardboard spacers on opposite ends of the main body frame part until it is taller than the esc and PDB on the main body frame part. Gorilla glue the spacers to each other and to the main body frame.

Drill holes on the clean frame part for the vibration damping balls. Drill holes in the exact same position also on the single main body frame part.

Afterwards, glue the main body frame part with holes to the spacers to cover the esc and PDB.

Glue the two arms on the opposite sides of the main body frame part then attach the motors to the arms using screws.

Attach the vibration damping balls to the holes, and add the clean body frame part. Do not glue! Place the receiver and flight controller on this clean part. I used Blu-tack again to keep them in place.

Check how much spacers you need to clear the flight controller. I needed to place one spacer on its side and four more spacers to clear the flight controller. Glue these spacers together and add them to both ends of the main body frame.

Glue the double main body frame to the top spacers. This will cover the flight controller and receiver.

Place the LiPo on the top body frame. Insert the wire through the hole to reach the PDB.

"She may not look like much, but she got it where it counts kid."

Step 8: Final Pre-flight Checklist

Connect the flight controller to the computer and calibrate the accelerometer. Place the quad on a level surface and click calibrate accelerometer.

Go to the motors tab and verify that all motors are running smoothly. Also verify that the motors are running in the correct direction.

Now, and only now, add the props to the motor. I didn't add the props before because you can have an accident like my friend who decided to add the props early, and accidentally armed his quad which sent his quad flying to the air and crashing.

Screw the prop adapter to the motor then insert the prop to the prop adapter.

Then insert the props through and screw the top part of the prop adapter to lock the prop in.

You're ready to fly now!

Epilogue:

I gave this to my friend (without the transmitter and charger and whatnot since he already has those) in a cardboard box, cause why not. I admit, the frame (doesn't look like much too) probably won't survive all those flips and acrobatic maneuvers, but I'm sure he'll change the frame anyway. What matters is the effort I put into this quad and I'm sure he'll like it.