Lets build our first quad

Intro

As I hopped into the RC hobby with planes, I was joined by a friend which was flying a quad. He bought a cheap almost ready to fly Eachine quad which was flying really well.

As I didn't wanted to have the same machine as him, I decided to build a small quad. Rated as a 5 inches quad (5 inches = prop size). I used the cheapest 21cm frame (~8.7 inches) I could found on banggood and build a quad around it.

The goal of the build was to be able to build and fly a quad for less than 100$. Lets see if we succeed in.

My quad

Buy list

To build a quad you'll need a frame, they are usally provided with a power board which include a BEC (Battery Eliminator Circuit) to provide 5 and 12V for the controller and other electronics like FPV stuff. As quad can be powerfull they are juiced through a XT60 connector like most of the LiPo used with them.

A few items for the quad

For this build I used a F3 controller, it is cheap and support a wide range of software. If you want to support the Seriouly Pro developpement prefere buy from the offical shop otherwise you will get a copy (a working one, but a copy).

That's all for the basics, here is the list :

Items Price ($)
21cm frame in 4mm $27
F3 Flight Controller $20
4 2205 2300KV brushless Motors $27
4 20A ESC $25
10 pairs of 5 inches props $6.9
M3 Nylon spacers $4.89
2200mAh 3C Lipo $17
TOTAL $127.8

We are a little bit over $100. You can spare a little $ with a all in one Flight Controller with 20A ESC which is really handy on small frame like this.

The space to put electronic board on this 21 cm frame is small, if you don't want to spend time to tiddy stuff around you can prefer larger frames like this one.

To the stuff above you will need some heat shrink, and wire to power on the flight controller and reiceiver from the power board. As I got a couple FPV cam working with 1 cell wires I choose this type of cable to power up my controller and receiver.

As I hope to use all the electronic on others projects later I choose to put bullet connector between the ESC and the motors. I think about puting XT30 connectors between the ESC and the power board to push the thing to the maximum put there wasn't enough space on my frame.

Bonus Items

Items Price ($)
10 Pairs 1S Battery Cables $2.55
20 pairs of 2mm Bullet Connector $5

Detail of the bullet connector between one ESC and one motor

Advices

Take your time. I spend about an hour to plan my build. As it was my first time I presented all the electronic and planned the wirering and soldering before hand. Do it ! The buildin process will look clearer and you will see if something is missing.

Update your flight controller and check if it's working properly. Before wirering the controller, test if it read the inputs from your transmitter. Have a look at this playlist from Painless 360 on the F3 controller. It will help you fly.

Never put props while inside. Quad propellers are really sharps, if you don't want to lose a finger or two wait until your quad is finished and tested to fasten your propes. They are not named blade for nothing. Be extra carefull.

Before flying configure your failsafe properly. You don't want you quad to fly away if it lose signal. Also learn to engage the security without looking at your transmitter you must know how to stop blades from spinning as you will be responsible of you quad damages if something go wrong.

Tools

Here is the bare minimum you will need to build your quad : - soldering iron - heat shrink - small hallen key to tighten motors to the frame - spare time of course ;-) - BEC to power on the receiver and the controller to test it

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