RC radio transmitter and receiver
You need 4 channels minimum but I am begging you to get one with 6 channels. Also get one that uses 2.4 GHz technology if you can. Turnigy has a 9 channel model
that is actually very inexpensive, and it runs on an AVR microcontroller that you can put custom firmware on
. Personally, I have a old $25 radio that uses 75 MHz FM but I've converted it into a 2.4 GHz radio using a conversion kit
Four brushless outrunner motors
are needed. I used hexTronics 20-22L
(this number represents the diameter and coil winding configuration of the motor, there's also a kv value that relates speed and power, higher kv = more
faster motor (thanks to the correction from slick8086, I was incorrect to relate power to Kv, it's the RPM that's faster if Kv is higher), 800 to 1200 is acceptable motors. They come with a ton of parts (the bullet connectors, heatshrink, propeller adapter, the screws you need, mounting plate, spare shaft and spare C-clip, all included). Get extras just in case one gets damaged in a crash.
Four brushless motor electronic speed controllers (ESC)
are needed. One that is rated for 18 amps is enough. I have heard good things about the Turnigy Plush ESCs
because they support high update frequencies (more frequent adjustments means more stable flight). I got the HobbyKing brand clones
of the Turnigy Plush ESCs because they are cheaper.
Some ESCs are "card programmable", meaning you can change their configuration using a cheap ($6) programming card
, which is really convenient. Buy the programming card that is compatible with the ESCs you've chosen. I got the Turnigy ESC programming card
because they are compatible with my ESCs.
You'll obviously need a battery. You will use a 3S1P lithium polymer battery that is rated at least 20C
(this is the discharge rating). 3S means 3 cells in series, 1P means one set in parallel. This will give you a combined 11.1 volts. I suggest a 2500 mAH capacity battery (or more). A general rule of thumb is doubling the capacity of the battery means 50% increase in flight time (due to the extra weight).
More info on batteries here: http://www.rcgroups.com/forums/showpost.php?p=1315199&postcount=1
Make sure you pay attention to the type of connector that comes attached to your battery. You're going to need to get the matching connector. I've personally built my entire helicopter using bullet connectors. 4.0mm bullet connectors for the battery
and 3.5mm bullet connectors
for everything else (the motors come with 3.5mm bullet connectors). (You can get other connectors such as XT-60 connectors
, just watch your polarities, also note that all my pictures show bullet connectors)
You need a lot of heat-shrink tubing
to act as insulation when using the 3.5mm bullet connectors. Get different colours so you can tell which wire is which.
You need 12 gauge stranded core wire
. It must be 12 gauge or thicker to handle the current. It must be stranded core so that it is flexible. Get different colours so you know which wire is which polarity. The best wire is fine stranded copper wire with silicon insulation, but this is expensive.
Get a good battery charger
, it must be able to balance and charge multi-cell lithium polymer batteries. I have one of these Turnigy chargers
that have many settings, a LCD, and cooling fan, very nice. I also use a laptop power brick to power the charger since an ordinary wall adapter won't be able to handle the current required.
Get a battery monitor
so you know when your battery is low. A lithium battery will become permanently damaged if you drain it below a certain threshold. Having a monitor will prevent you from damaging your battery. I have one of these that reports the status of each cell.
The quadcopter's frame
I use is this one from HobbyKing
. For $15, you get every part you need, plus every screw and nut you need. In comparison, a stick of aluminum would cost me $10 from Home Depot, which is not economical in comparison. I suggest you buy several frames so you have plenty of spare "arms" if you crash (plus plenty of spare screws and nuts).
must be in counter-rotating pairs (a "pusher" and a "puller"). I use 10x4.7 APC slow-fly propellers
. 10 indicates diameter in inches and 4.7 indicates pitch. Larger diameter means more lift but requires more powerful motors. 10 inches is about right for the frame size I am using.
You'll need a entire flight controller circuit
(meaning another entire bill of material), I will talk about this in detail later. Meanwhile, you'll need a USB-to-serial cable
) and an AVR programmer.
Plenty of servo cables
are required to connect stuff. A minimum of 6 female-to-female cables is required for the 6 channels from the RC radio receiver to the flight controller.
Velcro tape and double sided velcro strapping
will be useful as a lightweight way of mounting things and strapping in the battery.
Get a bubble/spirite level
(like this one
) to help with sensor calibration.
Make sure you get plenty of extras, stock pile on wire, cables, connectors, heat-shrink tubing, electrical tape, glue, screws, etc.