9

FEATURE

Build a drone

COMMISSIONING

YOUR MACHINE

hen you have assembled

the machine, before you fit

the propellers, you should

first give it a full visual

check, to ensure that you

catch obvious problems.

Then, connect a USB cable to

the flight controller, plug it into your PC, and run the

Betaflight Configurator software. This should power

up only the controller and receiver, and allow you

to verify that the controller and radio are working,

and configure any settings you may need. Only

when you are satisfied that all is in order should

you connect the battery, and spin up the motors

by operating the throttle. With no propellers fitted,

there will be vibration when the motors spin up, but

the scope for damage will be limited. You should be

able to tilt the machine and see the different motors

spin up as it attempts to right itself.

At this point, it’s worth talking about another

pitfall. When we first flew our machine, we had a

small crash and broke a propeller. Not unexpected,

and fortunately we’d bought spare propellers, as

W

you should too. So, why did we crash? Straight out

of the box, our machine had extremely sensitive

controls, to the extent that though it appeared to

work during our tests, in flight it was very difficult

to manoeuvre. The solutions were straightforward

enough – in its default settings, our flight controller

was set to fly in acro mode. This is a mode used by

racers and other advanced fliers, in which a lot of

the stability features in the flight controller software

are turned off, and instead of automatically trying to

maintain level flight, our machine was all over the

place. We had to enable self-levelling mode (called

‘angle’ in Betaflight Configurator, on the modes

screen), and bind it to our arm switch for everything

to return to normal.

We also decreased the sensitivity of our controls.

There are two places this can be done, either by

adjusting the rate and exponential settings on

our transmitter, or the way we did it in Betaflight

Configurator, by reducing the RC rate settings on

the PID tuning screen. We strongly suggest that you

don’t touch any other PID settings, unless you really

know what you are doing.

READY FOR FLIGHT

A multirotor might seem fairly harmless, but it can

be a dangerous machine. There is significant energy

in those propellers, and catching a finger or hand in

one at full speed can cause injury and pain. Once

we attach the propellers, it is important to treat the

machine as potentially dangerous. Be careful not

Below

The FlySky rate-

expo screen,

showing settings

to desensitise

the controls