Building a Quadcopter: A Beginner’s Guide

We decided to take part in a competition in which we were required to build a remotely piloted lighter than air craft. As it said lighter than air so we began to look at helium balloon option with propellers for guidance etc. but the tournament rules were a bit confusing and after three weeks of intense research we had decided that a helium balloon of required dimensions (2 ft. diameter/flying indoors) would at best float) i.e. it could not have the guidance system attached and still be expected to be lighter than air. Apparently the tournament supervisors realized this and they altered the rules cutting the lighter than air. Then our best option was of course to go for a quadcopter. Now we didn’t know anything about quadcopters. So we embarked on a mission to build a quadcoter. So this article is about how to make a quadcopter for amateurs.

What is a quadcopter?

It is a flying craft with 4 propellers. The rpm of the propellers needs only be changed to achieve the funtions of forward, backward, sideways, rotational flying.

Parts Needed:

As we went for the hobby part of quadcopters so we used all ready made parts from the hobby shops and hobbyist. It was basically a kit with mismatch parts.

List of Parts Required:

4 motors

Quadcopter frame (you can buy readymade or you can make yourself)

Flight controller board (FCB) (it is basically a circuit board with all the functions required by a quacopter pre feeded into it.)

Propellers (should be compatible with the motors, more on this later)

Battery (should be of optimum capacity, not too large not too small)

Electronic Speed Controllers (can be obtained readymade or if you are an electronics student you can design your own)

Radio Controller/ Transmitter/ TX-RX

Wires (different voltage capacities for attaching all the circuitry)

Power Distribution board (needed if you build the frame yourself)

Screws, /nuts and bolts (you’ll have to purchase from hobby shops because they are hexagonal shape not readily available in market)

Our build:

First of all I would suggest search the hobby forums and get in touch with a hobbyist, it’ll save you a lot of time and trouble.

We went for a hobbyking FS450 frame which is a 450 size (450 mm) quadcopter frame and comes ith a PCB for power distribution. For motors we went for the Turnigy 950 KV brushless outrunners. These can spin at a maximum rpm of 11000 rpm. By using online calculators we calculated that we would require large props of 8-10 inch size. We went for 1045 props. 10 indicates prop size and 45 indicated its pitch. These are relatively slow spinning motors drawing large current so we had to go for ESCs over 25 amps. We went for Turnigy plush 30 A ESCs. We got a 2200 mAh 3S LiPo battery of Turnigy. For the radio controller I would suggest that go for a good and popular radio controller as it would save you a lot of pain later. We went for a second hand Hobbyking controller 6ch which comes on the very low quality chart. And it was a lot of pain in the…well.

Item	Quantity
Turnigy Plush 30A ESC	4
Turnigy 950 KV motors	4
Hobbyking 6ch TX-RX	1
Hobbyking slowfly 1045 Props	8
Kk 2.0 FCB	1
FS450 frame	1
Screws, Nuts, Bolts	Unlimited

How to build:

  1.First have the following tools nearby. Solder iron, solder wire, cutter, hammer, plier, tape, double tape

  2.Solder the bullet connectors on the ESCs (if not already done so)

  3.Take the ESCs one by one and solder them onto the connections on the PCB (frame)

  4.Solder the battery’s wires on the PCB on the allotted slots.

  5.Fix the motors on the motor mounts provided on the respective arm of the frame.  

  6.Fix the arms of the frame on the frame board (PCB).

  7.Attach the battery and the receiver on the underside of PCB (or any feasible place)

  8.Make sure that the CG (center of gravity) of the whole assembly is on the exact center of the   PCB (frame board), if it is not then make corrections to do so.

  9.You can check the CG by tying a knot from the center of the assembly (PCB) and suspending it in mid-air.

 10.Take the 5V connecting wires or jumpers and attach at respective slots of receiver and FCB.

 11.Fix the props on the motors, make sure they are fixed tightly. You don’t want the props flying off in mid-flight (trust me it has happened)

 12.Fix two bright LEDs or LED tape (it is a piece of fabric with a lot of LEDs) on the front part of your quad copter so that while flying you know which side is front and which is back. Take a connection out to the battery wires for this tape.

 13.Congratulations, your quad copter is assembled.

How to fly:

Coming on to the flying bit, let me tell you clearly that it will be a miracle if you get it right up in the air in the first try. If you don’t want to take any risks (actually it is advisable) you should first practice with a toy quadcopter to get a hang of this thing. For our part we extensively tested for a day on mattresses spread out on the floor.  First you will have to calibrate the ESCs with the remote controller (TX) so that they (ESCs) know what the start and end points of her TX are. Process of calibration varies with ESCs and FCB. You can find it online.

After calibration you have to check whether each function on your TX prompts exactly the same response on your quadcopters. For example if you are giving throttle all the motors should speed up in unison, if you give forward pitch the two forward designated motors should speed up and the two backward designated motors should slow down.

Another thing to keep in mind is that some FCB come with a safety mechanism. You have to arm them after switching on the power. Arming process involves pulling both the knobs on the TX in the bottom right corner of the screen. An indicator led will turn on the FCB to indicate that the board has been armed. This prevents accidental starting of the motors.

Our Flight:

Unfortunately we were extremely short of time for the competition so we couldn’t fly it to our fill. But the few test flights we did after correcting all the glitches gave satisfactory results. We had to change the ESCs from the OPTO to Hobbyking Plush because the former were apparently not compatible with the kk2.0 FCB. Also we had earlier installed a MultiWii FCB which is a much superior board compared to the kk2.0 but for reasons unknown its accelerometer was behaving most weirdly.

Conclusion

I hope this article serves as a guide for any future aspirants to this hobby