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The Quadcopter


Kiel Graham, Josh Kramer and Eric Sabourin, Department of Mechanical Engineering, University of Ottawa



For our project we created a quad copter. The quad copter is a type of rotorcraft, which means that it uses rotors instead of fixed wings to generate lift. This type of aircraft was one of the first configurations to successfully implement a vertical takeoff. Rotorcraft have a wide variety of applications and uses, and one of their most useful features is the ability to take off and land vertically, eliminating the need for a runway.


For our project, we decided to create a 4 rotor rotorcraft, a quad copter. The quad copter offers several advantages in its design. First of all it is relatively simple and cheap to build and maintain due to its simple mechanical design. This simplicity allows for easy field repairs when required. Furthermore the quad copter has very stable flight characteristics, which make it useful for capturing images or lifting loads safely. With modern advancements quad copters can now perform highly complex aerial manoeuvres, which further increase the range of applications of quad copters. Some applications for quad copters in today’s society are real estate photography, military surveillance and transport, and exploring unsafe places.

 Transmitter and Receiver

The Transmitter and receiver used had the following specifications: a 2.4 GHz 4 channel transmitter with a 6 channel receiver.


We needed 4 output channels from the transmitter to control the thrust, rudder, ailerons, and elevators respectively. The thrust channel controls how much uniform power is supplied to all 4 motors and is used to control the altitude of the quad copter (left), and he ailerons channel controls the roll of the quad copter (right).

The rudder channel controls the yaw of the quad copter (left), and the elevators channel controls the pitch of the quad copter (right).

The block diagram demonstrates how the quadcopter transmitter signal goes to the receiver on the quadcopter, which then goes to the Pulse Width Modulator (PWM) and the Pulse Position Modulator (PPM) which converts the signal that the gyros and accelerator can understand to self-level the quadcopter and provide power to the motors. There is also the diagram of the go-pro camera and receiver used on the quadcopter.

The Frame

The frame was constructed mainly out of aluminum. 6061 Aluminum has a mass of 2.7 g/cm3. The mechanical properties are desired from the aluminum and they are offered in a light- weight material. The aluminum is rigid enough to resist flexing when the rotors are operating at full throttle and strong enough to resist breaking when the quadcopter crashes. The aluminum is relatively easy to machine and fairly cheap to purchase. 



For our design the frame is an X configuration. The X configuration was chosen over a + configuration for smoother flight and a better mix of motor integration from each channel. The Lengths of the X arms are 24” end to end and are made of 1” x 0.25” rectangular bars. There is one full-length bar and two half-length bars to keep the motors on the same plane. The bars are sandwiched between two 4” x 4” x 0.125” aluminum plates. The plates are used to keep the X configure rigid and to mount the controller and camera mount to the bottom. The camera mount is made from the same aluminum bars as the arms and was bent into shape to give a slight downward view for the camera for better filming angles when in flight. Below are the design drawings for the quad copter.



The weight of the quadcopter was minimized in multiple ways. The components of the quadcopter were assembled with small machine screws instead of bulkier nuts and bolts. Holes were drilled in areas of the frame that would not be used for mounting components to reduce weight, reduce drag and hold parts in place by running wires though the holes.


The microcontroller used for our quadcopter is the Hobbyking KK2.0 flight controller. The controller takes signals from the channels and transmits the signal to the necessary motors to make the desired action happen. The quadcopter flight would not be very smooth without the use of a microcontroller. The flight controller has fixed channels of throttle, rudder, aileron and elevator. If the throttle is increased all four of the motors speed up at the same rate, if the rudder stick is moved to the left or right either both the clockwise motors or counterclockwise motors speed up to rotate the quadcopter. If the aileron is increased left or right either the left half motors or right half motors speed up to move sideways. If the elevator stick is moved up or down the back two motors or front two motors speed up to move forward or backward.

 The microcontroller has an incorporated LCD screen, which makes it very simple to see that the user commands are inputted properly. The gains of each channel, other than thrust, are adjusted on screen, as opposed to turning potentiometers on controllers without LCD screens. The ESC’s are easily calibrated through the microcontroller and the LCD screen shows that the calibration was successful. The status of the sensors are displayed on the LCD screen as well so it is simple to problem solve instead of guessing where your errors may come from. The controller firmware was updated and slightly altered by connecting the controller to a laptop using aUSBasp adapter to flash the ATMEL Mega324PA chip on the controller.

The Motor

The motors used were the MT2213-935KV MultiStar Motor and Propeller Combo 10-4.5 CW CCW.  This comes with 4 motors and 4 propellers. Each motor generates 583g of thrust. When added together, the four motors can generate 2332g of thrust. When compared to the weight of the quadcopter, 1360g, it is evident that the motors provide enough thrust to lift up the quadcopter and move it around. The rotors spin at a rate of 935rpm/V and gives 200W of power.


The battery used was the Turnigy 2200mAh 3S 25C Lipo Pack, as it gave the required amount of power, was a relatively light battery for the power it provides, and it was cost effective. It discharges 25C and has a capacity of 2200mAh. The battery is composed of 3 cells. Each cell has a max voltage of 3.7V, which gives 11.1V for the entire battery.

Battery Elimination Circuit

In the Turnigy PLUSH – IBA speed controllers used, there are Battery Elimination Circuits (BEC), which regulate the dispersion of battery power. It allows the use of 1 battery to power both the motive part of the motor and the steering part.

It also has a Low-Voltage Cutoff (LVC) sensor that diverts power away from the motive part of the motor and sends more to the steering application when the battery power gets low. This allows the controller time to bring the quadcopter back when in the event of low battery. The LVC for the speed controllers is 2.6V per battery cell or 7.8V for the entire battery