Let's begin by taking a moment to discuss the design to the multirotor aircraft we will be building in this Instructable. If you are at all interested in multirotor aircraft, you have certainly heard of quadcopters, the most popular type of multirotor. Quadcopters are multirotors with four propellers. There are many tutorials around the Internet for building various types of quadcopters (I even wrote one myself).
Tricopters are another type of multirotor that only have three propellers to provide lift for the craft.
For some reason, tricopters are not nearly as popular as quadcopters and as a result, there are not many high-quality tutorials online about how to build them. Tricopters are a really elegant type of multirotor though, and they have a number of advantages over other types of multirotor:
Tricopters do have a couple important downsides though:
Instructable Table of Contents
In order to build your very own tricopter, you are going to need to order some parts, quite a few parts in fact. Before I list the parts used in this tutorial, I just wanted to make a note about the supplier I chose when purchasing components. I ordered all of the components used in this tutorial from HobbyKing. HobbyKing is an online retailer of a wide-range of hobby parts, including parts for building multirotor aircraft. The reason I chose to order components from HobbyKing is, quite simply, because their prices are very low. Now, I do not intend this page to be a review of HobbyKing, or of any of the products listed, but I just wanted to note that the trade-off for HobbyKing’s low prices is slow shipping speeds and non-existent customer service. This last point is probably the biggest drawback to using HobbyKing, their customer service is absolutely pathetic. If you don't want to use HobbyKing, you can usually find the parts you need from sellers on eBay.
Anyway, you will need the materials in the table below to construct your tricopter. I included some notes about each component below the table. The notes are numbered and correspond to the numbers in the left column of the table. One last detail and then I promise we will get to the parts list. HobbyKing has warehouses located in many countries, with their main warehouse located in Hong Kong. I found that ordering all of my tricopter parts from the Hong Kong (international) warehouse led to extremely high shipping costs (for me $114). So, after a lot of experimentation, I found that I could minimize shipping costs by ordering some components from the international warehouse, and some parts from the U.S.A. warehouse. I included a column in the table that tells from which warehouse I ordered each component.
|1||RotorBits Tri-Copter Mounting Plate||1||U.S.A.||HobbyKing|
|2||RotorBits Servo Mount Set||1||U.S.A.||HobbyKing|
|3||RotorBits Motor Mount (Universal)||2||U.S.A.||HobbyKing|
|4||RotorBits T Connector||3||U.S.A.||HobbyKing|
|5||Carbon Fiber Square Tube 10 x 10 x 250mm||3||U.S.A.||HobbyKing|
|6||Carbon Fiber Square Tube 10 x 10 x 100mm||1||U.S.A.||HobbyKing|
|7||RotorBits M2.5 x 20mm Screw||1||U.S.A.||HobbyKing|
|8||RotorBits M2.5 NyLock Nuts||1||U.S.A.||HobbyKing|
|9||Turnigy 2200mAh 3S 20C Lipo Pack||1*||U.S.A.||HobbyKing|
|10||Turnigy Accucel-6 50W 6A||1||U.S.A.||HobbyKing|
|11||Hobbyking KK2.1.5 Flight Controller||1||U.S.A.||HobbyKing|
|12||HKU5 5V/5A UBEC||1||U.S.A.||HobbyKing|
|13||Corona 919MG Digital Metal Gear Servo||1||International||HobbyKing|
|14||Turnigy Multistar 2213-980Kv 14Pole Multi-Rotor Outrunner||3||International||HobbyKing|
|15||Turnigy Multistar 20 Amp Multi-rotor Brushless ESC||3||International||HobbyKing|
|16||10x4.5 SF Props 2pc Standard Rotation/2 pc RH Rotation||3||International||HobbyKing|
|17||Turnigy 6X FHSS 2.4ghz Transmitter and Receiver*||1||International||HobbyKing|
|18||Turnigy Multistar ESC Programming Card||1||International||HobbyKing|
|19||10CM Male to Male Servo Lead||1||International||HobbyKing|
|20||Nylon Screw Phillips Head M3x8mm||1||International||HobbyKing|
XT60 to 6 X 3.5mm bullet Multistar ESC Power Breakout Cable
|22||PolyMax 3.5mm Gold Connectors||1||International||HobbyKing|
|23||Universal Propeller Balancer||1||International||HobbyKing|
|24||USBasp AVR Programming Device||1||International||HobbyKing|
|25||15CM Servo Lead Extension||1||International||HobbyKing|
|26||Male-Female Wire Jumper Cable||1||International||HobbyKing|
* The Turnigy 6X is a six-channel transmitter, which means it has plenty of channels for controlling a basic tricopter, however, if, and this is a bit of a complex topic for this first step of the tutorial, you wish to put a camera gimbal on your tricopter, you might want to upgrade to the Turnigy 9X, which has three additional channels which can be used to control the gimbal motors.
|27||Blue LED Strip||2||International||HobbyKing|
|28||Green LED Strip||1||International||HobbyKing|
|29||Turnigy Receiver Controlled Switch||1||International||HobbyKing|
The total cost of the parts, not including shipping, is about $245. Shipping obviously depends upon where you live, but it should be something around $50 total for the cheapest shipping option.
1-8 These parts are all in HobbyKing's Rotor Bits line of products. Rotor Bits is a modular multirotor construction system. The idea is like Legos for multirotors. Using different Rotor Bits parts, you can build just about any kind of multirotor.
9 The Turnigy 2200mAh lithium-polymer battery is the power source for the tricopter. You only need one battery for your tricopter, however, I recommend buying a second one so that in the field, you can quickly swap out the first battery after it goes flat and continue flying. Depending upon the payload I put on the my tricopter, and how aggressively I fly, I get anywhere from five to twelve minutes of flight time on a charge. This might not sound like a lot of time, but it actually feels like plenty of time when you are flying. Now you could buy a battery with more capacity, but batteries get rapidly more expensive with increasing capacity and they also get heavier so I like to just buy two smaller batteries.
10 The Accucel-6 is the charger for the battery. Note that you will need a 12V power source with a barrel jack connector to power the charger. Unfortunately, I don’t think HobbyKing sells one, but you can pick one up from any electronics retailer. You can actually also use your car battery as a power source for the charger using the included alligator clip connectors.
11 The HobbyKing KK2.1 flight controller is responsible for receiving commands from the pilot, monitoring data from its onboard sensors, doing calculations based on those commands and that sensor data, and then then issuing commands to the ESC to control the motors to move the tricopter. The HobbyKing KK2.1 is a fantastic flight controller but it does have a steep learning curve. The KK2.1 features an onboard LCD screen for its user-interface, meaning that programming the flight controller is extremely easy and does not require a laptop or specialized software. You will have to do a lot of research to understand the different settings, but once you do, it is trivially easy to change settings in the field if you have to. Plus the KK2.1 is extremely affordable. Later in this Instructable we will discuss programming and tuning your flight controller settings.
12 The UBEC is used to transform the 11.1V power supplied by the battery to 5V so it can be used to power the KK2.1 flight controller.
13 The servo is used for the rear motor of the tricopter. On tricopters the rear motor tilts in order to achieve yaw control (make the tircopter rotate around the z-axis).
14 The Turnigy Multistar 2213-980Kv 14Pole Multi-Rotor Outrunner are the motors we’ll use in this tutorial. Now when it comes to choosing motors for your tricopter, you have a near-infinite number of choices and I don’t want to make this step any longer than it already is. There is plenty of other information around the internet about choosing motors though.
15 The electronic speed controllers (ESCs) are the components that take commands from the flight controller (which in turn takes commands from you) and from those commands controls the tricopters’s three motors. We need one ESC per motor. Note that even though these are opto ESCs, we are not going to take advantage of the opto part because it is not really necessary in this craft.
16 These are the propellers for the tricopter (they come in packs of four). We only need three for our tricopter, but in a crash, the propellers almost always get broken, so you should definitely stock up.
17 The Turnigy 6X is a six-channel, Mode 2 radio transmitter. The transmitter features two control sticks that can move in two directions each, plus two toggle switches. The transmitter comes with a compatible receiver. You will need four AA batteries for the controller and you might want to get a lanyard so you can hang the transmitter around your neck, which makes it easier to control since your hands can concentrate on moving the sticks instead of supporting the weight of the transmitter.
18 This is a little card used to program and calibrate the ESCs (more on that later).
19 These three-wire servo connectors are used to connect the radio receiver to the KK2.1 flight controller.
20 These nylon screws are used to connect the flight controller to the Rotor Bits tricopter hubs. Nylon obviously does not conduct electricity, which is useful for mounting electronics, and it is also soft, helping to make certain you do not over-tighten the screws.
21 This cable harness is used to split the battery's power output into six pairs of 3.5mm bullet connectors. Three of the bullet connector pairs will be attached to the three ESCs. One will be used for attaching the UBEC. One will be used for connecting optional LEDs. And the last pair is extra, it can be used for a camera or something you add in the future.
22 We will solder these 3.5mm connectors to the input wires on the UBEC so that we can plug the UBEC into the battery wire harness.
23 The Universal Propeller Balancer is used to make sure both sides of the propellers weight exactly the same. Balancing the props will reduce the vibrations in our tricopter while in flight.
24 The wires from the servo are not long enough to reach to the flight controller so we will have to use this Servo Lead Extension to make the wires a bit longer.
25 We will use these Male-Female Wire Jumper Cables to fashion a wire harness for the power supply.
26 The jumper wires will be used to make some wiring harnesses and to connect the servo to the flight controller.
27-29 These optional components will be used to add LED lights to the tricopter in Step 36.