After my first Instructable published "Y220 - Mini transformed Tricopter", I've tried concluding whether if I could make another Tricopter (definitely, equipped with brushless motors) which is cheaper and smaller than size 220? So I started to re-considering every components from part to part and that's the beginning of this project.
Step 1: PART LISTS - OVERALL REVIEWS
Due to Q250 arm length of 10.5 cm, in my opinion, it may possibly be a smallest size of the quadcopter's arm available commercially. And the most important thing, it is very cheap when purchase it as a spare part.
Top & Bottom Frame
Then I looked at the three pieces of these arms then imagine what could be used instead of a Top and Bottom PCB Frame that can mount these 3 arms firmly. Then by luck, I found my old CCTV plastic wall mount with a circle shape and with 3 holes provided for screws fixing. Yet these holes are aligned 120 degree to each other that is perfect to fit all arms in a "Y" shape. So I decided to use it as a Bottom frame. And for Top Frame, I used a bath sink cover (surely, it's an unused one) which the size is similar to that of my old CCTV plastic wall mount. I found that surprisingly, the grid holes of the bath sink cover are fitting well when assembly them all together. Therefore, from this point, the roughly size of the whole assembled frame is about 200 mm from one of the front motors to a tail motor.
Servo mount mechanism
As I planned to use a TowerPro SG90 servo for this Baby Tricopter since I already have many of them on hands for miscellaneous projects. So I just needed to replicate the tail servo mechanism that can fit SG90 and it must be strong enough to hold a brushless motor size 1806, then I had an idea to adapted it from the Syma FPV Camera mount by a few modifications on it (see more detail on the STEP 4).
Step 2: PART LISTS - Power System and Other Parts Selection
According to the whole size of an assembly frame and due to my experience from making a Y220 Mini TriCopter, my estimation of the Power requirement of this Y200 Baby TriCopter should be smaller than Y220 aspects as the following details.
LiPo Battery required
For those other miscellaneous parts selection are as the lists below.
Power Distribution Board
Motor Cover Protection
Step 3: MOTORs AND ESCs PREPARATION
The main concept of this Baby Tricopter is to minimize the part lists and cost as much as possible. So I just avoid using the bullet connectors for Motors and ESCs wiring for the 2 front arms. But still applied them for the tail motors so that it is more flexible to adjust the wiring cable length and also change the motor direction (CW/CCW) if needed.
Step 4: TAIL ARM PRE ASS'Y
From the Syma FPV Camera mount, I need some modifications below.
- Drill some holes for a tail brushless motor main core and those 4 small holes for screws fixing.
- Drill some holes for servo main gear and arm/screws fixing.
- Bend the plastic mount at the 1/4 of the total length and making 2 areas being perpendicular to each other. At this step, I used a lighter and a stainless steel ruler to help finishing the process.
- Assembly Motor/Motor cover and Servo with arm all together on this modified mount.
- Then place them all onto the Tricopter's arm.
- Secure the servo body with an adhesive tape and tighten by cable ties.
- Apply a piece of velcro tape on the arm near the servo, later this space will be used for a LiPo placement.
It's all been done for the tail arm pre-ass'y.
Step 5: WIRING & FRAME ASS'Y
- Assembly ESC and Motor to each of the Tricopter arms.
- Assembly all 3 arms with the CCTV wall mount as a Bottom frame with screws size 2.5 x 5 mm (2 pcs for each arm). As the original wall mount has only 3 holes so I need to drill it for 3 additional holes.
- Adjust the position of the ESCs under the arms and secure them by cable ties.
- Manage the ESCs power cables (Red and Black wire) through the wall mount slots (already available there), then adjust the cable length to be long enough to be soldered to the PDB copper pads.
- Cut and strip the wires then soldering them all, at this step also including the JST male terminal for Lipo Battery connection.
- Apply the Bath sink cover on top of the frame, then secure it by 6 pieces of screws size 2.5 x 5 mm. In order to avoid the sharp edge of the bath sink cover, I added some tape all around its circumference for safety reason.
Step 6: FINAL ASS'Y
Flight controller and Receiver placement
There's not much technical issues at this step, so just finish the wiring between ESCs, Servo, CC3D Flight Controller and R6D Reciver. The only problem is that there is no room for placing the CC3D FC case between the Top and Bottom Frame, so I decided to put only the R6D Receiver into that space and place the FC on Top of the frame as in picture.
LiPo Battery placement
There's a space on the tail arm nearby the servo that perfectly fit the LiPo size 7.4V 2S 850mAh. I've checked the clearance with tail blade movement while the servo is moving from one end to another end. Secure it again with belt strap during the flight if needed.
Step 7: FIRST FLIGHT TEST & FC CONFIGURATION ADJUST
The setup for this Baby Tricopter using OpenPilot GCS is simple, just proceed it with Tricopter model. Only a note to select of the servo type as Analog type instead of Digital one.
First Flight Test
After a basic setup for CC3D FC, the result of the First Flight Test has a problem with Yaw controlling. As can be seen from this VDO that the Tricopter's tail is wagging too much, not really stable for hovering.
Yaw control adjustment
I came back to the OpenPilot GCS setting and tried adjusting some parameters as below.
- Rate Stabilization
On the PI setting for Yaw control, reduced the "I" value to 15 as in picture attached.
- Servo control
I also noticed later that the number of servo movement (throws) can impact the oscillating problem as well. I don't know exactly the optimal value to be used for others, but here I put the number from center to each ends as 250 steps. Which give a physical movement of the servo mount angle between +50 and -50 degrees from the center position. Below numbers are examples for those setting I've done in the Output configuration.
min = 1147 default (center) = 1397 max = 1647
After above adjustment, now my Baby Tricopter is more controllable, stable enough to stay hovering as can be seen from this VDO.
Step 8: OVERALL SPECIFICATION
I added this step just to summarize this little Baby Tricopter specifications for reference.
- Wheel based size : 200 mm
- All-Up Weight (AUW) : 255 g
- Overall width : 180 mm
- Overall length : 210 mm
- Flight time : 4 minutes (used 7.4V 2S 850mAh LiPo battery)
Step 9: COST ANALYSIS
- HMF Totem Q250 Arm 3 EA ($0.99 x 3)
- Brushless motor 1806 3 EA ($5.36 x 3)
- 10A ESC 3 EA ($3.75 x 3)
- SG90 Servo 1 EA ($2.35)
- CC3D Flight controller 1 EA ($9.56)
- R6D Radiolink Receiver 1 EA ($9.90)
- Power Distribution Board 1 EA ($1.04)
- Propeller 5040 3 EA ($1.59 per 4 ea)
- Motor cover protection 18 series 3 EA ($1.13 per 4 ea)
- JST Connector plug for battery connection 1 EA ($2.45 per 1 pair)
- LiPo battery 7.4V 2S 850mAh 1 EA ($8.50)
But there're some other parts that you may need to find it yourself.
- Top & Bottom frame
- Servo mount mechanism
I am always keen to see if anyone who duplicate this project can share of what materials are being used and how do you build it up.
Step 10: CRITICISM
As this Y200 Baby Tricopter is something like an experiment for me after my first Y220 Mini Tricopter has been done and published. Thus the main purpose of this Instructable is more likely to share my personal idea to adapt those unused stuffs (CCTV wall mount, Bath sink cover) to be fixed with the cheap Q250 arms. Definitely, it's not that beautiful or not even can perform a Racing Flight though. But most of all, I loved it and I'm happy of doing such things. I DO HOPE that you ENJOY it too.
If there should be any criticism, comments or suggestion, please don't hesitate to leave your comments and let me know what you're thinking. Probably, some of your comments could inspire me for the next other projects, who knows.
THANKS FOR WATCHING.