I love making RC flying machines, it’s a real challenge to get things flying. This build is about a tricopter, I have already made a hex and oct, and to be honest they were simple and easy to make and get flying. The bicopter I made was a real challenge and took 3 attempts to get flying with different designs and far too many propellers!!
So this project continues from where the bicopter finished. For those of you who haven't seen the bicopter have a look at my other instructables. The bicopter was going to be a flying rig for an “Action Man” however it was apparent that Mr Action Man had been eating too many pies and was far too heavy for the machine. So I decided to try again but this time with a larger tricopter.
Step 1: The Main Video Build.
The construction and set up is All covered in the videos.
(22 minutes and 19 minutes)
The first video is the test flights!
The Second Video starts from drawings and finish's with a completed model
The Third Video covers the full set up of the KK2.1.5 flight controller, and the adjustments to the "mixer editor", and finally the Test Flight.
At the bottom of this page you will find the PDF drawings.
Please make sure you check the printed size before cutting out all the bits.
I hope you enjoy.
Step 2: The Bits You Need
Bits needed for the model,
1. 1/8 or 3mm ply wood. About 600mm square.
2. Glue. I used Gorilla glue and Aliphatic wood glue.
3. 3 brushless motors V3508 360KV (ebay)
4. Propellers (1555)
5. 3 brushless ESC (HobbyKing)
6. Flight control board KK2.1.5 (HobbyKing)
7. One Front wheel 85mm dia (HobbyKing)
8. Two Rear Wheels 105mm dia (HobbyKing)
9. Front Servo Corona DS-339MG 4.4kg Torque (HobbyKing)
10. Link wire for servo to pivot, and connector to pod.
11. Battery (11.1Volt 3000mAh worked but 4 cell would be better) (HobbyKing)
12. Receiver and transmitter (if you don’t already have them)
13. Little bit of wiring for power.
14. Maybe one or two servo extension leads.
15. Bit of 3/16 brake pipe for steering wheel.
16. Brave Action man.
17. training frame for a 450 electric helicopter. (it saved the propellers!)
Step 3: The Design and Construction Method
So I started designing this machine by getting the motors and propellers then place on a bit of paper with action man and play around with the locations to get a good idea of how action man was going to sit. (And make sure the front propeller wasn’t going to cut his head off) Once I was happy with the general layout I started to design the main tub, then I added the 3 joining bits at the back then the two arms, it sounds simple but took a few evenings to complete the drawings.
So again I have used my tried and trusted construction method.
1. Design the parts using Qcad on a raspberry PI.
2. Print out the bits 1:1 Limit each bit to fit on A3 paper.
3. Stick the paper to the wood using a pritstick.
4. Nail two bits of ply together where required.
5. Cut out the bits on my fret saw (I really need to get a laser cutter).
6. Stick the bits together using gorilla glue or wood glue.
Step 4: More Information on the Design Idea
The motors I have chosen are V3508 360Kv motors and should be able to drive 1555 propellers, and if needed can be driven from 6 cells. I have also decided to play around with the tricopter layout to make it more ergonomic for Mr Action man. What this has meant is I am putting the yaw controlled motor at the front, and the other two static motors at the back, the action man can then sit with his legs either side of the front motor which will be angles forwarded by 20 deg. And the two rear motors angled and mounted below the support arms. As I write this I am unsure how this model will fly, and to get it of the ground I will provisionally put the flight control board on backwards. This will allow me to fly it like a “normal” tricopter but in my case the machine will be backwards. I could have been cleaver and not admitted this, after all you wouldn’t know that I can’t fly nose in!!!!
The front pivot is based around an elevated pod (so the propellers clears the action mans legs) the servo is then placed in the main structure, and the arm of the servo could go either side of the motor pivot to change yaw direction if required. The pivots for the front motor are M4 captive nuts, which are pulled into the back of the pod, and then M4 screws (and nuts) are used though the pivots. I explain this bit in the video and took pictures so you should be able to work it out.
Currently I am aiming to use a KK2.1.5 board which is easy to use and suitable for newbie’s.
There are a couple of things that need to be pointed out.
1.The rear arms are set back at an angle, SO the rear piece of ply is different from the front, so it’s very important to get them correct or the undercarriage won’t be straight.
2.And where the motor mounts on the arm the holes have been pre drilled in the mount area, but you must make sure you put the piece of wood the correct way up.
3.Also with the 3 motor mounts make sure you remember to drill a centre clearance hole for the shaft circlip (if fitted) And again make sure the mounting plate is the correct way up or the motor holes wont line up. Then you will either have to mount the motor 90 deg wrong or re-drill holes.
Step 5: Thoughts, Brainwaves, and Timetable
Thoughts, brainwaves, modifications or daft suggestions.
As a final point I am considering putting a pivot on the front propeller so it can be tilted more forward, this should give the machine faster forward speed with the two rear fans acting as wings????
And put a slanted cut in the rear arms so they can be twisted around to push a land craft along????
Change the link at the front to steer the front wheel????
Mount the unit on a simple hull????
So many ideas so little time!
3 – 4 evenings designing the model after the kids had gone to bed.
Friday Evening print out pages and stick patterns to wood.
Saturday cut out all bits.
Sunday Stick most bits together.
Monday Evening glue front pod together and add rear undercarriage.
Tuesday Evening fit all motors and front pod, front servo and FC.
Wednesday Evening wire up ESC and test force generated using kitchen scales.
Thursday Evening Finish battery wiring and clip all wires to frame.
Friday Evening set up flight control board.
Saturday Test fly.
Step 6: Remaining Pictures for Referance.
Please find above all the remaining pictures and supporting information.
you will find the calculations for the mixer editor.
Left to do.
Sort out the battery position.
get a 4 cell battery.
maybe choose a better servo. more torque.