I’m done with coaxial dualcopters. It’s a dead end of evolution: loud, not efficient, hard to tune, hard to fly. If you still want to make one, here is my 3D printed dualcopter on Thingiverse. Maybe you will have more luck than me…
The second generation of my 3D printed coaxial dualcopter is here! And this time it works almost as I wanted.
Just watch the video
On the more technical details:
- It runs INAV 2.0 with a custom mixer
- Thrust and yaw control is provided by 2 counter rotating propellers
- Upper motor is 2205 2300KV with 5×4.5×3 propeller rotation in CW direction
- Lower motor is 2205 2600KV with 4×4.5×3 propellers rotating CCW
- Control surfaces are rotated 45 degrees from the long axis to fit servos
flight controller is also 45 degrees rotated
- Any 9g servos will do
- runs on the 4S battery that has to be on the top of the device
- All 3D printed parts can be downloaded from Thingiverse
- 2205 2300KV brushless motor
- 2205 2600KV brushless motor (2300 also will do but will have less yaw authority)
- 5×54.5×3 propeller
- 4×4.5×3 propeller
- 2 14mm carbon pipes (12mm internal diameter), each around 270mm long
- 2 2g servos
- 3M bolts to secure the motors
- good adhesive tape to make control surface hinges
- hot glue
- flight controller compatible with INAV
- radio receiver
The first generation of my 3D Printed Dualcopter was not the best. It was flying. Somehow. Poorly. Crashed. But for a moment it was flying alright.
I'm slowly designing the second generation of Dualcopter. This time smaller in scale since instead of 10-inch propellers, it will be using 5-inch ones. And smaller 2205 motors. And some carbon fiber to support 3D printed elements and hopefully give it a little more structural strength.
The general idea is as follows:
- "Structure" will be provided by two vertical carbon pipes
- Motors and propellers will be in a duct. Not EDF, but almost. The idea is not to get more efficiency but to guide the air to the control surfaces. The goal is to have some control during descend too. Version without duct had none
- Upper motor will be 2205 2300KV with 5×3 3 bladed propeller
- Lower motor will be 2205 2600KV with 4×4 3 bladed propeller
- Lower prop will be working in the already accelerated air so it needs more pitch speed. More RPM and higher pitch = higher pitch speed
- 4S battery on top to move the center of gravity far from control surfaces to give them plenty of torque
- 2 9g servos
- flight controller running INAV
And that is more or less all… Will it work better than the previous one? I hope so 🙂
More than a year after staring this damn project, I finally decided what goes where. And on top of that, short description how Dualcopters works (or at least should work).
- There are two counter rotating propellers on top. They are responsible for thrust and YAW control
- When both props turns faster, dualcopter gains altitude
- When clockwise propeller turns faster, whole design starts to rotate counter-clockwise. When counter-clockwise propeller turns faster, it rotates clockwise
- Roll and Pitch axis control is archived by two flaps at the bottom of the design moved by two servos
- Since propellers are always rotating, there is almost always enoughair passing through flaps to have enough force for stability control and maneuvers
- To generate enough torque, center of gravity should be far above flaps. This way, even relatively small force on an end of long lever, there is always enough torque for roll and pitch stability
Keeping above in mind, it will look like this:
What is still missing? Place to put battery in and electronics. Next update as soon as I will have any update 😉
It's been exactly one year since my last update on Project Dualcopter. On 20th of October 2016 I've posted that there was a progress. Now, 12 months later, I once gain report, that there was a progress…. That was slow….
- I've finally installed control surfaces and servos
- I've finally decided where LiPo will go: to the top of the whole stack. I want CoG as far from control surfaces as possible. They will not generate much force, so I need as much torque as possible. So, long lever FTW
- My daughter called it Flying Bucket. Makes sense, right?
- Plans for next week: battery mount
3 weeks after my first post on Project Dualcopter, it's time for small update. The plan was to install servos and control surfaces. Instead, I've done:
- Basic electrical wiring for motors and ESCs. They have power now and are ready to be connected to flight controller
- To level shelf (above propellers) designed to hold flight controller and radio receiver
- Think for a moment about landing gear. Yeap, there will be some sort of shock absorbers
- Think for a moment where battery will be placed: as low as possible to keep center of gravity below center of thrust
- Decide which propeller should run clockwise and which should run counterclockwise: top should go clockwise, bottom should go counterclockwise
Flying season 2016 is slowly coming to an end on northern hemisphere. That means less time spent on an airfield and more time spent behind a desk. For this autumn I've found a very interesting, small project: Dualcopter.
Dualcopter is an UAV with two coaxial contra-rotating propellers and 2 control surfaces driven by servos. Lift and yaw are controlled by propellers, while pitch and roll by ailerons placed below motors. This video illustrates how it looks like:
My Dualcopter will be slightly different. Instead of foam and wood I will use 3D printed parts connected together CA glue and zip ties. Maybe it will not be super strong and probably will not survive any crash, but should be enough to make it fly for a minute or so. Almost all parts would be either 3D printed or taken from spare box. I'm not planning any new purchases.
- Motors: Turnigy MT2213 935KV
- Props: APC 1045 MR
- ESC: Afro 20A
- FC: Flip32 probably with INAV inside
- Battery: 1300mAh 3S
- Weight: around 800g with battery
So far, after 2 evenings I have this:
Two motors mounted on a frame.
Next step would be to build bottom section with ailerons and battery compartment.