[demigodspecial]

Hello. Is it possible to make single motor coaxial drone with librepilot? These is no opiton for single motor in vehicle menu. Can i do an custom or can i use helicopter for this? Sorry if this question is stupid. Im new at drones and flight controllers .

Regards.

[TheOtherCliff]

Yes.  It is not part of the setup wizard though.  You would set it up basically as a standard helicopter, which is also not handled by the wizard.  There are people here that have done it though and there is a section of the forum about it.

You will need to set it up as a heli, but then convert it to "custom" mixer so you can add to both of the throttles to change thrust, but add to one and subtract from the other to change yaw.  Or you could set it up entirely as a regular heli and use an external mixer that accepts yaw and throttle inputs and produces motor1 and motor2 outputs.

The pictures you show are not of a single motor, you of course actually control the two motors independently.  If you had a single motor with a reversing gearbox for the counter-rotating prop, you would need to change the (collective) pitch on at least one set of blades.  Adding pitch to one set of blades and subtracting pitch from the other set would be equivalent to speeding one motor up and slowing the other one down in the dual motor configuration.

[demigodspecial]

Thank you. Can also send me the forum link if possible?

[TheOtherCliff]

The Helicopter forum is on http://forum.librepilot.org
https://forum.librepilot.org/index.php?board=4.0

There is no "one click" setup, but you can set it up as a normal helicopter with roll and pitch controlling the paddles (fins at the bottom), then you will have to go to Custom mixer (on the Vehicle page) and make a second motor just like the first, but using the yaw output channel.

Finally, set up a temporary quadcopter (+, not X) and convert it to Custom so you can see how it handles roll with motors #2 and #4.  Your project will need to configure yaw on your two motors the way the test setup configures roll on motors #2 and #4.

Now you have a helicopter with roll and pitch going to the paddles at the bottom, and where an increase of the throttle stick makes both motors go faster and a left yaw command makes one motor faster and the other motor slower.  One motor will be the original motor output channel, and the other motor will be the original yaw output channel.

[TheOtherCliff]

(after a recent question in PM)

There are two ways of making a coaxial dual copter that I can think of:
- like a helicopter it would have a swash plate and roll and pitch servos, but it would not have a tail rotor (example: Blade CX)
- with roll and pitch vanes underneath that act like like a hovering fixed wing rudder and elevator (mechanically much simpler to build from scratch)

Which way will you build it or do you have a different design in mind?

Have you thought about how you will mount your props and what kind of props you want?

[demigodspecial]

I will try like a helicpter first than i cant try second. I dont have a design yet like i said im new in drones and librepilot. I will use 10*5 props which is coming with the motor.

[TheOtherCliff]

So you have props and prop mounts and they are fixed pitch.  This means that you must build vanes below the props to control roll and pitch.  You won't be making anything with a swash plate.

[mr_w]

You could also do it like those 3ch toy helicopters do, with horizontal tail fan for pitch control. So you have throttle, pitch and yaw. Enough for moving around.

[TheOtherCliff]

I think those have those blades with the weights at 45 degrees so they are inherently very stable.

He only has regular props, not "auto stabilizing props", so he will need roll / pitch (/yaw) stabilization.

[demigodspecial]

My project is something like those:




Thank you for comments.

[demigodspecial]

So you have props and prop mounts and they are fixed pitch.  This means that you must build vanes below the props to control roll and pitch.  You won't be making anything with a swash plate.

yes

[demigodspecial]

I think those have those blades with the weights at 45 degrees so they are inherently very stable.

He only has regular props, not "auto stabilizing props", so he will need roll / pitch (/yaw) stabilization.

i want to use 2 servos for roll and pitch. Contra motor for yaw.

[TheOtherCliff]

I described the beginnings of a setup for that exact configuration back in this posting.
https://forum.librepilot.org/index.php?topic=3520.msg24076#msg24076

As I said, we don't have a setting for this but is is possible.  You will need to manually configure the mixer with a cross between + quad (to get the two motors to do yaw) and normal helicopter (to get the roll and pitch servos to do roll and pitch).