Reverse Tricopter-VTOL Plane

Development Team
102

Hi Rolf,

I am currently working on a Tandem Bicopter which tilts its only front motor for forward flight just like Mozart 2.

Can you teach me how did you manage to adapt the code to turn 180 degree into Reverse Tricopter?

And how did you adapt the code for the front motor to tilt?

Here is my post! Tandem Bicopter transit into Cessna

Hope you can help me!

Peter

103

Hi Peter,

our trimotor VTOL can be thought of as a “backward flying tri with vector-yaw and the rear motor tiltable”. Therefore the motor matrix itself did not need to be changed. Peter Hall @iampete has helped and extended the code: Reverse Tricopter-VTOL Plane - #9 by iampete
More in your thread Tandem Bicopter transit into Cessna

Rolf

1 Like
104

Hi Rolf, Hi peter,
I am quite new to building drones. Recently i got an idea to try VTOL with Y6 and then to forward flight and cruise with minimal power usage, Then I got this wonderful thread which answered most of my doubts and encouraged to proceed further.
Main objective of the design is to have a payload capacity as well as a long range efficient flight. After going through your design and bit of calculation on my side I have decided to do a modification of the mozart 2. Below are the modifications i would like to do and need inputs and advice on the same.

  1. Going for Y5 2 coaxial rear rotors and 1 single tilt rotor in the front.
  2. moving the CG way back so most of the lifting to be done by rear 2 coaxials and the front tilt will be used for pitch stability.
  3. My doubt here is can the front single rotor be configured different (more focused for forward flight) than other two rear coaxials ? What modifications is required from Flight controller side ?
  4. Same as morazt 2 rear 2 coaxials will be turned off during the forward flight and front single rotor to provide all the thrust needed for forward flight.

So is it possible I can straight away start from arduplane 4.09 done for mozart 2 or does it require more modifications ?
Please advice.

Thanks and Regards,
ilay

105

Hi Ilay, welcome to the forum.

I have a question of understanding: Do you want to use the rear coax motors for torque compensation and not make them tiltable? (Not sure if that makes sense) . If you are making them tiltable, why coax motors ?

The front motor on our model has to generate less static thrust than the rear motors. The motor and propeller can therefore be better optimized for efficiency at cruising speed in fixed-wing mode.

If the rear motors are tiltable, it could work therorethically. But I wouldn’t start with a firmware that is now almost 3 years “old”, but use the latest stable. There have been many improvements in the VTOL area in the meantime. As a flight controller, I would definitely choose one with LUA script capability, because this gives you many options for making individual changes without having to change the complex firmware yourself.

Rolf

106

Thanks for the response.

Going for coax to add more lifting force to support a payload while remaining compact and not for the torque compensation. Since I plan to use a single rotor in the front, there will be anyway a net torque to counter. For which I have to make the coax tiltable like you did or I have to explore I can tilt the front prop around the longitudinal axis just like in a normal tricopter. I understand it will become complex as I have to tilt the same for forward motion as well.

Yes that’s what I am trying to achieve as well, optimising the front motor for forward flight for pretty long range. But my doubt still remains that with using a different motor and prop for the front than the rear 2 and still can the FC keep the vehicle stable in vtol/hover ?. Is it natively supported in ardupilot ? (Like a tricopter with 2 coax and one single rotor)

Thanks for the insight I will explore into LCU scripting if I can achieve this.

Thanks and regards,
Ilay

107

In order for the concept of carrying as little load as possible on the front engine when hovering to work, the center of gravity must be as close as possible to the rear engines.

cg
cg880×499 75.1 KB

We have therefore chosen a heavily filed wing.
You can see the center of gravity marked in the picture.

Rolf

108

Hi,

I am building a tiltrotor tricopter with a similar configuration as yours. Only difference is mine has two 90° tiltrotor instead of one unlike yours at the rear. Currently the FC thinks like those motors at front, so instead of stabilizing, it destabilizes the plane.

So I found the library that you used for changing the configuration. There is a problem for me about implementing the code.
Is there a chance to explain me how to upload the library on Mission Planner?