I am thinking of getting a Lynxmotion VTail 500. I have no background in drones, but have a background in electronics and coding.
Would you advise starting with an X-quad instead?
The reason is because after I get going, I would like to add wings and turn it into a VTOL. What do you think of this idea?
Thanks,
Brom
Please note that for VTOL there will be a pusher prop.
Hi Brom,
If you have no background in flying drones, I would advise you to choose an X-Quad as you pointed out.
They are lot more stable and predictable than a VTail setup.
Something like our Lynxmotion HQuad500
As for the future project, a VTOL might use some of the electronics but will be a completely different build.
All the best,
Thanks for the reply dialfonzo.
VTOL = VTail + wings + pusher prop?
Are VTails less stable because they are a W and not an X or H? Or is it because the two tail rotors are partially opposing each other. If the tail is flattened, does that not become a quad?
My application is not racing or acrobatics. It is for personal use and I would like to photograph and videograph natural scenery. So range and flytime is paramount for me. That is where the wings come in. With wings it can takeoff vertically, fly to destination, hover, fly back and land vertically.
For your VTail, what kind and brand of FC would you recommend? Would I need to modify the firmware given that it is a VTail and if I may want to reduce the tail angle?
Brom,
VTOL is just a name for a vertical takoff plane.
When building such a platform, one will probably create something from the ground up or use a Plane and modify it.
Most flight controller will stabilize and use equal amount of response to all corners of the UAV.
With a VTail you get a side trust not a vertical one which make it unstable. It is mostly made for forward flight (like a tricopter) than stable flight.
The “ArduPilot” project does have a VTail configuration.
Code is used in the PixHawk and other similar flight controllers.
All the best,
Thank you dialfonzo. Your information is very helpful.
Yes, I am mostly interested in forward flight, range, airtime, and LRFPV. In addition to videography, it will be good for search and rescue, delivery etc.
What do you think of this idea. Convert the VTail or the Quad into a quasi-quadcopter/quasi-tricopter by reducing the size of the two tail motors/props and increasing size of two front motors/props (the tail rotors are in the same plane with no side thrust). Then bring the two tail motors closer together or even make them coaxial. I would think the PX4 ArduPilot should be able to handle this?
Then add wings/stabilizer/rudder and a 90 degree tilt mechanism for the two tail rotors.
I would like to start from a drone rather than a plane, because drones are lighter and easier to attach peripherals. Also I get the option, if required, to tilt the wings back and out of way when droning.
That would be a Y4 configuration (two tail motor mounted coaxial) and would be supported in ArduPilot (here).
Thanks dialfonzo. You have convinced me to start from the HQuad500 frame. What is the largest prop it can take?
Is the Quadrino compatible with both Ardupilot and PX4? How do Ardupilot and PX4 compare? Can it handle digital servos?
Do you have a PDB?
What is a BEC?
Thanks
Hi Brom,
Take a look at the drawing in the dimension section of the product HERE. That would be the suggested prop size, if you want to go bigger you have the proportion there.
The Lynxmotion Quadrino Nano is an Arduino compatible microcontroller with sensors on board to allow for a flight controller project.
It will run MultiWii 2.4, not an optimized software like Ardupilot.
Ardupilot is a code / software and run on multiple devices like PixHawk and CubePilot so they all have similar en results.
Regarding Digital Servos, it depends on the hardware you select.
The base combo comes with a wiring harness (this one) but wiring otherwise would be on the customer side.
BEC - Is a fancy thing to say voltage regulation for something else, usually 5V output to power a RC receiver or flight controller.
All the best,
A pusher prop is not necessarily needed in a VTOL configuration.
Based on the User’s initial post and some of the first replies, the better solution as previously stated was to obtain a plane type RC unit and reconfigure it for VTOL. This involves some ducted fans cut and placed into the wings that rotate 90 degrees from vertical into horizonal positions during flight.
As the aircraft then rises in the vertical state and as the Ducts rotate, it will self-convert from the vertical to the horizonal state. The transition is sloped towards the front of the aircraft. Once fully transitioned, the slope declines to its full horizonal state and the aircraft is then flown in the traditional manor as an RC plane.
For landing, the reverse is performed with the ducted fans rotating their 90 degrees back to the vertical state. Again, the flight slope is experienced and the aircraft will also slow down naturally during the declining slope. With a little practice, one can learn the proper distance to the landing pad and pre-judge the declining slope so that the aircraft is positioned correctly for its landing. The pilot ensures the aircraft is facing into the wind so that flaps and rudders can function correctly for minor adjustments, along with a few nudges of the ducted fans here and there for a proper vertical landing on a pad.
It is the thrust of the Ducted fans that do the work, not a third push prop. There are no third push props on Osprey. It is the same principle being described. The pilot understands the slope and transitions to and from VTOL into/from horizonal flight and uses it accordingly.
All of which can be software controlled with servos on an RC. But its a airplane platform to initially build from, not the proposed one in the initial posting. Locate a V Tail RC plane as the base to design from. The Ducted Fans will do the initial lift and once rotated 90 degrees, then propel like a prop driven plane. Servos can do 180 degrees so if your center position is the vertical, +90 would be forward and -90 could also be used at times to perform a reverse motion and landing. You would want the fan units to be non ganged, meaning you can control each one’s servo position, separately. This could also be a software option to gang them together or control them separately. Un-ganged control allows for vertical rotations while in place in a hover in addition to the flaps and rudder.
And to account for aerodynamics, you would want both a clockwise turning ducted fan, and a counter clockwise turning one on the other wing. The two would cancel out the tendency for the craft to naturally spin which ever way the props were turning, if both are either CW or CCW ones. This also can be used for very small rotational adjustments in place while hover, by slowing down one ducted fan. The natural change if rotations between the two motors will cause a rotation, very very slowly, since one fan is spinning faster then the other, causing a rotational drift that is proportional to the number of times one motor shaft spins verses the other motor shaft. What you are doing at that point is reducing the counter rotation effect that normally is used to cancel inherent rotation. RC transmitters have Trim adjustments on them. Normally you would trim the props so they cancel out rotation. Adjust the trim slightly and one will spin faster or slower then the other prop in the fan, causing the rotation to reappear instead of canceling out. Again, this also can be controlled with software, if that is your approach. The software would be controlling the trim and not the RC controller.
So no, a pusher prop is not necessarily needed if the proper thrust is used the ducted fans.
Hope this helps.
Acigan International
Design Division
