Quad Plane Feedback Thread

This thread is for quad plane testing feedback.

@sjwilks Anything meaningful to report?

@LorenzMeier Ada has made pretty good progress the last couple of days and transition in missions appears to be working now though a real flight test will be needed to verify this. SITL isn’t quite there yet with VTOL and the issue we are seeing there are likely sim related only.

The weather forecast looks horrible for the next days but we’ll be bench testing the Fun Cub VTOL tomorrow and as soon as it’s dry enough do some test flights next week.

Once we have verified things are working well we’ll put together updated docs to help others get their VTOLs flying missions. It’s going to be very cool stuff :wink:

We’ll share videos of course. As always.


We’ll be after VTOL testers too once our initial tests pass. Anyone watching here should stay posted and let us know if you have a standard VTOL (aka quad plane) ready for testing.

I have a Bixler with an aluminum H-Frame built into it, that I wanted to build into a tilt-quadrotor using a KK2.1 with OpenAeroVTOL firmware. However, now I see that PX4 supports VTOLs, I’d much rather use it instead. Just need to source a Pixhawk board of some sort for this project, then I’ll have test data to contribute as well :slightly_smiling:

It won’t strictly be the FunCub QuadPlane, maybe closer to the QuadRanger - but that should be a matter of minimal tuning, right?

@olex The configuration for a quadplane is no different. I would suggest you investigate what kind of weight you will be adding and what kind of drive you will be using for the quad. A good tool for this is ecalc.ch

If you need any help let us know.

Good luck!

Thanks for the info! I’ve built more than a few multirotors and planes over the last couple years, so yeah, I’ll make sure the lift motors TWR is at least 2:1, as well as choose a correct CG (same location for plane and copter, based on where the Bixler’s CG would normally be). I’ll go ahead and make a build thread if it’s ok with the forum here.

One question: do I absolutely need the digital airspeed sensor? It’s the only thing I’d have to buy separately for the project. Does the VTOL firmware require airpeed info for transition calculations, and can’t the reported GPS speed be used instead?

Currently an airspeed sensor is required.
For your quad setup i would consider that a VTOL is usualy not an agile machine. 2:1 ratio is quite high for this and would add unneeded weight that will interfere with the fixed wing setup. I would recommend not going higher than 1.4:1. It’s more than enough to take off and keep the vehicle stable and also minimizes the impact on the fixed wing.

A build log is very welcome.

OK, I see. Does it have to be the “new” I2C digital sensor, or will the old-style analog APM airspeed probe work as well?

On TWR: I guess I see the point. I’m planning on a fairly low-cost setup, using an old Bixler 1 airframe and 5x NTM 2826-1200kv motors. The lifting motors will be turning HQ 9043 Endurance props, on 3S power they should give ~750-800g of thrust per motor. The total weight should end somewhere in the 1,5-2kg ballpark, so the TWR would be around ~1.5-2:1 - I’ll do more accurate estimations when I have all the components and a chance to weigh them.

Gorgeous job Lorenz !! I was looking to this enhancement 1 year ago :slightly_smiling:
We plan to test it but we don’t know on which platform : Volantex Ranger or a UAV Talon.

The UAV seems to have a higher top speed.

  1. Do you think that UAV Talon could be a good platform for this (with same modifications you did on the Ranger) ?

Another question :
2. Is it possible to inhibit the yaw when in quad mode ? In this way, the plane will move front to the wind :slightly_smiling:


Weathervane is already implemented for the quad plane. It will not try to hold yaw at all cost.

Hi Sebastien,

I selected the Ranger above the Talon due too the bigger wingspan and mostly because it seems to me that there is not enough clearing behind the talon wing.