VTOL Quadplane - Pixhawk 2.1 or Pixhawk 4? Ardupilot or PX4?

Hello!
I would like to ask and discuss with you about your opinion for right choice.
We want to modify the ultra-light aircraft to eVTOL (quadplane) and one of the intermediate steps for us is the construction of a scale model with wingspan up to 3 meters.
We need to do right transitions from take off to horizontal flight and then to vertical landing.
We would also like the model to be able to land veritally at the point specified by the coordinates.
I was looking for different autopilots and ended up at Pixhawk.Cube Orange but i also found Pixhawk 4. Is it newer / better version?
Is there also difference that Cube is Arduopilot and Pixhawk 4 is PX4?
Can you help me which is better?
In the future we want to test our Quadplane concept on real aircraft and we are looking for some certifiable autopilot in the future.
Is Pixhawk a good start?
Thanks for all your replies!
Have a nice day,

Hi Michal - I think someone else would be better suited to advise on the various hardware but I can tell you that you should be ok to load PX4 or Ardupilot on your Pixhawk 4. Best of luck

Pixhawk4 is fine. Cube is fine. The current benchmarks are those with H7 mcu’s such as CubeOrange, Durandal, CUAV X7 or mRo ControlZeroH7. There’s others like Matek H743 or CUAV Nora that also use STM32H7 processors but with reduced features.
Don’t pay any attention to “Pixhawk” in a name. It just means that the manufacturer has a licensing agreement with the trademark owner, not that the board or manufacturer is any better or worse than any other.

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@Michal_Schreiner Maybe you can try CUAV X7 and I am happy to work with you on Quadplane.

Quadplane:

Raefly VTOL with X7

Hello @cuav_le,
I like to try Cuav X7 for my Quadplane, but now I have bought Nora. Can you clarify what is benefits of using X7 instead of Nora?
Can you give me objective reason, that X7 is better than Nora (or other brand), that I should use X7… Tks

NORA is as good as X7; we use X7 because it can be used with CAN PDB, which can reduce a lot of wiring.

Maybe I can expand on the OP question- are there specific hardware limitations for Quadplane firmware?

Does it inherently need a more powerful FC, or would something slightly older like a Pixracer work fine?

One issue is to make sure that you have enough outputs to control your VTOL motors, tilt rotors, control surfaces, etc. Also, for any setup, due to flash memory limitations, some boards do not include all ArduPilot features. You can read more about this in the Firmware Limitations section of the Wiki.

A Pixracer will work fine as long as you have sufficient outputs for your vehicle.

I am still using Pixhawk 1 (aka v2.4.8) flight controllers for my VTOLs. The user can gain casing improvements for anti-vibration and temperature control, and have redundant sensors when using the STM32H7 processor. However, it seems a grey area between a hobby grade project and a more professional UAV platform. It may depend upon one’s budget and goals.

It would be interesting to see what percentage of the processor is being used during a hover with different processors. A default value of 300 for SCHED_LOOP_RATE suggests there is plenty of processing power even with the popular STM32F4. The last time I saw a significant increase in hardware performance was when we changed from APM 2.6 controllers to Pixhawk 1 controllers.

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Hi @Michal_Schreiner ,

I just want to share my experience, that I have tried several “Pixhawk”, start from Pixhawk Radiolink, P. Hobbyking, P. 3DR, Pixracer, Matek F765, Holybro Pixhawk4, Cube black, Cube Orange with Here3, Cuav Nora with Neo pro GPS. I want to find “the best” or “the most reliable” autopilot for my Quadplane… I found that currently 3 manufacturer are excellent : Cube Orange, CUAV and Holybro…If your UAV is industrial grade, I recommend use these products. I am impressed with GPS from CUAV (Neo3 pro) and Holybro. They can get about 30 sats, while other only can get only about 16 - 20 sats.with the same configuration… I am a bit disappointed with Here3 GPS, that only can get 20 sats. at the same condition. Even though they claim as RTK ready using Ublox M8P …Hope this information is useful…

Just to add, I understand that @Greg has built many UAVs , so I believe his advice is very useful…