Single Copter software change to horizontal flight

By my understanding, single copter mainly operates in vertical position with the offset circa +/- 30 - 40 degrees.
I am wondering, is it possible to expand the single copter’s flight capabilities in horizontal flight? I mean, transition to horizontal flight using the copter software without switching to plane or tailsitter modes. I would imagine that transition requires massive amount of power in case of copter’s traditional design. I am guessing turning off limits in copter mode is not the way only. Any suggestion or direction I have to follow, please.

I don’t think so, at least for attitude, velocity and position controlled modes in acro you can fly in any orientation you want. Copter guidance isn’t suitable for horizontal flight.

You should use tailsitter plane configuration Tailsitter Planes — Plane documentation

I’ve added small wings to my single copter. What parameters, should I change to allow it fly horizontally, and even nose down like a plane?

The default parameter, I believe, is 45 deg from vertical. If I set it to 0 degrees it will allow it to pitch 90 deg making it fly horizontally, like a plane.

I would like to disable that all together so I can even point down / fly nose down.

Please let me know what should be done to accomplish that.

Once again Copter firmware isn’t suitable for horizontal flight. You can increase attitude limits but it will still be flying like a multirotor.

Coincidently I’m interested in the same thing. It’d be great if someon who knows the ArduCopter software well, could offer his advise.
Being able to also fly in an “airplane mode” offers several advantages over a tail-sitter. Especially if the predominant mode of operation is a single copter.
Beside, trying to implement and learn new software (ArduPilot) in a single copter (!) will take a long time, and spells… crushes that will total the copter.

In my case I am adding two very small wings to my single copter. No controlling surfaces on the wings.

If flying in Acro allows for that, it is great news. However, the description of Acro says: “holds attitude, no self-level”. I just wonder how “holds attitude” would work when fluing “like an airplane”. Deffinately it cound not be done by autmatic throttle adjustment. Unless there is a way to disable the “holding attitude” for Acro only, I don’t see Acro as an option.

There is also a Sport mode, but the same thing: “works like Alt-Hold, but holds pitch and roll when sticks centered”.

Lastly - is it feasible to disable Angle_Max? If so, will it do what we are looking for? Something tells me it will not.

Attitude is not Altitude former is orientation in space and later is height over datum.

Acro “Holds attitude” mens that it keeps orientation in space, throttle is under manual control.
It will fight any attitude disturbances.

Thank you Lupus for the clarification.
This makes all the difference in the world. So Acro it is. Now I can give it a try!

Out of curiosity - what will likely happen if one switches from Arco to Stabilize or to Alt-Hold while flying horyzinatlly like a plane? Will the copter manage to right itsel up, or it’s too much to ask of it?

Will try to switch after bringing the copter to a semi-vertical flight, but it’d be good to know.

It depends on the design. Flight controller will do its best.