In recent years, many start-ups have appeared that intend to gain a foothold in new flight modalities, both drones and small passenger planes (most of them electric), and they present their prototypes to obtain financing and see if they are capable of find their niche in a very competitive market.
Recently I have seen the idea of the company PteroDynamics that seems to me really original and novel. These people use a wing in their aircraft that rotates and folds 90 degrees, so that the motors attached to the wing can support it like a helicopter or a normal airplane.
A esa ala variable la han llamado “transwing” y es algo novedoso que ya han patentado. Han realizado varios prototipos a una pequeña escala ( sin llegar a los 4 metros de envergadura de ala ) y les han hecho volar por radiocontrol para analizar las características del vuelo.
A video can be seen at: https://youtu.be/3uNboCgDOKQ
The most delicate part is the wing transition system, as it must be a very robust and fail-safe mechanism. In aeronautics, any type of failure is catastrophic.
This type of aircraft has the advantage that when its wing is extended the lift is much greater and it can reach greater distances with the same battery in the case of a flight with electric motors.
As I say, the idea is original and could become operational, but there is still a lot of work to be done to have a minimally viable product.
The V22 Osprey aircraft was designed with a different but somewhat similar idea (see photo below) and it took more than 20 years to fly with guarantees despite the fact that there was a large company behind the project.
It remains to be seen how PteroDynamics evolves, and if the project were viable it would not be unusual for the company to be acquired by a larger one with the economic means to be able to make a reliable aircraft
Time will tell.
EN 
ES