virtuPIC wrote:
Yes, I confess. I don't know much about rotorcrafts. Especially
regarding gyrocopters my knowledge is even more limited.

However, on the net I just stumbled over UFO HeliThruster. Rumors are
that it is rather stable. The manufacturer not only sells kits but
also (FAA-?) certified planes.

If I would buy such a certified HeliThruster, fit it with the
necessary instruments, and give it an N-registration, would I be
allowed to fly it IFR given that I had the necessary pilot
certificates? Would I be allowed to fly it outside US?

Thank you for sharing your knowledge!
virtuPIC

With the certified probably not. With the EX-AB sure, if you can get the DAR
to write the limitations correctly.

If you do this let us know. We are always looking for a deal on good used
avionics and salvage is usually a pretty good place to look.