Here are the things I have noticed on the Carter Copters site during the development of the aircraft....
They use a corvette engine...
They don't want to develop the aircraft for certification...just want to develop the technology for someone else to certificate...(that's the hard part...)
They have not gone as fast as a 500D yet....
Something happens regularly during tests that halt progress...
Seems these folks have found a way to get a NASA grant, and are trying to get as much from the government before someone figures out these guy's don't have a clue...
Just my opinion...I could be wrong....