Have you ever done Airworthiness certification on other homebuilt
helicopters? Such as the helicycle, Scorpion, AW95, etc.?

Yes, I had the honor of certifying the first turbine Helicycle and have done
several since.
I have also certified several Rotorway Execs, Mini 500s and a couple AW type
helicopters.

If so, what kind of problems did you encounter?

Problems? The only kit I've heard anything bad about was the Ultrasport, and in
fairness since there was only one there isn't any "second opinion"
The guy eliminated two of the four tailrotor blades. Added two supports to the
tail boom to keep it from swaying. Built up what he said was a very weak
landing gear and had to redesign the mast with a thicker wall due to flexing.
The Hirth became a boat anchor and he now claims to be flying trouble free.

And what type of
certification did you issue?
Experimental, Amateur-built
Tom