As part of his Aeronautical Engineering thesis research he designed a set of aluminum rotor blades for a two-place gyroplane. Having designed a practical rotor system for a two-place gyro, he moved on to the design of a gyroplane to go with the new blades. The result was the Hollmann Sportster.
1980: 11082 Bel Aire Ct. Cupertino, CA 95014, USA.
1995-7: 3 Harris Ct., Bldg. S., Monterey, CA 93940, USA.
2009: 5 Harris Court, Bldg. S, Monterey, CA 93940, USA.