Issued Patents 1997
Showing 1–2 of 2 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 5642982 | Retraction/extension mechanism for variable diameter rotors | Edward W. Gronenthal | 1997-07-01 |
| 5636969 | Torque tube/spar assembly for variable diameter helicopter rotors | Edward W. Gronenthal, W. Donald Jepson | 1997-06-10 |