Issued Patents 1989
Showing 1–2 of 2 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 4863351 | Airscrew or propeller for propelling an aircraft | Karl H. Gronau | 1989-09-05 |
| 4795308 | Obstacle in front of a propeller | Siegfried Hosemann | 1989-01-03 |
Showing 1–2 of 2 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 4863351 | Airscrew or propeller for propelling an aircraft | Karl H. Gronau | 1989-09-05 |
| 4795308 | Obstacle in front of a propeller | Siegfried Hosemann | 1989-01-03 |