| Clue | Source | Date |
|---|---|---|
| Gasses | ||
| Some aircraft engines | Premier Sunday | 16 Aug 2020 |
| Powerful engines | Eugene Sheffer | 11 Dec 2019 |
| Jack in steamrollers (only half working) for aero engines | ||
| Engines that require assisted takeoffs | ||
| Powerful engines | ||
| Aircraft propellers without moving parts | ||
| Certain plane engines |