| Year | 1992 |
| Date | 07-Feb |
| Volume | 168 |
| Issue | 3,914 |
| Page | 141 |
| Category | Hot Air Matters |
| Part | 4 |
| Title | Hot Air Engines: The Whys and Wherefores ... |
| Author | "Robbie" Robbins |
| Notes | Discusses ramifications, cylinder details for a simple engine. Two free pistons, reversible cycles, a change in the works |