| Year | 2008 |
| Date | 11-Apr |
| Volume | 200 |
| Issue | 4,323 |
| Page | 433 |
| Category | Heat Engine |
| Part | |
| Title | Simple Vacuum Engine With An Internal Valve (Free plan) |
| Author | Jan Ridders (Netherlands) |
| Notes | Conventional valve design issues, working principles, advantages of this design, some specifications, push rod, adjusting the engine, adjustment of the spirit burner, engine performance, troubleshooting, finally, drawings |