Activity for Martin Yorkâ
| Type | On... | Excerpt | Status | Date |
|---|---|---|---|---|
| Question | — |
Air transport breaks down How much would the gravitational force (on earth) have to increase to make air-travel impractical (not impossible as escape by space flight to other planets would be a nice option). But to a point where the use of fixed winged aircraft becomes impractical as the energy required by propeller/jet engin... (more) |
— | over 9 years ago |