Timeline for Invisible Coilgun Propagation
Current License: CC BY-SA 4.0
6 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Sep 28, 2020 at 22:04 | comment | added | Cort Ammon | The reason it ends up being counterintuitive is that our brain isn't very good at keeping track of the air after it's hit the sail, so we sort of forget about the second half of the system (the air leaving the sail and entering the airstream). But if we collect all of the numbers and equations carefully, there's no violations of laws here. | |
| Sep 28, 2020 at 22:03 | comment | added | Cort Ammon | @iCodeSometime Mythbusters did it in Blow Your Own Sail. The physics is counterintuitive, but makes a whole lot more sense if you replace the sail with a U shaped tube that captures all of the air. This basically turns the fan into a ducted fan that's pointing backwads, and obviously will cause forward motion. As long as the net movement of the air is backwards, conservation of momentum will drive you forward. | |
| Sep 28, 2020 at 12:01 | comment | added | iCodeSometime | Ah, maybe depending on the angle? If the fan is blowing up more towards the sail, much of it's force would be downward, so if the sail was reflecting more directly rearward, I suppose that makes sense | |
| Sep 28, 2020 at 11:59 | comment | added | iCodeSometime | Do you have any documentation you could share? Surely the fan pushes the sailboat back at least as much as the reflected wind pushes it forwards. Where is the extra energy coming from? | |
| Sep 28, 2020 at 5:31 | comment | added | pwf | Actually, you can propel a boat that way. It's not as efficient as turning the fan around and blowing it out the back of the boat, but it works, as long as the sail can reflect the wind backwards. I've built such a sail board as a demo. | |
| Sep 28, 2020 at 2:40 | history | answered | niels nielsen | CC BY-SA 4.0 |