General > General Technical Chat

Mess with your minds: A wind powered craft going faster than a tail wind speed.

<< < (217/285) > >>

fourfathom:

--- Quote from: IanB on December 23, 2021, 10:12:02 pm ---
--- Quote from: electrodacus on December 23, 2021, 09:46:06 pm ---The thing you seems to ignore is that vehicle being faster than wind in same direction can not be pushed by the wind.
There is no such problem in the yo-yo example.

--- End quote ---

The yo-yo going faster than the string in the same direction as the string cannot be pulled by the string.

--- End quote ---

Yesterday I tried that yo-yo experiment, using a spool of rope (I have spools of rope I use on my boat).  I wanted to check that the difference in circumference between the spool and the level of the rope gave the same result as the "geared wheels on two conveyor belt".  It was as close as I could measure.  I would have been astounded if the result were otherwise, but since this whole subject can be non-intuitive I figured it was a test worth doing.  I could shoot a video, but that's already been done.

IanB:

--- Quote from: fourfathom on December 23, 2021, 11:13:35 pm ---Yesterday I tried that yo-yo experiment, using a spool of rope (I have spools of rope I use on my boat).  I wanted to check that the difference in circumference between the spool and the level of the rope gave the same result as the "geared wheels on two conveyor belt".  It was as close as I could measure.  I would have been astounded if the result were otherwise, but since this whole subject can be non-intuitive I figured it was a test worth doing.  I could shoot a video, but that's already been done.

--- End quote ---

No, no, no, you don't understand. If the string is being pulled along at, say, 1 cm/s, then the yo-yo cannot go faster than 1 cm/s in the same direction, because then it would be going faster than the string that is pulling it, and it could no longer receive any energy from the string   ;)

Don't you see how obvious this is?

bdunham7:

--- Quote from: IanB on December 23, 2021, 11:18:31 pm --- If the string is being pulled along at, say, 1 cm/s, then the yo-yo cannot go faster than 1 cm/s in the same direction, because then it would be going faster than the string that is pulling it, and it could no longer receive any energy from the string   ;)

Don't you see how obvious this is?

--- End quote ---

You obviously don't understand quantum stick-slip hysteresis in tensioned fiber traction systems.  But of course, the yo-yo can't go faster than the string indefinitely, only for short period of time.  Or string.

Brumby:
I draw attention to my earlier question:


--- Quote from: Brumby on December 23, 2021, 07:55:01 am ---
--- Quote ---Blackbird propeller swept area is a massive 20m^2 and all the energy Blackbird needs to get to that record 28mph speed is just around 6Wh easily stored with not much pressure on such a massive swept area.

--- End quote ---
Are you saying that energy is stored across the entire swept area of the propeller?

--- End quote ---

electrodacus:

--- Quote from: IanB on December 23, 2021, 11:18:31 pm ---
No, no, no, you don't understand. If the string is being pulled along at, say, 1 cm/s, then the yo-yo cannot go faster than 1 cm/s in the same direction, because then it would be going faster than the string that is pulling it, and it could no longer receive any energy from the string   ;)

Don't you see how obvious this is?

--- End quote ---

Funny you get this but do not get that wind can not push a vehicle when vehicle travels faster than the wind in same direction.

Navigation

[0] Message Index

[#] Next page

[*] Previous page

There was an error while thanking
Thanking...
Go to full version
Powered by SMFPacks Advanced Attachments Uploader Mod