A crazy idea about an electric thruster

tcmtech

Joined Nov 4, 2013
2,867
But the calculation suggests that it is possible. At least mathematics does not lie to us.
The most common problem with this logic is this greatly overlooked bit.

Theory says theory and reality are the same. Reality however typically disagrees.

I can't begin to recall how many ideas I have heard of now that due to some goons lack of being able to connect reality and its actions to scribblings and numbers on paper have turned out to be totally impossible because of that one little oversight of can what was imagined fit into the reality of the laws of nature that dictates our lives and the actions of every aspect of existence as we know it.
 

WBahn

Joined Mar 31, 2012
32,922
I have to acknowledgment the momentum is not conserved if it works. My description maybe wrong, but the calculations should be OK.
If momentum is not conserved, then that should be screaming out to you that either your mathematical model is not consistent with the real world or that your calculations on that model are not correct.
 

Thread Starter

ZhixianLin

Joined Dec 7, 2015
0
Hey guys,

I have found some more powerful mathematical tools to prove my design. I will put them in my paper and show you later.

Thanks!
 

Wendy

Joined Mar 24, 2008
23,796
Guys, there is a reason I moved this to off topic.

You can get thrust from a directional antenna. Whether it is enough to be useful in the real world is another story. You can do something similar with lasers. I've enjoyed stories by Niven that had that as a theme. I couldn't help wonder though, what happens to the poor sap who gets downstream 100 light years away.
 

WBahn

Joined Mar 31, 2012
32,922
All you have "proven" is that momentum isn't conserved when you don't bother to include everything that is interacting.
 

Thread Starter

ZhixianLin

Joined Dec 7, 2015
0
So, your device is a

Yes, it is, if the basket is the whole universe. It also like a flying helicopter in a sealed box, the helicopter does not have to consider any problem of momentum conservation with the box, it just need to push the air. The vacuum is just like the air, it can be pushed also.
 

WBahn

Joined Mar 31, 2012
32,922
Yes, it is, if the basket is the whole universe. It also like a flying helicopter in a sealed box, the helicopter does not have to consider any problem of momentum conservation with the box, it just need to push the air. The vacuum is just like the air, it can be pushed also.
Really? Okay, then put a helicopter in a sealed box and tie a string between the bottom of the helicopter and the bottom of the inside of the box and have the helicopter pick the box up.

Gee, doesn't work, does it?

Any your "push the vacuum" nonsense sounds like it's straight out of the for the show MacGyver where he "showed" that a neon filled tube would suck up the phosphorous out of a vacuum chamber.
 

Thread Starter

ZhixianLin

Joined Dec 7, 2015
0
Really? Okay, then put a helicopter in a sealed box and tie a string between the bottom of the helicopter and the bottom of the inside of the box and have the helicopter pick the box up.

Gee, doesn't work, does it?

Any your "push the vacuum" nonsense sounds like it's straight out of the for the show MacGyver where he "showed" that a neon filled tube would suck up the phosphorous out of a vacuum chamber.
The box is the whole universe, why you need to tie a string with the universe?
 

cmartinez

Joined Jan 17, 2007
8,783
The box is the whole universe, why you need to tie a string with the universe?
Zhix, what's your point? Why don't you try to build this thing yourself and then come back and tell us your results: If the principle you're talking about is so simple, it should be fairly easy and inexpensive to build a small working prototype.

One last thing, according to your calculations, assuming 100% efficiency, how many watts of power would you need to generate one gram of thrust in a vacuum?
 

Thread Starter

ZhixianLin

Joined Dec 7, 2015
0
Zhix, what's your point? Why don't you try to build this thing yourself and then come back and tell us your results: If the principle you're talking about is so simple, it should be fairly easy and inexpensive to build a small working prototype.

One last thing, according to your calculations, assuming 100% efficiency, how many watts of power would you need to generate one gram of thrust in a vacuum?
Yes, I will find my way to build it and maybe not come back. No matter how many calculations is still useless, so I say no more calculations.
 

cmartinez

Joined Jan 17, 2007
8,783
Yes, I will find my way to build it and maybe not come back. No matter how many calculations is still useless, so I say no more calculations.
That's very convenient... if you're not willing to do the hard work and persuade us with facts, and not just calculations, why did you come here in the first place?
 
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