An explanation for the Emdrive

Beyond the boundaries of established science an avalanche of exotic ideas compete for our attention. Experts tell us that these ideas should not be permitted to take up the time of working scientists, and for the most part they are surely correct. But what about the gems in the rubble pile? By what ground-rules might we bring extraordinary new possibilities to light?

Moderators: MGmirkin, bboyer

An explanation for the Emdrive

Unread postby Keith Ness » Thu Dec 01, 2016 5:01 am

This thread is to continue where I left off posting on my explanation for the Emdrive in the Electric Universe sub-forum thread below, since my explanation suggests a significant limitation to Newton’s third law, and doesn’t explicitly refer to electric universe theory:

viewtopic.php?f=3&t=16507&p=116242#p116242

...Shawyer also says the two end plates are spherical sections (concentric, from what I can see) a microwave resonant distance apart, and it's only the interaction between the end plates which generates the thrust, at least ideally. I still say the fact that group velocity decreases with aperture size represents a momentum transfer, but if you're going to consider just the end plates, then there's still the following to consider.

When you strike a convex surface, the impact drives the convex surface together, reinforcing and hardening the surface against the impact, and distributing the impact over the convex surface more effectively than in less convex surfaces. When you strike a concave surface, just the opposite happens. The impact pushes the impact site away from the rest of the concave surface, weakening and softening the surface against the impact, and localizing the impact to the impact site more effectively than in less concave surfaces. So again, the smaller, convex end spreads less easily and receives more momentum, and the larger, concave end spreads more easily and receives more heat.


Here's Shawyer's explanation video:

https://www.youtube.com/watch?v=wBtk6xWDrwY

His explanation of how the large end gets hit harder than the small end but the chamber moves in the direction of the small end thoroughly does not satisfy me.

Here's a link containing a diagram of the heat distribution:

http://www.nextbigfuture.com/2015/02/mo ... ation.html


Also, it occurs to me that if you throw a racquet ball directly at a wall in a ship so that the racquet ball bounces directly back at you, then the racquet ball, by virtue of it still being in motion relative to the ship, did not dump all the momentum of the throw into the ship when it bounced off the wall, and did instead provide its own internal angular deflectors by virtue of its own bounciness/stretchiness, and will not have dumped all its momentum into the ship until it stops moving relative to the ship (and even then, its bounciness on impacts will have laterally dissipated some of the momentum given to it by the throw).

So, in order to provide an example of my explanation which hopefully makes the allocation of deflectiveness and momentum clearer, consider having your back up against the inside front wall of a spaceship in zero-g, placing a bowling ball under your feet with you directly between the ball and the wall behind you, and extending your whole body as hard as you can directly away from the wall to push the bowling ball directly towards the back wall of the ship, giving the ship a good amount of forward momentum, and the ball a good amount of rearward momentum. The bowling ball travels straight for a while down a tube, then comes to a gentle curve in the tube, gentle enough to change the direction of the bowling ball 90 degrees, heading towards the side wall of the ship, while reducing the momentum of the bowling ball by only half, and converting some of that loss of momentum into thrust into the ship’s rear wall, thus reducing but not eliminating the ship’s forward momentum. The bowling ball is then heading directly towards the side wall at about half its former speed, and it passes through a gently springing gate which takes a little more momentum out of the ball to get out of the ball’s way and then shut behind the ball again. Then the bowling ball hits a big spring on the side wall, and bounces gently back towards the gate, which has a big spring on the side the ball is heading towards, and the gate does not swing in the direction the ball is now heading. The ball then dissipates its remaining momentum harmlessly in successive lateral bounces off the gate and side wall. When the ball comes to rest, an operator picks it up and throws it to you at a speed which exactly cancels out the forward momentum the ship gained. Oh no, is the process ruined? Nope, you’ve got a bowling ball coming at you, and it is easy to see that, the more exactly you catch the ball in the reverse process of how it was thrown to you, then the more exactly the forward momentum will be restored when you catch the ball. You are then free to repeat the process, this time with the ship moving forward faster relative to the last time you did it. Of course, as before, in order that your ship does move straight forward in this example, you have another team doing the same thing at the same time in a bilaterally symmetrical chamber next to yours.

Image

And again, as usual, if I am missing something in one or more of my examples or elsewhere, please let me know.
Keith Ness
 
Posts: 38
Joined: Fri Jun 06, 2014 6:53 am

Re: An explanation for the Emdrive

Unread postby Keith Ness » Tue Dec 06, 2016 10:46 am

I posted the above example of the bowling ball, which is essentially the same as the racquetball and fans-in-rings examples, in NASASpaceflight forums, and it got shot down. Although no clear reason was given, in retrospect I suspect it's because all I was doing in such examples was just converting ALL forward/rearward momentum of the system to lateral momentum. Oh well.

I've more recently posted my original billiard ball example (modified so the billiard balls remain fixed to the ship's movement until the cue ball stops accelerating, although I'm not sure that's necessary), in the NASASpaceflight forums, and am awaiting feedback on that...
Keith Ness
 
Posts: 38
Joined: Fri Jun 06, 2014 6:53 am

Re: An explanation for the Emdrive

Unread postby mamuso » Thu Dec 08, 2016 1:18 pm

Think about the act of throwing the ball.
mamuso
 
Posts: 25
Joined: Wed Mar 21, 2012 5:13 pm

Re: An explanation for the Emdrive

Unread postby Keith Ness » Fri Dec 09, 2016 7:41 am

mamuso wrote:Think about the act of throwing the ball.


You mean in step 4? Okay, so he throws the ball forward, giving the ball forward momentum, and giving the ship equal and opposite rearward momentum. Then the front operator catches the ball, eliminating the forward momentum of the ball, as well as the rearward momentum the throw gave the ship. Thus the inertial frame of reference from before the throw is restored. Anything else?


And, as for this statement I made:
Although no clear reason was given, in retrospect I suspect it's because all I was doing in such examples was just converting ALL forward/rearward momentum of the system to lateral momentum.


...Well, in further retrospect, maybe I don't suspect that that is all I was doing so much as I suspect that the example too strongly left open the possibility that that is all I was doing.
Keith Ness
 
Posts: 38
Joined: Fri Jun 06, 2014 6:53 am

Re: An explanation for the Emdrive

Unread postby Keith Ness » Sun Dec 11, 2016 11:37 am

Yeah, I'm definitely on shaky ground here, with some weak considerations of momentum exchange during collision. It may well be nothing more than a mad idea.

You can see the thread here (I start on page 14):

https://forum.nasaspaceflight.com/index ... ic=41732.0

Apparently my expectation for the billiard balls is totally wrong according to their descriptions of basic classical mechanics, but I can't figure out how it is empirically wrong. Oh well, I leave it a mystery for me to solve some other time.
Keith Ness
 
Posts: 38
Joined: Fri Jun 06, 2014 6:53 am

Re: An explanation for the Emdrive

Unread postby Keith Ness » Thu Dec 15, 2016 11:05 am

After looking into basic mechanics, I've seen that the false assumption that energy and momentum must covary is where my explanation went wrong.

Well this demonstrates points I've made elsewhere about what happens when you leap before you look. But more than that, even though I had decided to take this leap without looking just for fun, once I thought I'd found something within this leap, I still managed to get really carried away with it...
Keith Ness
 
Posts: 38
Joined: Fri Jun 06, 2014 6:53 am


Return to New Insights and Mad Ideas

Who is online

Users browsing this forum: No registered users and 4 guests