### Author Topic: EM Drive Developments - related to space flight applications - Thread 3  (Read 1875232 times)

#### RotoSequence

• Full Member
• Posts: 777
• Liked: 572
• Likes Given: 780
##### Re: EM Drive Developments - related to space flight applications - Thread 3
« Reply #6120 on: 08/01/2015 11:52 PM »
I have no idea what that represents.  Please explain and elaborate for those of us on a different wavelength

When the topic drifted towards increasing or decreasing cone-angles to maximize the difference in areas between small and large bases, my thoughts drifted to the Shawyer type geometries with hemispherical ends:

Which, when grown to maximize the difference between the small end and large end, leads me to a large base that approximates a sphere with a truncated cone subtracted from it:

I'm not going to be surprised if I'm simply not groking something fundamental that makes this train of thought a bit hair-brained.

#### Rodal

• Senior Member
• Posts: 5895
• USA
• Liked: 6045
• Likes Given: 5325
##### Re: EM Drive Developments - related to space flight applications - Thread 3
« Reply #6121 on: 08/02/2015 12:01 AM »
I have no idea what that represents.  Please explain and elaborate for those of us on a different wavelength

When the topic drifted towards increasing or decreasing cone-angles to maximize the difference in areas between small and large bases, my thoughts drifted to the Shawyer type geometries with hemispherical ends:

Which, when grown to maximize the difference between the small end and large end, leads me to a large base that approximates a sphere with a truncated cone subtracted from it:

I'm not going to be surprised if I'm simply not groking something fundamental that makes this train of thought a bit hair-brained.

I don't see right away how to closed-form analyze that geometry (or to imagine what it looks like in 3D)
but thanks for bringing out of the box thinking in the best tradition of American ingenuity
« Last Edit: 08/02/2015 12:08 AM by Rodal »

#### leomillert

• Member
• Posts: 34
• Liked: 21
• Likes Given: 12
##### Re: EM Drive Developments - related to space flight applications - Thread 3
« Reply #6122 on: 08/02/2015 12:19 AM »
Quote
I don't see right away how to closed-form analyze that geometry (or to imagine what it looks like in 3D)
but thanks for bringing out of the box thinking in the best tradition of American ingenuity

If I understand it correctly, the 3D solid would be a sphere with a void in the format of a cone with rounded tip, which ends at the center of the sphere.

@RotoSequence correct me if I'm wrong.
« Last Edit: 08/02/2015 12:19 AM by leomillert »

#### RotoSequence

• Full Member
• Posts: 777
• Liked: 572
• Likes Given: 780
##### Re: EM Drive Developments - related to space flight applications - Thread 3
« Reply #6123 on: 08/02/2015 12:24 AM »
Quote
I don't see right away how to closed-form analyze that geometry (or to imagine what it looks like in 3D)
but thanks for bringing out of the box thinking in the best tradition of American ingenuity

If I understand it correctly, the 3D solid would be a sphere with a void in the format of a cone with rounded tip, which ends at the center of the sphere.

@RotoSequence correct me if I'm wrong.

You are correct.

Half of the sphere:

« Last Edit: 08/02/2015 12:25 AM by RotoSequence »

#### SeeShells

• Senior Member
• Posts: 2335
• Every action there's a reaction we try to grasp.
• United States
• Liked: 2982
• Likes Given: 2601
##### Re: EM Drive Developments - related to space flight applications - Thread 3
« Reply #6124 on: 08/02/2015 12:28 AM »
Quote
I don't see right away how to closed-form analyze that geometry (or to imagine what it looks like in 3D)
but thanks for bringing out of the box thinking in the best tradition of American ingenuity

If I understand it correctly, the 3D solid would be a sphere with a void in the format of a cone with rounded tip, which ends at the center of the sphere.

@RotoSequence correct me if I'm wrong.
I think you're quite right. Take that 2D and round it out pull the plug out of it like a frustum and bingo. I see it too so if it's wrong there are two crazies on here...

#### Rodal

• Senior Member
• Posts: 5895
• USA
• Liked: 6045
• Likes Given: 5325
##### Re: EM Drive Developments - related to space flight applications - Thread 3
« Reply #6125 on: 08/02/2015 12:31 AM »
The Yang/Shell dimensions with cone half angle at 6 degrees had TM113 and TE012 both resonate at near 2.45 GHz.

This geometry (now officially entered into the World Book Of Paranormal EM Drive Phenomena) resonates with TE012 at 2.45 GHz but the TM11 modes are further apart:

TM112= 2.23227 GHz
TM113= 2.64095 GHz

So aero will have to model it in Meep with a loop antenna or we have no resonance at 2.45 GHz
« Last Edit: 08/02/2015 12:36 AM by Rodal »

#### Rodal

• Senior Member
• Posts: 5895
• USA
• Liked: 6045
• Likes Given: 5325
##### Re: EM Drive Developments - related to space flight applications - Thread 3
« Reply #6126 on: 08/02/2015 12:35 AM »
Quote
I don't see right away how to closed-form analyze that geometry (or to imagine what it looks like in 3D)
but thanks for bringing out of the box thinking in the best tradition of American ingenuity

If I understand it correctly, the 3D solid would be a sphere with a void in the format of a cone with rounded tip, which ends at the center of the sphere.

@RotoSequence correct me if I'm wrong.
I think you're quite right. Take that 2D and round it out pull the plug out of it like a frustum and bingo. I see it too so if it's wrong there are two crazies on here...

YEs, I see the 3D shape all right.  I dont't see what waves will be resonating inside it though...

To have spherical waves resonate inside it, the entrant shape should be a pointy cone with a pointy vertex, as in radars.

It should be a sphere with a pointy cone cut-out into it.
« Last Edit: 08/02/2015 12:35 AM by Rodal »

#### SeeShells

• Senior Member
• Posts: 2335
• Every action there's a reaction we try to grasp.
• United States
• Liked: 2982
• Likes Given: 2601
##### Re: EM Drive Developments - related to space flight applications - Thread 3
« Reply #6127 on: 08/02/2015 12:38 AM »
Are we over with the calculations on the Yang frustum? I should have caught it Dr. Rodal but my low IQ pen with a lower IQ driving it missed it.

So I'm going to be making bad data look good.

Shell

#### leomillert

• Member
• Posts: 34
• Liked: 21
• Likes Given: 12
##### Re: EM Drive Developments - related to space flight applications - Thread 3
« Reply #6128 on: 08/02/2015 12:39 AM »
If I understand correctly, because cut-off doesn't apply to tapered cavities, the small bases' diameter can be as small as desired.
If we take RotoSequence's idea of the solid with Rodal's adjustment, that would mean an sphere with as little void as possible (in the form of a cone of pointy tip).
Does this sound plausible?
« Last Edit: 08/02/2015 12:42 AM by leomillert »

#### A_M_Swallow

• Elite Veteran
• Senior Member
• Posts: 8182
• South coast of England
• Liked: 258
• Likes Given: 107
##### Re: EM Drive Developments - related to space flight applications - Thread 3
« Reply #6129 on: 08/02/2015 12:45 AM »

This should make what I'm saying a little clearer. Using @Notsosureofit's theory. From this, we can see how the design of the frustum could be maximized for thrust. What puzzles me is why we are working in microwaves when the equation clearly shows that lower frequency is better.
Todd

Change one thing at a time. This started with (a) microwaves, (b) microwave ovens as a cheap source and (c) no underlying theory.

#### leomillert

• Member
• Posts: 34
• Liked: 21
• Likes Given: 12
##### Re: EM Drive Developments - related to space flight applications - Thread 3
« Reply #6130 on: 08/02/2015 12:48 AM »
If I understand correctly, because cut-off doesn't apply to tapered cavities, the small bases' diameter can be as small as desired.
If we take RotoSequence's idea of the solid with Rodal's adjustment, that would mean an sphere with as little void as possible (in the form of a cone of pointy tip).
Does this sound plausible?
No problem with that.  A radar geometry are two cones on the same axis of axisymmetry with their pointy cones touching each other, one cone pointing up and the other cone pointing down. Spherical waves emanate from the common tip.

This would be just the asymmetrical form with just one pointy cone and spherical waves coming out from the tip.

Sounds like we just got a new design on the table

#### Rodal

• Senior Member
• Posts: 5895
• USA
• Liked: 6045
• Likes Given: 5325
##### Re: EM Drive Developments - related to space flight applications - Thread 3
« Reply #6131 on: 08/02/2015 12:52 AM »
It is just the hollow spherical female part of the hollow male spherical cone:

Any area on a sphere which is equal in area to the square of its radius, when observed from its center, subtends precisely one steradian
« Last Edit: 08/02/2015 12:54 AM by Rodal »

#### WarpTech

• Full Member
• Posts: 1307
• Do it!
• Vista, CA
• Liked: 1351
• Likes Given: 1815
##### Re: EM Drive Developments - related to space flight applications - Thread 3
« Reply #6132 on: 08/02/2015 01:02 AM »
If I understand correctly, because cut-off doesn't apply to tapered cavities, the small bases' diameter can be as small as desired.
If we take RotoSequence's idea of the solid with Rodal's adjustment, that would mean an sphere with as little void as possible (in the form of a cone of pointy tip).
Does this sound plausible?

Not to me. He started this thinking it was taking what I said to the extreme, but I think he went beyond that. I don't even recognize it anymore. :-/ Incremental changes guys! Let's not stray too far from what we're focusing on.
Todd

#### Rodal

• Senior Member
• Posts: 5895
• USA
• Liked: 6045
• Likes Given: 5325
##### Re: EM Drive Developments - related to space flight applications - Thread 3
« Reply #6133 on: 08/02/2015 01:05 AM »
If I understand correctly, because cut-off doesn't apply to tapered cavities, the small bases' diameter can be as small as desired.
If we take RotoSequence's idea of the solid with Rodal's adjustment, that would mean an sphere with as little void as possible (in the form of a cone of pointy tip).
Does this sound plausible?

Not to me. He started this thinking it was taking what I said to the extreme, but I think he went beyond that. I don't even recognize it anymore. :-/ Incremental changes guys! Let's not stray too far from what we're focusing on.
Todd
Don't you like ice cream cones?
« Last Edit: 08/02/2015 01:07 AM by Rodal »

#### SeeShells

• Senior Member
• Posts: 2335
• Every action there's a reaction we try to grasp.
• United States
• Liked: 2982
• Likes Given: 2601
##### Re: EM Drive Developments - related to space flight applications - Thread 3
« Reply #6134 on: 08/02/2015 01:07 AM »
The Yang/Shell dimensions with cone half angle at 6 degrees had TM113 and TE012 both resonate at near 2.45 GHz.

This geometry (now officially entered into the World Book Of Paranormal EM Drive Phenomena) resonates with TE012 at 2.45 GHz but the TM11 modes are further apart:

TM112= 2.23227 GHz
TM113= 2.64095 GHz

So aero will have to model it in Meep with a loop antenna or we have no resonance at 2.45 GHz
Go ahead make me feel bad Jose',  I'm about ready to take a brick to the first frustum I'm so frustrumed.

#### WarpTech

• Full Member
• Posts: 1307
• Do it!
• Vista, CA
• Liked: 1351
• Likes Given: 1815
##### Re: EM Drive Developments - related to space flight applications - Thread 3
« Reply #6135 on: 08/02/2015 01:09 AM »

This should make what I'm saying a little clearer. Using @Notsosureofit's theory. From this, we can see how the design of the frustum could be maximized for thrust. What puzzles me is why we are working in microwaves when the equation clearly shows that lower frequency is better.
Todd

Change one thing at a time. This started with (a) microwaves, (b) microwave ovens as a cheap source and (c) no underlying theory.

Thanks, I think I've narrowed down the theory candidates over the past week. Plotting what would be the phase velocity in what I posted above, it appears there is a significant boost in thrust-to-power ratio if we allow the small end to be much smaller than the big end, like  1/10th the size. Basically, thrust depends almost entirely on the side wall force, not the small end. We want to maximize force on the walls, like @Rodal's plot below. It also seems, operating at around 100MHz, is not an unmanageable model either.
Todd

#### Rodal

• Senior Member
• Posts: 5895
• USA
• Liked: 6045
• Likes Given: 5325
##### Re: EM Drive Developments - related to space flight applications - Thread 3
« Reply #6136 on: 08/02/2015 01:12 AM »
The Yang/Shell dimensions with cone half angle at 6 degrees had TM113 and TE012 both resonate at near 2.45 GHz.

This geometry (now officially entered into the World Book Of Paranormal EM Drive Phenomena) resonates with TE012 at 2.45 GHz but the TM11 modes are further apart:

TM112= 2.23227 GHz
TM113= 2.64095 GHz

So aero will have to model it in Meep with a loop antenna or we have no resonance at 2.45 GHz
Go ahead make me feel bad Jose',  I'm about ready to take a brick to the first frustum I'm so frustrumed.
Just as long as you don't throw the brick at me

#### deltaMass

• Full Member
• Posts: 955
• A Brit in California
• Liked: 671
• Likes Given: 275
##### Re: EM Drive Developments - related to space flight applications - Thread 3
« Reply #6137 on: 08/02/2015 01:16 AM »

I for one welcome our insectoid overlords
« Last Edit: 08/02/2015 01:18 AM by deltaMass »

#### WarpTech

• Full Member
• Posts: 1307
• Do it!
• Vista, CA
• Liked: 1351
• Likes Given: 1815
##### Re: EM Drive Developments - related to space flight applications - Thread 3
« Reply #6138 on: 08/02/2015 01:20 AM »
The Yang/Shell dimensions with cone half angle at 6 degrees had TM113 and TE012 both resonate at near 2.45 GHz.

This geometry (now officially entered into the World Book Of Paranormal EM Drive Phenomena) resonates with TE012 at 2.45 GHz but the TM11 modes are further apart:

TM112= 2.23227 GHz
TM113= 2.64095 GHz

So aero will have to model it in Meep with a loop antenna or we have no resonance at 2.45 GHz
Go ahead make me feel bad Jose',  I'm about ready to take a brick to the first frustum I'm so frustrumed.
Just as long as you don't throw the brick at me

Like I said, I don't build anything until I understand what it is I'm building. I don't wing-it, I'm a tinker-er. I'll build a prototype of something I can predict and then tinker with it until it works or I understand why it doesn't. Although, I must admit it's a lot easier simulating a printed circuit board than it is building mechanical models. Don't get too frustrated Shell, it's a journey.
Todd

#### Rodal

• Senior Member
• Posts: 5895
• USA
• Liked: 6045
• Likes Given: 5325
##### Re: EM Drive Developments - related to space flight applications - Thread 3
« Reply #6139 on: 08/02/2015 01:25 AM »

I for one welcome our insectoid overlords

Tags: