Community > Forum > Technology & Science > EMdrive - moment of truth

EMdrive - moment of truth

Posted by: sanman - Fri Sep 18, 2009 5:46 am
Post new topic Reply to topic
 [ 25 posts ] 
EMdrive - moment of truth 
Author Message
Space Walker
Space Walker
avatar
Joined: Tue Sep 15, 2009 11:59 pm
Posts: 188
Post EMdrive - moment of truth   Posted on: Fri Sep 18, 2009 5:46 am
Here's an interesting article about a new breakthrough in the manufacture of a superconducting radio-frequency cavity:

http://nextbigfuture.com/2009/09/superc ... avity.html

If this new cavity were tested for EMdrive purposes, could it reveal a new mechanism for propulsion?

Hopefully a superconducting cavity would clearly prove or disprove the concept, to remove all doubt.
(the implication being propulsion without onboard propellant mass)


Back to top
Profile
Space Station Commander
Space Station Commander
User avatar
Joined: Mon May 31, 2004 9:47 pm
Posts: 816
Location: Yerushalayim (Jerusalem) - capital of Israel!
Post Re: EMdrive - moment of truth   Posted on: Fri Sep 18, 2009 1:14 pm
How does the EM drive operate without propellent? Where does it get its energy from? And what does a superconducting cavity have to do with anything?

_________________
“Once you have tasted flight, you will forever walk the earth with your eyes turned skyward, for there you have been, and there you will always long to return.”
-Anonymous


Back to top
Profile WWW
Space Station Commander
Space Station Commander
User avatar
Joined: Mon May 31, 2004 9:47 pm
Posts: 816
Location: Yerushalayim (Jerusalem) - capital of Israel!
Post Re: EMdrive - moment of truth   Posted on: Fri Sep 18, 2009 2:24 pm
I think that the EMdrive uses electricity for propellent, and therefore is OK with the Law of conservation of energy. Is that correct?

_________________
“Once you have tasted flight, you will forever walk the earth with your eyes turned skyward, for there you have been, and there you will always long to return.”
-Anonymous


Back to top
Profile WWW
Space Walker
Space Walker
avatar
Joined: Tue Sep 15, 2009 11:59 pm
Posts: 188
Post Re: EMdrive - moment of truth   Posted on: Sat Sep 19, 2009 1:03 am
My understanding is that the EMdrive steals energy (or momentum) from photons.

The photons are bouncing around inside the resonant cavity, and of course if something is hitting both sides of a cavity, then you expect that the forces would be balanced, so that it results in no net movement.

But with tiny objects like photons, there are additional quantum effects to consider.

The cavity can be tailored to have an asymmetric shape, so that the opposite sides of it will each have different amounts of quantum interaction with the photons. It is this difference which apparently allows the photon to exchange more momentum in hitting one side of the cavity than in hitting the other, thus resulting in net movement.
This lopsided behavior seems to be due to quantum effects.

Likewise you might ask, when an LED produces photons - where did they come from? Who put the photons inside that LED in the first place, so that they can just come out in a never-ending stream? Is there a hidden backdoor inside that LED, which some little elves are stuffing photons into?
And those photons have momentum, as we know. So if the photons are just magically shooting out of the LED while having momentum, then Newton's law of action-reaction says that the LED is being pushed in the opposite direction. Each photon is giving a kick to the LED as it leaves, to push it the other way.

The difference with this resonant cavity idea is that each photon gives many kicks before leaving, resulting in a bigger push than the usual. The reason for the many kicks is because it's bouncing back and forth inside the cavity.


Back to top
Profile
Space Station Commander
Space Station Commander
User avatar
Joined: Mon May 31, 2004 9:47 pm
Posts: 816
Location: Yerushalayim (Jerusalem) - capital of Israel!
Post Re: EMdrive - moment of truth   Posted on: Mon Jan 11, 2010 4:33 pm
sanman wrote:
My understanding is that the EMdrive steals energy (or momentum) from photons.

The photons are bouncing around inside the resonant cavity, and of course if something is hitting both sides of a cavity, then you expect that the forces would be balanced, so that it results in no net movement.

But with tiny objects like photons, there are additional quantum effects to consider.

The cavity can be tailored to have an asymmetric shape, so that the opposite sides of it will each have different amounts of quantum interaction with the photons. It is this difference which apparently allows the photon to exchange more momentum in hitting one side of the cavity than in hitting the other, thus resulting in net movement.
This lopsided behavior seems to be due to quantum effects.

Likewise you might ask, when an LED produces photons - where did they come from? Who put the photons inside that LED in the first place, so that they can just come out in a never-ending stream? Is there a hidden backdoor inside that LED, which some little elves are stuffing photons into?
And those photons have momentum, as we know. So if the photons are just magically shooting out of the LED while having momentum, then Newton's law of action-reaction says that the LED is being pushed in the opposite direction. Each photon is giving a kick to the LED as it leaves, to push it the other way.

The difference with this resonant cavity idea is that each photon gives many kicks before leaving, resulting in a bigger push than the usual. The reason for the many kicks is because it's bouncing back and forth inside the cavity.

I thought that photons were massless, so that they have no momentum

_________________
“Once you have tasted flight, you will forever walk the earth with your eyes turned skyward, for there you have been, and there you will always long to return.”
-Anonymous


Back to top
Profile WWW
Space Station Commander
Space Station Commander
User avatar
Joined: Mon Oct 06, 2003 9:22 pm
Posts: 843
Location: New York, NY
Post Re: EMdrive - moment of truth   Posted on: Mon Jan 11, 2010 5:54 pm
energy of a photon is E=h*nu (frequency). similarly by E^2=p^2*c^2 + m^2*c^4 this gives p=h*nu/c=m*c. so the effective mass is p/c. this isn't a real mass, but it does explain several "mass-like" effects that photons display, such as the event horizon of a black hole, or the exchange between matter and energy in nuclear reactions (well, there's more to the latter than just that but whatever). so photons bouncing off of something do impart momentum to the reflector. this is the basic principal behind a solar sail, and also the source of the "radiation pressure" perturbation (not considered a perturbation for solar sails and stuff that relies on it for propulsion) that must be accounted for in the orbital mechanics of satellites.

_________________
Cornell 2010- Applied and Engineering Physics

Software Developer

Also, check out my fractals


Back to top
Profile
Spaceflight Trainee
Spaceflight Trainee
avatar
Joined: Tue Sep 15, 2009 12:44 am
Posts: 23
Post Re: EMdrive - moment of truth   Posted on: Thu Feb 04, 2010 5:56 am
I propose an engine we already understand, basically, a modified car engine that can work in space, my name is trevor and I am an inventor. You can check it out at http://trv1070x.hpage.com.

The combustion version of this engine is basically a modified internal combustion engine but, it will enable a vehicle to vertically ascend and descend and move through the air without the aid of wings etc. On a whole it consists of multiple units and the following engine operation is of each unit not of the engine on a whole.

A clear idea of how a unit works is this example. Two cue balls are on a pool table some distance apart (ball 1 and ball 2). A pool stick is used to strike ball one. Ball one in turn strike ball 2 and come to an immediate stop while ball 2 speeds off with all the force and speed of ball 1.

Ball 1 is a modified piston and the harness of the combustion explosion and ball 2 is the vehicle. Ball 1 strikes ball 2 transferring its motion into it (motion induction). The engine is named “motion induction engine”.

The combustion explosion occurs within a modified combustion cylinder and pushes the modified piston (ball 1). The modified piston then accelerates and contacts the vehicle (ball 2) from across a cushion. No connecting rod, crankshaft, gear, or transmission is used; the modified piston directly contacts the vehicle from across a cushion. This takes place within a modified engine block. The modified piston, only moves forward and backward within the cylinder as it conducts the energy of the combustion explosions directly to the body of the vehicle, pushing the vehicle. Two modified pistons are actually used in a single unit; this has to do with dealing with the counter force of the explosion.

The units are organized to form an engine or engines. For a car to be lifted into the air a unit is placed next to each wheel, these four units’ forms an engine named “peripheral engine”. Other types of engines such as “central engine” and “re-entry engine” can also be formed by organizing units. Engines are formed as required by the particular vehicle. The central engine is used to push the car forward or backward, to the right or left, brake or stop the car.

There are several versions and variations of the motion induction engine of which the electromagnetic versions are faster and better.

More information and inventions are available at the above site; it will give a clear understanding of the engine, or email trevorcandi@gmail.com.


Back to top
Profile
Space Walker
Space Walker
User avatar
Joined: Thu Sep 17, 2009 2:25 pm
Posts: 160
Location: Ireland
Post Re: EMdrive - moment of truth   Posted on: Thu Feb 04, 2010 1:06 pm
On a pool table, a certain amount of backspin is required to stop the cue ball when it strikes the object ball. In a frictionless environment, the same mechanics are possible but require perfectly elastic materials. These materials don't exist, although the ceramics used in pools balls are a close approximation. If they were perfectly elastic, you wouldn't hear the clicking noise when they strike each other.

The second major flaw in your invention is that you have no way to get the piston to return to it's starting position. Doing so will require the engine/vehicle to also move back to it's starting position. It's the law of conservation of energy, specifically kinetic energy/momentum. It sounds similar to trying to fly by repeatedly punching yourself with uppercuts to the chin. If I'm wrong about this, please elaborate on how this is supposed to work.

johno

inventor wrote:
I propose an engine we already understand, basically, a modified car engine that can work in space, my name is trevor and I am an inventor. You can check it out at http://trv1070x.hpage.com.

The combustion version of this engine is basically a modified internal combustion engine but, it will enable a vehicle to vertically ascend and descend and move through the air without the aid of wings etc. On a whole it consists of multiple units and the following engine operation is of each unit not of the engine on a whole.

A clear idea of how a unit works is this example. Two cue balls are on a pool table some distance apart (ball 1 and ball 2). A pool stick is used to strike ball one. Ball one in turn strike ball 2 and come to an immediate stop while ball 2 speeds off with all the force and speed of ball 1.

Ball 1 is a modified piston and the harness of the combustion explosion and ball 2 is the vehicle. Ball 1 strikes ball 2 transferring its motion into it (motion induction). The engine is named “motion induction engine”.

The combustion explosion occurs within a modified combustion cylinder and pushes the modified piston (ball 1). The modified piston then accelerates and contacts the vehicle (ball 2) from across a cushion. No connecting rod, crankshaft, gear, or transmission is used; the modified piston directly contacts the vehicle from across a cushion. This takes place within a modified engine block. The modified piston, only moves forward and backward within the cylinder as it conducts the energy of the combustion explosions directly to the body of the vehicle, pushing the vehicle. Two modified pistons are actually used in a single unit; this has to do with dealing with the counter force of the explosion.

The units are organized to form an engine or engines. For a car to be lifted into the air a unit is placed next to each wheel, these four units’ forms an engine named “peripheral engine”. Other types of engines such as “central engine” and “re-entry engine” can also be formed by organizing units. Engines are formed as required by the particular vehicle. The central engine is used to push the car forward or backward, to the right or left, brake or stop the car.

There are several versions and variations of the motion induction engine of which the electromagnetic versions are faster and better.

More information and inventions are available at the above site; it will give a clear understanding of the engine, or email trevorcandi@gmail.com.


Back to top
Profile
Spaceflight Trainee
Spaceflight Trainee
avatar
Joined: Tue Sep 15, 2009 12:44 am
Posts: 23
Post Re: EMdrive - moment of truth   Posted on: Fri Feb 05, 2010 4:22 am
You could take a look at the diagram of the engine at http://trv1070x.hpage.com and read the free “How the combustion motion induction engine works” booklet, it has diagrams and explanations. There are also other inventions such as “airborne road car” etc at the site.

(A) Back spin and elastic materials
However, it is not essential for the first ball to come to a stop when it collides with the second ball. My “two cue balls on a pool table” analogy might be misleading where the stopping of ball 2 is concerned. What is essential is that there is energy transfer between balls.

I will reiterate the analogy for the benefit of other readers. Two cue balls are on a pool table (ball 1 and 2). A pool stick is used to strike ball 1. Ball 1 in turn strike ball 2 and come to an immediate stop while ball 2 speeds off with all the energy and speed of ball 2.

The essential principle of the analogy is that there is the transfer of motion from one object to the other (motion induction). This is the principle on which the engine functions the engine is named “motion induction engine” (MIE).

Keep in mind this engine (its combustion version, which is what we are speaking about) is an extensive modification of a car’s engine (internal combustion engine). Ball 1 is actually a modified piston and ball 2 is the vehicle. The pool table would be a modified engine block in which there is a modified combustion cylinder in which the modified piston is. The difference between the motion induction engine and a car’s engine are basically the modifications and arrangement of the components, engine block, combustion cylinder etc. An important point about this engine to understand is, its not a centralize engine like a car’s engine. When you open the bonnet of a car you see a single engine. The MIE consists of several motion induction engines each is called a unit. The engine operation principle related to the two cue balls is the operation of a single unit, not of the operation of the engine on a whole. Units are used to form engines.

(B) Balls clicking and ball return
The combustion explosion pushes ball 1 (modified piston) it accelerates and contacts the vehicle from across a cushioning mechanism. This cushioning mechanism can be pressurize air, a spring etc. The cushion prevents direct contact between ball 1 and 2, there is no contact sound. Direct contact is not essential for energy transfer. The cushion is also used to push back the piston (AKA fly back the piston). The cushion is used to solve 2 problems at the same time.

(C)
If you look at the diagram of the engine unit at the above site you will notice two modified piston are used and the modified combustion cylinder is in the shape of a half circle with straight cylindrical ends. This is the case in order to deal productively with the counter-force of the combustion explosion. Check the booklet at the above site it speaks to counter force, virtual engine platform, piston fly back etc. But if it’s still unclear let me know.


Back to top
Profile
Moderator
Moderator
avatar
Joined: Mon Feb 09, 2004 4:01 am
Posts: 747
Location: New Zealand
Post Re: EMdrive - moment of truth   Posted on: Fri Feb 05, 2010 6:19 am
On the pool table, Ball 1 gets its energy from the cue stick, an external source. Ball 1 doesn't bounce into itself to get the energy to bounce into Ball 2.

_________________
What goes up better doggone well stay up! - Morgan Gravitronics, Company Slogan.


Back to top
Profile ICQ YIM
Space Walker
Space Walker
User avatar
Joined: Thu Sep 17, 2009 2:25 pm
Posts: 160
Location: Ireland
Post Re: EMdrive - moment of truth   Posted on: Fri Feb 05, 2010 10:25 am
inventor wrote:
You could take a look at the diagram of the engine at http://trv1070x.hpage.com and read the free “How the combustion motion induction engine works” booklet, it has diagrams and explanations.


I did. My original comments still stand because I can see flaws in it that you can't. This sometimes happens to designers and engineers. The design process requires you to look at a problem from a different perspective to a casual observer.

inventor wrote:
(B) Balls clicking and ball return
The combustion explosion pushes ball 1 (modified piston) it accelerates and contacts the vehicle from across a cushioning mechanism.


The combustion explosion also pushes the unit/engine/vehicle in the opposite direction with an equal amount of momentum. Forget about your half circle connecting the 2 pistons, it won't work like you think it does. Velocity is direction + speed, you can't change the direction of the hot gases for free, they will push against the walls of your half circle tube as they change direction. You're still trying to fly by punching yourself into the air or kicking yourself up the ass.

inventor wrote:
The cushion is also used to push back the piston (AKA fly back the piston). The cushion is used to solve 2 problems at the same time.


Ask yourself a question please. If your cushion of air can push back the piston, why do you need fuel and explosive gas in the first place. Surely you could have a cushion of air in the combustion chamber that would work just as well. Thinking about this question may help you to see the fundamental flaw in your invention.

johno


Back to top
Profile
Space Walker
Space Walker
avatar
Joined: Mon Sep 21, 2009 10:43 pm
Posts: 146
Location: Webster, TX
Post Re: EMdrive - moment of truth   Posted on: Fri Feb 05, 2010 2:11 pm
johno wrote:
The design process requires you to look at a problem from a different perspective to a casual observer


boy, have I learned that the hard way a few times.

While, I've not looked at your website yet, I must still agree with johno on this one. So one of your ideas turns out to be a dud, so what? you know how many pages of concepts and designs I have sitting around my home that would likely never work or amount to anything? :lol: , more than I want to admit. The big thing is, no matter what ideas you have, or how unlikely they are to come to fruition, so long as you learn something in the process of exploring those ideas, it makes them worth it. You also have to know when it is time to move on from a concept that will take you nowhere, or worse in the wrong direction.

Think of Babe Ruth.... how many times did he have to strike out in order to hit as many home runs that he did?

I don't think anyone here is trying to target you or your ideas, just trying to help you learn. I do give you props though, for being able to come onto a forum like this and present your ideas. I've got a combined cycle engine concept I've thought about discussing, but I don't think I've got the gumption for that one yet, lol. No one likes being told their ideas are wrong, or flawed, but it takes guts to be able to face that, take the critiques with humility and learn from them.


Back to top
Profile
Space Walker
Space Walker
User avatar
Joined: Thu Sep 17, 2009 2:25 pm
Posts: 160
Location: Ireland
Post Re: EMdrive - moment of truth   Posted on: Fri Feb 05, 2010 8:51 pm
johno wrote:
Ask yourself a question please. If your cushion of air can push back the piston, why do you need fuel and explosive gas in the first place. Surely you could have a cushion of air in the combustion chamber that would work just as well. Thinking about this question may help you to see the fundamental flaw in your invention.


A thought occurred to me this evening about the energy transfers inside your engine. The pistons you use are just compressing gas, using a different chamber of compressed gas as the source of power. If you remove the pistons from the engine, the mechanics of the system remain the same. You are using compressed gas to create pressure against the walls of the combustion chamber. And that's pretty much all it does.

If you disagree, think about what effect changing the mass of the pistons would have on the engine. If you increase the mass, do you think it will change the way the engine works? In what way will it change it? If you decrease the mass will it change the way the engine works? In what way will it change it? Now decrease the mass of the pistons until they are just a massless disk with just 2 dimensions. Now you have a situation which is exactly the same as having no pistons. I think you will find it easier to understand that your engine won't work now.

johno


Back to top
Profile
Space Station Commander
Space Station Commander
User avatar
Joined: Mon Dec 18, 2006 11:15 pm
Posts: 904
Location: Columbus, GA USA
Post Re: EMdrive - moment of truth   Posted on: Mon Feb 08, 2010 2:07 am
Unfortunately, Johno is right. What allows those billiard balls to exchange energy was that the que stick was attached to a firmly planted player. About all this mechanism can do is oscillate back and forth with the motion of the pistons, because each cycle must exert an identical amount of energy and momentum.

Its interesting "outside the box thinking" and really how "Orion" and laser propelled craft function (energy transfers to a gas which pushes against a craft. But without an outside input of that motion it can't go anywhere.


Back to top
Profile
Space Station Commander
Space Station Commander
User avatar
Joined: Wed Aug 18, 2004 8:47 am
Posts: 521
Location: Science Park, Cambridge, UK
Post Re: EMdrive - moment of truth   Posted on: Mon Feb 08, 2010 9:54 am
I think the best way to demonstrate this is the build it. It's sounds like a pretty simple task, plenty of old engine blocks around. Just do it.

(Not saying it will work - it won't, just that that it can be tested fairly easily)


Back to top
Profile
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 25 posts ] 
 

Who is online 

Users browsing this forum: No registered users and 27 guests


© 2014 The International Space Fellowship, developed by Gabitasoft Interactive. All Rights Reserved.  Privacy Policy | Terms of Use