Talk-Polywell.org

hanelyp wrote:

ravingdave wrote:If you follow the physics it doesn't violate any rules or laws. The theory is entirely dependent on Mach's theory of inertia. If Mach was correct, then this device ought to work. As I mentioned earlier, John G. Cramer was hired by Nasa to investigate the "Mach effect." However, the experiment appears to have been a failure due to technical difficulties.

As I understand it, a M/E thruster is supposed to use the rest of the universe as reaction mass. Given a black box containing a working thruster, how would you experimentally demonstrate that the device is conserving momentum when the 'inertial' observer is being pushed on?

From an engineering stand point all that matters (heh) is that the device produces a thrust. If momentum is not conserved that would be very interesting. Practically it matters not if momentum is conserved.

hanelyp wrote: As I understand it, a M/E thruster is supposed to use the rest of the universe as reaction mass. Given a black box containing a working thruster, how would you experimentally demonstrate that the device is conserving momentum when the 'inertial' observer is being pushed on?

How do you demonstrate a car is conserving momentum when the observer's whole world is being pushed on?

Ok, so assuming this works and I like playing with such things because it is fun. So assuming this works, I have a question.
How would the acceleration of such a drive be "felt" by the passengers. If you can understand what I mean. I mean if mass is negative, then the g forces experienced by the spaceship go where?
I can see 3 scenarios:

1.
direction of acceleration of spaceship: -------------->
Acceleration: 0g 1g 2g
direction of "gravity" felt by passengers: 0 ->1g ->2g

2.
direction of acceleration of spaceship: -------------->
Acceleration: 0g 1g 2g
direction of "gravity" felt by passengers: 0 0 0

3.
direction of acceleration of spaceship: -------------->
Acceleration: 0g 1g 2g
direction of "gravity" felt by passengers: 0 <-1g <-2g



Case 2 would probably be ideal, because high g accelerations would be possible without killing passengers and equipment.
Case 1 would leave some room to work with. E.g. one could provide additional acceleration with a "normal" engine and so again work against the negative g forces. I hope that makes sense.
Case 3 would of course be the least desireable, because it means that only short bursts at multiple Gs acceleration would be possible (I would assume that humans dont like being subjected to multiple Gs for weeks or months).

I keep thinking about it, but I cant really get the thing nailed down.
Anyone care to shed some light on this?

Crapp this board killed all my spaces... Now my tables are out of alignement.

Pure speculation:

The acceleration is only on those objects in the B x V field. Since they are attached to the frame the "force" also accelerates the frame. Assuming humans in the frame they get accelerated as well.

A rocket engine with no exhaust.

Skipjack wrote:Crapp this board killed all my spaces... Now my tables are out of alignement.

Try using "code".

MSimon wrote:Pure speculation:

The acceleration is only on those objects in the B x V field. Since they are attached to the frame the "force" also accelerates the frame. Assuming humans in the frame they get accelerated as well.

A rocket engine with no exhaust.

.... However .... (semi-sci-fi-mode here):

If we were able to get something off the ground with such a unit (e.g. counteract a planet's gravity), that would also mean we're able to generate artificial gravity on a ship in a similar manner. When properly applied, the shipboard gravity generators would compensate for the acceleration created by the drive, therefore acting as an effective inertial dampener.

Yipes. Real, viable fusion reactors, useful interplanetary travel, what's next? This is really starting to sound like Firefly territory...

The exciting thing about this is that with no mass ejection probes to other star systems become viable. Assuming one or two other problems get solved.

The mass fraction for fuel goes way down because you do not have to accelerate exhaust mass. Even if you can't get 1.1 g of acceleration from the planet surface one of these things in space becomes immensely useful.

Stoney3K wrote:.... However .... (semi-sci-fi-mode here):

If we were able to get something off the ground with such a unit (e.g. counteract a planet's gravity), that would also mean we're able to generate artificial gravity on a ship in a similar manner. When properly applied, the shipboard gravity generators would compensate for the acceleration created by the drive, therefore acting as an effective inertial dampener.

Yipes. Real, viable fusion reactors, useful interplanetary travel, what's next? This is really starting to sound like Firefly territory...

This paper touches on artificial gravity. Woodward claims the possible formation of wormholes or Alcubiere warp effects. Also the possibility of tapping energy directly ftom the Gravinertial effect, and instantaneous FTL communications.

MSimon wrote:The exciting thing about this is that with no mass ejection probes to other star systems become viable. Assuming one or two other problems get solved.

The mass fraction for fuel goes way down because you do not have to accelerate exhaust mass. Even if you can't get 1.1 g of acceleration from the planet surface one of these things in space becomes immensely useful.

What I assume is the first problem is that trying to design a machine that could go through interstellar space at .1c is so mind boggling that it scares me just to type it. Think of building something that could the gas, let alone the occasional grain to sand traveling at 18,600 miles per second. And that is just to get somewhere else in 40 years. Ow.

On your second point, even if it could only do .1 g, it would reduce the mass of the ship, making it easier to lift.

pfrit wrote:

MSimon wrote:The exciting thing about this is that with no mass ejection probes to other star systems become viable. Assuming one or two other problems get solved.

The mass fraction for fuel goes way down because you do not have to accelerate exhaust mass. Even if you can't get 1.1 g of acceleration from the planet surface one of these things in space becomes immensely useful.

What I assume is the first problem is that trying to design a machine that could go through interstellar space at .1c is so mind boggling that it scares me just to type it. Think of building something that could the gas, let alone the occasional grain to sand traveling at 18,600 miles per second. And that is just to get somewhere else in 40 years. Ow.

On your second point, even if it could only do .1 g, it would reduce the mass of the ship, making it easier to lift.

1.1 g would give you a net acceleration of .1 g at the surface of the earth.

MSimon wrote:

pfrit wrote:

MSimon wrote:The exciting thing about this is that with no mass ejection probes to other star systems become viable. Assuming one or two other problems get solved.

The mass fraction for fuel goes way down because you do not have to accelerate exhaust mass. Even if you can't get 1.1 g of acceleration from the planet surface one of these things in space becomes immensely useful.

What I assume is the first problem is that trying to design a machine that could go through interstellar space at .1c is so mind boggling that it scares me just to type it. Think of building something that could the gas, let alone the occasional grain to sand traveling at 18,600 miles per second. And that is just to get somewhere else in 40 years. Ow.

On your second point, even if it could only do .1 g, it would reduce the mass of the ship, making it easier to lift.

1.1 g would give you a net acceleration of .1 g at the surface of the earth.

Yeah but .1 g would make the ship weigh 10% less. I'd settle for that.

No, Msimon is saying it would accellerate off of earths surface at 1 m/s^2, as in it is lifting off of it's own power. That would be a best case scenario, but even if it doesn't happen, any ejection-less thruster would mean "indefinite" in space acceleration which means you could get up a pretty healthy clip on your way to alpha centauri, Epsilon Erindai, or even the galactic black hole.

Well, if I am not mistaken, you have to accelerate at 1g (10 m/sec^2) for "just" a year to reach the speed of light.
Now as Msimon said, with an engine that does not need to exhaust anything this is much easier, than with a chemical or even nuclear engine that has to expell some mass in order to generate thrust (because you need a lot of fuel to take with you on that trip).
Now the reason why I was asking this question is.
If you accelerate at 1g with an "normal" engine that has a reaction mass, you have the equivalent of "earths gravity" pointing the oposite direction.
So if you accelerate towards Alpha Centauri at one g, you have a gravitational pull towards earth of one g (well and plus the gravity of earth and other celestial bodies in the vicinity, but lets ignore those for this exercise and assume that we are in space far away from any stars). That way you basically have artificial gravity on board of the ship.
But with an engine that "makes the mass of the ship and anything in it negative", what happens then?
Where do the g- forces point? Towards earth? Towards Alpha Centauri? Are there any g forces at all? That is what I dont understand. Intuitively I would say that with negative mass, the forces of acceleration point into a negative direction. So instead of towards earth your "artificial gravity" would point towards Alpha Centauri. But maybe I am wrong here and it is still just a normal acceleration. Or maybe there is no forces "feelable" at all? All these would have implications on what a spaceship like this, should it ever be built, would be capable of. You should not accelerate with more than 1 g for polonged periods of time, if the inhabitants get to feel the full g forces either direction. But, if the direction of the g forces was inverse to "nature", then noone would stop you from adding an additional "normal" engine, that could provide additional acceleration and therefore acceleration forces that point in the "normal" direction. Then your Mach- drive could accelerate at 2 g and your "normal" engines accelerates at 1 g and all the "crew" feels is 1g.
Thats why I am asking the question.

an engine that "makes the mass of the ship and anything in it negative"

Where did you get this from? If my understanding of the Mach Effect (ME) is accurate, you have to have a change in the internal energy of the "mass" in order to "see" or "use" the ME. The internal energy of the ship is not being changed, so the mass of the ship is not changing. Only the dielectric in the "ME Drive" is changing. The thrust comes from the ME Drive and is applied to the structure of the ship to accelarate the ship. That accelaration would feel the same to the ship and the humans onboard whether it was a chemical rocket, nuclear rocket, ion drive, or ME drive. (Of course, I could be completely wrong! )

Also, Pfrit is saying if a 100 lb ship got 10 lbs of thrust from a ME Drive, that would be great. MSimon is saying the same 100 lb ship gets 110 lbs of thrust. Two different things.