# The Naked Scientists Forum

### Author Topic: Wharp Drive? S.Ilinca magnetic jet engine on Oberth effect  (Read 18984 times)

#### Ilinca Sergiu

• Full Member
• Posts: 50
• zero mass air electric engine S.Ilinca
##### Re: Wharp Drive? S.Ilinca magnetic jet engine on Oberth effect
« Reply #25 on: 14/07/2014 14:42:28 »
Ok, I think there's a few reasons why your posts haven't gotten much response.

First, posting lots of different posts with different images is going to overwhelm any reader.  If you can summarize your point or question in a single, concise post, it's a lot likelier to get responses.

Second, although you may not be able to improve this, I think there's a language barrier.  I can't understand much of what you're trying to ask here, so I can't really comment on it.

Coming back to your question about the Oberth effect and gravity: the Oberth effect says, as Atomic-S points out, that it is more efficient to carry fuel with you in multi-stage rockets than not, since fuel moving with you at high speeds has a lot of kinetic energy due to its motion in addition to its chemical potential energy.

Gravity is a separate force in the universe that doesn't have anything to do with the Oberth effect.

Yes JP you're right to understand my question needed to simplify these physical model to one very simple.
Probably easier is impossible.
Far away in space is the space station. At the station there is a Elevator without ceiling and the Elevator shaft is also open to space. On the floor of the Elevator has the ball weighing 1kg . In this Elevator is an astronaut he takes the ball and throws it up with the speed 10 m/s. The ball flies out of the station with the speed 10 m/s. The thrust obtained station from throwing the ball is Ftrast=m*v=10kgf.
This Elevator is also the ability to move up and down with very large accelerations (10000g). The movement of the Elevator up and down with any accelerations and velocities has no impact on the total momentum of the station. He will always be ( 0 ). In the absence of Fthrust the station will make only oscillatory movements.
If the Elevator will be acceleration in 10000g the ball on the floor will have a weight of 10,000kg or 10T. The astronaut will not be able to pick up the ball and throw up. And the astronaut will not withstand this acceleration. Now to throw the ball during acceleration of the lift we need Superman. I.e. this person should be 10,000 times stronger than ordinary cosmonaut. During acceleration Elevator Superman takes the ball with weight 10T and throws it up with the speed in 10 m/s.
Now what may be the pressure on the floor of the Elevator from this shot and accordingly Fthrust ?
Obviously it will be much greater than in the case without acceleration. And it is :– the weight of the ball M=10000 kg, speed 10m/s,.. F thrust = M*v=100000kgf (I know weight not mass, but how differently? ). Do not forget that the total momentum of the system without Fthrust is ( 0 ) and these 100,000kgf will be increase the total momentum of the system?

PS:  I see a similarity with Oberth effect.---- But the acceleration of the Elevator will always be time-limited. Choose a while acceleration during which the Elevator will get the speed to 1000 m/s. As now be considered F thrust ?
According to the Oberth formula m(v*vb): ball mass = 1kg, ball speed=10m/s, Elevator speed=1000m/s , F thrust=m(v*vb)=10000kgf

#### Atomic-S

• Hero Member
• Posts: 935
• Thanked: 19 times
##### Re: Wharp Drive? S.Ilinca magnetic jet engine on Oberth effect
« Reply #26 on: 02/08/2014 05:44:34 »
I have looked through your post and think I am beginning to understand this. When a mass is ejected from a moving vehicle, it will receive more "thrust" than when the same mass is ejected by the same process from the vehicle at rest.  Furthermore, according to http://en.wikipedia.org/wiki/Oberth_effect , when that takes place at low gravitational potential, it is more effective than when it takes place at high gravitational potential.

All that is true if it is correctly understood.  It is important, however, to understand it correctly.  There is one major problem area that can lead to an incorrect understanding, and that is when there is misunderstadning of the difference between velocity, momentum, and acceleration.  All three of these quantities measure motion, but they are not identical and do not have identical significances in terms of the physics.

To move a spaceship, you must change its velocity. Velocity = momentum/mass.  This is done by expelling exhaust, and due to the conservation of momentum, the change in the vehicle's momentum is equal and opposite to that of the exhaust. Because the exhaust momentum is also mass * velocity, the largest possible velocity (for a given exhaust mass) is what is needed.  This is where conventional rockets have limitations because of the limited exhaust velocities chemically possible, but the Oberth Effect allows us to partly get around this by retaining much of the fuel on board prior to burning, which builds up its own momentum, rendering it more effective in an energy sense when it finally does burn.

Now as to the role of gravity in all this:  the citation http://en.wikipedia.org/wiki/Oberth_effect does indeed state that the Oberth Effect is more effective on a spacecraft when it is nearer the gravitating body, but we must not misunderstand why.  When thus speaking, the cited reference is speaking in terms of a spacecraft moving according to orbital dynamics, and not in terms of one sitting stationary on the launch pad.  It is very important we understand that, because only in the case of the orbiting spacecraft is it correct to say that the Oberth Effect increases the effectiveness of fuel.  The reason why low gravitational potential increases the effectiveness of the fuel when in orbital motion is that the lower gravitational potential results in a higher orbital velocity at that point.  And also, the Oberth Effect will be effective in this situation only if the thrust is in the same direction as the motion of the ship.  A spacecraft sitting on the launch pad derives no benefit from the Oberth Effect at the time of launch because it has not yet built up any speed.

Furthermore, even when the space craft is orbiting and is at low potential and derives gain from the Oberth Effect, this gain is in kinetic energy, not speed and not thrust.  The change of speed produced by the Oberth Effect when orbiting at the low point in its orbit will be the same as the change in speed derived when orbiting in the high point of the orbit, although the change in kinetic energy at the low point will be greater because kinetic energy = 1/2 m*v2.  That does not mean, however, that the Oberth Effect is of no value. The ship has still gained more speed for the fuel spent than it could have under different circumstances.

I realize that the foregoing probably is considerably less than a full explanation of all this, but  I wish to move on to the question of engines. I do not fully understand your engine diagrams, but it appears that it has something to do with designing the engine to pre-accelerate the fuel to a high speed before igniting it, by putting it through a turbine, and that, because the fuel now moves, prior to combustion, faster with respect to the rocket than it previously did, there should be greater thrust generated.

I believe that the answer to that is that yes, this effect will happen if we have the right design.  It appears from your diagrams that you would place the nozzles on a spinning arm, or set of arms, so that when a nozzle is moving rearward, it would then be fired, resulting in a higher exhaust velocity and greater thrust.  I believe that that analysis is incorrect when expressed in that way, but that the correct explanation is that when the nozzle fires, the thrust it generates is no different than it would under any other circumstance, but that the thrust is harnessed differently.  Being on the moving arm, when it fires, the arm adds not thrust but work to the process by pushing against the nozzle thrust while simultaneously pushing in the opposite direction against the spacecraft frame, increasing the distance between both under the influence of the nozzle thrust, which has the effect of doing extra work on the spacecraft frame over and above the work that the nozzle exhaust is doing.

So yes, the scheme seems able to be able to derive greater momentum change of the spacecraft per unit of fuel expended that can a simple rocket nozzle mounted directly to the frame.  However, there are certain complications.  Specifically, in order to keep the arm moving during this process, there must be an additional source of motive power, otherwise the thrust would cause it to stop.  Where will that power come from?  An internal combustion engine that burns extra fuel is one possibility, and I do not know whether fuel burned this way would be more efficient than the same fuel burned in an extra fixed nozzle used instead (although I suspect it may well be).  We are not limited to using burned fuel for this purpose; the arm could be driven by an electric drive powered by solar cells or a nuclear generator.

So yes, I think you are right that an engine based on this principle may be capable of more efficient use of fuel, and greater range, than  conventional rockets.  Just how much better is hard to know without doing a lot of detailed calculations.

#### Atomic-S

• Hero Member
• Posts: 935
• Thanked: 19 times
##### Re: Wharp Drive? S.Ilinca magnetic jet engine on Oberth effect
« Reply #27 on: 02/08/2014 06:03:38 »
Upon further considering this problem, it occurs to me that an essential part of the process is what  happens to the fuel between the time that it leaves the tank and reaches the nozzle. Because of the spinning arm, its momentum changes during the time that it travels from the pivot point to the nozzle.  That change would be substantial in this situation because the arm would have to be spinning quite rapidly and/or be quite long for the effect to be significant.  During the time when the fuel is transiting along the arm from pivot to nozzle, its inertia tends to retard the arm's motion (as seen from aboard the craft), which is compensated by the motive power driving the arm.  In the process of thus compensating, the motor that drives the arm experiences thrust generated by the unburned fuel's change of momentum as it travels along  the arm, and this is where the system derives the extra propulsion that it generates.

#### Ilinca Sergiu

• Full Member
• Posts: 50
• zero mass air electric engine S.Ilinca
##### Re: Wharp Drive? S.Ilinca magnetic jet engine on Oberth effect
« Reply #28 on: 03/08/2014 09:18:17 »
Thank Atomic-S for trying to understand this engine and for a very good comment. Just want to clarify some important details. Burning of the propellant occurs simultaneously with the acceleration of the nozzle. Or on models with Elevator throw the ball occurs during the acceleration of the Elevator (to throw away not only mass, but also increased the weight of propellant).
« Last Edit: 12/08/2014 12:07:47 by Ilinca Sergiu »

#### Ilinca Sergiu

• Full Member
• Posts: 50
• zero mass air electric engine S.Ilinca
##### Re: Wharp Drive? S.Ilinca magnetic jet engine on Oberth effect
« Reply #29 on: 03/08/2014 09:59:15 »
I think this is Oberth effect. But today it is used only reverse view .When the spacecraft passes periapsis gravity celestial body brake the spacecraft ( the bigger the ship's speed and gravity the more will be this brake and the more engine thrust).
« Last Edit: 12/08/2014 12:10:08 by Ilinca Sergiu »

#### Ilinca Sergiu

• Full Member
• Posts: 50
• zero mass air electric engine S.Ilinca
##### Re: Wharp Drive? S.Ilinca magnetic jet engine on Oberth effect
« Reply #30 on: 03/08/2014 11:10:44 »
I think Oberth effect on the orbit can be compared with swings. Appears in periapsis when appears the weight of burning fuel.
« Last Edit: 05/08/2014 07:41:31 by Ilinca Sergiu »

#### Ilinca Sergiu

• Full Member
• Posts: 50
• zero mass air electric engine S.Ilinca
##### Re: Wharp Drive? S.Ilinca magnetic jet engine on Oberth effect
« Reply #31 on: 03/08/2014 11:30:34 »
Oberth effect on the multi-stage rocket (change of acceleration).

#### Ilinca Sergiu

• Full Member
• Posts: 50
• zero mass air electric engine S.Ilinca
##### Re: Wharp Drive? S.Ilinca magnetic jet engine on Oberth effect
« Reply #32 on: 03/08/2014 12:02:58 »
The passage periapsis of the rocket can be compared with the passage obstacles of bullet.

#### Ilinca Sergiu

• Full Member
• Posts: 50
• zero mass air electric engine S.Ilinca
##### Re: Wharp Drive? S.Ilinca magnetic jet engine on Oberth effect
« Reply #33 on: 03/08/2014 12:37:32 »
The increase of kinetic energy in Obert effect does not arise from any relative velocities but from the increased potential energy of the fuel in nozzle. Oberth effect are the reflection of the law of energy conservation.
« Last Edit: 12/08/2014 12:12:44 by Ilinca Sergiu »

#### Atomic-S

• Hero Member
• Posts: 935
• Thanked: 19 times
##### Re: Wharp Drive? S.Ilinca magnetic jet engine on Oberth effect
« Reply #34 on: 08/08/2014 07:10:41 »

I am still a bit confused on your physics. Going over one of your diagrams, I have found some errors, and have so indicated:

#### Atomic-S

• Hero Member
• Posts: 935
• Thanked: 19 times
##### Re: Wharp Drive? S.Ilinca magnetic jet engine on Oberth effect
« Reply #35 on: 08/08/2014 07:42:33 »

Having carefully studied this diagram, I think that it is not correct unless certain phenomena are taken into account, which do not appear to be taken into account here.  We must not confuse thrust and mass. They are not the same thing.  In this diagram, if the extra force created for the purpose of separating the outer reference frame (that of the ship) from the inner reference frame (the nozzle carriage or "elevator") is less than the thrust being generated by the combustion in the nozzle, the two reference frames will not separate at all, but the one will ram into the other, locking to it and giving the thrust for the simple (upper diagram) situation.  If the separation force is made greater than the nozzle thrust, the reference frames will separate, but the acceleration of the nozzle will be less than before because it is experiencing conflicting forces:  that of its own gasses and that of the separation force, which are opposing. The ship itself will receive only the separation force, which is equal and opposite in the two directions it acts, which might well be greater than the  nozzle thrust, however for that to happen, the acceleration of the nozzle must be a finite number, requiring that the nozzle mass be greater than zero.  Your diagrams no where mention the mass of the nozzle (or of the elevator in the diagrams having elevators), but it actually matters.

I believe you have incorrectly analyzed the problem.  Your proposed engine may work, but for different reasons than you have stated.  I however strongly suspect that an essential feature of the problem is that for the engine to do so,  it must be furnished with additional power over and above what is generated by the combustion of the fuel being burned in the nozzle.  I don't quite understand your design, but it seems that you have provided for such additional power through a magnetic coil, the exact function of which I don't understand, but based on what I havde said, the energetics would seem to be valid, even if your analysis of them is not..

#### Ilinca Sergiu

• Full Member
• Posts: 50
• zero mass air electric engine S.Ilinca
##### Re: Wharp Drive? S.Ilinca magnetic jet engine on Oberth effect
« Reply #36 on: 08/08/2014 10:30:27 »
Sorry there are errors in my picture. It's because I'm not a student wants to get the score for the correctness of the calculation. For me important proportions and relationships.

#### Ilinca Sergiu

• Full Member
• Posts: 50
• zero mass air electric engine S.Ilinca
##### Re: Wharp Drive? S.Ilinca magnetic jet engine on Oberth effect
« Reply #37 on: 08/08/2014 12:04:09 »

Having carefully studied this diagram, I think that it is not correct unless certain phenomena are taken into account, which do not appear to be taken into account here.  We must not confuse thrust and mass. They are not the same thing.  In this diagram, if the extra force created for the purpose of separating the outer reference frame (that of the ship) from the inner reference frame (the nozzle carriage or "elevator") is less than the thrust being generated by the combustion in the nozzle, the two reference frames will not separate at all, but the one will ram into the other, locking to it and giving the thrust for the simple (upper diagram) situation.  If the separation force is made greater than the nozzle thrust, the reference frames will separate, but the acceleration of the nozzle will be less than before because it is experiencing conflicting forces:  that of its own gasses and that of the separation force, which are opposing. The ship itself will receive only the separation force, which is equal and opposite in the two directions it acts, which might well be greater than the  nozzle thrust, however for that to happen, the acceleration of the nozzle must be a finite number, requiring that the nozzle mass be greater than zero.  Your diagrams no where mention the mass of the nozzle (or of the elevator in the diagrams having elevators), but it actually matters.

I believe you have incorrectly analyzed the problem.  Your proposed engine may work, but for different reasons than you have stated.  I however strongly suspect that an essential feature of the problem is that for the engine to do so,  it must be furnished with additional power over and above what is generated by the combustion of the fuel being burned in the nozzle.  I don't quite understand your design, but it seems that you have provided for such additional power through a magnetic coil, the exact function of which I don't understand, but based on what I havde said, the energetics would seem to be valid, even if your analysis of them is not..
Really I guess what F traction in this case (acceleration nozzle or Elevator) is equivalent to the mass ,or weight of burning fuel is equivalent to the mass of that fuel. Also assume that this equivalence is the mechanism of Oberth effect.
Equivalence principle:
(Inertial mass).(Acceleration) =(Intensity of the gravitational field).(Gravitational mass),
everyone agrees.
But,
(Inertial mass)=(Gravitational mass)  .......m identical W
and
(Acceleration) =(Intensity of the gravitational field).........a identical gravitational field,
all disagree.
Yes maybe I am wrong but I do not find clear explanations or similarity in the ordinary course of physics. How to calculate it?

#### Ilinca Sergiu

• Full Member
• Posts: 50
• zero mass air electric engine S.Ilinca
##### Re: Wharp Drive? S.Ilinca magnetic jet engine on Oberth effect
« Reply #38 on: 08/08/2014 13:36:39 »

Having carefully studied this diagram, I think that it is not correct unless certain phenomena are taken into account, which do not appear to be taken into account here.  We must not confuse thrust and mass. They are not the same thing.  In this diagram, if the extra force created for the purpose of separating the outer reference frame (that of the ship) from the inner reference frame (the nozzle carriage or "elevator") is less than the thrust being generated by the combustion in the nozzle, the two reference frames will not separate at all, but the one will ram into the other, locking to it and giving the thrust for the simple (upper diagram) situation.  If the separation force is made greater than the nozzle thrust, the reference frames will separate, but the acceleration of the nozzle will be less than before because it is experiencing conflicting forces:  that of its own gasses and that of the separation force, which are opposing. The ship itself will receive only the separation force, which is equal and opposite in the two directions it acts, which might well be greater than the  nozzle thrust, however for that to happen, the acceleration of the nozzle must be a finite number, requiring that the nozzle mass be greater than zero.  Your diagrams no where mention the mass of the nozzle (or of the elevator in the diagrams having elevators), but it actually matters.

I believe you have incorrectly analyzed the problem.  Your proposed engine may work, but for different reasons than you have stated.  I however strongly suspect that an essential feature of the problem is that for the engine to do so,  it must be furnished with additional power over and above what is generated by the combustion of the fuel being burned in the nozzle.  I don't quite understand your design, but it seems that you have provided for such additional power through a magnetic coil, the exact function of which I don't understand, but based on what I havde said, the energetics would seem to be valid, even if your analysis of them is not..

Yes, you can consider rocket engine as a material object from which to repell but which are not repelled. More correct ? Yes if his thrust is very large and push mass is very small. But and here is the question? How will resist to the external force the working rocket engine what will be its inertness?

#### Ilinca Sergiu

• Full Member
• Posts: 50
• zero mass air electric engine S.Ilinca
##### Re: Wharp Drive? S.Ilinca magnetic jet engine on Oberth effect
« Reply #39 on: 12/08/2014 13:20:45 »

Having carefully studied this diagram, I think that it is not correct unless certain phenomena are taken into account, which do not appear to be taken into account here.  We must not confuse thrust and mass. They are not the same thing.  In this diagram, if the extra force created for the purpose of separating the outer reference frame (that of the ship) from the inner reference frame (the nozzle carriage or "elevator") is less than the thrust being generated by the combustion in the nozzle, the two reference frames will not separate at all, but the one will ram into the other, locking to it and giving the thrust for the simple (upper diagram) situation.  If the separation force is made greater than the nozzle thrust, the reference frames will separate, but the acceleration of the nozzle will be less than before because it is experiencing conflicting forces:  that of its own gasses and that of the separation force, which are opposing. The ship itself will receive only the separation force, which is equal and opposite in the two directions it acts, which might well be greater than the  nozzle thrust, however for that to happen, the acceleration of the nozzle must be a finite number, requiring that the nozzle mass be greater than zero.  Your diagrams no where mention the mass of the nozzle (or of the elevator in the diagrams having elevators), but it actually matters.

I believe you have incorrectly analyzed the problem.  Your proposed engine may work, but for different reasons than you have stated.  I however strongly suspect that an essential feature of the problem is that for the engine to do so,  it must be furnished with additional power over and above what is generated by the combustion of the fuel being burned in the nozzle.  I don't quite understand your design, but it seems that you have provided for such additional power through a magnetic coil, the exact function of which I don't understand, but based on what I havde said, the energetics would seem to be valid, even if your analysis of them is not..

On my figure, the coil means a linear motor and has only one function-to accelerate the rocket engine. But I think it is better to accelerate the jet engine with railgun (coil can not withstand high accelerations).
Yes, the mass of the rocket engine will have a value (its acceleration will consume energy) but it will not affect the total momentum of the system.
I think this engine can be interpreted as the work or power (i.e. how to start Oberth effect)

P.S.I replaced the images with Elevator.

#### Ilinca Sergiu

• Full Member
• Posts: 50
• zero mass air electric engine S.Ilinca
##### Re: Wharp Drive? S.Ilinca magnetic jet engine on Oberth effect
« Reply #40 on: 16/08/2014 10:38:20 »
As will be burning fuel when nozzle acceleratingin in 30000g or 300000m/s2 (acceleration of normal railgun) ?
If the fuel acceleration is approximately equal to the acceleration of nozzle-I think that will be a nuclear fusion reaction similar to the reaction of the white dwarf.

#### Ilinca Sergiu

• Full Member
• Posts: 50
• zero mass air electric engine S.Ilinca
##### Re: Wharp Drive? S.Ilinca magnetic jet engine on Oberth effect
« Reply #41 on: 18/08/2014 15:02:39 »
I think if make this engine with the nuclear fusion reaction - will look something like this.
If without nuclear fusion reaction-- will look too, something like this but without nozzle coil.

#### Ilinca Sergiu

• Full Member
• Posts: 50
• zero mass air electric engine S.Ilinca
##### Re: Wharp Drive? S.Ilinca magnetic jet engine on Oberth effect
« Reply #42 on: 28/08/2014 14:25:19 »
Perhaps more relevant is if consider a similar system from a position of (N) power.
(With position (N) and (A) starts and the explanation of Oberth effect).
« Last Edit: 28/08/2014 14:28:52 by Ilinca Sergiu »

#### Atomic-S

• Hero Member
• Posts: 935
• Thanked: 19 times
##### Re: Wharp Drive? S.Ilinca magnetic jet engine on Oberth effect
« Reply #43 on: 22/10/2014 06:50:33 »
It is clear that, using your rail gun design as an example, that if you attach, to the movable arm, an engine generating thrust in the opposite direction, then the acceleration of the arm-engine system will be retarded to a lesser value than it would have had if the engine were not operating.  That is because with the engine operating, the engine-arm system is affected by opposing forces: That of the magnetic thrust from the rails and that of the rocket thrust from the engine; leaving a lesser net force.  This, however, would not reduce the overall momentum imparted to the ship, but would rather increase it.  You are correct about that.  The reason it will increase it, is that the thrust being received by the ship is simply that of the electromagnetic system, and that will be the same whether the engine is firing or not (to a first approximation, neglecting possible other complications.)  However, the time during which the arm-engine system will remain between the rails will be greater when the engine is firing, due to the conflicting forces received by that system, and because it remains between the rails longer, the magnetic force has a longer period of time to act on the ship frame, resulting in a greater overall change in the ship's momentum.  I believe you are correct in concluding that this system will generate greater overall propulsion, although I am still not sure your mathemtics is right, because you said
Quote
(F) thrust of rocket engine behaves identically to the (m) mass (to get the same speed they require the same amount of power.
I believe you are erroneously here equating thrust and mass, and they will not behave the same way.

Nevertheless, to be a practical propulsion system, your design requires that once the arm-engine system reaches the end of the rails, it must be returned to its starting position to be fired again. That require a reverse force to draw it back into the ship.  Correspondingly, the ship will receive a reverse force, which will undo some of the propulsion generated.  However, because the gasses that were expelled during the first cycle will not be returned, the return mass is less than the initial mass, and will not fully cancel the original propulsion. Then the engine can be fired again and expelled as before, creating another cycle of thrust.  The net result of all this is that the average exhaust velocity from the ship will be greater than with simple combustion, and the propulsion derived from the fuel will be greater than the propulsion using burning only.  However, it is necessary to furnish the electrical power to operate the railgun.  You will need some source for that.  Also,  the magnitude of the improved performance in excess of a simple rocket may not be what you have calculated, because I am not sure you are doing it correctly, although I still don't quite understand it.

#### Ilinca Sergiu

• Full Member
• Posts: 50
• zero mass air electric engine S.Ilinca
##### Re: Wharp Drive? S.Ilinca magnetic jet engine on Oberth effect
« Reply #44 on: 24/10/2014 14:38:20 »
Yes, this proposed system will be unbalanced by the following obvious reasons:
1. The presence of fuel in a jet engine on the repulsion trajectory, and its absence (or fewer ) on the returning trajectory .
2. Increase the speed of the working substance ( V working substance + V jet engine).
This is an obvious facts that do not require validation. Based on these two factors ,increase the total momentum of the system does not justify the additional mass associated with the construction of the engine and power system.
But there are two another possible factor:
3. Increase the static component of the thrust of jet engine at high accelerations .
4. Presumably appearance of the Obert effect .
The last two factors is possible and I try to pay attention to them.
They exist or not can be confirmed or refuted experimentally. Most likely they don't exist. But the question is ,that if these two factors will manifest (this can be checked with a model jet engine and rubber harness )?
The answer: the chance to make sub light engine (interstellar) at the current level of science and technology.

#### Ilinca Sergiu

• Full Member
• Posts: 50
• zero mass air electric engine S.Ilinca
##### Re: Wharp Drive? S.Ilinca magnetic jet engine on Oberth effect
« Reply #45 on: 27/10/2014 09:08:35 »
It is clear that, using your rail gun design as an example, that if you attach, to the movable arm, an engine generating thrust in the opposite direction, then the acceleration of the arm-engine system will be retarded to a lesser value than it would have had if the engine were not operating.  That is because with the engine operating, the engine-arm system is affected by opposing forces: That of the magnetic thrust from the rails and that of the rocket thrust from the engine; leaving a lesser net force.  This, however, would not reduce the overall momentum imparted to the ship, but would rather increase it.  You are correct about that.  The reason it will increase it, is that the thrust being received by the ship is simply that of the electromagnetic system, and that will be the same whether the engine is firing or not (to a first approximation, neglecting possible other complications.)  However, the time during which the arm-engine system will remain between the rails will be greater when the engine is firing, due to the conflicting forces received by that system, and because it remains between the rails longer, the magnetic force has a longer period of time to act on the ship frame, resulting in a greater overall change in the ship's momentum.  I believe you are correct in concluding that this system will generate greater overall propulsion, although I am still not sure your mathemtics is right, because you said
Quote
(F) thrust of rocket engine behaves identically to the (m) mass (to get the same speed they require the same amount of power.
I believe you are erroneously here equating thrust and mass, and they will not behave the same way.

Nevertheless, to be a practical propulsion system, your design requires that once the arm-engine system reaches the end of the rails, it must be returned to its starting position to be fired again. That require a reverse force to draw it back into the ship.  Correspondingly, the ship will receive a reverse force, which will undo some of the propulsion generated.  However, because the gasses that were expelled during the first cycle will not be returned, the return mass is less than the initial mass, and will not fully cancel the original propulsion. Then the engine can be fired again and expelled as before, creating another cycle of thrust.  The net result of all this is that the average exhaust velocity from the ship will be greater than with simple combustion, and the propulsion derived from the fuel will be greater than the propulsion using burning only.  However, it is necessary to furnish the electrical power to operate the railgun.  You will need some source for that.  Also,  the magnitude of the improved performance in excess of a simple rocket may not be what you have calculated, because I am not sure you are doing it correctly, although I still don't quite understand it.

Without mathematics.Imagine yourself instead of the person in the picture and try to understand what he would push these carts (in what conditions it will be equally hard to push two carts?).
« Last Edit: 27/10/2014 18:08:38 by Ilinca Sergiu »

#### Ilinca Sergiu

• Full Member
• Posts: 50
• zero mass air electric engine S.Ilinca
##### Re: Wharp Drive? S.Ilinca magnetic jet engine on Oberth effect
« Reply #46 on: 15/11/2014 11:47:41 »
I'll try to explain in more detail. The man pushes the nozzle against the force of thrust. Physically, it is difficult for him to do. If he pushes the nozzle certain distance within a certain time, he spends some power. The sooner he does it, the more he gets tired (consumes more power).This power is transferred to his feet on the ground surface or to another mass (for example a moving platform).
The same thing happens if someone pushes some mass which applies a very small acceleration. If this acceleration  not exist ,that people will push any weight without power consumption.
In this case, the equivalence between (F) and (m) will not be ,the nozzle will resist movement and the mass will not. I.e. this equivalence will shift giving speed only the mass but not the nozzle. But this is a perfect case because in reality, it is necessary to give first some acceleration to get the velocity (which occurs when nozzle is in acceleration  I described at the beginning). If such an ideal case was that ,the system could unbalance even more than the equivalence of (F) and (m).

#### Ilinca Sergiu

• Full Member
• Posts: 50
• zero mass air electric engine S.Ilinca
##### Re: Wharp Drive? S.Ilinca magnetic jet engine on Oberth effect
« Reply #47 on: 15/11/2014 12:22:42 »
If the engine will not work,  the total momentum of the system always be zero.

#### Ilinca Sergiu

• Full Member
• Posts: 50
• zero mass air electric engine S.Ilinca
##### Re: Wharp Drive? S.Ilinca magnetic jet engine on Oberth effect
« Reply #48 on: 18/12/2014 13:44:35 »
Sublight spaceship with the engine on Oberth effect,will look like this-

#### Ilinca Sergiu

• Full Member
• Posts: 50
• zero mass air electric engine S.Ilinca
##### Re: Wharp Drive? S.Ilinca magnetic jet engine on Oberth effect
« Reply #49 on: 30/12/2014 14:43:07 »
I think this engine will look something like this .And will have a 2 stroke of work:
« Last Edit: 30/12/2014 16:12:23 by Ilinca Sergiu »

#### The Naked Scientists Forum

##### Re: Wharp Drive? S.Ilinca magnetic jet engine on Oberth effect
« Reply #49 on: 30/12/2014 14:43:07 »