EmDrive (Propelantless microwave resonant reactor by Roger Shawyer)
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 Scooped by Alain Coetmeur onto EmDrive (Propelantless microwave resonant reactor by Roger Shawyer)

# Chinese say the 'EmDrive' may change the future of space propulsion - VR-Zone

Chinese scientists have built and tested a British inventor’s design of a new type of space propulsion drive.  Once scoffed as an impossible device by his British counterparts, China says that it not only works but it will change the satellite...
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# EmDrive (Propelantless microwave resonant reactor by Roger Shawyer)

Just a tech-watch on a possible revolution with EmDrive (Propelantless microwave resonant reactor by Roger Shawyer). Not sure it works. Not sure it cannot work. Just watching. by AlainCo of http://www.lenr-forum.com , @alain_co https://twitter.com/alain_co
Curated by Alain Coetmeur
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## EmDrive - FAQ

Alain Coetmeur's insight:

FAQ

Theory

1.
Q. Is the thrust produced by the EmDrive a reactionless force?
A. No, the thrust is the result of the reaction between the end plates of the waveguide and the Electromagnetic wave propagated within it.

2.
Q. How can a net force be produced by a closed waveguide?
A. At the propagation velocities (greater than one tenth the speed of light) the effects of special relativity must be considered. Different reference planes have to be used for the EM wave and the waveguide itself. The thruster is therefore an open system and a net force can be produced.

3.
Q. Why does the net force not get balanced out by the axial component of the sidewall force?
A. The net force is not balanced out by the axial component of the sidewall force because there is a highly non linear relationship between waveguide diameter and group velocity. (e.g. at cut off diameter, the group velocity is zero, the guide wavelength is infinity, but the diameter is clearly not zero.) The design of the cavity is such that the ratio of end wall forces is maximised, whilst the axial component of the sidewall force is reduced to a negligible value.

4.
Q. Does the theory of the EmDrive contravene the accepted laws of physics or electromagnetic theory?
A. The EmDrive does not violate any known law of physics. The basic laws that are applied in the theory of the EmDrive operation are as follows:

Newton’s laws are applied in the derivation of the basic static thrust equation (Equation 11 in the theory paper) and have also been demonstrated to apply to the EmDrive experimentally.

The law of conservation of momentum is the basis of Newtons laws and therefore applies to the EmDrive. It is satisfied both theoretically and experimentally.

The law of conservation of energy is the basis of the dynamic thrust equation which applies to the EmDrive under acceleration,(see Equation 16 in the theory paper).

The principles of electromagnetic theory are used to derive the basic design equations.

5.
Q. Why does the EmDrive not contravene the conservation of momentum when it operates in free space?
A. The EmDrive cannot violate the conservation of momentum. The electromagnetic wave momentum is built up in the resonating cavity, and is transferred to the end walls upon reflection. The momentum gained by the EmDrive plus the momentum lost by the electromagnetic wave equals zero. The direction and acceleration that is measured, when the EmDrive is tested on a dynamic test rig, comply with Newtons laws and confirm that the law of conservation of momentum is satisfied.

6.
Q. Is the EmDrive a form of perpetual motion machine?
A. The EmDrive obeys the law of conservation of energy and is therefore not a perpetual motion machine. Energy must be expended to accelerate the EmDrive (see Equation 16 of the theory paper). Once the EmDrive is switched off, Newton’s laws ensure that motion is constant unless it is acted upon by another force.

7.
Q. Why does the thrust decrease as the spacecraft velocity along the thrust vector increases?
A. As the spacecraft accelerates along the thrust vector, energy is lost by the engine and gained as additional kinetic energy by the spacecraft. This energy can be defined as the thrust multiplied by the distance through which the thrust acts. For a given acceleration period, the higher the mean velocity, the longer the distance travelled, hence the higher the energy lost by the engine.
This loss of stored energy from the resonant cavity leads to a reduction in Q and hence a reduction of thrust.

Test procedures

8.
Q. Has buoyancy been allowed for?
A. Buoyancy has been allowed for in the initial experiments and then eliminated by hermetically sealing the thruster.

9.
Q. Are there any convection currents which might affect the results?
A. Convection currents did not affect the results, as measurements were taken with the thrust vector up, down and horizontal. Test runs were also carried out using a thermal simulation heater to quantify the effects of change of coolant temperature.

10.
Q. Has stiffness in cables and pipes been allowed for?
A. The only connections to the balance were high flex electrical links

11.
Q. Has friction in any pivots been allowed for?
A. Static thrust measurements were carried out using 3 different techniques – a counterbalance rig with a knife edge pivot, a direct weighing method using a 16kg balance (0.1 gm resolution), and with the thruster suspended from a spring balance with the weight partly offloaded on to an electronic balance.

12.
Q. Have electromagnetic effects been taken into account? These include interactions between current-carrying conductors and between such conductors carrying RF currents and nearby metallic structures in which currents might be induced.
A. Stray electromagnetic effects were eliminated by using different test rigs, by testing two thrusters with very different mounting structures, and by changing the orientation by 90 degrees to eliminate the Earth’s magnetic field.

13.
Q. Is there any ionization within the air, which might cause electrostatic charging and resulting forces?
A. Electrostatic charges were eliminated by the comprehensive earthing required for safety reasons, and to provide the return path for the magnetron anode current.

14.
Q. Could RF pick-up measurement circuits have produced erroneous results?
A. EMC tests were carried out on the instrumentation to eliminate the effects of RF pick up.

15.
Q. Could acceleration be caused by spurious torques generated by the air bearing?
A. Dynamic tests are preceded by an acceleration calibration test, using standard weights to determine the air bearing friction.

16.
Q. Could acceleration be caused by anomalous thermal or electromagnetic effects?
A. Acceleration and deceleration tests have been carried out in both clockwise and anti-clockwise directions Acceleration from rest only starts when the magnetron output frequency matches the resonant frequency of the engine, following an initial warm-up period.

Applications

17.
Q. Can the technology be qualified for space applications?
A. Yes, all the basic microwave, power supply, thermal and control technologies are similar to flight equipment currently used on high power communication satellites.

18.
Q. How can the EmDrive produce enough thrust for terrestrial applications?
A. The second generation engines will be capable of producing a specific thrust of 30kN/kW. Thus for 1 kilowatt (typical of the power in a microwave oven) a static thrust of 3 tonnes can be obtained, which is enough to support a large car. This is clearly adequate for terrestrial transport applications.
The static thrust/power ratio is calculated assuming a superconducting EmDrive with a Q of 5 x 109. This Q value is routinely achieved in superconducting cavities.
Note however, because the EmDrive obeys the law of conservation of energy, this thrust/power ratio rapidly decreases if the EmDrive is used to accelerate the vehicle along the thrust vector. (See Equation 16 of the theory paper). Whilst the EmDrive can provide lift to counter gravity, (and is therefore not losing kinetic energy), auxiliary propulsion is required to provide the kinetic energy to accelerate the vehicle.

Alain Coetmeur's comment, August 24, 2013 7:38 AM
It seems hard to believe, but if they did as they say, it seems experimentally hard to criticize.
For theoretical reasons, they seems to have well studied (and have been criticized), and incredulity is probably based on misunderstanding of relativistic effects.
If EmDrive is erroneous, it is probably both a strange experimental artifact that survives many checking, and tricky detail in the computations, that were not noticed by critics.
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## MiHsC/QI vs New Galaxy Data

It is crucial for theorists like me to pay close attention to new data, and observational astrophysicist Prof Stacy McGaugh has a habit
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## EmDrive: si torna a parlare del motore impossibile

Il motore rivoluzionario (impossibile, per molti) torna a fare discutere: funziona? Lo sapremo presto.
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## Gaia clocks speedy cosmic expansion - BBC News

Europe’s Gaia space telescope measures the expansion rate of the Universe and finds it to be speeding apart faster than other key assessments have suggested.
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## Breakfast at the 100 Year Starship

I went to the 100 Year Starship Symposium in Orlando, Florida, last year and presented some of my work on "Quantised Inertia and FTL"
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## My thoughts On The EmDrive

I show that the EmDrive could work without breaking physics but does that mean that it will take us to the stars? Isaac's Video
Alain Coetmeur's insight:
hum,
to verify 8)
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## [1609.06642] MOND impact of the recently updated mass-discrepancy-acceleration relation

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## In rotating galaxies, distribution of normal matter precisely determines gravitational acceleration

Researchers have found a significant new relationship in spiral and irregular galaxies: the acceleration observed in rotation curves tightly correlates with the gravitational acceleration expected from the visible mass only. The discovery may alter the understanding of dark matter and the internal dynamics of galaxies.
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## Exotic Space Propulsion including Mach Propulsion and EMDrive will be discussed at Space Studies Institute conference

The Estes Park Advanced Propulsion Workshop, 20-22 September 2016, organized by the Space Studies Institute (SSI), will featur
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## Scientists at Estes Park Explore EmDrive and Other Propulsion Physics Breakthrough Research | Hacked

Waiting for the publication of the NASA Eagleworks EmDrive paper in December, some preliminary results could be revealed at a 3-day workshop starting today.
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## NSF-1701 EMDrive Space Propulsion Project - Phase II Testing

I am one of less than a dozen people in the world working on building a controversial new electromagnetic engine known as the EMDrive.
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## [Trad] L’EMdrive qui défie la physique bientôt revu par les pairs (mais fonctionne-t-il ?)

(1300 mots ~ 10 min) si on en croit le Dr. José Rodal du forum NASA Spaceflight, l’article à propos de l’expérience, “Measurement of Impulsive Thrust from a Closed Radio Frequency Cavity in Vacuum” signé Harold White & al., vient tout juste d’être autorisé à être publié dans la revue scientifique à comité de lecture…
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## Can the ‘impossible’ space drive survive falsification in orbit? | ExtremeTech

At this point, the EM Drive will be important -- if not for revolutionizing space travel, then at least fo
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## Mach Effect Propulsion Theory Updates

Theory of a Mach Effect Thruster I The Mach Effect Thruster (MET) is a propellant—less space drive which uses Mach’s principle to produc
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## Mach Effect Thrusters (Mets) And “Over-Unity” Energy Production

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## EmDrive: Miracle or Debacle? A look at this 'next-gen' space tech

The EmDrive is undeniably the hottest topic in near-futuristic space technology recently. Almost too hot in fact.
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## "New Natural Law of the Cosmos" --Challenges Current Theories of Dark Matter

A team led by Case Western Reserve University researchers has found a significant new relationship in spiral and irregular galaxies: the acceleration observed in rotation curves tightly correlates with the gravitational acceleration expected from the visible mass only. I
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## ‘Onmogelijke’ EM-Drive uitgetest in de ruimte | Sneap.nl

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## The ‘impossible’ EM Drive is about to be tested in space:

The EM Drive is one of the most controversial pieces of technology in the realm of space science, and it's about to be put to the test for the first time. Theoretically, the EM Drive can generate thrust without producing exhaust. That means it's basically a rocket engine that runs without rocket fuel. Scientists who have…
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## Mach Effect Propulsion Theory Updates

Theory of a Mach Effect Thruster I The Mach Effect Thruster (MET) is a propellant—less space drive which uses Mach’s principle to produc
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## SSI at Exotic Propulsion Workshop | Space Studies Institute

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## Acceleration relation found among spiral and irregular galaxies challenges current understanding of dark matter

In the late 1970s, astronomers Vera Rubin and Albert Bosma independently found that spiral galaxies rotate at a nearly constant speed: the velocity of stars and gas inside a galaxy does not decrease with radius, as one woul
Alain Coetmeur's insight:
A nail in the coffin of Dark Matter and one point for MiHsC?
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## WTF is an EM Drive?? w Greg Smithwick from the Solocal Pasco Podcast | The Baboon Room

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## Компания Cannae готовится к запуску первого спутника с "невозможным" двигателем EMDrive ~ Двигатель прогресса

Компания Cannae, которая занимается разработкой 1-го из вариантов реализации технологии "неосуществимого" двигателя EMDrive, передала лицензию на внедрен
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## The difference between matter, antimatter, dark matter, and negative matter

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## EmDrive: Controversial space propulsion will be discussed by scientists at an actual conference

The Space Studies Institute is to hold a conference in Colorado discussing breakthroughs in space propulsion.
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